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#2102 From: "Rob Denney" <proa@...>
Date: Tue Nov 7, 2006 1:34 am
Subject:: Re: Re: Appliance garage
proaharry
Offline Offline
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G'day,
 
Excellent.  Any ideas what you want it to look like, or dimensions?  Let me know, I (or you if you like) will sketch it, we can discuss it and proceed from there.
 
regards
rob.
----- Original Message -----
Sent: Tuesday, November 07, 2006 3:29 AM
Subject: [harryproa] Re: Appliance garage

> Getting the rudders off the hulls is the next step for the cruisers,
and this is may be a better way than hanging them off the beams.  Do
you want to try it on your boat?
>

I can see the rudders in the LW hull, or on them as recently drawn, or
in the appliance garage.  I just see the AG as an alternative and
possibly a fairly bombproof one.  There are elegant solutions and
possibly more low tech ones.  And as the motor (where used) needs to go
somewhere relatively solid anyway...

I would like to try this on mine, I want rugged, and easy to build
foils.  And I don't want to have to climb out on the hull as would be
required with a cheers like solution, or to teeter on a beam around an
open hole when reducing sail or adjusting rudders.  And I want a simple
system patform for wind vanes or autohelm.



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#2101 From: "Rob Denney" <proa@...>
Date: Tue Nov 7, 2006 1:11 am
Subject:: Re: Re: masts
proaharry
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An excellent post.  Many thanks for the research.
 
regards,
 
Rob
----- Original Message -----
Sent: Tuesday, November 07, 2006 5:44 AM
Subject: [harryproa] Re: masts


  After much research, I agree with both Peter and Rob.

  In summary:  epoxy cracking likely occurs in first tension on the leading edge, while structural failure of the mast likely occurs in compression on the trailing edge.  The cracking sound will probably be more of an issue for carbon and less of an issue for kiri/glass.   Also, it appears that  Rob's cold vacuum process for creating spars is superior to the heated autoclave process, and carbon and kevlar laminates are better than aluminum in terms of long-term fatigue.

  The rest of this long post contains some of the links and explanation.  It's not definitive, but at least it has some real data.

---

EPOXY PROPERTIES

  I originally made two faulty assumptions:  a) epoxy stretches more than it actually does, and b) epoxy is isotropic, i.e., it has the same modulus in both compression and tension.  The first assumption stemmed from the fact that the flexible epoxies used in some repair work are different from the stiff epoxies used to create masts.  The second assumption came from some research refers to epoxies as being quasi-isotropic, which I misinterpreted.

  Thanks to Peter for pointing out that epoxy has different modulii for tension and compression.  Unfortunately it took me over half a day to get actual numbers to verify this.

  As far as stretch goes:

    http://www.tech.plym.ac.uk/sme/MATS324/MATS324A5%20CFI.htm

    Epoxy only elongates to 2% before cracking, while carbon fiber can elongate up to 10% before failure, and E-glass to 3.37%.  As the leading edge of a mast stretches, the epoxy will crack before carbon fibers or E-glass fibers will break.

  As far as modulus goes:

    http://www.rpi.edu/locker/38/001238/pdfs/load.pdf
    http://www.google.com/search?q=cache::www.rpi.edu/locker/38/001238/pdfs/load.pdf
    (same as above, but html version)

  Epoxy alone has a modulus that is 17% greater in compression than in tension, and an epoxy/carbon composite has a modulus that is 21% greater in compression than in tension.  Both epoxy and epoxy/carbon composite will stretch more under a given force in tension than they will shrink under the same force in compression.

---

MAST CRACKING

Scenario A: flexible unstayed carbon mast

  If the mast is designed to be flexible, the smaller tension modulus means that the windward side of the mast will stretch more in tension than the leeward side will shrink in compression, and epoxy's earlier failure due to strain means that the stretching is going to crack the epoxy while leaving the carbon fibers intact.  These cracks will weaken the mast, but won't themselves represent a structural failure because the undamaged carbon is still very strong.

Scenario B: stiff unstayed carbon mast

  If the mast is stiff enough to keep the epoxy from elongating past its strain limit, cracks won't occur in tension on that windward edge.  Instead, cracks will develop from compression in the leeward edge as the matrix starts to buckle.  This is not necessarily better than the flexible mast, just different.

Scenario C: kiri/glass mast

  Because of wood's inherent flexibility, and the lower modulus of fiberglass when compared to carbon, the cracking is likely in the epoxy on the windward edge.  I don't have a modulus or strain data for kiri to test this.

---

MAST FAILURE

   When a failure does occur, it will likely happen on the leeward edge under compression.  This is because the fibers under tension require no support, and therefore don't put buckling stress on the matrix, while the fibers under compression will eventually buckle once the epoxy fails to keep them in column.  Worded differently, the compressed side is stiffer than the stretched side, but ultimately more susceptible to failure.

Scenario A: flexible unstayed carbon mast

  This mast will provide warning before failure, with the leading edge cracking before the trailing edge buckles. That's definitely a plus.  However, the cracks will weaken the mast over time  The more cracks there are in the epoxy matrix, the less it will be able to keep the fibers from buckling, and the more likely it will fail in compression.  Moral of the story: avoid stresses that cause the cracking sound.

Scenario B: stiff unstayed carbon mast

  For a stiff carbon mast, this means that there won't be the benefit of hearing the micro-cracks in the leading edge as the mast gets stressed.  That's a bummer if the mast has not been designed to be strong enough to handle the dynamic loads involved in a huge gust capsizing the boat.  If the mast is strong enough, the issue then becomes making the boat strong enough to handle the stress, while also surviving the knockdown.  Many folks would rather have the mast fail.

Scenario C: kiri/glass mast

  Failure will likely be in compression because wood does better in tension than compression, and a hollow mast will eventually buckle in compression when subjected to too much force.  Fortunately, the cracking should be less of an issue with the kiri/glass mast.  First, the kiri itself is going to provide more resistance to compression than the glass/epoxy skin.  Second, even if the epoxy is cracked, the glass will still hold tension, and will still help prevent the kiri from buckling.

---

VACUUM-BAGGING VERSUS AUTOCLAVE

    http://www.gmtcomposites.com/the_autoclave_myth.htm

  Autoclaved prepreg masts are stronger and stiffer in tension and compression, while vacuum bagged masts are better in shear.  Six on one side, a half-dozen on the other.  However, vacuum-bagged masts can be made in one long piece, regardless of length.  Autoclaved masts, on the other hand, must be spliced together from sections that fit in the autoclave.  For a small mast, this doesn't matter.  For a large mast, this means joints between sections, and that's less desirable than a single piece.

---

FATIGUE

    http://www.tech.plym.ac.uk/sme/MATS324/MATS324A5%20CFI.htm

  "Under a static load of 50% ultimate stress, the probability of survival for carbon/epoxy, Kevlar/epoxy and glass/epoxy over a 30 year period are 99.99%, 99.8% and 22% respectively.  Under a load of 40% ultimate stress, the survival probability for glass/epoxy is 97%"

    http://www.cstcomposites.com/505_carbon_spar.htm

  "Fatigue resistance orders of magnitude better than Aluminium  .Life Span - pretty well indefinite with normal sailing loads apart from normal wear and tear."

  Not that anyone needed a reason to like carbon.  I've just seen fans of aluminum insulting carbon's ability to resist fatigue.  I suppose early designs could have had problems, but that would seem to be a design or manufacturing issue, not a materials issue.

       - Mike




Peter Southwood wrote:
Hi Rob,
I dont see why the resin should crack because the carbon is stiffer. If the resin cracks it is because it is stressed beyond its maximum strength. The stiffer the fibres, the less likely the resin is to reach failure strain before the fibres. More likely the resin cracks because it is too stiff for the fibres and does not have a matching strain at failure.
Cheers,
Peter
----- Original Message -----
From: Rob Denney
Sent: Friday, November 03, 2006 7:23 AM
Subject: Re: [harryproa] Re: masts

G'day,
Yes, but the stiffer it is, the more cracking there will be.  My understanding of this is that the noise is the resin cracking as the carbon is so much stiffer.  With glass and kiri, there may be less cracking, or it may just happen at a higher load.  Regardless, I think you will get plenty of warning.  Maybe test a piece of kiri and glass by bending it until it starts to crack, then see how much more it will take before it is visibly damaged.  This may give you some idea of how far you can go past the cracking stage.
 
regards,

Rob 
----- Original Message -----
Sent: Friday, November 03, 2006 1:13 PM
Subject: Re: [harryproa] Re: masts

Rob,
 
Is composite glass/kiri?
 
Doug
 


Rob Denney <proa@...> wrote:
If it is composite, you will hear a lot of creaking and cracking before it breaks.  I would work on one of them doing the lifting as in a capsize you will probably have dumped one of them.
 
regards,

Rob
----- Original Message -----
Sent: Thursday, November 02, 2006 12:13 PM
Subject: Re: [harryproa] Re: masts

Robert,
 
I'd like to sense a failure ahead of the crack, split whatever, so as to salvage the mast and simply add more glass around the outside. But that would be a fairly satisfactory level of strength if they - cause there are two of them - raise the hull.
 
Doug

Robert <cateran1949@...> wrote:
Easy enough to check if the masts are strong enough. Load them up by
trying to lift the ww hull with a 100kg weight sitting on it.
I was looking at the characteristics of quality bamboo section and it
looks considerable better than glass weight for weight with 4GPa
youngs modulus and a breaking strain of 30kg/mm 2. It may be worth
considering for cheap masts. I am considering it myself for skinning
cores in areas where exra stiffness is wanted without the expense of
carbon. Hope carbon becomes more easily available and cheaper as it
is by far the best material.
Robert
-- In harryproa@..., "Robert" <cateran1949@y...> wrote:
>
> --- In harryproa@..., Doug Haines <doha720@y...>
wrote:
> >
> > Hi,
> >   
> >   Just meant swinging around on the water, like anchored in the
sea
> breeze comes in 20knots.
> >   
> >   I was wondering about general ideas about swinging around
coming
> from experienced multihullers out there. Like when you anchor a
> bigger boat out further where the wind is. What about two anchors
30
> degrees apart?
> >   
> >   Mast is same as boat - kiri strip and glass.
> >   I've tapered the tops to half dimensions. There is a round pole
> up a metre and a half into the mast that slots in the hull. I hope
it
> is all not going to break.
> >   Obviously it is heavy but is cheaper.
> >   
> >   Doug
> >   
> >   
> >  
> > Myriam & Youri <wangka@s...> wrote:
> >        
> >
> >     v\:* {behavior:url(#default#VML);}  o\:* {behavior:url
> (#default#VML);}  w\:* {behavior:url(#default#VML);}  .shape
> {behavior:url(#default#VML);}        st1\:*{behavior:url
> (#default#ieooui) }                Dear Doug,
> >   
> >   
> >     Dear Wangkas,
> >
> >     
> >
> >     Nice pictures and all, but where is a finished sailing boat?
> >               We know it takes a long time, but sometimes we have
> other worries on our minds … like carbon spars for classical yachts
> where we have to sort out two boats, masts, booms, sprits, poles
> etc,  we have to make molds and plugs for rudders, keels and bulbs,

> for the carbon parts we are achieving and testing  a construction
> method VAPM (vacuum assisted pressure molding that gives us
autoclave
> quality laminates (not only on the voids ratio but also on the
> compression side) in our pressure molds( compression +-5 Bars)
which
> can produce one piece parts, which is not possible by standard
> autoclave procedures. We are also currently testing a method for
> direct CNC mold cutting for parts construction …
> >
> >     Also, what do you hope to acheive with around beam?
> >
> >      They are not only rounded in length but also elliptical in
> section and will be constructed VAPM… less windage, better stress
> distribution, less wave interference …
> >
> >     Thanks again for your mast section, it is coming together.
> >               We are glad, how are you going to construct it ? …
> >
> >     The boat really swings around at the moment without masts up
> and I wonder if it can be helped? More a question for the cruising
> boaters - do you plan doing cruising Elementarries?
> >               What do you mean with swinging around ? I suspect
we
> will but that depends on the interest shown … for the moment we
have
> some asks for quotes from France, Switzerland and Germany …
> >   
> >   
> >   Best regards,
> >   
> >   
> >   Myriam & Youri
> >   Wangka bvba
> >   Belgium
> >   
> >   e-mail. info@w...
> >   web. www.wangkaboats.eu
> >   
> >   
> >   
> >
> >     
> >
> >     yaendenboom <wangka@s...> wrote:
> >
> >     Dear people,
> >
> > Our site has been updated.
> > We kindly invite you to have a look at:
> >     www.wangkaboats.eu
> >
> > Suggestions and criticism is welcome at:
> >     info@w...
> >
> > Thank you very much,
> >
> > Myriam & Youri
> > Wangka bvba
> > Belgium
> >
> >
> >
> >
> >
> >
> >
> >   
> >    Send instant messages to your online friends
> http://uk.messenger.yahoo.com 
> >
> > 
> >
> >  Send instant messages to your online friends
> http://uk.messenger.yahoo.com
> >
>




Send instant messages to your online friends http://uk.messenger.yahoo.com

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#2100 From: "Robert" <cateran1949@...>
Date: Tue Nov 7, 2006 12:06 am
Subject:: Re: masts
cateran1949
Offline Offline
Send Email Send Email
 
-Thanks Mike,
  I didn't realise that carbon had greater stetch before breaking than
glass.
My thought on the creaking and cracking concur with yours that it is
probably the resin not being able to stretch enoughand some breaking
of the fibre resin bond. I also think that the cross fibresresin
attachment needed to keep the compression side from buckling may also
crack. The concern to me is that the cracing on the ww side weakens
the side for subsequent compression when the load changes. The 99.9%
stability is nice to read.
  Robert -- In harryproa@..., Mike Crawford
<jmichael@g...> wrote:
>
>
>   After much research, I agree with both Peter and Rob.
>
>   In summary:  epoxy cracking likely occurs in first tension on the
> leading edge, while structural failure of the mast likely occurs in
> compression on the trailing edge.  The cracking sound will probably
be
> more of an issue for carbon and less of an issue for kiri/glass.
Also,
> it appears that  Rob's cold vacuum process for creating spars is
> superior to the heated autoclave process, and carbon and kevlar
> laminates are better than aluminum in terms of long-term fatigue.
>
>   The rest of this long post contains some of the links and
> explanation.  It's not definitive, but at least it has some real
data.
>
> ---
>
> EPOXY PROPERTIES
>
>   I originally made two faulty assumptions:  a) epoxy stretches
more
> than it actually does, and b) epoxy is isotropic, i.e., it has the
same
> modulus in both compression and tension.  The first assumption
stemmed
> from the fact that the flexible epoxies used in some repair work
are
> different from the stiff epoxies used to create masts.  The second
> assumption came from some research refers to epoxies as being
> quasi-isotropic, which I misinterpreted.
>
>   Thanks to Peter for pointing out that epoxy has different modulii
for
> tension and compression.  Unfortunately it took me over half a day
to
> get actual numbers to verify this.
>
>   As far as stretch goes:
>
>     http://www.tech.plym.ac.uk/sme/MATS324/MATS324A5%20CFI.htm
>
>     Epoxy only elongates to 2% before cracking, while carbon fiber
can
> elongate up to 10% before failure, and E-glass to 3.37%.  As the
leading
> edge of a mast stretches, the epoxy will crack before carbon fibers
or
> E-glass fibers will break.
>
>   As far as modulus goes:
>
>     http://www.rpi.edu/locker/38/001238/pdfs/load.pdf
>
> http://www.google.com/search?
q=cache::www.rpi.edu/locker/38/001238/pdfs/load.pdf
>     (same as above, but html version)
>
>   Epoxy alone has a modulus that is 17% greater in compression than
in
> tension, and an epoxy/carbon composite has a modulus that is 21%
greater
> in compression than in tension.  Both epoxy and epoxy/carbon
composite
> will stretch more under a given force in tension than they will
shrink
> under the same force in compression.
>
> ---
>
> MAST CRACKING
>
> Scenario A: flexible unstayed carbon mast
>
>   If the mast is designed to be flexible, the smaller tension
modulus
> means that the windward side of the mast will stretch more in
tension
> than the leeward side will shrink in compression, and epoxy's
earlier
> failure due to strain means that the stretching is going to crack
the
> epoxy while leaving the carbon fibers intact.  These cracks will
weaken
> the mast, but won't themselves represent a structural failure
because
> the undamaged carbon is still very strong.
>
> Scenario B: stiff unstayed carbon mast
>
>   If the mast is stiff enough to keep the epoxy from elongating
past its
> strain limit, cracks won't occur in tension on that windward edge.
> Instead, cracks will develop from compression in the leeward edge
as the
> matrix starts to buckle.  This is not necessarily better than the
> flexible mast, just different.
>
> Scenario C: kiri/glass mast
>
>   Because of wood's inherent flexibility, and the lower modulus of
> fiberglass when compared to carbon, the cracking is likely in the
epoxy
> on the windward edge.  I don't have a modulus or strain data for
kiri to
> test this.
>
> ---
>
> MAST FAILURE
>
>    When a failure does occur, it will likely happen on the leeward
edge
> under compression.  This is because the fibers under tension
require no
> support, and therefore don't put buckling stress on the matrix,
while
> the fibers under compression will eventually buckle once the epoxy
fails
> to keep them in column.  Worded differently, the compressed side is
> stiffer than the stretched side, but ultimately more susceptible to
failure.
>
> Scenario A: flexible unstayed carbon mast
>
>   This mast will provide warning before failure, with the leading
edge
> cracking before the trailing edge buckles. That's definitely a
plus.
> However, the cracks will weaken the mast over time  The more cracks
> there are in the epoxy matrix, the less it will be able to keep the
> fibers from buckling, and the more likely it will fail in
compression.
> Moral of the story: avoid stresses that cause the cracking sound.
>
> Scenario B: stiff unstayed carbon mast
>
>   For a stiff carbon mast, this means that there won't be the
benefit of
> hearing the micro-cracks in the leading edge as the mast gets
stressed.
> That's a bummer if the mast has not been designed to be strong
enough to
> handle the dynamic loads involved in a huge gust capsizing the
boat.  If
> the mast is strong enough, the issue then becomes making the boat
strong
> enough to handle the stress, while also surviving the knockdown.
Many
> folks would rather have the mast fail.
>
> Scenario C: kiri/glass mast
>
>   Failure will likely be in compression because wood does better in
> tension than compression, and a hollow mast will eventually buckle
in
> compression when subjected to too much force.  Fortunately, the
cracking
> should be less of an issue with the kiri/glass mast.  First, the
kiri
> itself is going to provide more resistance to compression than the
> glass/epoxy skin.  Second, even if the epoxy is cracked, the glass
will
> still hold tension, and will still help prevent the kiri from
buckling.
>
> ---
>
> VACUUM-BAGGING VERSUS AUTOCLAVE
>
>     http://www.gmtcomposites.com/the_autoclave_myth.htm
>
>   Autoclaved prepreg masts are stronger and stiffer in tension and
> compression, while vacuum bagged masts are better in shear.  Six on
one
> side, a half-dozen on the other.  However, vacuum-bagged masts can
be
> made in one long piece, regardless of length.  Autoclaved masts, on
the
> other hand, must be spliced together from sections that fit in the
> autoclave.  For a small mast, this doesn't matter.  For a large
mast,
> this means joints between sections, and that's less desirable than
a
> single piece.
>
> ---
>
> FATIGUE
>
>     http://www.tech.plym.ac.uk/sme/MATS324/MATS324A5%20CFI.htm
>
>   "Under a static load of 50% ultimate stress, the probability of
> survival for carbon/epoxy, Kevlar/epoxy and glass/epoxy over a 30
year
> period are 99.99%, 99.8% and 22% respectively.  Under a load of 40%
> ultimate stress, the survival probability for glass/epoxy is 97%"
>
>     http://www.cstcomposites.com/505_carbon_spar.htm
>
>   "Fatigue resistance orders of magnitude better than
Aluminium  .Life
> Span - pretty well indefinite with normal sailing loads apart from
> normal wear and tear."
>
>   Not that anyone needed a reason to like carbon.  I've just seen
fans
> of aluminum insulting carbon's ability to resist fatigue.  I
suppose
> early designs could have had problems, but that would seem to be a
> design or manufacturing issue, not a materials issue.
>
>        - Mike
>
>
>
>
> Peter Southwood wrote:
>
> > Hi Rob,
> > I dont see why the resin should crack because the carbon is
stiffer.
> > If the resin cracks it is because it is stressed beyond its
maximum
> > strength. The stiffer the fibres, the less likely the resin is to
> > reach failure strain before the fibres. More likely the resin
cracks
> > because it is too stiff for the fibres and does not have a
matching
> > strain at failure.
> > Cheers,
> > Peter
> >
> >     ----- Original Message -----
> >     From: Rob Denney <mailto:proa@i...>
> >     To: harryproa@...
> >     <mailto:harryproa@...>
> >     Sent: Friday, November 03, 2006 7:23 AM
> >     Subject: Re: [harryproa] Re: masts
> >
> >     G'day,
> >     Yes, but the stiffer it is, the more cracking there will be.
My
> >     understanding of this is that the noise is the resin cracking
as
> >     the carbon is so much stiffer.  With glass and kiri, there
may be
> >     less cracking, or it may just happen at a higher load.
> >     Regardless, I think you will get plenty of warning.  Maybe
test a
> >     piece of kiri and glass by bending it until it starts to
crack,
> >     then see how much more it will take before it is visibly
damaged.
> >     This may give you some idea of how far you can go past the
> >     cracking stage.
> >
> >     regards,
> >
> >     Rob
> >
> >         ----- Original Message -----
> >         From: Doug Haines <mailto:doha720@y...>
> >         To: harryproa@...
> >         <mailto:harryproa@...>
> >         Sent: Friday, November 03, 2006 1:13 PM
> >         Subject: Re: [harryproa] Re: masts
> >
> >         Rob,
> >
> >         Is composite glass/kiri?
> >
> >         Doug
> >
> >
> >
> >         Rob Denney <proa@i... <mailto:proa@i...>> wrote:
> >
> >             If it is composite, you will hear a lot of creaking
and
> >             cracking before it breaks.  I would work on one of
them
> >             doing the lifting as in a capsize you will probably
have
> >             dumped one of them.
> >
> >             regards,
> >
> >             Rob
> >
> >                 ----- Original Message -----
> >                 From: Doug Haines <mailto:doha720@y...>
> >                 To: harryproa@...
> >                 <mailto:harryproa@...>
> >                 Sent: Thursday, November 02, 2006 12:13 PM
> >                 Subject: Re: [harryproa] Re: masts
> >
> >                 Robert,
> >
> >                 I'd like to sense a failure ahead of the crack,
split
> >                 whatever, so as to salvage the mast and simply add
> >                 more glass around the outside. But that would be a
> >                 fairly satisfactory level of strength if they -
cause
> >                 there are two of them - raise the hull.
> >
> >                 Doug
> >
> >                 Robert <cateran1949@y...
> >                 <mailto:cateran1949@y...>> wrote:
> >
> >                     Easy enough to check if the masts are strong
> >                     enough. Load them up by
> >                     trying to lift the ww hull with a 100kg weight
> >                     sitting on it.
> >                     I was looking at the characteristics of
quality
> >                     bamboo section and it
> >                     looks considerable better than glass weight
for
> >                     weight with 4GPa
> >                     youngs modulus and a breaking strain of
30kg/mm 2.
> >                     It may be worth
> >                     considering for cheap masts. I am considering
it
> >                     myself for skinning
> >                     cores in areas where exra stiffness is wanted
> >                     without the expense of
> >                     carbon. Hope carbon becomes more easily
available
> >                     and cheaper as it
> >                     is by far the best material.
> >                     Robert
> >                     -- In harryproa@..., "Robert"
> >                     <cateran1949@y...> wrote:
> >                     >
> >                     > --- In harryproa@..., Doug
Haines
> >                     <doha720@y...>
> >                     wrote:
> >                     > >
> >                     > > Hi,
> >                     > >
> >                     > >   Just meant swinging around on the water,
> >                     like anchored in the
> >                     sea
> >                     > breeze comes in 20knots.
> >                     > >
> >                     > >   I was wondering about general ideas
about
> >                     swinging around
> >                     coming
> >                     > from experienced multihullers out there.
Like
> >                     when you anchor a
> >                     > bigger boat out further where the wind is.
What
> >                     about two anchors
> >                     30
> >                     > degrees apart?
> >                     > >
> >                     > >   Mast is same as boat - kiri strip and
glass.
> >                     > >   I've tapered the tops to half
dimensions.
> >                     There is a round pole
> >                     > up a metre and a half into the mast that
slots
> >                     in the hull. I hope
> >                     it
> >                     > is all not going to break.
> >                     > >   Obviously it is heavy but is cheaper.
> >                     > >
> >                     > >   Doug
> >                     > >
> >                     > >
> >                     > >
> >                     > > Myriam & Youri <wangka@s...> wrote:
> >                     > >
> >                     > >
> >                     > >     v\:* {behavior:url(#default#VML);}
o\:*
> >                     {behavior:url
> >                     > (#default#VML);}  w\:*
> >                     {behavior:url(#default#VML);}  .shape
> >                     > {behavior:url(#default#VML);}
> >                     st1\:*{behavior:url
> >                     > (#default#ieooui) }                Dear
Doug,
> >                     > >
> >                     > >
> >                     > >     Dear Wangkas,
> >                     > >
> >                     > >
> >                     > >
> >                     > >     Nice pictures and all, but where is a
> >                     finished sailing boat?
> >                     > >               We know it takes a long
time,
> >                     but sometimes we have
> >                     > other worries on our minds ... like carbon
spars
> >                     for classical yachts
> >                     > where we have to sort out two boats, masts,
> >                     booms, sprits, poles
> >                     > etc,  we have to make molds and plugs for
> >                     rudders, keels and bulbs,
> >                     ...
> >                     > for the carbon parts we are achieving and
> >                     testing  a construction
> >                     > method VAPM (vacuum assisted pressure
molding
> >                     that gives us
> >                     autoclave
> >                     > quality laminates (not only on the voids
ratio
> >                     but also on the
> >                     > compression side) in our pressure molds(
> >                     compression +-5 Bars)
> >                     which
> >                     > can produce one piece parts, which is not
> >                     possible by standard
> >                     > autoclave procedures. We are also currently
> >                     testing a method for
> >                     > direct CNC mold cutting for parts
construction ...
> >                     > >
> >                     > >     Also, what do you hope to acheive with
> >                     around beam?
> >                     > >
> >                     > >      They are not only rounded in length
but
> >                     also elliptical in
> >                     > section and will be constructed VAPM... less
> >                     windage, better stress
> >                     > distribution, less wave interference ...
> >                     > >
> >                     > >     Thanks again for your mast section,
it is
> >                     coming together.
> >                     > >               We are glad, how are you
going
> >                     to construct it ? ...
> >                     > >
> >                     > >     The boat really swings around at the
> >                     moment without masts up
> >                     > and I wonder if it can be helped? More a
> >                     question for the cruising
> >                     > boaters - do you plan doing cruising
Elementarries?
> >                     > >               What do you mean with
swinging
> >                     around ? I suspect
> >                     we
> >                     > will but that depends on the interest
shown ...
> >                     for the moment we
> >                     have
> >                     > some asks for quotes from France,
Switzerland
> >                     and Germany ...
> >                     > >
> >                     > >
> >                     > >   Best regards,
> >                     > >
> >                     > >
> >                     > >   Myriam & Youri
> >                     > >   Wangka bvba
> >                     > >   Belgium
> >                     > >
> >                     > >   e-mail. info@w...
> >                     > >   web. www.wangkaboats.eu
> >                     > >
> >                     > >
> >                     > >
> >                     > >
> >                     > >
> >                     > >
> >                     > >     yaendenboom <wangka@s...> wrote:
> >                     > >
> >                     > >     Dear people,
> >                     > >
> >                     > > Our site has been updated.
> >                     > > We kindly invite you to have a look at:
> >                     > >     www.wangkaboats.eu
> >                     > >
> >                     > > Suggestions and criticism is welcome at:
> >                     > >     info@w...
> >                     > >
> >                     > > Thank you very much,
> >                     > >
> >                     > > Myriam & Youri
> >                     > > Wangka bvba
> >                     > > Belgium
> >                     > >
> >                     > >
> >                     > >
> >                     > >
> >                     > >
> >                     > >
> >                     > >
> >                     > >
> >                     > >    Send instant messages to your online
friends
> >                     > http://uk.messenger.yahoo.com
> >                     <http://uk.messenger.yahoo.com/>
> >                     > >
> >                     > >
> >                     > >
> >                     > >  Send instant messages to your online
friends
> >                     > http://uk.messenger.yahoo.com
> >                     <http://uk.messenger.yahoo.com/>
> >                     > >
> >                     >
> >
> >
> >
> >
> >                 Send instant messages to your online friends
> >                 http://uk.messenger.yahoo.com
> >                 --------------------------------------------------
----------------------
> >                 Internal Virus Database is out-of-date.
> >                 Checked by AVG Free Edition.
> >                 Version: 7.1.385 / Virus Database: 268.11.5/426 -
> >                 Release Date: 8/23/2006
> >
> >
> >         ----------------------------------------------------------
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> >         The all-new Yahoo! Mail
> >
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an.html>
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>

#2099 From: Mike Crawford <jmichael@...>
Date: Mon Nov 6, 2006 9:44 pm
Subject:: Re: masts
jmichaelcraw...
Online Now Online Now
Send Email Send Email
 

  After much research, I agree with both Peter and Rob.

  In summary:  epoxy cracking likely occurs in first tension on the leading edge, while structural failure of the mast likely occurs in compression on the trailing edge.  The cracking sound will probably be more of an issue for carbon and less of an issue for kiri/glass.   Also, it appears that  Rob's cold vacuum process for creating spars is superior to the heated autoclave process, and carbon and kevlar laminates are better than aluminum in terms of long-term fatigue.

  The rest of this long post contains some of the links and explanation.  It's not definitive, but at least it has some real data.

---

EPOXY PROPERTIES

  I originally made two faulty assumptions:  a) epoxy stretches more than it actually does, and b) epoxy is isotropic, i.e., it has the same modulus in both compression and tension.  The first assumption stemmed from the fact that the flexible epoxies used in some repair work are different from the stiff epoxies used to create masts.  The second assumption came from some research refers to epoxies as being quasi-isotropic, which I misinterpreted.

  Thanks to Peter for pointing out that epoxy has different modulii for tension and compression.  Unfortunately it took me over half a day to get actual numbers to verify this.

  As far as stretch goes:

    http://www.tech.plym.ac.uk/sme/MATS324/MATS324A5%20CFI.htm

    Epoxy only elongates to 2% before cracking, while carbon fiber can elongate up to 10% before failure, and E-glass to 3.37%.  As the leading edge of a mast stretches, the epoxy will crack before carbon fibers or E-glass fibers will break.

  As far as modulus goes:

    http://www.rpi.edu/locker/38/001238/pdfs/load.pdf
    http://www.google.com/search?q=cache::www.rpi.edu/locker/38/001238/pdfs/load.pdf
    (same as above, but html version)

  Epoxy alone has a modulus that is 17% greater in compression than in tension, and an epoxy/carbon composite has a modulus that is 21% greater in compression than in tension.  Both epoxy and epoxy/carbon composite will stretch more under a given force in tension than they will shrink under the same force in compression.

---

MAST CRACKING

Scenario A: flexible unstayed carbon mast

  If the mast is designed to be flexible, the smaller tension modulus means that the windward side of the mast will stretch more in tension than the leeward side will shrink in compression, and epoxy's earlier failure due to strain means that the stretching is going to crack the epoxy while leaving the carbon fibers intact.  These cracks will weaken the mast, but won't themselves represent a structural failure because the undamaged carbon is still very strong.

Scenario B: stiff unstayed carbon mast

  If the mast is stiff enough to keep the epoxy from elongating past its strain limit, cracks won't occur in tension on that windward edge.  Instead, cracks will develop from compression in the leeward edge as the matrix starts to buckle.  This is not necessarily better than the flexible mast, just different.

Scenario C: kiri/glass mast

  Because of wood's inherent flexibility, and the lower modulus of fiberglass when compared to carbon, the cracking is likely in the epoxy on the windward edge.  I don't have a modulus or strain data for kiri to test this.

---

MAST FAILURE

   When a failure does occur, it will likely happen on the leeward edge under compression.  This is because the fibers under tension require no support, and therefore don't put buckling stress on the matrix, while the fibers under compression will eventually buckle once the epoxy fails to keep them in column.  Worded differently, the compressed side is stiffer than the stretched side, but ultimately more susceptible to failure.

Scenario A: flexible unstayed carbon mast

  This mast will provide warning before failure, with the leading edge cracking before the trailing edge buckles. That's definitely a plus.  However, the cracks will weaken the mast over time  The more cracks there are in the epoxy matrix, the less it will be able to keep the fibers from buckling, and the more likely it will fail in compression.  Moral of the story: avoid stresses that cause the cracking sound.

Scenario B: stiff unstayed carbon mast

  For a stiff carbon mast, this means that there won't be the benefit of hearing the micro-cracks in the leading edge as the mast gets stressed.  That's a bummer if the mast has not been designed to be strong enough to handle the dynamic loads involved in a huge gust capsizing the boat.  If the mast is strong enough, the issue then becomes making the boat strong enough to handle the stress, while also surviving the knockdown.  Many folks would rather have the mast fail.

Scenario C: kiri/glass mast

  Failure will likely be in compression because wood does better in tension than compression, and a hollow mast will eventually buckle in compression when subjected to too much force.  Fortunately, the cracking should be less of an issue with the kiri/glass mast.  First, the kiri itself is going to provide more resistance to compression than the glass/epoxy skin.  Second, even if the epoxy is cracked, the glass will still hold tension, and will still help prevent the kiri from buckling.

---

VACUUM-BAGGING VERSUS AUTOCLAVE

    http://www.gmtcomposites.com/the_autoclave_myth.htm

  Autoclaved prepreg masts are stronger and stiffer in tension and compression, while vacuum bagged masts are better in shear.  Six on one side, a half-dozen on the other.  However, vacuum-bagged masts can be made in one long piece, regardless of length.  Autoclaved masts, on the other hand, must be spliced together from sections that fit in the autoclave.  For a small mast, this doesn't matter.  For a large mast, this means joints between sections, and that's less desirable than a single piece.

---

FATIGUE

    http://www.tech.plym.ac.uk/sme/MATS324/MATS324A5%20CFI.htm

  "Under a static load of 50% ultimate stress, the probability of survival for carbon/epoxy, Kevlar/epoxy and glass/epoxy over a 30 year period are 99.99%, 99.8% and 22% respectively.  Under a load of 40% ultimate stress, the survival probability for glass/epoxy is 97%"

    http://www.cstcomposites.com/505_carbon_spar.htm

  "Fatigue resistance orders of magnitude better than Aluminium  .Life Span - pretty well indefinite with normal sailing loads apart from normal wear and tear."

  Not that anyone needed a reason to like carbon.  I've just seen fans of aluminum insulting carbon's ability to resist fatigue.  I suppose early designs could have had problems, but that would seem to be a design or manufacturing issue, not a materials issue.

       - Mike




Peter Southwood wrote:
Hi Rob,
I dont see why the resin should crack because the carbon is stiffer. If the resin cracks it is because it is stressed beyond its maximum strength. The stiffer the fibres, the less likely the resin is to reach failure strain before the fibres. More likely the resin cracks because it is too stiff for the fibres and does not have a matching strain at failure.
Cheers,
Peter
----- Original Message -----
From: Rob Denney
Sent: Friday, November 03, 2006 7:23 AM
Subject: Re: [harryproa] Re: masts

G'day,
Yes, but the stiffer it is, the more cracking there will be.  My understanding of this is that the noise is the resin cracking as the carbon is so much stiffer.  With glass and kiri, there may be less cracking, or it may just happen at a higher load.  Regardless, I think you will get plenty of warning.  Maybe test a piece of kiri and glass by bending it until it starts to crack, then see how much more it will take before it is visibly damaged.  This may give you some idea of how far you can go past the cracking stage.
 
regards,

Rob 
----- Original Message -----
Sent: Friday, November 03, 2006 1:13 PM
Subject: Re: [harryproa] Re: masts

Rob,
 
Is composite glass/kiri?
 
Doug
 


Rob Denney <proa@...> wrote:
If it is composite, you will hear a lot of creaking and cracking before it breaks.  I would work on one of them doing the lifting as in a capsize you will probably have dumped one of them.
 
regards,

Rob
----- Original Message -----
Sent: Thursday, November 02, 2006 12:13 PM
Subject: Re: [harryproa] Re: masts

Robert,
 
I'd like to sense a failure ahead of the crack, split whatever, so as to salvage the mast and simply add more glass around the outside. But that would be a fairly satisfactory level of strength if they - cause there are two of them - raise the hull.
 
Doug

Robert <cateran1949@...> wrote:
Easy enough to check if the masts are strong enough. Load them up by
trying to lift the ww hull with a 100kg weight sitting on it.
I was looking at the characteristics of quality bamboo section and it
looks considerable better than glass weight for weight with 4GPa
youngs modulus and a breaking strain of 30kg/mm 2. It may be worth
considering for cheap masts. I am considering it myself for skinning
cores in areas where exra stiffness is wanted without the expense of
carbon. Hope carbon becomes more easily available and cheaper as it
is by far the best material.
Robert
-- In harryproa@..., "Robert" <cateran1949@y...> wrote:
>
> --- In harryproa@..., Doug Haines <doha720@y...>
wrote:
> >
> > Hi,
> >   
> >   Just meant swinging around on the water, like anchored in the
sea
> breeze comes in 20knots.
> >   
> >   I was wondering about general ideas about swinging around
coming
> from experienced multihullers out there. Like when you anchor a
> bigger boat out further where the wind is. What about two anchors
30
> degrees apart?
> >   
> >   Mast is same as boat - kiri strip and glass.
> >   I've tapered the tops to half dimensions. There is a round pole
> up a metre and a half into the mast that slots in the hull. I hope
it
> is all not going to break.
> >   Obviously it is heavy but is cheaper.
> >   
> >   Doug
> >   
> >   
> >  
> > Myriam & Youri <wangka@s...> wrote:
> >        
> >
> >     v\:* {behavior:url(#default#VML);}  o\:* {behavior:url
> (#default#VML);}  w\:* {behavior:url(#default#VML);}  .shape
> {behavior:url(#default#VML);}        st1\:*{behavior:url
> (#default#ieooui) }                Dear Doug,
> >   
> >   
> >     Dear Wangkas,
> >
> >     
> >
> >     Nice pictures and all, but where is a finished sailing boat?
> >               We know it takes a long time, but sometimes we have
> other worries on our minds … like carbon spars for classical yachts
> where we have to sort out two boats, masts, booms, sprits, poles
> etc,  we have to make molds and plugs for rudders, keels and bulbs,

> for the carbon parts we are achieving and testing  a construction
> method VAPM (vacuum assisted pressure molding that gives us
autoclave
> quality laminates (not only on the voids ratio but also on the
> compression side) in our pressure molds( compression +-5 Bars)
which
> can produce one piece parts, which is not possible by standard
> autoclave procedures. We are also currently testing a method for
> direct CNC mold cutting for parts construction …
> >
> >     Also, what do you hope to acheive with around beam?
> >
> >      They are not only rounded in length but also elliptical in
> section and will be constructed VAPM… less windage, better stress
> distribution, less wave interference …
> >
> >     Thanks again for your mast section, it is coming together.
> >               We are glad, how are you going to construct it ? …
> >
> >     The boat really swings around at the moment without masts up
> and I wonder if it can be helped? More a question for the cruising
> boaters - do you plan doing cruising Elementarries?
> >               What do you mean with swinging around ? I suspect
we
> will but that depends on the interest shown … for the moment we
have
> some asks for quotes from France, Switzerland and Germany …
> >   
> >   
> >   Best regards,
> >   
> >   
> >   Myriam & Youri
> >   Wangka bvba
> >   Belgium
> >   
> >   e-mail. info@w...
> >   web. www.wangkaboats.eu
> >   
> >   
> >   
> >
> >     
> >
> >     yaendenboom <wangka@s...> wrote:
> >
> >     Dear people,
> >
> > Our site has been updated.
> > We kindly invite you to have a look at:
> >     www.wangkaboats.eu
> >
> > Suggestions and criticism is welcome at:
> >     info@w...
> >
> > Thank you very much,
> >
> > Myriam & Youri
> > Wangka bvba
> > Belgium
> >
> >
> >
> >
> >
> >
> >
> >   
> >    Send instant messages to your online friends
> http://uk.messenger.yahoo.com 
> >
> > 
> >
> >  Send instant messages to your online friends
> http://uk.messenger.yahoo.com
> >
>




Send instant messages to your online friends http://uk.messenger.yahoo.com

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#2098 From: "proaconstrictor" <proaconstrictor@...>
Date: Mon Nov 6, 2006 7:29 pm
Subject:: Re: Appliance garage
proaconstrictor
Offline Offline
Send Email Send Email
 
> Getting the rudders off the hulls is the next step for the cruisers,
and this is may be a better way than hanging them off the beams.  Do
you want to try it on your boat?
>

I can see the rudders in the LW hull, or on them as recently drawn, or
in the appliance garage.  I just see the AG as an alternative and
possibly a fairly bombproof one.  There are elegant solutions and
possibly more low tech ones.  And as the motor (where used) needs to go
somewhere relatively solid anyway...

I would like to try this on mine, I want rugged, and easy to build
foils.  And I don't want to have to climb out on the hull as would be
required with a cheers like solution, or to teeter on a beam around an
open hole when reducing sail or adjusting rudders.  And I want a simple
system patform for wind vanes or autohelm.

#2097 From: "Robert" <cateran1949@...>
Date: Mon Nov 6, 2006 8:13 am
Subject:: Re: masts
cateran1949
Offline Offline
Send Email Send Email
 
It would be nice to know the cause, as it may have implications for
fatigue or simply to put my mind at rest when I hear the boat
creaking and cracking in a storm and I am lying back in the bunk
waiting for the storm to ease.
  Robert
  --- In harryproa@..., "proaconstrictor"
<proaconstrictor@y...> wrote:
>
> --- In harryproa@..., "Peter Southwood"
> <peter.southwood@t...> wrote:
> >
> >
> > Yes, but what is the relevance?
> > Cheers,
> > Peter
> >   ----- Original Message -----
> >   From: proaconstrictor
> >   To: harryproa@...
> >   Sent: Friday, November 03, 2006 9:41 PM
> >   Subject: [harryproa] Re: masts
> >
>
> Nice one!
>

#2096 From: "Rob Denney" <proa@...>
Date: Mon Nov 6, 2006 12:08 am
Subject:: Re: Appliance garage
proaharry
Offline Offline
Send Email Send Email
 
G'day,

Alter your details at the bottom of this page:
http://www.steamradio.com/mailman/listinfo/multihulls

Multihulls mailing list      (Multihulls@...)
 
Glad you like the idea.  Hopefully a few more people will also and we can actually have a meaningful comparison.
 
regards,
 
Rob
----- Original Message -----
Sent: Monday, November 06, 2006 2:16 AM
Subject: Re: [harryproa] Appliance garage

Rob,
 
I googled multihull mailing list and got confused.  Can you give me that link.  I have run across it but never joined.
 
Thanks.
 
I am inchanted with the thought of an open 400 sf sail class race!
 
John
 
On Sun, 5 Nov 2006 21:41:47 +0800 "Rob Denney" <proa@...> writes:
G'day,
 
Good thinking.  There is a 60 footer on the drawing board which uses something similar, but midway between the hulls.  Owner paid us to build a 15' version, then part way through it decided he wanted to go canal boating round Europe, so could we design a canal boat as well.  Looks like Rudolph (Blind Date will be building it), no idea what is happening with his proas.
 
Getting the rudders off the hulls is the next step for the cruisers, and this is may be a better way than hanging them off the beams.  Do you want to try it on your boat?
 
Not sure if you are on the multihull mailing list, but I have just suggested a new class.  400 sq' sail area, no other rules.  First race around a one mile dia circle in SF a fortnight before the solo transpac which is the second race. 
 
regards,
 
Rob
----- Original Message -----
Sent: Saturday, November 04, 2006 3:43 AM
Subject: [harryproa] Appliance garage

I think I have solved the rudder problem.  Why not build a third
hull!  Seriously just a small thing that runs between the beams where
the current rudder slides, and indeed outboard at both ends a tiny
amount. This hull would really be a pod that probably does not touch
the water, but allows the ready and sturdy mounting of fixtures.  if
you want a motor, ok cut it out for  motor mount of sled.  Want two
fixed boards like cheers or Kauri, make to BD slots.  Want a central
slot or two to balance a monosail build a few of those.  want a
sliding slot for a continuously repositionable board, use thee pod to
make that a stiff structure.  Want two fully rotating boards, then
build them solidly in ball bearing rotateable tubes.  etc.. 
hopefully this would get rid of the Mickey Mouse mountings problem. 

This will make the area near the LW hull solid rather than an open
hole to fall through.  Allow controls in all modes of board-dom to be
above the deckline.  Make it no more likely these boards/mountings
will fail than any other boards.  Eliminate carbon in the boards or
mountings, if a person doesn't want to go that route.  Slamming and
all that shouldn't be a problem since the actual height this pod is
at , is a design decision.  It could be flush to the underside of the
deck with no additional water exposure, though in that case one would
have to stay with the highly cantilevered boards.  There would still
be a more solid mounting and above deck protrusion for all the
boards.  Or one could try to find a lower sweet spot right down to
some immersion in order to maximize the efficiency of the boards.  It
certainly isn't a hull, since displacement is not to be encouraged. 
It's just there for the boards and outboards etc...  If there is some
unused space it could be used for sitting standing, storage, gin pole
mounting, anything useful.



Internal Virus Database is out-of-date.
Checked by AVG Free Edition.
Version: 7.1.385 / Virus Database: 268.11.5/426 - Release Date: 8/23/2006
 


Internal Virus Database is out-of-date.
Checked by AVG Free Edition.
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#2095 From: john h wright <jhargrovewright2@...>
Date: Sun Nov 5, 2006 6:16 pm
Subject:: Re: Appliance garage
jhargrovewri...
Offline Offline
Send Email Send Email
 
Rob,
 
I googled multihull mailing list and got confused.  Can you give me that link.  I have run across it but never joined.
 
Thanks.
 
I am inchanted with the thought of an open 400 sf sail class race!
 
John
 
On Sun, 5 Nov 2006 21:41:47 +0800 "Rob Denney" <proa@...> writes:
G'day,
 
Good thinking.  There is a 60 footer on the drawing board which uses something similar, but midway between the hulls.  Owner paid us to build a 15' version, then part way through it decided he wanted to go canal boating round Europe, so could we design a canal boat as well.  Looks like Rudolph (Blind Date will be building it), no idea what is happening with his proas.
 
Getting the rudders off the hulls is the next step for the cruisers, and this is may be a better way than hanging them off the beams.  Do you want to try it on your boat?
 
Not sure if you are on the multihull mailing list, but I have just suggested a new class.  400 sq' sail area, no other rules.  First race around a one mile dia circle in SF a fortnight before the solo transpac which is the second race. 
 
regards,
 
Rob
----- Original Message -----
Sent: Saturday, November 04, 2006 3:43 AM
Subject: [harryproa] Appliance garage

I think I have solved the rudder problem.  Why not build a third
hull!  Seriously just a small thing that runs between the beams where
the current rudder slides, and indeed outboard at both ends a tiny
amount. This hull would really be a pod that probably does not touch
the water, but allows the ready and sturdy mounting of fixtures.  if
you want a motor, ok cut it out for  motor mount of sled.  Want two
fixed boards like cheers or Kauri, make to BD slots.  Want a central
slot or two to balance a monosail build a few of those.  want a
sliding slot for a continuously repositionable board, use thee pod to
make that a stiff structure.  Want two fully rotating boards, then
build them solidly in ball bearing rotateable tubes.  etc.. 
hopefully this would get rid of the Mickey Mouse mountings problem. 

This will make the area near the LW hull solid rather than an open
hole to fall through.  Allow controls in all modes of board-dom to be
above the deckline.  Make it no more likely these boards/mountings
will fail than any other boards.  Eliminate carbon in the boards or
mountings, if a person doesn't want to go that route.  Slamming and
all that shouldn't be a problem since the actual height this pod is
at , is a design decision.  It could be flush to the underside of the
deck with no additional water exposure, though in that case one would
have to stay with the highly cantilevered boards.  There would still
be a more solid mounting and above deck protrusion for all the
boards.  Or one could try to find a lower sweet spot right down to
some immersion in order to maximize the efficiency of the boards.  It
certainly isn't a hull, since displacement is not to be encouraged. 
It's just there for the boards and outboards etc...  If there is some
unused space it could be used for sitting standing, storage, gin pole
mounting, anything useful.



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Checked by AVG Free Edition.
Version: 7.1.385 / Virus Database: 268.11.5/426 - Release Date: 8/23/2006
 

#2094 From: "Rob Denney" <proa@...>
Date: Sun Nov 5, 2006 1:41 pm
Subject:: Re: Appliance garage
proaharry
Offline Offline
Send Email Send Email
 
G'day,
 
Good thinking.  There is a 60 footer on the drawing board which uses something similar, but midway between the hulls.  Owner paid us to build a 15' version, then part way through it decided he wanted to go canal boating round Europe, so could we design a canal boat as well.  Looks like Rudolph (Blind Date will be building it), no idea what is happening with his proas.
 
Getting the rudders off the hulls is the next step for the cruisers, and this is may be a better way than hanging them off the beams.  Do you want to try it on your boat?
 
Not sure if you are on the multihull mailing list, but I have just suggested a new class.  400 sq' sail area, no other rules.  First race around a one mile dia circle in SF a fortnight before the solo transpac which is the second race. 
 
regards,
 
Rob
----- Original Message -----
Sent: Saturday, November 04, 2006 3:43 AM
Subject: [harryproa] Appliance garage

I think I have solved the rudder problem.  Why not build a third
hull!  Seriously just a small thing that runs between the beams where
the current rudder slides, and indeed outboard at both ends a tiny
amount. This hull would really be a pod that probably does not touch
the water, but allows the ready and sturdy mounting of fixtures.  if
you want a motor, ok cut it out for  motor mount of sled.  Want two
fixed boards like cheers or Kauri, make to BD slots.  Want a central
slot or two to balance a monosail build a few of those.  want a
sliding slot for a continuously repositionable board, use thee pod to
make that a stiff structure.  Want two fully rotating boards, then
build them solidly in ball bearing rotateable tubes.  etc.. 
hopefully this would get rid of the Mickey Mouse mountings problem. 

This will make the area near the LW hull solid rather than an open
hole to fall through.  Allow controls in all modes of board-dom to be
above the deckline.  Make it no more likely these boards/mountings
will fail than any other boards.  Eliminate carbon in the boards or
mountings, if a person doesn't want to go that route.  Slamming and
all that shouldn't be a problem since the actual height this pod is
at , is a design decision.  It could be flush to the underside of the
deck with no additional water exposure, though in that case one would
have to stay with the highly cantilevered boards.  There would still
be a more solid mounting and above deck protrusion for all the
boards.  Or one could try to find a lower sweet spot right down to
some immersion in order to maximize the efficiency of the boards.  It
certainly isn't a hull, since displacement is not to be encouraged. 
It's just there for the boards and outboards etc...  If there is some
unused space it could be used for sitting standing, storage, gin pole
mounting, anything useful.



Internal Virus Database is out-of-date.
Checked by AVG Free Edition.
Version: 7.1.385 / Virus Database: 268.11.5/426 - Release Date: 8/23/2006

#2093 From: "proaconstrictor" <proaconstrictor@...>
Date: Sat Nov 4, 2006 4:46 pm
Subject:: Re: masts
proaconstrictor
Offline Offline
Send Email Send Email
 
--- In harryproa@..., "Peter Southwood"
<peter.southwood@t...> wrote:
>
>
> Yes, but what is the relevance?
> Cheers,
> Peter
>   ----- Original Message -----
>   From: proaconstrictor
>   To: harryproa@...
>   Sent: Friday, November 03, 2006 9:41 PM
>   Subject: [harryproa] Re: masts
>

Nice one!

#2092 From: "Peter Southwood" <peter.southwood@...>
Date: Sat Nov 4, 2006 4:27 am
Subject:: Re: Re: masts
pbsouthwood
Offline Offline
Send Email Send Email
 
 
Yes, but what is the relevance?
Cheers,
Peter
----- Original Message -----
Sent: Friday, November 03, 2006 9:41 PM
Subject: [harryproa] Re: masts

If the modulus of the resin and fiber were the same we wouldn't need
to add the fiber in the first place.  There is an order of magnatude
difference for epoxy glass, and even epoxy wood...  I'm guessing...

-- In harryproa@..., Mike Crawford <jmichael@g...>
wrote:
>
>
>   ;-)
>
>   I have a degree in structural engineering, but not in carbon
masts. 
> Let's call it an educated guess.  Food for thought, at least.
>
>        - Mike
>
>
>
> Peter Southwood wrote:
>
> > Mike,
> > Is this something you know or something you guess?
> > Cheers,
> > Peter
> >
> >     ----- Original Message -----
> >     *From:* Mike Crawford <mailto:jmichael@g...>
> >     *To:* harryproa@...
> >     <mailto:harryproa@...>
> >     *Sent:* Friday, November 03, 2006 4:03 PM
> >     *Subject:* [harryproa] Re: masts
> >
> >     Peter,
> >
> >       The point about matching strains is a good one, but I
believe
> >     the carbon's modulus is magnitudes higher than that of the
epoxy
> >     matrix, so we won't likely see a failure from the carbon
> >     stretching past the epoxy's limit.  This would be especially
true
> >     with epoxy, which has a bit of give to it.  Case in point:
look at
> >     how much the upper section of the Rare Bird mast can stretch
and
> >     flex without any sort of failure.
> >
> >       My guess is that the failure would occur from the resin
being
> >     compressed past its limit.  Since the carbon is very strong
under
> >     tension, we probably won't see a failure on the windward side
of
> >     the mast, which is being stretched as it bends away from the
> >     wind.  The leeward side of the mast is the opposite, though,
being
> >     compressed by the same mast bend.
> >
> >       As strong as carbon fiber is in tension, as with any fiber,
it's
> >     nowhere near as effective at resisting being compressed along
its
> >     length.  While the resin will help keep the individual fibers
in
> >     column, and they'll be able they can carry some of the load in
> >     compression, the resin itself will take a lot of the
compression
> >     load as well.
> >
> >       This is a likely point for failure and cracking.  The carbon
> >     fiber will keep the windward side taut, and prevent the resin
from
> >     stretching past the point where it will crack, but it won't be
> >     able to provide the same support in compression.  The force
will
> >     eventually buckle the resin matrix.
> >
> >            - Mike
> >
> >
> >
> >     Peter Southwood wrote:
> >
> >>     Hi Rob,
> >>     I dont see why the resin should crack because the carbon is
> >>     stiffer. If the resin cracks it is because it is stressed
beyond
> >>     its maximum strength. The stiffer the fibres, the less
likely the
> >>     resin is to reach failure strain before the fibres. More
likely
> >>     the resin cracks because it is too stiff for the fibres and
does
> >>     not have a matching strain at failure.
> >>     Cheers,
> >>     Peter
> >>
> >>         ----- Original Message -----
> >>         From: Rob Denney <mailto:proa@i...>
> >>         To: harryproa@...
> >>         <mailto:harryproa@...>
> >>         Sent: Friday, November 03, 2006 7:23 AM
> >>         Subject: Re: [harryproa] Re: masts
> >>
> >>         G'day,
> >>         Yes, but the stiffer it is, the more cracking there will
be.
> >>         My understanding of this is that the noise is the resin
> >>         cracking as the carbon is so much stiffer.  With glass
and
> >>         kiri, there may be less cracking, or it may just happen
at a
> >>         higher load.  Regardless, I think you will get plenty of
> >>         warning.  Maybe test a piece of kiri and glass by
bending it
> >>         until it starts to crack, then see how much more it will
take
> >>         before it is visibly damaged.  This may give you some
idea of
> >>         how far you can go past the cracking stage.
> >>         
> >>         regards,
> >>
> >>         Rob
> >>
> >>             ----- Original Message -----
> >>             From: Doug Haines <mailto:doha720@y...>
> >>             To: harryproa@...
> >>             <mailto:harryproa@...>
> >>             Sent: Friday, November 03, 2006 1:13 PM
> >>             Subject: Re: [harryproa] Re: masts
> >>
> >>             Rob,
> >>             
> >>             Is composite glass/kiri?
> >>             
> >>             Doug
> >>             
> >>
> >>
> >>             Rob Denney <proa@i... <mailto:proa@i...>>
> >>             wrote:
> >>
> >>                 If it is composite, you will hear a lot of
creaking
> >>                 and cracking before it breaks.  I would work on
one
> >>                 of them doing the lifting as in a capsize you
will
> >>                 probably have dumped one of them.
> >>                 
> >>                 regards,
> >>
> >>                 Rob
> >>
> >>                     ----- Original Message -----
> >>                     From: Doug Haines <mailto:doha720@y...>
> >>                     To: harryproa@...
> >>                     <mailto:harryproa@...>
> >>                     Sent: Thursday, November 02, 2006 12:13 PM
> >>                     Subject: Re: [harryproa] Re: masts
> >>
> >>                     Robert,
> >>                     
> >>                     I'd like to sense a failure ahead of the
crack,
> >>                     split whatever, so as to salvage the mast and
> >>                     simply add more glass around the outside. But
> >>                     that would be a fairly satisfactory level of
> >>                     strength if they - cause there are two of
them -
> >>                     raise the hull.
> >>                     
> >>                     Doug
> >>
> >>                     Robert <cateran1949@y...
> >>                     <mailto:cateran1949@y...>> wrote:
> >>
> >>                         Easy enough to check if the masts are
strong
> >>                         enough. Load them up by
> >>                         trying to lift the ww hull with a 100kg
> >>                         weight sitting on it.
> >>                         I was looking at the characteristics of
> >>                         quality bamboo section and it
> >>                         looks considerable better than glass
weight
> >>                         for weight with 4GPa
> >>                         youngs modulus and a breaking strain of
> >>                         30kg/mm 2. It may be worth
> >>                         considering for cheap masts. I am
considering
> >>                         it myself for skinning
> >>                         cores in areas where exra stiffness is
wanted
> >>                         without the expense of
> >>                         carbon. Hope carbon becomes more easily
> >>                         available and cheaper as it
> >>                         is by far the best material.
> >>                         Robert
> >>                         -- In
harryproa@..., "Robert"
> >>                         <cateran1949@y...> wrote:
> >>                         >
> >>                         > --- In harryproa@...,
Doug
> >>                         Haines <doha720@y...>
> >>                         wrote:
> >>                         > >
> >>                         > > Hi,
> >>                         > >  
> >>                         > >   Just meant swinging around on the
> >>                         water, like anchored in the
> >>                         sea
> >>                         > breeze comes in 20knots.
> >>                         > >  
> >>                         > >   I was wondering about general ideas
> >>                         about swinging around
> >>                         coming
> >>                         > from experienced multihullers out
there.
> >>                         Like when you anchor a
> >>                         > bigger boat out further where the wind
is.
> >>                         What about two anchors
> >>                         30
> >>                         > degrees apart?
> >>                         > >  
> >>                         > >   Mast is same as boat - kiri strip
and
> >>                         glass.
> >>                         > >   I've tapered the tops to half
> >>                         dimensions. There is a round pole
> >>                         > up a metre and a half into the mast
that
> >>                         slots in the hull. I hope
> >>                         it
> >>                         > is all not going to break.
> >>                         > >   Obviously it is heavy but is
cheaper.
> >>                         > >  
> >>                         > >   Doug
> >>                         > >  
> >>                         > >  
> >>                         > > 
> >>                         > > Myriam & Youri <wangka@s...> wrote:
> >>                         > >       
> >>                         > >
> >>                         > >     v\:* {behavior:url
(#default#VML);}
> >>                         o\:* {behavior:url
> >>                         > (#default#VML);}  w\:*
> >>                         {behavior:url(#default#VML);}  .shape
> >>                         > {behavior:url(#default#VML);}      
> >>                         st1\:*{behavior:url
> >>                         > (#default#ieooui) }               
Dear Doug,
> >>                         > >  
> >>                         > >  
> >>                         > >     Dear Wangkas,
> >>                         > >
> >>                         > >    
> >>                         > >
> >>                         > >     Nice pictures and all, but where
is a
> >>                         finished sailing boat?
> >>                         > >               We know it takes a long
> >>                         time, but sometimes we have
> >>                         > other worries on our minds ... like
carbon
> >>                         spars for classical yachts
> >>                         > where we have to sort out two boats,
masts,
> >>                         booms, sprits, poles
> >>                         > etc,  we have to make molds and plugs
for
> >>                         rudders, keels and bulbs,
> >>                         ...
> >>                         > for the carbon parts we are achieving
and
> >>                         testing  a construction
> >>                         > method VAPM (vacuum assisted pressure
> >>                         molding that gives us
> >>                         autoclave
> >>                         > quality laminates (not only on the
voids
> >>                         ratio but also on the
> >>                         > compression side) in our pressure molds
(
> >>                         compression +-5 Bars)
> >>                         which
> >>                         > can produce one piece parts, which is
not
> >>                         possible by standard
> >>                         > autoclave procedures. We are also
currently
> >>                         testing a method for
> >>                         > direct CNC mold cutting for parts
> >>                         construction ...
> >>                         > >
> >>                         > >     Also, what do you hope to acheive
> >>                         with around beam?
> >>                         > >
> >>                         > >      They are not only rounded in
length
> >>                         but also elliptical in
> >>                         > section and will be constructed VAPM...
> >>                         less windage, better stress
> >>                         > distribution, less wave
interference ...
> >>                         > >
> >>                         > >     Thanks again for your mast
section,
> >>                         it is coming together.
> >>                         > >               We are glad, how are
you
> >>                         going to construct it ? ...
> >>                         > >
> >>                         > >     The boat really swings around at
the
> >>                         moment without masts up
> >>                         > and I wonder if it can be helped? More
a
> >>                         question for the cruising
> >>                         > boaters - do you plan doing cruising
> >>                         Elementarries?
> >>                         > >               What do you mean with
> >>                         swinging around ? I suspect
> >>                         we
> >>                         > will but that depends on the interest
shown
> >>                         ... for the moment we
> >>                         have
> >>                         > some asks for quotes from France,
> >>                         Switzerland and Germany ...
> >>                         > >  
> >>                         > >  
> >>                         > >   Best regards,
> >>                         > >  
> >>                         > >  
> >>                         > >   Myriam & Youri
> >>                         > >   Wangka bvba
> >>                         > >   Belgium
> >>                         > >  
> >>                         > >   e-mail. info@w...
> >>                         > >   web. www.wangkaboats.eu
> >>                         > >  
> >>                         > >  
> >>                         > >  
> >>                         > >
> >>                         > >    
> >>                         > >
> >>                         > >     yaendenboom <wangka@s...> wrote:
> >>                         > >
> >>                         > >     Dear people,
> >>                         > >
> >>                         > > Our site has been updated.
> >>                         > > We kindly invite you to have a look
at:
> >>                         > >     www.wangkaboats.eu
> >>                         > >
> >>                         > > Suggestions and criticism is welcome
at:
> >>                         > >     info@w...
> >>                         > >
> >>                         > > Thank you very much,
> >>                         > >
> >>                         > > Myriam & Youri
> >>                         > > Wangka bvba
> >>                         > > Belgium
> >>                         > >
> >>                         > >
> >>                         > >
> >>                         > >
> >>                         > >
> >>                         > >
> >>                         > >
> >>                         > >  
> >>                         > >    Send instant messages to your
online
> >>                         friends
> >>                         > http://uk.messenger.yahoo.com
> >>                         <http://uk.messenger.yahoo.com/>
> >>                         > >
> >>                         > >
> >>                         > >
> >>                         > >  Send instant messages to your online
> >>                         friends
> >>                         > http://uk.messenger.yahoo.com
> >>                         <http://uk.messenger.yahoo.com/>
> >>                         > >
> >>                         >
> >>
> >>
> >>
> >>
> >>                     Send instant messages to your online friends
> >>                     http://uk.messenger.yahoo.com
> >>                     ---------------------------------------------
---------------------------
> >>                     Internal Virus Database is out-of-date.
> >>                     Checked by AVG Free Edition.
> >>                     Version: 7.1.385 / Virus Database:
268.11.5/426 -
> >>                     Release Date: 8/23/2006
> >>
> >>
> >>             -----------------------------------------------------
-------------------
> >>             The all-new Yahoo! Mail
> >>            
<http://us.rd.yahoo.com/mail/uk/taglines/default/nowyoucan/free_from_i
sp/*http://us.rd.yahoo.com/evt=40565/*http://uk.docs.yahoo.com/nowyouc
an.html>
> >>             goes wherever you go - free your email address from
your
> >>             Internet provider.
> >>             -----------------------------------------------------
-------------------
> >>             Internal Virus Database is out-of-date.
> >>             Checked by AVG Free Edition.
> >>             Version: 7.1.385 / Virus Database: 268.11.5/426 -
Release
> >>             Date: 8/23/2006
> >>
> >>         ---------------------------------------------------------
---------------
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> >>         Checked by AVG Free Edition.
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> >>         Date: 2006/10/27
> >>
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Date:
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> >
> >
>




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#2091 From: "Peter Southwood" <peter.southwood@...>
Date: Fri Nov 3, 2006 3:57 pm
Subject:: Re: Re: masts
pbsouthwood
Offline Offline
Send Email Send Email
 
Hi Mike,
Fair enough, I am in a similar position, as a machanical engineer, but with some background in composites which is unfortunately largely forgotten.
However, at the risk of opening my mouth to change feet, I will comment.
If I remember correctly, the matrix (resin) is generally stronger in compression than tension.
Carbon is strong in tension, and in compression if sufficiently supported in column.
Depending on the resin and fibre it is possible for either to fail first as the load increases. Both must have the same strain, as there is no slip between martix and fibre, so the one which reaches its strain limit first will fail first. This may be different for tension and compression.
It is frequently the case that the fibres can withstand greater strain before failing in tension than the matrix. When this happens the matrix develops lots of microscopic cracks, but the composite generally holds together and does not lose a great deal of strength or stiffness, but may lose some chemical resistance. The same magnitude of compressive stress/strain may not cause the same cracking.
So my guess is that the crackling noise is the matrix failing under tension. This can happen long before the ultimate failure of the laminate.
Maybe somone can explain better?
Cheers,
Peter
----- Original Message -----
Sent: Friday, November 03, 2006 5:23 PM
Subject: [harryproa] Re: masts


  ;-)

  I have a degree in structural engineering, but not in carbon masts.  Let's call it an educated guess.  Food for thought, at least.

       - Mike



Peter Southwood wrote:
Mike,
Is this something you know or something you guess?
Cheers,
Peter
----- Original Message -----
Sent: Friday, November 03, 2006 4:03 PM
Subject: [harryproa] Re: masts

Peter,

  The point about matching strains is a good one, but I believe the carbon's modulus is magnitudes higher than that of the epoxy matrix, so we won't likely see a failure from the carbon stretching past the epoxy's limit.  This would be especially true with epoxy, which has a bit of give to it.  Case in point: look at how much the upper section of the Rare Bird mast can stretch and flex without any sort of failure. 

  My guess is that the failure would occur from the resin being compressed past its limit.  Since the carbon is very strong under tension, we probably won't see a failure on the windward side of the mast, which is being stretched as it bends away from the wind.  The leeward side of the mast is the opposite, though, being compressed by the same mast bend. 

  As strong as carbon fiber is in tension, as with any fiber, it's nowhere near as effective at resisting being compressed along its length.  While the resin will help keep the individual fibers in column, and they'll be able they can carry some of the load in compression, the resin itself will take a lot of the compression load as well.

  This is a likely point for failure and cracking.  The carbon fiber will keep the windward side taut, and prevent the resin from stretching past the point where it will crack, but it won't be able to provide the same support in compression.  The force will eventually buckle the resin matrix.

       - Mike



Peter Southwood wrote:
Hi Rob,
I dont see why the resin should crack because the carbon is stiffer. If the resin cracks it is because it is stressed beyond its maximum strength. The stiffer the fibres, the less likely the resin is to reach failure strain before the fibres. More likely the resin cracks because it is too stiff for the fibres and does not have a matching strain at failure.
Cheers,
Peter
----- Original Message -----
From: Rob Denney
Sent: Friday, November 03, 2006 7:23 AM
Subject: Re: [harryproa] Re: masts

G'day,
Yes, but the stiffer it is, the more cracking there will be.  My understanding of this is that the noise is the resin cracking as the carbon is so much stiffer.  With glass and kiri, there may be less cracking, or it may just happen at a higher load.  Regardless, I think you will get plenty of warning.  Maybe test a piece of kiri and glass by bending it until it starts to crack, then see how much more it will take before it is visibly damaged.  This may give you some idea of how far you can go past the cracking stage.
 
regards,

Rob 
----- Original Message -----
Sent: Friday, November 03, 2006 1:13 PM
Subject: Re: [harryproa] Re: masts

Rob,
 
Is composite glass/kiri?
 
Doug
 


Rob Denney <proa@...> wrote:
If it is composite, you will hear a lot of creaking and cracking before it breaks.  I would work on one of them doing the lifting as in a capsize you will probably have dumped one of them.
 
regards,

Rob
----- Original Message -----
Sent: Thursday, November 02, 2006 12:13 PM
Subject: Re: [harryproa] Re: masts

Robert,
 
I'd like to sense a failure ahead of the crack, split whatever, so as to salvage the mast and simply add more glass around the outside. But that would be a fairly satisfactory level of strength if they - cause there are two of them - raise the hull.
 
Doug

Robert <cateran1949@...> wrote:
Easy enough to check if the masts are strong enough. Load them up by
trying to lift the ww hull with a 100kg weight sitting on it.
I was looking at the characteristics of quality bamboo section and it
looks considerable better than glass weight for weight with 4GPa
youngs modulus and a breaking strain of 30kg/mm 2. It may be worth
considering for cheap masts. I am considering it myself for skinning
cores in areas where exra stiffness is wanted without the expense of
carbon. Hope carbon becomes more easily available and cheaper as it
is by far the best material.
Robert
-- In harryproa@..., "Robert" <cateran1949@y...> wrote:
>
> --- In harryproa@..., Doug Haines <doha720@y...>
wrote:
> >
> > Hi,
> >   
> >   Just meant swinging around on the water, like anchored in the
sea
> breeze comes in 20knots.
> >   
> >   I was wondering about general ideas about swinging around
coming
> from experienced multihullers out there. Like when you anchor a
> bigger boat out further where the wind is. What about two anchors
30
> degrees apart?
> >   
> >   Mast is same as boat - kiri strip and glass.
> >   I've tapered the tops to half dimensions. There is a round pole
> up a metre and a half into the mast that slots in the hull. I hope
it
> is all not going to break.
> >   Obviously it is heavy but is cheaper.
> >   
> >   Doug
> >   
> >   
> >  
> > Myriam & Youri <wangka@s...> wrote:
> >        
> >
> >     v\:* {behavior:url(#default#VML);}  o\:* {behavior:url
> (#default#VML);}  w\:* {behavior:url(#default#VML);}  .shape
> {behavior:url(#default#VML);}        st1\:*{behavior:url
> (#default#ieooui) }                Dear Doug,
> >   
> >   
> >     Dear Wangkas,
> >
> >     
> >
> >     Nice pictures and all, but where is a finished sailing boat?
> >               We know it takes a long time, but sometimes we have
> other worries on our minds … like carbon spars for classical yachts
> where we have to sort out two boats, masts, booms, sprits, poles
> etc,  we have to make molds and plugs for rudders, keels and bulbs,

> for the carbon parts we are achieving and testing  a construction
> method VAPM (vacuum assisted pressure molding that gives us
autoclave
> quality laminates (not only on the voids ratio but also on the
> compression side) in our pressure molds( compression +-5 Bars)
which
> can produce one piece parts, which is not possible by standard
> autoclave procedures. We are also currently testing a method for
> direct CNC mold cutting for parts construction …
> >
> >     Also, what do you hope to acheive with around beam?
> >
> >      They are not only rounded in length but also elliptical in
> section and will be constructed VAPM… less windage, better stress
> distribution, less wave interference …
> >
> >     Thanks again for your mast section, it is coming together.
> >               We are glad, how are you going to construct it ? …
> >
> >     The boat really swings around at the moment without masts up
> and I wonder if it can be helped? More a question for the cruising
> boaters - do you plan doing cruising Elementarries?
> >               What do you mean with swinging around ? I suspect
we
> will but that depends on the interest shown … for the moment we
have
> some asks for quotes from France, Switzerland and Germany …
> >   
> >   
> >   Best regards,
> >   
> >   
> >   Myriam & Youri
> >   Wangka bvba
> >   Belgium
> >   
> >   e-mail. info@w...
> >   web. www.wangkaboats.eu
> >   
> >   
> >   
> >
> >     
> >
> >     yaendenboom <wangka@s...> wrote:
> >
> >     Dear people,
> >
> > Our site has been updated.
> > We kindly invite you to have a look at:
> >     www.wangkaboats.eu
> >
> > Suggestions and criticism is welcome at:
> >     info@w...
> >
> > Thank you very much,
> >
> > Myriam & Youri
> > Wangka bvba
> > Belgium
> >
> >
> >
> >
> >
> >
> >
> >   
> >    Send instant messages to your online friends
> http://uk.messenger.yahoo.com 
> >
> > 
> >
> >  Send instant messages to your online friends
> http://uk.messenger.yahoo.com
> >
>




Send instant messages to your online friends http://uk.messenger.yahoo.com

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Checked by AVG Free Edition.
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Checked by AVG Free Edition.
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Checked by AVG Free Edition.
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#2090 From: "proaconstrictor" <proaconstrictor@...>
Date: Fri Nov 3, 2006 7:41 pm
Subject:: Re: masts
proaconstrictor
Offline Offline
Send Email Send Email
 
If the modulus of the resin and fiber were the same we wouldn't need
to add the fiber in the first place.  There is an order of magnatude
difference for epoxy glass, and even epoxy wood...  I'm guessing...

-- In harryproa@..., Mike Crawford <jmichael@g...>
wrote:
>
>
>   ;-)
>
>   I have a degree in structural engineering, but not in carbon
masts.
> Let's call it an educated guess.  Food for thought, at least.
>
>        - Mike
>
>
>
> Peter Southwood wrote:
>
> > Mike,
> > Is this something you know or something you guess?
> > Cheers,
> > Peter
> >
> >     ----- Original Message -----
> >     *From:* Mike Crawford <mailto:jmichael@g...>
> >     *To:* harryproa@...
> >     <mailto:harryproa@...>
> >     *Sent:* Friday, November 03, 2006 4:03 PM
> >     *Subject:* [harryproa] Re: masts
> >
> >     Peter,
> >
> >       The point about matching strains is a good one, but I
believe
> >     the carbon's modulus is magnitudes higher than that of the
epoxy
> >     matrix, so we won't likely see a failure from the carbon
> >     stretching past the epoxy's limit.  This would be especially
true
> >     with epoxy, which has a bit of give to it.  Case in point:
look at
> >     how much the upper section of the Rare Bird mast can stretch
and
> >     flex without any sort of failure.
> >
> >       My guess is that the failure would occur from the resin
being
> >     compressed past its limit.  Since the carbon is very strong
under
> >     tension, we probably won't see a failure on the windward side
of
> >     the mast, which is being stretched as it bends away from the
> >     wind.  The leeward side of the mast is the opposite, though,
being
> >     compressed by the same mast bend.
> >
> >       As strong as carbon fiber is in tension, as with any fiber,
it's
> >     nowhere near as effective at resisting being compressed along
its
> >     length.  While the resin will help keep the individual fibers
in
> >     column, and they'll be able they can carry some of the load in
> >     compression, the resin itself will take a lot of the
compression
> >     load as well.
> >
> >       This is a likely point for failure and cracking.  The carbon
> >     fiber will keep the windward side taut, and prevent the resin
from
> >     stretching past the point where it will crack, but it won't be
> >     able to provide the same support in compression.  The force
will
> >     eventually buckle the resin matrix.
> >
> >            - Mike
> >
> >
> >
> >     Peter Southwood wrote:
> >
> >>     Hi Rob,
> >>     I dont see why the resin should crack because the carbon is
> >>     stiffer. If the resin cracks it is because it is stressed
beyond
> >>     its maximum strength. The stiffer the fibres, the less
likely the
> >>     resin is to reach failure strain before the fibres. More
likely
> >>     the resin cracks because it is too stiff for the fibres and
does
> >>     not have a matching strain at failure.
> >>     Cheers,
> >>     Peter
> >>
> >>         ----- Original Message -----
> >>         From: Rob Denney <mailto:proa@i...>
> >>         To: harryproa@...
> >>         <mailto:harryproa@...>
> >>         Sent: Friday, November 03, 2006 7:23 AM
> >>         Subject: Re: [harryproa] Re: masts
> >>
> >>         G'day,
> >>         Yes, but the stiffer it is, the more cracking there will
be.
> >>         My understanding of this is that the noise is the resin
> >>         cracking as the carbon is so much stiffer.  With glass
and
> >>         kiri, there may be less cracking, or it may just happen
at a
> >>         higher load.  Regardless, I think you will get plenty of
> >>         warning.  Maybe test a piece of kiri and glass by
bending it
> >>         until it starts to crack, then see how much more it will
take
> >>         before it is visibly damaged.  This may give you some
idea of
> >>         how far you can go past the cracking stage.
> >>
> >>         regards,
> >>
> >>         Rob
> >>
> >>             ----- Original Message -----
> >>             From: Doug Haines <mailto:doha720@y...>
> >>             To: harryproa@...
> >>             <mailto:harryproa@...>
> >>             Sent: Friday, November 03, 2006 1:13 PM
> >>             Subject: Re: [harryproa] Re: masts
> >>
> >>             Rob,
> >>
> >>             Is composite glass/kiri?
> >>
> >>             Doug
> >>
> >>
> >>
> >>             Rob Denney <proa@i... <mailto:proa@i...>>
> >>             wrote:
> >>
> >>                 If it is composite, you will hear a lot of
creaking
> >>                 and cracking before it breaks.  I would work on
one
> >>                 of them doing the lifting as in a capsize you
will
> >>                 probably have dumped one of them.
> >>
> >>                 regards,
> >>
> >>                 Rob
> >>
> >>                     ----- Original Message -----
> >>                     From: Doug Haines <mailto:doha720@y...>
> >>                     To: harryproa@...
> >>                     <mailto:harryproa@...>
> >>                     Sent: Thursday, November 02, 2006 12:13 PM
> >>                     Subject: Re: [harryproa] Re: masts
> >>
> >>                     Robert,
> >>
> >>                     I'd like to sense a failure ahead of the
crack,
> >>                     split whatever, so as to salvage the mast and
> >>                     simply add more glass around the outside. But
> >>                     that would be a fairly satisfactory level of
> >>                     strength if they - cause there are two of
them -
> >>                     raise the hull.
> >>
> >>                     Doug
> >>
> >>                     Robert <cateran1949@y...
> >>                     <mailto:cateran1949@y...>> wrote:
> >>
> >>                         Easy enough to check if the masts are
strong
> >>                         enough. Load them up by
> >>                         trying to lift the ww hull with a 100kg
> >>                         weight sitting on it.
> >>                         I was looking at the characteristics of
> >>                         quality bamboo section and it
> >>                         looks considerable better than glass
weight
> >>                         for weight with 4GPa
> >>                         youngs modulus and a breaking strain of
> >>                         30kg/mm 2. It may be worth
> >>                         considering for cheap masts. I am
considering
> >>                         it myself for skinning
> >>                         cores in areas where exra stiffness is
wanted
> >>                         without the expense of
> >>                         carbon. Hope carbon becomes more easily
> >>                         available and cheaper as it
> >>                         is by far the best material.
> >>                         Robert
> >>                         -- In
harryproa@..., "Robert"
> >>                         <cateran1949@y...> wrote:
> >>                         >
> >>                         > --- In harryproa@...,
Doug
> >>                         Haines <doha720@y...>
> >>                         wrote:
> >>                         > >
> >>                         > > Hi,
> >>                         > >
> >>                         > >   Just meant swinging around on the
> >>                         water, like anchored in the
> >>                         sea
> >>                         > breeze comes in 20knots.
> >>                         > >
> >>                         > >   I was wondering about general ideas
> >>                         about swinging around
> >>                         coming
> >>                         > from experienced multihullers out
there.
> >>                         Like when you anchor a
> >>                         > bigger boat out further where the wind
is.
> >>                         What about two anchors
> >>                         30
> >>                         > degrees apart?
> >>                         > >
> >>                         > >   Mast is same as boat - kiri strip
and
> >>                         glass.
> >>                         > >   I've tapered the tops to half
> >>                         dimensions. There is a round pole
> >>                         > up a metre and a half into the mast
that
> >>                         slots in the hull. I hope
> >>                         it
> >>                         > is all not going to break.
> >>                         > >   Obviously it is heavy but is
cheaper.
> >>                         > >
> >>                         > >   Doug
> >>                         > >
> >>                         > >
> >>                         > >
> >>                         > > Myriam & Youri <wangka@s...> wrote:
> >>                         > >
> >>                         > >
> >>                         > >     v\:* {behavior:url
(#default#VML);}
> >>                         o\:* {behavior:url
> >>                         > (#default#VML);}  w\:*
> >>                         {behavior:url(#default#VML);}  .shape
> >>                         > {behavior:url(#default#VML);}
> >>                         st1\:*{behavior:url
> >>                         > (#default#ieooui) }
Dear Doug,
> >>                         > >
> >>                         > >
> >>                         > >     Dear Wangkas,
> >>                         > >
> >>                         > >
> >>                         > >
> >>                         > >     Nice pictures and all, but where
is a
> >>                         finished sailing boat?
> >>                         > >               We know it takes a long
> >>                         time, but sometimes we have
> >>                         > other worries on our minds ... like
carbon
> >>                         spars for classical yachts
> >>                         > where we have to sort out two boats,
masts,
> >>                         booms, sprits, poles
> >>                         > etc,  we have to make molds and plugs
for
> >>                         rudders, keels and bulbs,
> >>                         ...
> >>                         > for the carbon parts we are achieving
and
> >>                         testing  a construction
> >>                         > method VAPM (vacuum assisted pressure
> >>                         molding that gives us
> >>                         autoclave
> >>                         > quality laminates (not only on the
voids
> >>                         ratio but also on the
> >>                         > compression side) in our pressure molds
(
> >>                         compression +-5 Bars)
> >>                         which
> >>                         > can produce one piece parts, which is
not
> >>                         possible by standard
> >>                         > autoclave procedures. We are also
currently
> >>                         testing a method for
> >>                         > direct CNC mold cutting for parts
> >>                         construction ...
> >>                         > >
> >>                         > >     Also, what do you hope to acheive
> >>                         with around beam?
> >>                         > >
> >>                         > >      They are not only rounded in
length
> >>                         but also elliptical in
> >>                         > section and will be constructed VAPM...
> >>                         less windage, better stress
> >>                         > distribution, less wave
interference ...
> >>                         > >
> >>                         > >     Thanks again for your mast
section,
> >>                         it is coming together.
> >>                         > >               We are glad, how are
you
> >>                         going to construct it ? ...
> >>                         > >
> >>                         > >     The boat really swings around at
the
> >>                         moment without masts up
> >>                         > and I wonder if it can be helped? More
a
> >>                         question for the cruising
> >>                         > boaters - do you plan doing cruising
> >>                         Elementarries?
> >>                         > >               What do you mean with
> >>                         swinging around ? I suspect
> >>                         we
> >>                         > will but that depends on the interest
shown
> >>                         ... for the moment we
> >>                         have
> >>                         > some asks for quotes from France,
> >>                         Switzerland and Germany ...
> >>                         > >
> >>                         > >
> >>                         > >   Best regards,
> >>                         > >
> >>                         > >
> >>                         > >   Myriam & Youri
> >>                         > >   Wangka bvba
> >>                         > >   Belgium
> >>                         > >
> >>                         > >   e-mail. info@w...
> >>                         > >   web. www.wangkaboats.eu
> >>                         > >
> >>                         > >
> >>                         > >
> >>                         > >
> >>                         > >
> >>                         > >
> >>                         > >     yaendenboom <wangka@s...> wrote:
> >>                         > >
> >>                         > >     Dear people,
> >>                         > >
> >>                         > > Our site has been updated.
> >>                         > > We kindly invite you to have a look
at:
> >>                         > >     www.wangkaboats.eu
> >>                         > >
> >>                         > > Suggestions and criticism is welcome
at:
> >>                         > >     info@w...
> >>                         > >
> >>                         > > Thank you very much,
> >>                         > >
> >>                         > > Myriam & Youri
> >>                         > > Wangka bvba
> >>                         > > Belgium
> >>                         > >
> >>                         > >
> >>                         > >
> >>                         > >
> >>                         > >
> >>                         > >
> >>                         > >
> >>                         > >
> >>                         > >    Send instant messages to your
online
> >>                         friends
> >>                         > http://uk.messenger.yahoo.com
> >>                         <http://uk.messenger.yahoo.com/>
> >>                         > >
> >>                         > >
> >>                         > >
> >>                         > >  Send instant messages to your online
> >>                         friends
> >>                         > http://uk.messenger.yahoo.com
> >>                         <http://uk.messenger.yahoo.com/>
> >>                         > >
> >>                         >
> >>
> >>
> >>
> >>
> >>                     Send instant messages to your online friends
> >>                     http://uk.messenger.yahoo.com
> >>                     ---------------------------------------------
---------------------------
> >>                     Internal Virus Database is out-of-date.
> >>                     Checked by AVG Free Edition.
> >>                     Version: 7.1.385 / Virus Database:
268.11.5/426 -
> >>                     Release Date: 8/23/2006
> >>
> >>
> >>             -----------------------------------------------------
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> >>             The all-new Yahoo! Mail
> >>
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an.html>
> >>             goes wherever you go - free your email address from
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> >>             Internet provider.
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-------------------
> >>             Internal Virus Database is out-of-date.
> >>             Checked by AVG Free Edition.
> >>             Version: 7.1.385 / Virus Database: 268.11.5/426 -
Release
> >>             Date: 8/23/2006
> >>
> >>         ---------------------------------------------------------
---------------
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> >>         Checked by AVG Free Edition.
> >>         Version: 7.1.409 / Virus Database: 268.13.17/505 -
Release
> >>         Date: 2006/10/27
> >>
> >     --------------------------------------------------------------
----------
> >     Internal Virus Database is out-of-date.
> >     Checked by AVG Free Edition.
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> >     2006/10/27
> >
> >
>

#2089 From: "proaconstrictor" <proaconstrictor@...>
Date: Fri Nov 3, 2006 7:43 pm
Subject:: Appliance garage
proaconstrictor
Offline Offline
Send Email Send Email
 
I think I have solved the rudder problem.  Why not build a third
hull!  Seriously just a small thing that runs between the beams where
the current rudder slides, and indeed outboard at both ends a tiny
amount. This hull would really be a pod that probably does not touch
the water, but allows the ready and sturdy mounting of fixtures.  if
you want a motor, ok cut it out for  motor mount of sled.  Want two
fixed boards like cheers or Kauri, make to BD slots.  Want a central
slot or two to balance a monosail build a few of those.  want a
sliding slot for a continuously repositionable board, use thee pod to
make that a stiff structure.  Want two fully rotating boards, then
build them solidly in ball bearing rotateable tubes.  etc..
hopefully this would get rid of the Mickey Mouse mountings problem.

This will make the area near the LW hull solid rather than an open
hole to fall through.  Allow controls in all modes of board-dom to be
above the deckline.  Make it no more likely these boards/mountings
will fail than any other boards.  Eliminate carbon in the boards or
mountings, if a person doesn't want to go that route.  Slamming and
all that shouldn't be a problem since the actual height this pod is
at , is a design decision.  It could be flush to the underside of the
deck with no additional water exposure, though in that case one would
have to stay with the highly cantilevered boards.  There would still
be a more solid mounting and above deck protrusion for all the
boards.  Or one could try to find a lower sweet spot right down to
some immersion in order to maximize the efficiency of the boards.  It
certainly isn't a hull, since displacement is not to be encouraged.
It's just there for the boards and outboards etc...  If there is some
unused space it could be used for sitting standing, storage, gin pole
mounting, anything useful.

#2088 From: Mike Crawford <jmichael@...>
Date: Fri Nov 3, 2006 3:23 pm
Subject:: Re: masts
jmichaelcraw...
Online Now Online Now
Send Email Send Email
 

  ;-)

  I have a degree in structural engineering, but not in carbon masts.  Let's call it an educated guess.  Food for thought, at least.

       - Mike



Peter Southwood wrote:
Mike,
Is this something you know or something you guess?
Cheers,
Peter
----- Original Message -----
Sent: Friday, November 03, 2006 4:03 PM
Subject: [harryproa] Re: masts

Peter,

  The point about matching strains is a good one, but I believe the carbon's modulus is magnitudes higher than that of the epoxy matrix, so we won't likely see a failure from the carbon stretching past the epoxy's limit.  This would be especially true with epoxy, which has a bit of give to it.  Case in point: look at how much the upper section of the Rare Bird mast can stretch and flex without any sort of failure. 

  My guess is that the failure would occur from the resin being compressed past its limit.  Since the carbon is very strong under tension, we probably won't see a failure on the windward side of the mast, which is being stretched as it bends away from the wind.  The leeward side of the mast is the opposite, though, being compressed by the same mast bend. 

  As strong as carbon fiber is in tension, as with any fiber, it's nowhere near as effective at resisting being compressed along its length.  While the resin will help keep the individual fibers in column, and they'll be able they can carry some of the load in compression, the resin itself will take a lot of the compression load as well.

  This is a likely point for failure and cracking.  The carbon fiber will keep the windward side taut, and prevent the resin from stretching past the point where it will crack, but it won't be able to provide the same support in compression.  The force will eventually buckle the resin matrix.

       - Mike



Peter Southwood wrote:
Hi Rob,
I dont see why the resin should crack because the carbon is stiffer. If the resin cracks it is because it is stressed beyond its maximum strength. The stiffer the fibres, the less likely the resin is to reach failure strain before the fibres. More likely the resin cracks because it is too stiff for the fibres and does not have a matching strain at failure.
Cheers,
Peter
----- Original Message -----
From: Rob Denney
Sent: Friday, November 03, 2006 7:23 AM
Subject: Re: [harryproa] Re: masts

G'day,
Yes, but the stiffer it is, the more cracking there will be.  My understanding of this is that the noise is the resin cracking as the carbon is so much stiffer.  With glass and kiri, there may be less cracking, or it may just happen at a higher load.  Regardless, I think you will get plenty of warning.  Maybe test a piece of kiri and glass by bending it until it starts to crack, then see how much more it will take before it is visibly damaged.  This may give you some idea of how far you can go past the cracking stage.
 
regards,

Rob 
----- Original Message -----
Sent: Friday, November 03, 2006 1:13 PM
Subject: Re: [harryproa] Re: masts

Rob,
 
Is composite glass/kiri?
 
Doug
 


Rob Denney <proa@...> wrote:
If it is composite, you will hear a lot of creaking and cracking before it breaks.  I would work on one of them doing the lifting as in a capsize you will probably have dumped one of them.
 
regards,

Rob
----- Original Message -----
Sent: Thursday, November 02, 2006 12:13 PM
Subject: Re: [harryproa] Re: masts

Robert,
 
I'd like to sense a failure ahead of the crack, split whatever, so as to salvage the mast and simply add more glass around the outside. But that would be a fairly satisfactory level of strength if they - cause there are two of them - raise the hull.
 
Doug

Robert <cateran1949@...> wrote:
Easy enough to check if the masts are strong enough. Load them up by
trying to lift the ww hull with a 100kg weight sitting on it.
I was looking at the characteristics of quality bamboo section and it
looks considerable better than glass weight for weight with 4GPa
youngs modulus and a breaking strain of 30kg/mm 2. It may be worth
considering for cheap masts. I am considering it myself for skinning
cores in areas where exra stiffness is wanted without the expense of
carbon. Hope carbon becomes more easily available and cheaper as it
is by far the best material.
Robert
-- In harryproa@..., "Robert" <cateran1949@y...> wrote:
>
> --- In harryproa@..., Doug Haines <doha720@y...>
wrote:
> >
> > Hi,
> >   
> >   Just meant swinging around on the water, like anchored in the
sea
> breeze comes in 20knots.
> >   
> >   I was wondering about general ideas about swinging around
coming
> from experienced multihullers out there. Like when you anchor a
> bigger boat out further where the wind is. What about two anchors
30
> degrees apart?
> >   
> >   Mast is same as boat - kiri strip and glass.
> >   I've tapered the tops to half dimensions. There is a round pole
> up a metre and a half into the mast that slots in the hull. I hope
it
> is all not going to break.
> >   Obviously it is heavy but is cheaper.
> >   
> >   Doug
> >   
> >   
> >  
> > Myriam & Youri <wangka@s...> wrote:
> >        
> >
> >     v\:* {behavior:url(#default#VML);}  o\:* {behavior:url
> (#default#VML);}  w\:* {behavior:url(#default#VML);}  .shape
> {behavior:url(#default#VML);}        st1\:*{behavior:url
> (#default#ieooui) }                Dear Doug,
> >   
> >   
> >     Dear Wangkas,
> >
> >     
> >
> >     Nice pictures and all, but where is a finished sailing boat?
> >               We know it takes a long time, but sometimes we have
> other worries on our minds … like carbon spars for classical yachts
> where we have to sort out two boats, masts, booms, sprits, poles
> etc,  we have to make molds and plugs for rudders, keels and bulbs,

> for the carbon parts we are achieving and testing  a construction
> method VAPM (vacuum assisted pressure molding that gives us
autoclave
> quality laminates (not only on the voids ratio but also on the
> compression side) in our pressure molds( compression +-5 Bars)
which
> can produce one piece parts, which is not possible by standard
> autoclave procedures. We are also currently testing a method for
> direct CNC mold cutting for parts construction …
> >
> >     Also, what do you hope to acheive with around beam?
> >
> >      They are not only rounded in length but also elliptical in
> section and will be constructed VAPM… less windage, better stress
> distribution, less wave interference …
> >
> >     Thanks again for your mast section, it is coming together.
> >               We are glad, how are you going to construct it ? …
> >
> >     The boat really swings around at the moment without masts up
> and I wonder if it can be helped? More a question for the cruising
> boaters - do you plan doing cruising Elementarries?
> >               What do you mean with swinging around ? I suspect
we
> will but that depends on the interest shown … for the moment we
have
> some asks for quotes from France, Switzerland and Germany …
> >   
> >   
> >   Best regards,
> >   
> >   
> >   Myriam & Youri
> >   Wangka bvba
> >   Belgium
> >   
> >   e-mail. info@w...
> >   web. www.wangkaboats.eu
> >   
> >   
> >   
> >
> >     
> >
> >     yaendenboom <wangka@s...> wrote:
> >
> >     Dear people,
> >
> > Our site has been updated.
> > We kindly invite you to have a look at:
> >     www.wangkaboats.eu
> >
> > Suggestions and criticism is welcome at:
> >     info@w...
> >
> > Thank you very much,
> >
> > Myriam & Youri
> > Wangka bvba
> > Belgium
> >
> >
> >
> >
> >
> >
> >
> >   
> >    Send instant messages to your online friends
> http://uk.messenger.yahoo.com 
> >
> > 
> >
> >  Send instant messages to your online friends
> http://uk.messenger.yahoo.com
> >
>




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#2087 From: "Peter Southwood" <peter.southwood@...>
Date: Fri Nov 3, 2006 3:02 pm
Subject:: Re: Re: masts
pbsouthwood
Offline Offline
Send Email Send Email
 
Mike,
Is this something you know or something you guess?
Cheers,
Peter
----- Original Message -----
Sent: Friday, November 03, 2006 4:03 PM
Subject: [harryproa] Re: masts

Peter,

  The point about matching strains is a good one, but I believe the carbon's modulus is magnitudes higher than that of the epoxy matrix, so we won't likely see a failure from the carbon stretching past the epoxy's limit.  This would be especially true with epoxy, which has a bit of give to it.  Case in point: look at how much the upper section of the Rare Bird mast can stretch and flex without any sort of failure. 

  My guess is that the failure would occur from the resin being compressed past its limit.  Since the carbon is very strong under tension, we probably won't see a failure on the windward side of the mast, which is being stretched as it bends away from the wind.  The leeward side of the mast is the opposite, though, being compressed by the same mast bend. 

  As strong as carbon fiber is in tension, as with any fiber, it's nowhere near as effective at resisting being compressed along its length.  While the resin will help keep the individual fibers in column, and they'll be able they can carry some of the load in compression, the resin itself will take a lot of the compression load as well.

  This is a likely point for failure and cracking.  The carbon fiber will keep the windward side taut, and prevent the resin from stretching past the point where it will crack, but it won't be able to provide the same support in compression.  The force will eventually buckle the resin matrix.

       - Mike



Peter Southwood wrote:
Hi Rob,
I dont see why the resin should crack because the carbon is stiffer. If the resin cracks it is because it is stressed beyond its maximum strength. The stiffer the fibres, the less likely the resin is to reach failure strain before the fibres. More likely the resin cracks because it is too stiff for the fibres and does not have a matching strain at failure.
Cheers,
Peter
----- Original Message -----
From: Rob Denney
Sent: Friday, November 03, 2006 7:23 AM
Subject: Re: [harryproa] Re: masts

G'day,
Yes, but the stiffer it is, the more cracking there will be.  My understanding of this is that the noise is the resin cracking as the carbon is so much stiffer.  With glass and kiri, there may be less cracking, or it may just happen at a higher load.  Regardless, I think you will get plenty of warning.  Maybe test a piece of kiri and glass by bending it until it starts to crack, then see how much more it will take before it is visibly damaged.  This may give you some idea of how far you can go past the cracking stage.
 
regards,

Rob 
----- Original Message -----
Sent: Friday, November 03, 2006 1:13 PM
Subject: Re: [harryproa] Re: masts

Rob,
 
Is composite glass/kiri?
 
Doug
 


Rob Denney <proa@...> wrote:
If it is composite, you will hear a lot of creaking and cracking before it breaks.  I would work on one of them doing the lifting as in a capsize you will probably have dumped one of them.
 
regards,

Rob
----- Original Message -----
Sent: Thursday, November 02, 2006 12:13 PM
Subject: Re: [harryproa] Re: masts

Robert,
 
I'd like to sense a failure ahead of the crack, split whatever, so as to salvage the mast and simply add more glass around the outside. But that would be a fairly satisfactory level of strength if they - cause there are two of them - raise the hull.
 
Doug

Robert <cateran1949@...> wrote:
Easy enough to check if the masts are strong enough. Load them up by
trying to lift the ww hull with a 100kg weight sitting on it.
I was looking at the characteristics of quality bamboo section and it
looks considerable better than glass weight for weight with 4GPa
youngs modulus and a breaking strain of 30kg/mm 2. It may be worth
considering for cheap masts. I am considering it myself for skinning
cores in areas where exra stiffness is wanted without the expense of
carbon. Hope carbon becomes more easily available and cheaper as it
is by far the best material.
Robert
-- In harryproa@..., "Robert" <cateran1949@y...> wrote:
>
> --- In harryproa@..., Doug Haines <doha720@y...>
wrote:
> >
> > Hi,
> >   
> >   Just meant swinging around on the water, like anchored in the
sea
> breeze comes in 20knots.
> >   
> >   I was wondering about general ideas about swinging around
coming
> from experienced multihullers out there. Like when you anchor a
> bigger boat out further where the wind is. What about two anchors
30
> degrees apart?
> >   
> >   Mast is same as boat - kiri strip and glass.
> >   I've tapered the tops to half dimensions. There is a round pole
> up a metre and a half into the mast that slots in the hull. I hope
it
> is all not going to break.
> >   Obviously it is heavy but is cheaper.
> >   
> >   Doug
> >   
> >   
> >  
> > Myriam & Youri <wangka@s...> wrote:
> >        
> >
> >     v\:* {behavior:url(#default#VML);}  o\:* {behavior:url
> (#default#VML);}  w\:* {behavior:url(#default#VML);}  .shape
> {behavior:url(#default#VML);}        st1\:*{behavior:url
> (#default#ieooui) }                Dear Doug,
> >   
> >   
> >     Dear Wangkas,
> >
> >     
> >
> >     Nice pictures and all, but where is a finished sailing boat?
> >               We know it takes a long time, but sometimes we have
> other worries on our minds … like carbon spars for classical yachts
> where we have to sort out two boats, masts, booms, sprits, poles
> etc,  we have to make molds and plugs for rudders, keels and bulbs,

> for the carbon parts we are achieving and testing  a construction
> method VAPM (vacuum assisted pressure molding that gives us
autoclave
> quality laminates (not only on the voids ratio but also on the
> compression side) in our pressure molds( compression +-5 Bars)
which
> can produce one piece parts, which is not possible by standard
> autoclave procedures. We are also currently testing a method for
> direct CNC mold cutting for parts construction …
> >
> >     Also, what do you hope to acheive with around beam?
> >
> >      They are not only rounded in length but also elliptical in
> section and will be constructed VAPM… less windage, better stress
> distribution, less wave interference …
> >
> >     Thanks again for your mast section, it is coming together.
> >               We are glad, how are you going to construct it ? …
> >
> >     The boat really swings around at the moment without masts up
> and I wonder if it can be helped? More a question for the cruising
> boaters - do you plan doing cruising Elementarries?
> >               What do you mean with swinging around ? I suspect
we
> will but that depends on the interest shown … for the moment we
have
> some asks for quotes from France, Switzerland and Germany …
> >   
> >   
> >   Best regards,
> >   
> >   
> >   Myriam & Youri
> >   Wangka bvba
> >   Belgium
> >   
> >   e-mail. info@w...
> >   web. www.wangkaboats.eu
> >   
> >   
> >   
> >
> >     
> >
> >     yaendenboom <wangka@s...> wrote:
> >
> >     Dear people,
> >
> > Our site has been updated.
> > We kindly invite you to have a look at:
> >     www.wangkaboats.eu
> >
> > Suggestions and criticism is welcome at:
> >     info@w...
> >
> > Thank you very much,
> >
> > Myriam & Youri
> > Wangka bvba
> > Belgium
> >
> >
> >
> >
> >
> >
> >
> >   
> >    Send instant messages to your online friends
> http://uk.messenger.yahoo.com 
> >
> > 
> >
> >  Send instant messages to your online friends
> http://uk.messenger.yahoo.com
> >
>




Send instant messages to your online friends http://uk.messenger.yahoo.com

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#2086 From: Mike Crawford <jmichael@...>
Date: Fri Nov 3, 2006 2:03 pm
Subject:: Re: masts
jmichaelcraw...
Online Now Online Now
Send Email Send Email
 
Peter,

  The point about matching strains is a good one, but I believe the carbon's modulus is magnitudes higher than that of the epoxy matrix, so we won't likely see a failure from the carbon stretching past the epoxy's limit.  This would be especially true with epoxy, which has a bit of give to it.  Case in point: look at how much the upper section of the Rare Bird mast can stretch and flex without any sort of failure. 

  My guess is that the failure would occur from the resin being compressed past its limit.  Since the carbon is very strong under tension, we probably won't see a failure on the windward side of the mast, which is being stretched as it bends away from the wind.  The leeward side of the mast is the opposite, though, being compressed by the same mast bend. 

  As strong as carbon fiber is in tension, as with any fiber, it's nowhere near as effective at resisting being compressed along its length.  While the resin will help keep the individual fibers in column, and they'll be able they can carry some of the load in compression, the resin itself will take a lot of the compression load as well.

  This is a likely point for failure and cracking.  The carbon fiber will keep the windward side taut, and prevent the resin from stretching past the point where it will crack, but it won't be able to provide the same support in compression.  The force will eventually buckle the resin matrix.

       - Mike



Peter Southwood wrote:
Hi Rob,
I dont see why the resin should crack because the carbon is stiffer. If the resin cracks it is because it is stressed beyond its maximum strength. The stiffer the fibres, the less likely the resin is to reach failure strain before the fibres. More likely the resin cracks because it is too stiff for the fibres and does not have a matching strain at failure.
Cheers,
Peter
----- Original Message -----
From: Rob Denney
Sent: Friday, November 03, 2006 7:23 AM
Subject: Re: [harryproa] Re: masts

G'day,
Yes, but the stiffer it is, the more cracking there will be.  My understanding of this is that the noise is the resin cracking as the carbon is so much stiffer.  With glass and kiri, there may be less cracking, or it may just happen at a higher load.  Regardless, I think you will get plenty of warning.  Maybe test a piece of kiri and glass by bending it until it starts to crack, then see how much more it will take before it is visibly damaged.  This may give you some idea of how far you can go past the cracking stage.
 
regards,

Rob 
----- Original Message -----
Sent: Friday, November 03, 2006 1:13 PM
Subject: Re: [harryproa] Re: masts

Rob,
 
Is composite glass/kiri?
 
Doug
 


Rob Denney <proa@...> wrote:
If it is composite, you will hear a lot of creaking and cracking before it breaks.  I would work on one of them doing the lifting as in a capsize you will probably have dumped one of them.
 
regards,

Rob
----- Original Message -----
Sent: Thursday, November 02, 2006 12:13 PM
Subject: Re: [harryproa] Re: masts

Robert,
 
I'd like to sense a failure ahead of the crack, split whatever, so as to salvage the mast and simply add more glass around the outside. But that would be a fairly satisfactory level of strength if they - cause there are two of them - raise the hull.
 
Doug

Robert <cateran1949@...> wrote:
Easy enough to check if the masts are strong enough. Load them up by
trying to lift the ww hull with a 100kg weight sitting on it.
I was looking at the characteristics of quality bamboo section and it
looks considerable better than glass weight for weight with 4GPa
youngs modulus and a breaking strain of 30kg/mm 2. It may be worth
considering for cheap masts. I am considering it myself for skinning
cores in areas where exra stiffness is wanted without the expense of
carbon. Hope carbon becomes more easily available and cheaper as it
is by far the best material.
Robert
-- In harryproa@..., "Robert" <cateran1949@y...> wrote:
>
> --- In harryproa@..., Doug Haines <doha720@y...>
wrote:
> >
> > Hi,
> >   
> >   Just meant swinging around on the water, like anchored in the
sea
> breeze comes in 20knots.
> >   
> >   I was wondering about general ideas about swinging around
coming
> from experienced multihullers out there. Like when you anchor a
> bigger boat out further where the wind is. What about two anchors
30
> degrees apart?
> >   
> >   Mast is same as boat - kiri strip and glass.
> >   I've tapered the tops to half dimensions. There is a round pole
> up a metre and a half into the mast that slots in the hull. I hope
it
> is all not going to break.
> >   Obviously it is heavy but is cheaper.
> >   
> >   Doug
> >   
> >   
> >  
> > Myriam & Youri <wangka@s...> wrote:
> >        
> >
> >     v\:* {behavior:url(#default#VML);}  o\:* {behavior:url
> (#default#VML);}  w\:* {behavior:url(#default#VML);}  .shape
> {behavior:url(#default#VML);}        st1\:*{behavior:url
> (#default#ieooui) }                Dear Doug,
> >   
> >   
> >     Dear Wangkas,
> >
> >     
> >
> >     Nice pictures and all, but where is a finished sailing boat?
> >               We know it takes a long time, but sometimes we have
> other worries on our minds … like carbon spars for classical yachts
> where we have to sort out two boats, masts, booms, sprits, poles
> etc,  we have to make molds and plugs for rudders, keels and bulbs,

> for the carbon parts we are achieving and testing  a construction
> method VAPM (vacuum assisted pressure molding that gives us
autoclave
> quality laminates (not only on the voids ratio but also on the
> compression side) in our pressure molds( compression +-5 Bars)
which
> can produce one piece parts, which is not possible by standard
> autoclave procedures. We are also currently testing a method for
> direct CNC mold cutting for parts construction …
> >
> >     Also, what do you hope to acheive with around beam?
> >
> >      They are not only rounded in length but also elliptical in
> section and will be constructed VAPM… less windage, better stress
> distribution, less wave interference …
> >
> >     Thanks again for your mast section, it is coming together.
> >               We are glad, how are you going to construct it ? …
> >
> >     The boat really swings around at the moment without masts up
> and I wonder if it can be helped? More a question for the cruising
> boaters - do you plan doing cruising Elementarries?
> >               What do you mean with swinging around ? I suspect
we
> will but that depends on the interest shown … for the moment we
have
> some asks for quotes from France, Switzerland and Germany …
> >   
> >   
> >   Best regards,
> >   
> >   
> >   Myriam & Youri
> >   Wangka bvba
> >   Belgium
> >   
> >   e-mail. info@w...
> >   web. www.wangkaboats.eu
> >   
> >   
> >   
> >
> >     
> >
> >     yaendenboom <wangka@s...> wrote:
> >
> >     Dear people,
> >
> > Our site has been updated.
> > We kindly invite you to have a look at:
> >     www.wangkaboats.eu
> >
> > Suggestions and criticism is welcome at:
> >     info@w...
> >
> > Thank you very much,
> >
> > Myriam & Youri
> > Wangka bvba
> > Belgium
> >
> >
> >
> >
> >
> >
> >
> >   
> >    Send instant messages to your online friends
> http://uk.messenger.yahoo.com 
> >
> > 
> >
> >  Send instant messages to your online friends
> http://uk.messenger.yahoo.com
> >
>




Send instant messages to your online friends http://uk.messenger.yahoo.com

Internal Virus Database is out-of-date.
Checked by AVG Free Edition.
Version: 7.1.385 / Virus Database: 268.11.5/426 - Release Date: 8/23/2006


The all-new Yahoo! Mail goes wherever you go - free your email address from your Internet provider.


Internal Virus Database is out-of-date.
Checked by AVG Free Edition.
Version: 7.1.385 / Virus Database: 268.11.5/426 - Release Date: 8/23/2006


No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.1.409 / Virus Database: 268.13.17/505 - Release Date: 2006/10/27

#2085 From: "Rob Denney" <proa@...>
Date: Fri Nov 3, 2006 12:05 pm
Subject:: Re: Re: masts
proaharry
Offline Offline
Send Email Send Email
 
G'day,
 
Makes sense, I think.  I am pretty sure that a carbon laminate cracks sooner than a wood epoxy one, but have absolutely no data to back this up.  Must try some tests some time, although not sure how to set it up.  Will be interesting to see what Doug finds out.
 
regards,

Rob
----- Original Message -----
Sent: Friday, November 03, 2006 2:01 PM
Subject: Re: [harryproa] Re: masts

Hi Rob,
I dont see why the resin should crack because the carbon is stiffer. If the resin cracks it is because it is stressed beyond its maximum strength. The stiffer the fibres, the less likely the resin is to reach failure strain before the fibres. More likely the resin cracks because it is too stiff for the fibres and does not have a matching strain at failure.
Cheers,
Peter
----- Original Message -----
From: Rob Denney
Sent: Friday, November 03, 2006 7:23 AM
Subject: Re: [harryproa] Re: masts

G'day,
Yes, but the stiffer it is, the more cracking there will be.  My understanding of this is that the noise is the resin cracking as the carbon is so much stiffer.  With glass and kiri, there may be less cracking, or it may just happen at a higher load.  Regardless, I think you will get plenty of warning.  Maybe test a piece of kiri and glass by bending it until it starts to crack, then see how much more it will take before it is visibly damaged.  This may give you some idea of how far you can go past the cracking stage.
 
regards,

Rob
 
----- Original Message -----
Sent: Friday, November 03, 2006 1:13 PM
Subject: Re: [harryproa] Re: masts

Rob,
 
Is composite glass/kiri?
 
Doug
 


Rob Denney <proa@...> wrote:
If it is composite, you will hear a lot of creaking and cracking before it breaks.  I would work on one of them doing the lifting as in a capsize you will probably have dumped one of them.
 
regards,

Rob
----- Original Message -----
Sent: Thursday, November 02, 2006 12:13 PM
Subject: Re: [harryproa] Re: masts

Robert,
 
I'd like to sense a failure ahead of the crack, split whatever, so as to salvage the mast and simply add more glass around the outside. But that would be a fairly satisfactory level of strength if they - cause there are two of them - raise the hull.
 
Doug

Robert <cateran1949@...> wrote:
Easy enough to check if the masts are strong enough. Load them up by
trying to lift the ww hull with a 100kg weight sitting on it.
I was looking at the characteristics of quality bamboo section and it
looks considerable better than glass weight for weight with 4GPa
youngs modulus and a breaking strain of 30kg/mm 2. It may be worth
considering for cheap masts. I am considering it myself for skinning
cores in areas where exra stiffness is wanted without the expense of
carbon. Hope carbon becomes more easily available and cheaper as it
is by far the best material.
Robert
-- In harryproa@..., "Robert" <cateran1949@y...> wrote:
>
> --- In harryproa@..., Doug Haines <doha720@y...>
wrote:
> >
> > Hi,
> >   
> >   Just meant swinging around on the water, like anchored in the
sea
> breeze comes in 20knots.
> >   
> >   I was wondering about general ideas about swinging around
coming
> from experienced multihullers out there. Like when you anchor a
> bigger boat out further where the wind is. What about two anchors
30
> degrees apart?
> >   
> >   Mast is same as boat - kiri strip and glass.
> >   I've tapered the tops to half dimensions. There is a round pole
> up a metre and a half into the mast that slots in the hull. I hope
it
> is all not going to break.
> >   Obviously it is heavy but is cheaper.
> >   
> >   Doug
> >   
> >   
> >  
> > Myriam & Youri <wangka@s...> wrote:
> >        
> >
> >     v\:* {behavior:url(#default#VML);}  o\:* {behavior:url
> (#default#VML);}  w\:* {behavior:url(#default#VML);}  .shape
> {behavior:url(#default#VML);}        st1\:*{behavior:url
> (#default#ieooui) }                Dear Doug,
> >   
> >   
> >     Dear Wangkas,
> >
> >     
> >
> >     Nice pictures and all, but where is a finished sailing boat?
> >               We know it takes a long time, but sometimes we have
> other worries on our minds … like carbon spars for classical yachts
> where we have to sort out two boats, masts, booms, sprits, poles
> etc,  we have to make molds and plugs for rudders, keels and bulbs,

> for the carbon parts we are achieving and testing  a construction
> method VAPM (vacuum assisted pressure molding that gives us
autoclave
> quality laminates (not only on the voids ratio but also on the
> compression side) in our pressure molds( compression +-5 Bars)
which
> can produce one piece parts, which is not possible by standard
> autoclave procedures. We are also currently testing a method for
> direct CNC mold cutting for parts construction …
> >
> >     Also, what do you hope to acheive with around beam?
> >
> >      They are not only rounded in length but also elliptical in
> section and will be constructed VAPM… less windage, better stress
> distribution, less wave interference …
> >
> >     Thanks again for your mast section, it is coming together.
> >               We are glad, how are you going to construct it ? …
> >
> >     The boat really swings around at the moment without masts up
> and I wonder if it can be helped? More a question for the cruising
> boaters - do you plan doing cruising Elementarries?
> >               What do you mean with swinging around ? I suspect
we
> will but that depends on the interest shown … for the moment we
have
> some asks for quotes from France, Switzerland and Germany …
> >   
> >   
> >   Best regards,
> >   
> >   
> >   Myriam & Youri
> >   Wangka bvba
> >   Belgium
> >   
> >   e-mail. info@w...
> >   web. www.wangkaboats.eu
> >   
> >   
> >   
> >
> >     
> >
> >     yaendenboom <wangka@s...> wrote:
> >
> >     Dear people,
> >
> > Our site has been updated.
> > We kindly invite you to have a look at:
> >     www.wangkaboats.eu
> >
> > Suggestions and criticism is welcome at:
> >     info@w...
> >
> > Thank you very much,
> >
> > Myriam & Youri
> > Wangka bvba
> > Belgium
> >
> >
> >
> >
> >
> >
> >
> >   
> >    Send instant messages to your online friends
> http://uk.messenger.yahoo.com 
> >
> > 
> >
> >  Send instant messages to your online friends
> http://uk.messenger.yahoo.com
> >
>




Send instant messages to your online friends http://uk.messenger.yahoo.com

Internal Virus Database is out-of-date.
Checked by AVG Free Edition.
Version: 7.1.385 / Virus Database: 268.11.5/426 - Release Date: 8/23/2006


The all-new Yahoo! Mail goes wherever you go - free your email address from your Internet provider.


Internal Virus Database is out-of-date.
Checked by AVG Free Edition.
Version: 7.1.385 / Virus Database: 268.11.5/426 - Release Date: 8/23/2006


No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.1.409 / Virus Database: 268.13.17/505 - Release Date: 2006/10/27


Internal Virus Database is out-of-date.
Checked by AVG Free Edition.
Version: 7.1.385 / Virus Database: 268.11.5/426 - Release Date: 8/23/2006

#2084 From: "Peter Southwood" <peter.southwood@...>
Date: Fri Nov 3, 2006 6:01 am
Subject:: Re: Re: masts
pbsouthwood
Offline Offline
Send Email Send Email
 
Hi Rob,
I dont see why the resin should crack because the carbon is stiffer. If the resin cracks it is because it is stressed beyond its maximum strength. The stiffer the fibres, the less likely the resin is to reach failure strain before the fibres. More likely the resin cracks because it is too stiff for the fibres and does not have a matching strain at failure.
Cheers,
Peter
----- Original Message -----
From: Rob Denney
Sent: Friday, November 03, 2006 7:23 AM
Subject: Re: [harryproa] Re: masts

G'day,
Yes, but the stiffer it is, the more cracking there will be.  My understanding of this is that the noise is the resin cracking as the carbon is so much stiffer.  With glass and kiri, there may be less cracking, or it may just happen at a higher load.  Regardless, I think you will get plenty of warning.  Maybe test a piece of kiri and glass by bending it until it starts to crack, then see how much more it will take before it is visibly damaged.  This may give you some idea of how far you can go past the cracking stage.
 
regards,

Rob
 
----- Original Message -----
Sent: Friday, November 03, 2006 1:13 PM
Subject: Re: [harryproa] Re: masts

Rob,
 
Is composite glass/kiri?
 
Doug
 


Rob Denney <proa@...> wrote:
If it is composite, you will hear a lot of creaking and cracking before it breaks.  I would work on one of them doing the lifting as in a capsize you will probably have dumped one of them.
 
regards,

Rob
----- Original Message -----
Sent: Thursday, November 02, 2006 12:13 PM
Subject: Re: [harryproa] Re: masts

Robert,
 
I'd like to sense a failure ahead of the crack, split whatever, so as to salvage the mast and simply add more glass around the outside. But that would be a fairly satisfactory level of strength if they - cause there are two of them - raise the hull.
 
Doug

Robert <cateran1949@...> wrote:
Easy enough to check if the masts are strong enough. Load them up by
trying to lift the ww hull with a 100kg weight sitting on it.
I was looking at the characteristics of quality bamboo section and it
looks considerable better than glass weight for weight with 4GPa
youngs modulus and a breaking strain of 30kg/mm 2. It may be worth
considering for cheap masts. I am considering it myself for skinning
cores in areas where exra stiffness is wanted without the expense of
carbon. Hope carbon becomes more easily available and cheaper as it
is by far the best material.
Robert
-- In harryproa@..., "Robert" <cateran1949@y...> wrote:
>
> --- In harryproa@..., Doug Haines <doha720@y...>
wrote:
> >
> > Hi,
> >   
> >   Just meant swinging around on the water, like anchored in the
sea
> breeze comes in 20knots.
> >   
> >   I was wondering about general ideas about swinging around
coming
> from experienced multihullers out there. Like when you anchor a
> bigger boat out further where the wind is. What about two anchors
30
> degrees apart?
> >   
> >   Mast is same as boat - kiri strip and glass.
> >   I've tapered the tops to half dimensions. There is a round pole
> up a metre and a half into the mast that slots in the hull. I hope
it
> is all not going to break.
> >   Obviously it is heavy but is cheaper.
> >   
> >   Doug
> >   
> >   
> >  
> > Myriam & Youri <wangka@s...> wrote:
> >        
> >
> >     v\:* {behavior:url(#default#VML);}  o\:* {behavior:url
> (#default#VML);}  w\:* {behavior:url(#default#VML);}  .shape
> {behavior:url(#default#VML);}        st1\:*{behavior:url
> (#default#ieooui) }                Dear Doug,
> >   
> >   
> >     Dear Wangkas,
> >
> >     
> >
> >     Nice pictures and all, but where is a finished sailing boat?
> >               We know it takes a long time, but sometimes we have
> other worries on our minds … like carbon spars for classical yachts
> where we have to sort out two boats, masts, booms, sprits, poles
> etc,  we have to make molds and plugs for rudders, keels and bulbs,

> for the carbon parts we are achieving and testing  a construction
> method VAPM (vacuum assisted pressure molding that gives us
autoclave
> quality laminates (not only on the voids ratio but also on the
> compression side) in our pressure molds( compression +-5 Bars)
which
> can produce one piece parts, which is not possible by standard
> autoclave procedures. We are also currently testing a method for
> direct CNC mold cutting for parts construction …
> >
> >     Also, what do you hope to acheive with around beam?
> >
> >      They are not only rounded in length but also elliptical in
> section and will be constructed VAPM… less windage, better stress
> distribution, less wave interference …
> >
> >     Thanks again for your mast section, it is coming together.
> >               We are glad, how are you going to construct it ? …
> >
> >     The boat really swings around at the moment without masts up
> and I wonder if it can be helped? More a question for the cruising
> boaters - do you plan doing cruising Elementarries?
> >               What do you mean with swinging around ? I suspect
we
> will but that depends on the interest shown … for the moment we
have
> some asks for quotes from France, Switzerland and Germany …
> >   
> >   
> >   Best regards,
> >   
> >   
> >   Myriam & Youri
> >   Wangka bvba
> >   Belgium
> >   
> >   e-mail. info@w...
> >   web. www.wangkaboats.eu
> >   
> >   
> >   
> >
> >     
> >
> >     yaendenboom <wangka@s...> wrote:
> >
> >     Dear people,
> >
> > Our site has been updated.
> > We kindly invite you to have a look at:
> >     www.wangkaboats.eu
> >
> > Suggestions and criticism is welcome at:
> >     info@w...
> >
> > Thank you very much,
> >
> > Myriam & Youri
> > Wangka bvba
> > Belgium
> >
> >
> >
> >
> >
> >
> >
> >   
> >    Send instant messages to your online friends
> http://uk.messenger.yahoo.com 
> >
> > 
> >
> >  Send instant messages to your online friends
> http://uk.messenger.yahoo.com
> >
>




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#2083 From: "Rob Denney" <proa@...>
Date: Fri Nov 3, 2006 5:23 am
Subject:: Re: Re: masts
proaharry
Offline Offline
Send Email Send Email
 
G'day,
Yes, but the stiffer it is, the more cracking there will be.  My understanding of this is that the noise is the resin cracking as the carbon is so much stiffer.  With glass and kiri, there may be less cracking, or it may just happen at a higher load.  Regardless, I think you will get plenty of warning.  Maybe test a piece of kiri and glass by bending it until it starts to crack, then see how much more it will take before it is visibly damaged.  This may give you some idea of how far you can go past the cracking stage.
 
regards,

Rob
 
----- Original Message -----
Sent: Friday, November 03, 2006 1:13 PM
Subject: Re: [harryproa] Re: masts

Rob,
 
Is composite glass/kiri?
 
Doug
 


Rob Denney <proa@...> wrote:
If it is composite, you will hear a lot of creaking and cracking before it breaks.  I would work on one of them doing the lifting as in a capsize you will probably have dumped one of them.
 
regards,

Rob
----- Original Message -----
Sent: Thursday, November 02, 2006 12:13 PM
Subject: Re: [harryproa] Re: masts

Robert,
 
I'd like to sense a failure ahead of the crack, split whatever, so as to salvage the mast and simply add more glass around the outside. But that would be a fairly satisfactory level of strength if they - cause there are two of them - raise the hull.
 
Doug

Robert <cateran1949@...> wrote:
Easy enough to check if the masts are strong enough. Load them up by
trying to lift the ww hull with a 100kg weight sitting on it.
I was looking at the characteristics of quality bamboo section and it
looks considerable better than glass weight for weight with 4GPa
youngs modulus and a breaking strain of 30kg/mm 2. It may be worth
considering for cheap masts. I am considering it myself for skinning
cores in areas where exra stiffness is wanted without the expense of
carbon. Hope carbon becomes more easily available and cheaper as it
is by far the best material.
Robert
-- In harryproa@..., "Robert" <cateran1949@y...> wrote:
>
> --- In harryproa@..., Doug Haines <doha720@y...>
wrote:
> >
> > Hi,
> >   
> >   Just meant swinging around on the water, like anchored in the
sea
> breeze comes in 20knots.
> >   
> >   I was wondering about general ideas about swinging around
coming
> from experienced multihullers out there. Like when you anchor a
> bigger boat out further where the wind is. What about two anchors
30
> degrees apart?
> >   
> >   Mast is same as boat - kiri strip and glass.
> >   I've tapered the tops to half dimensions. There is a round pole
> up a metre and a half into the mast that slots in the hull. I hope
it
> is all not going to break.
> >   Obviously it is heavy but is cheaper.
> >   
> >   Doug
> >   
> >   
> >  
> > Myriam & Youri <wangka@s...> wrote:
> >        
> >
> >     v\:* {behavior:url(#default#VML);}  o\:* {behavior:url
> (#default#VML);}  w\:* {behavior:url(#default#VML);}  .shape
> {behavior:url(#default#VML);}        st1\:*{behavior:url
> (#default#ieooui) }                Dear Doug,
> >   
> >   
> >     Dear Wangkas,
> >
> >     
> >
> >     Nice pictures and all, but where is a finished sailing boat?
> >               We know it takes a long time, but sometimes we have
> other worries on our minds … like carbon spars for classical yachts
> where we have to sort out two boats, masts, booms, sprits, poles
> etc,  we have to make molds and plugs for rudders, keels and bulbs,

> for the carbon parts we are achieving and testing  a construction
> method VAPM (vacuum assisted pressure molding that gives us
autoclave
> quality laminates (not only on the voids ratio but also on the
> compression side) in our pressure molds( compression +-5 Bars)
which
> can produce one piece parts, which is not possible by standard
> autoclave procedures. We are also currently testing a method for
> direct CNC mold cutting for parts construction …
> >
> >     Also, what do you hope to acheive with around beam?
> >
> >      They are not only rounded in length but also elliptical in
> section and will be constructed VAPM… less windage, better stress
> distribution, less wave interference …
> >
> >     Thanks again for your mast section, it is coming together.
> >               We are glad, how are you going to construct it ? …
> >
> >     The boat really swings around at the moment without masts up
> and I wonder if it can be helped? More a question for the cruising
> boaters - do you plan doing cruising Elementarries?
> >               What do you mean with swinging around ? I suspect
we
> will but that depends on the interest shown … for the moment we
have
> some asks for quotes from France, Switzerland and Germany …
> >   
> >   
> >   Best regards,
> >   
> >   
> >   Myriam & Youri
> >   Wangka bvba
> >   Belgium
> >   
> >   e-mail. info@w...
> >   web. www.wangkaboats.eu
> >   
> >   
> >   
> >
> >     
> >
> >     yaendenboom <wangka@s...> wrote:
> >
> >     Dear people,
> >
> > Our site has been updated.
> > We kindly invite you to have a look at:
> >     www.wangkaboats.eu
> >
> > Suggestions and criticism is welcome at:
> >     info@w...
> >
> > Thank you very much,
> >
> > Myriam & Youri
> > Wangka bvba
> > Belgium
> >
> >
> >
> >
> >
> >
> >
> >   
> >    Send instant messages to your online friends
> http://uk.messenger.yahoo.com 
> >
> > 
> >
> >  Send instant messages to your online friends
> http://uk.messenger.yahoo.com
> >
>




Send instant messages to your online friends http://uk.messenger.yahoo.com

Internal Virus Database is out-of-date.
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#2082 From: Doug Haines <doha720@...>
Date: Fri Nov 3, 2006 5:13 am
Subject:: Re: Re: masts
doha720
Offline Offline
Send Email Send Email
 
Rob,
 
Is composite glass/kiri?
 
Doug
 


Rob Denney <proa@...> wrote:
If it is composite, you will hear a lot of creaking and cracking before it breaks.  I would work on one of them doing the lifting as in a capsize you will probably have dumped one of them.
 
regards,

Rob
----- Original Message -----
Sent: Thursday, November 02, 2006 12:13 PM
Subject: Re: [harryproa] Re: masts

Robert,
 
I'd like to sense a failure ahead of the crack, split whatever, so as to salvage the mast and simply add more glass around the outside. But that would be a fairly satisfactory level of strength if they - cause there are two of them - raise the hull.
 
Doug

Robert <cateran1949@...> wrote:
Easy enough to check if the masts are strong enough. Load them up by
trying to lift the ww hull with a 100kg weight sitting on it.
I was looking at the characteristics of quality bamboo section and it
looks considerable better than glass weight for weight with 4GPa
youngs modulus and a breaking strain of 30kg/mm 2. It may be worth
considering for cheap masts. I am considering it myself for skinning
cores in areas where exra stiffness is wanted without the expense of
carbon. Hope carbon becomes more easily available and cheaper as it
is by far the best material.
Robert
-- In harryproa@..., "Robert" <cateran1949@y...> wrote:
>
> --- In harryproa@..., Doug Haines <doha720@y...>
wrote:
> >
> > Hi,
> >   
> >   Just meant swinging around on the water, like anchored in the
sea
> breeze comes in 20knots.
> >   
> >   I was wondering about general ideas about swinging around
coming
> from experienced multihullers out there. Like when you anchor a
> bigger boat out further where the wind is. What about two anchors
30
> degrees apart?
> >   
> >   Mast is same as boat - kiri strip and glass.
> >   I've tapered the tops to half dimensions. There is a round pole
> up a metre and a half into the mast that slots in the hull. I hope
it
> is all not going to break.
> >   Obviously it is heavy but is cheaper.
> >   
> >   Doug
> >   
> >   
> >  
> > Myriam & Youri <wangka@s...> wrote:
> >        
> >
> >     v\:* {behavior:url(#default#VML);}  o\:* {behavior:url
> (#default#VML);}  w\:* {behavior:url(#default#VML);}  .shape
> {behavior:url(#default#VML);}        st1\:*{behavior:url
> (#default#ieooui) }                Dear Doug,
> >   
> >   
> >     Dear Wangkas,
> >
> >     
> >
> >     Nice pictures and all, but where is a finished sailing boat?
> >               We know it takes a long time, but sometimes we have
> other worries on our minds … like carbon spars for classical yachts
> where we have to sort out two boats, masts, booms, sprits, poles
> etc,  we have to make molds and plugs for rudders, keels and bulbs,

> for the carbon parts we are achieving and testing  a construction
> method VAPM (vacuum assisted pressure molding that gives us
autoclave
> quality laminates (not only on the voids ratio but also on the
> compression side) in our pressure molds( compression +-5 Bars)
which
> can produce one piece parts, which is not possible by standard
> autoclave procedures. We are also currently testing a method for
> direct CNC mold cutting for parts construction …
> >
> >     Also, what do you hope to acheive with around beam?
> >
> >      They are not only rounded in length but also elliptical in
> section and will be constructed VAPM… less windage, better stress
> distribution, less wave interference …
> >
> >     Thanks again for your mast section, it is coming together.
> >               We are glad, how are you going to construct it ? …
> >
> >     The boat really swings around at the moment without masts up
> and I wonder if it can be helped? More a question for the cruising
> boaters - do you plan doing cruising Elementarries?
> >               What do you mean with swinging around ? I suspect
we
> will but that depends on the interest shown … for the moment we
have
> some asks for quotes from France, Switzerland and Germany …
> >   
> >   
> >   Best regards,
> >   
> >   
> >   Myriam & Youri
> >   Wangka bvba
> >   Belgium
> >   
> >   e-mail. info@w...
> >   web. www.wangkaboats.eu
> >   
> >   
> >   
> >
> >     
> >
> >     yaendenboom <wangka@s...> wrote:
> >
> >     Dear people,
> >
> > Our site has been updated.
> > We kindly invite you to have a look at:
> >     www.wangkaboats.eu
> >
> > Suggestions and criticism is welcome at:
> >     info@w...
> >
> > Thank you very much,
> >
> > Myriam & Youri
> > Wangka bvba
> > Belgium
> >
> >
> >
> >
> >
> >
> >
> >   
> >    Send instant messages to your online friends
> http://uk.messenger.yahoo.com 
> >
> > 
> >
> >  Send instant messages to your online friends
> http://uk.messenger.yahoo.com
> >
>




Send instant messages to your online friends http://uk.messenger.yahoo.com

Internal Virus Database is out-of-date.
Checked by AVG Free Edition.
Version: 7.1.385 / Virus Database: 268.11.5/426 - Release Date: 8/23/2006


The all-new Yahoo! Mail goes wherever you go - free your email address from your Internet provider.

#2081 From: "Robert" <cateran1949@...>
Date: Fri Nov 3, 2006 3:40 am
Subject:: Re: masts
cateran1949
Offline Offline
Send Email Send Email
 
-I was giving a lecture the other day about diffusion rates of CO2
across stomata of tree leaves- big topic at the moment with CO2
increases effectively doubling the gradient- and a student said she
couldn't understand the maths. I said  glibly 'its easy' and started
to go through the calculations. Oops! I'd stuffed up some simple
arithmetic. She could understand it when I got it right.

If you can get carbon tow at $30 or even $100 a kg its a no brainer
for the weight savings on a mast, especially seeing it's weight where
you don't want it.
  Robert


-- In harryproa@..., "Rob Denney" <proa@i...> wrote:
>
> G'day,
>
> You are right (and I am wrong) about 2 masts vs one.  The stiffness
and the strength are different, and it is the strength which needs to
be enough to tip the boat over on either mast of a schooner.  I will
redo some of my calculations for the bigger boats.
>
> Not so sure about the load attachments to test the mast, but no
doubt if there are 5 attachments to the top half and it tips the boat
over, the mast will not break in normal use.
>
> Re carbon tow at $30/kg.  The actual mast is made up of about 60%
carbon and 40% resin.  The resin costs about $13 per kg so the actual
mast cost is considerably less.  There is also a lot less wastage
than with a wooden mast, which also needs glassing for protection,
but this adds nothing to the stiffness.
>
> regards,
>
> Rob
>   ----- Original Message -----
>   From: Robert
>   To: harryproa@...
>   Sent: Wednesday, November 01, 2006 11:41 AM
>   Subject: [harryproa] Re: masts
>
>
>   -I would have thought that with the safety factor needed for
gusts
>   and wave actions it wouldn't need quite that level of load
spreading.
>   The mast has to be able to handle gusts while in a wave trough at
the
>   same time as being jerked around by chop. I would have thought
that
>   just a spread load for the top half would be enough., especially
as
>   that is where the moments are. By the way, working on the figures
for
>   loadings on masts makes me more impressed by the Visionarry mast.
>
>   My calculations though, don't come out as two una rigs weighing
that
>   much more than a single rig of the same area when the extra
stiffness
>   required for  working sail area of the taller rig are considered.
Add
>   30% to the top of the mast with the same taper and there is
nothing
>   left to attach a halliard to.  The short masts need to have
enough
>   strength each to be able to lift the ww hull and therefore the
bottom
>   2m need to be about the same, but only need to have enough
stiffness
>   to carry half that load of working sail. I am not sure how much
extra
>   weight is needed to give that stiffness for the taller mast or
>   whether it is a natural consequence of the materials stiffness to
>   strength ratio. If the latter I can see the extra 30-40% weight
of
>   the two mast set up. I see the main advantage of a single rig is
>   catching cleaner air in light conditons, rather than weight.
>   regards,
>   robert
>   -- In harryproa@..., "Rob Denney" <proa@i...>
wrote:
>   >
>   > G'day,
>   >
>   > Not that easy as the pulling load has to be evenly distributed
>   along the mast.  Needs a lot of pulleys so that the single load
can
>   be dissipated to minimum 10 points along the mast.
>   >
>   > regards,
>   >
>   > Rob----- Original Message -----
>   >   From: Robert
>   >   To: harryproa@...
>   >   Sent: Tuesday, October 31, 2006 4:38 PM
>   >   Subject: [harryproa] Re: masts
>   >
>   >
>   >   Easy enough to check if the masts are strong enough. Load
them up
>   by
>   >   trying to lift the ww hull with a 100kg weight sitting on it.
>   >   I was looking at the characteristics of quality bamboo
section
>   and it
>   >   looks considerable better than glass weight for weight with
4GPa
>   >   youngs modulus and a breaking strain of 30kg/mm 2. It may be
>   worth
>   >   considering for cheap masts. I am considering it myself for
>   skinning
>   >   cores in areas where exra stiffness is wanted without the
expense
>   of
>   >   carbon. Hope carbon becomes more easily available and cheaper
as
>   it
>   >   is by far the best material.
>   >   Robert
>   >   -- In harryproa@..., "Robert"
<cateran1949@y...>
>   wrote:
>   >   >
>   >   > --- In harryproa@..., Doug Haines
<doha720@y...>
>   >   wrote:
>   >   > >
>   >   > > Hi,
>   >   > >
>   >   > >   Just meant swinging around on the water, like anchored
in
>   the
>   >   sea
>   >   > breeze comes in 20knots.
>   >   > >
>   >   > >   I was wondering about general ideas about swinging
around
>   >   coming
>   >   > from experienced multihullers out there. Like when you
anchor a
>   >   > bigger boat out further where the wind is. What about two
>   anchors
>   >   30
>   >   > degrees apart?
>   >   > >
>   >   > >   Mast is same as boat - kiri strip and glass.
>   >   > >   I've tapered the tops to half dimensions. There is a
round
>   pole
>   >   > up a metre and a half into the mast that slots in the hull.
I
>   hope
>   >   it
>   >   > is all not going to break.
>   >   > >   Obviously it is heavy but is cheaper.
>   >   > >
>   >   > >   Doug
>   >   > >
>   >   > >
>   >   > >
>   >   > > Myriam & Youri <wangka@s...> wrote:
>   >   > >
>   >   > >
>   >   > >     v\:* {behavior:url(#default#VML);}  o\:* {behavior:url
>   >   > (#default#VML);}  w\:* {behavior:url
(#default#VML);}  .shape
>   >   > {behavior:url(#default#VML);}        st1\:*{behavior:url
>   >   > (#default#ieooui) }                Dear Doug,
>   >   > >
>   >   > >
>   >   > >     Dear Wangkas,
>   >   > >
>   >   > >
>   >   > >
>   >   > >     Nice pictures and all, but where is a finished
sailing
>   boat?
>   >   > >               We know it takes a long time, but sometimes
we
>   have
>   >   > other worries on our minds . like carbon spars for
classical
>   yachts
>   >   > where we have to sort out two boats, masts, booms, sprits,
>   poles
>   >   > etc,  we have to make molds and plugs for rudders, keels
and
>   bulbs,
>   >   .
>   >   > for the carbon parts we are achieving and testing  a
>   construction
>   >   > method VAPM (vacuum assisted pressure molding that gives us
>   >   autoclave
>   >   > quality laminates (not only on the voids ratio but also on
the
>   >   > compression side) in our pressure molds( compression +-5
Bars)
>   >   which
>   >   > can produce one piece parts, which is not possible by
standard
>   >   > autoclave procedures. We are also currently testing a
method
>   for
>   >   > direct CNC mold cutting for parts construction .
>   >   > >
>   >   > >     Also, what do you hope to acheive with around beam?
>   >   > >
>   >   > >      They are not only rounded in length but also
elliptical
>   in
>   >   > section and will be constructed VAPM. less windage, better
>   stress
>   >   > distribution, less wave interference .
>   >   > >
>   >   > >     Thanks again for your mast section, it is coming
>   together.
>   >   > >               We are glad, how are you going to construct
>   it ? .
>   >   > >
>   >   > >     The boat really swings around at the moment without
masts
>   up
>   >   > and I wonder if it can be helped? More a question for the
>   cruising
>   >   > boaters - do you plan doing cruising Elementarries?
>   >   > >               What do you mean with swinging around ? I
>   suspect
>   >   we
>   >   > will but that depends on the interest shown . for the
moment we
>   >   have
>   >   > some asks for quotes from France, Switzerland and Germany .
>   >   > >
>   >   > >
>   >   > >   Best regards,
>   >   > >
>   >   > >
>   >   > >   Myriam & Youri
>   >   > >   Wangka bvba
>   >   > >   Belgium
>   >   > >
>   >   > >   e-mail. info@w...
>   >   > >   web. www.wangkaboats.eu
>   >   > >
>   >   > >
>   >   > >
>   >   > >
>   >   > >
>   >   > >
>   >   > >     yaendenboom <wangka@s...> wrote:
>   >   > >
>   >   > >     Dear people,
>   >   > >
>   >   > > Our site has been updated.
>   >   > > We kindly invite you to have a look at:
>   >   > >     www.wangkaboats.eu
>   >   > >
>   >   > > Suggestions and criticism is welcome at:
>   >   > >     info@w...
>   >   > >
>   >   > > Thank you very much,
>   >   > >
>   >   > > Myriam & Youri
>   >   > > Wangka bvba
>   >   > > Belgium
>   >   > >
>   >   > >
>   >   > >
>   >   > >
>   >   > >
>   >   > >
>   >   > >
>   >   > >
>   >   > >    Send instant messages to your online friends
>   >   > http://uk.messenger.yahoo.com
>   >   > >
>   >   > >
>   >   > >
>   >   > >  Send instant messages to your online friends
>   >   > http://uk.messenger.yahoo.com
>   >   > >
>   >   >
>   >
>   >
>   >
>   >
>   >
>   >
>   > ----------------------------------------------------------------
----
>   ----------
>   >
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>   >   Checked by AVG Free Edition.
>   >   Version: 7.1.385 / Virus Database: 268.11.5/426 - Release
Date:
>   8/23/2006
>   >
>
>
>
>
>
>
> --------------------------------------------------------------------
----------
>
>
>   Internal Virus Database is out-of-date.
>   Checked by AVG Free Edition.
>   Version: 7.1.385 / Virus Database: 268.11.5/426 - Release Date:
8/23/2006
>

#2080 From: "jjtctaylor" <jtaylor412@...>
Date: Fri Nov 3, 2006 1:38 am
Subject:: Hull Speed
jjtctaylor
Offline Offline
Send Email Send Email
 
Rob, ...... or anyone else on the forum...

Ever figure out what is hull speed for an asymmetric proa design ?  Or how the
current
mathematical approximations are affected by the difference in hull lengths and
underwater
profile ?

Likely the lack of on the water experience and measurement equipment may affect
the
possibility of evaluating the issue.  But, was curious if before "Rare Bird" was
or is sold off
did any acurate test made to compare predicted versus actual performance?  Same
goes
for the elementaries although not sure whether they are displacement, planing or
mixed
hull speeds.

JT

#2079 From: "Rob Denney" <proa@...>
Date: Thu Nov 2, 2006 12:38 pm
Subject:: Re: Re: masts
proaharry
Offline Offline
Send Email Send Email
 
If it is composite, you will hear a lot of creaking and cracking before it breaks.  I would work on one of them doing the lifting as in a capsize you will probably have dumped one of them.
 
regards,

Rob
----- Original Message -----
Sent: Thursday, November 02, 2006 12:13 PM
Subject: Re: [harryproa] Re: masts

Robert,
 
I'd like to sense a failure ahead of the crack, split whatever, so as to salvage the mast and simply add more glass around the outside. But that would be a fairly satisfactory level of strength if they - cause there are two of them - raise the hull.
 
Doug

Robert <cateran1949@...> wrote:
Easy enough to check if the masts are strong enough. Load them up by
trying to lift the ww hull with a 100kg weight sitting on it.
I was looking at the characteristics of quality bamboo section and it
looks considerable better than glass weight for weight with 4GPa
youngs modulus and a breaking strain of 30kg/mm 2. It may be worth
considering for cheap masts. I am considering it myself for skinning
cores in areas where exra stiffness is wanted without the expense of
carbon. Hope carbon becomes more easily available and cheaper as it
is by far the best material.
Robert
-- In harryproa@..., "Robert" <cateran1949@y...> wrote:
>
> --- In harryproa@..., Doug Haines <doha720@y...>
wrote:
> >
> > Hi,
> >   
> >   Just meant swinging around on the water, like anchored in the
sea
> breeze comes in 20knots.
> >   
> >   I was wondering about general ideas about swinging around
coming
> from experienced multihullers out there. Like when you anchor a
> bigger boat out further where the wind is. What about two anchors
30
> degrees apart?
> >   
> >   Mast is same as boat - kiri strip and glass.
> >   I've tapered the tops to half dimensions. There is a round pole
> up a metre and a half into the mast that slots in the hull. I hope
it
> is all not going to break.
> >   Obviously it is heavy but is cheaper.
> >   
> >   Doug
> >   
> >   
> >  
> > Myriam & Youri <wangka@s...> wrote:
> >        
> >
> >     v\:* {behavior:url(#default#VML);}  o\:* {behavior:url
> (#default#VML);}  w\:* {behavior:url(#default#VML);}  .shape
> {behavior:url(#default#VML);}        st1\:*{behavior:url
> (#default#ieooui) }                Dear Doug,
> >   
> >   
> >     Dear Wangkas,
> >
> >     
> >
> >     Nice pictures and all, but where is a finished sailing boat?
> >               We know it takes a long time, but sometimes we have
> other worries on our minds … like carbon spars for classical yachts
> where we have to sort out two boats, masts, booms, sprits, poles
> etc,  we have to make molds and plugs for rudders, keels and bulbs,

> for the carbon parts we are achieving and testing  a construction
> method VAPM (vacuum assisted pressure molding that gives us
autoclave
> quality laminates (not only on the voids ratio but also on the
> compression side) in our pressure molds( compression +-5 Bars)
which
> can produce one piece parts, which is not possible by standard
> autoclave procedures. We are also currently testing a method for
> direct CNC mold cutting for parts construction …
> >
> >     Also, what do you hope to acheive with around beam?
> >
> >      They are not only rounded in length but also elliptical in
> section and will be constructed VAPM… less windage, better stress
> distribution, less wave interference …
> >
> >     Thanks again for your mast section, it is coming together.
> >               We are glad, how are you going to construct it ? …
> >
> >     The boat really swings around at the moment without masts up
> and I wonder if it can be helped? More a question for the cruising
> boaters - do you plan doing cruising Elementarries?
> >               What do you mean with swinging around ? I suspect
we
> will but that depends on the interest shown … for the moment we
have
> some asks for quotes from France, Switzerland and Germany …
> >   
> >   
> >   Best regards,
> >   
> >   
> >   Myriam & Youri
> >   Wangka bvba
> >   Belgium
> >   
> >   e-mail. info@w...
> >   web. www.wangkaboats.eu
> >   
> >   
> >   
> >
> >     
> >
> >     yaendenboom <wangka@s...> wrote:
> >
> >     Dear people,
> >
> > Our site has been updated.
> > We kindly invite you to have a look at:
> >     www.wangkaboats.eu
> >
> > Suggestions and criticism is welcome at:
> >     info@w...
> >
> > Thank you very much,
> >
> > Myriam & Youri
> > Wangka bvba
> > Belgium
> >
> >
> >
> >
> >
> >
> >
> >   
> >    Send instant messages to your online friends
> http://uk.messenger.yahoo.com 
> >
> > 
> >
> >  Send instant messages to your online friends
> http://uk.messenger.yahoo.com
> >
>




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#2078 From: "Rob Denney" <proa@...>
Date: Thu Nov 2, 2006 12:36 pm
Subject:: Re: site update
proaharry
Offline Offline
Send Email Send Email
 
Yes, Harrigami and Harry.  Anchored out with the lead mines.  It is worst in tidal areas or with swirling winds because the boats move around quicker.  If there are no boats near yours to bump into, I would not worry about it.
 
regards,

Rob
----- Original Message -----
Sent: Thursday, November 02, 2006 12:07 PM
Subject: Re: [harryproa] site update

Rob,
 
You are talking about boats like the harrigami that you anchored a few times?
 
Bucket I understand.
 
Elemntarry is so small I see it tight up against the shore out of the wind - only here at Mandurah I'm on the opposite side of the channel to the wind direction, and ave a low scrub sandy finger that sbreaks no wind.
I imagined the bigger boats will tend to stay off shore further - not that they can't get fairly close in, in about a foot or two of water?
 
Doug

Rob Denney <proa@...> wrote:
G'day,
 
I used a bridle from the bows and adjusted it so the join was near enough the middle of the boat.  Worked pretty well, but the boat still blew around in the wind a lot more than the monos so I dropped a bucket in the water and tied it to the aft beam.  Slowed it down a bit more.  Two anchors will not help much as the boat swings before the warps get tight and take the load.  You could try one from each end and keep them fairly tight but a big scope is required.
 
regards,

Rob 
----- Original Message -----
Sent: Monday, October 30, 2006 7:25 PM
Subject: RE: [harryproa] site update

Hi,
 
Just meant swinging around on the water, like anchored in the sea breeze comes in 20knots.
 
I was wondering about general ideas about swinging around coming from experienced multihullers out there. Like when you anchor a bigger boat out further where the wind is. What about two anchors 30 degrees apart?
 
Mast is same as boat - kiri strip and glass.
I've tapered the tops to half dimensions. There is a round pole up a metre and a half into the mast that slots in the hull. I hope it is all not going to break.
Obviously it is heavy but is cheaper.
 
Doug
 
 

Myriam & Youri <wangka@...> wrote:
Dear Doug,
 
 
Dear Wangkas,
 
Nice pictures and all, but where is a finished sailing boat?
            We know it takes a long time, but sometimes we have other worries on our minds … like carbon spars for classical yachts where we have to sort out two boats, masts, booms, sprits, poles etc,  we have to make molds and plugs for rudders, keels and bulbs, … for the carbon parts we are achieving and testing  a construction method VAPM (vacuum assisted pressure molding that gives us autoclave quality laminates (not only on the voids ratio but also on the compression side) in our pressure molds( compression +-5 Bars) which can produce one piece parts, which is not possible by standard autoclave procedures. We are also currently testing a method for direct CNC mold cutting for parts construction …
Also, what do you hope to acheive with around beam?
 They are not only rounded in length but also elliptical in section and will be constructed VAPM… less windage, better stress distribution, less wave interference …
Thanks again for your mast section, it is coming together.
            We are glad, how are you going to construct it ?
The boat really swings around at the moment without masts up and I wonder if it can be helped? More a question for the cruising boaters - do you plan doing cruising Elementarries?
            What do you mean with swinging around ? I suspect we will but that depends on the interest shown … for the moment we have some asks for quotes from France, Switzerland and Germany
 
 
Best regards,
 
 
Myriam & Youri
Wangka bvba
Belgium
 
e-mail. info@...
 
 
 
 
yaendenboom <wangka@...> wrote:
Dear people,

Our site has been updated.
We kindly invite you to have a look at:
   
www.wangkaboats.eu

Suggestions and criticism is welcome at:
   
info@...

Thank you very much,

Myriam & Youri
Wangka bvba
Belgium






 
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Version: 7.1.385 / Virus Database: 268.11.5/426 - Release Date: 8/23/2006

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#2077 From: Doug Haines <doha720@...>
Date: Thu Nov 2, 2006 4:13 am
Subject:: Re: Re: masts
doha720
Offline Offline
Send Email Send Email
 
Robert,
 
I'd like to sense a failure ahead of the crack, split whatever, so as to salvage the mast and simply add more glass around the outside. But that would be a fairly satisfactory level of strength if they - cause there are two of them - raise the hull.
 
Doug

Robert <cateran1949@...> wrote:
Easy enough to check if the masts are strong enough. Load them up by
trying to lift the ww hull with a 100kg weight sitting on it.
I was looking at the characteristics of quality bamboo section and it
looks considerable better than glass weight for weight with 4GPa
youngs modulus and a breaking strain of 30kg/mm 2. It may be worth
considering for cheap masts. I am considering it myself for skinning
cores in areas where exra stiffness is wanted without the expense of
carbon. Hope carbon becomes more easily available and cheaper as it
is by far the best material.
Robert
-- In harryproa@..., "Robert" <cateran1949@y...> wrote:
>
> --- In harryproa@..., Doug Haines <doha720@y...>
wrote:
> >
> > Hi,
> >   
> >   Just meant swinging around on the water, like anchored in the
sea
> breeze comes in 20knots.
> >   
> >   I was wondering about general ideas about swinging around
coming
> from experienced multihullers out there. Like when you anchor a
> bigger boat out further where the wind is. What about two anchors
30
> degrees apart?
> >   
> >   Mast is same as boat - kiri strip and glass.
> >   I've tapered the tops to half dimensions. There is a round pole
> up a metre and a half into the mast that slots in the hull. I hope
it
> is all not going to break.
> >   Obviously it is heavy but is cheaper.
> >   
> >   Doug
> >   
> >   
> >  
> > Myriam & Youri <wangka@s...> wrote:
> >        
> >
> >     v\:* {behavior:url(#default#VML);}  o\:* {behavior:url
> (#default#VML);}  w\:* {behavior:url(#default#VML);}  .shape
> {behavior:url(#default#VML);}        st1\:*{behavior:url
> (#default#ieooui) }                Dear Doug,
> >   
> >   
> >     Dear Wangkas,
> >
> >     
> >
> >     Nice pictures and all, but where is a finished sailing boat?
> >               We know it takes a long time, but sometimes we have
> other worries on our minds … like carbon spars for classical yachts
> where we have to sort out two boats, masts, booms, sprits, poles
> etc,  we have to make molds and plugs for rudders, keels and bulbs,

> for the carbon parts we are achieving and testing  a construction
> method VAPM (vacuum assisted pressure molding that gives us
autoclave
> quality laminates (not only on the voids ratio but also on the
> compression side) in our pressure molds( compression +-5 Bars)
which
> can produce one piece parts, which is not possible by standard
> autoclave procedures. We are also currently testing a method for
> direct CNC mold cutting for parts construction …
> >
> >     Also, what do you hope to acheive with around beam?
> >
> >      They are not only rounded in length but also elliptical in
> section and will be constructed VAPM… less windage, better stress
> distribution, less wave interference …
> >
> >     Thanks again for your mast section, it is coming together.
> >               We are glad, how are you going to construct it ? …
> >
> >     The boat really swings around at the moment without masts up
> and I wonder if it can be helped? More a question for the cruising
> boaters - do you plan doing cruising Elementarries?
> >               What do you mean with swinging around ? I suspect
we
> will but that depends on the interest shown … for the moment we
have
> some asks for quotes from France, Switzerland and Germany …
> >   
> >   
> >   Best regards,
> >   
> >   
> >   Myriam & Youri
> >   Wangka bvba
> >   Belgium
> >   
> >   e-mail. info@w...
> >   web. www.wangkaboats.eu
> >   
> >   
> >   
> >
> >     
> >
> >     yaendenboom <wangka@s...> wrote:
> >
> >     Dear people,
> >
> > Our site has been updated.
> > We kindly invite you to have a look at:
> >     www.wangkaboats.eu
> >
> > Suggestions and criticism is welcome at:
> >     info@w...
> >
> > Thank you very much,
> >
> > Myriam & Youri
> > Wangka bvba
> > Belgium
> >
> >
> >
> >
> >
> >
> >
> >   
> >    Send instant messages to your online friends
> http://uk.messenger.yahoo.com 
> >
> > 
> >
> >  Send instant messages to your online friends
> http://uk.messenger.yahoo.com
> >
>




Send instant messages to your online friends http://uk.messenger.yahoo.com


#2076 From: Doug Haines <doha720@...>
Date: Thu Nov 2, 2006 4:07 am
Subject:: Re: site update
doha720
Offline Offline
Send Email Send Email
 
Rob,
 
You are talking about boats like the harrigami that you anchored a few times?
 
Bucket I understand.
 
Elemntarry is so small I see it tight up against the shore out of the wind - only here at Mandurah I'm on the opposite side of the channel to the wind direction, and ave a low scrub sandy finger that sbreaks no wind.
I imagined the bigger boats will tend to stay off shore further - not that they can't get fairly close in, in about a foot or two of water?
 
Doug

Rob Denney <proa@...> wrote:
G'day,
 
I used a bridle from the bows and adjusted it so the join was near enough the middle of the boat.  Worked pretty well, but the boat still blew around in the wind a lot more than the monos so I dropped a bucket in the water and tied it to the aft beam.  Slowed it down a bit more.  Two anchors will not help much as the boat swings before the warps get tight and take the load.  You could try one from each end and keep them fairly tight but a big scope is required.
 
regards,

Rob 
----- Original Message -----
Sent: Monday, October 30, 2006 7:25 PM
Subject: RE: [harryproa] site update

Hi,
 
Just meant swinging around on the water, like anchored in the sea breeze comes in 20knots.
 
I was wondering about general ideas about swinging around coming from experienced multihullers out there. Like when you anchor a bigger boat out further where the wind is. What about two anchors 30 degrees apart?
 
Mast is same as boat - kiri strip and glass.
I've tapered the tops to half dimensions. There is a round pole up a metre and a half into the mast that slots in the hull. I hope it is all not going to break.
Obviously it is heavy but is cheaper.
 
Doug
 
 

Myriam & Youri <wangka@...> wrote:
Dear Doug,
 
 
Dear Wangkas,
 
Nice pictures and all, but where is a finished sailing boat?
            We know it takes a long time, but sometimes we have other worries on our minds … like carbon spars for classical yachts where we have to sort out two boats, masts, booms, sprits, poles etc,  we have to make molds and plugs for rudders, keels and bulbs, … for the carbon parts we are achieving and testing  a construction method VAPM (vacuum assisted pressure molding that gives us autoclave quality laminates (not only on the voids ratio but also on the compression side) in our pressure molds( compression +-5 Bars) which can produce one piece parts, which is not possible by standard autoclave procedures. We are also currently testing a method for direct CNC mold cutting for parts construction …
Also, what do you hope to acheive with around beam?
 They are not only rounded in length but also elliptical in section and will be constructed VAPM… less windage, better stress distribution, less wave interference …
Thanks again for your mast section, it is coming together.
            We are glad, how are you going to construct it ?
The boat really swings around at the moment without masts up and I wonder if it can be helped? More a question for the cruising boaters - do you plan doing cruising Elementarries?
            What do you mean with swinging around ? I suspect we will but that depends on the interest shown … for the moment we have some asks for quotes from France, Switzerland and Germany
 
 
Best regards,
 
 
Myriam & Youri
Wangka bvba
Belgium
 
e-mail. info@...
 
 
 
 
yaendenboom <wangka@...> wrote:
Dear people,

Our site has been updated.
We kindly invite you to have a look at:
   
www.wangkaboats.eu

Suggestions and criticism is welcome at:
   
info@...

Thank you very much,

Myriam & Youri
Wangka bvba
Belgium






 
 Send instant messages to your online friends http://uk.messenger.yahoo.com __._,_.___ __,_._,___

Send instant messages to your online friends http://uk.messenger.yahoo.com

Internal Virus Database is out-of-date.
Checked by AVG Free Edition.
Version: 7.1.385 / Virus Database: 268.11.5/426 - Release Date: 8/23/2006

Send instant messages to your online friends http://uk.messenger.yahoo.com


#2075 From: "Rob Denney" <proa@...>
Date: Thu Nov 2, 2006 2:08 am
Subject:: Re: video of visionary
proaharry
Offline Offline
Send Email Send Email
 
G'day,
 
Not as whippy as it looks, but could be stiffer, I agree.  The sail also needs a bit of work.  With a bit more cunningham, the sail would have pre bent the mast which would have stiffened it some.
 
The bow is not very high, so always looks pressed.   Need to compare it to a tri lee hull rather than a cat.   This boat ended up a bit heavier than the design which doesn't help either.   
 
Keep the comments coming.  Hopefully the video will be up on the web page again soon.
 
regards,
 
Rob
----- Original Message -----
From: ntsrfer
Sent: Wednesday, November 01, 2006 11:35 PM
Subject: [harryproa] video of visionary

Hello ,I was watching the video of the visionary sail, sweet looking
boat. But I have a few questions? The mast looks very whippy or flexing
alot with the sail ? Also the bow seemed to be almost over powered? or
riding very low in the water for the sea state and wind strength? Just
curious.

Todd



Internal Virus Database is out-of-date.
Checked by AVG Free Edition.
Version: 7.1.385 / Virus Database: 268.11.5/426 - Release Date: 8/23/2006

#2074 From: "ntsrfer" <ktsrfer@...>
Date: Wed Nov 1, 2006 3:35 pm
Subject:: video of visionary
ntsrfer
Offline Offline
Send Email Send Email
 
Hello ,I was watching the video of the visionary sail, sweet looking
boat. But I have a few questions? The mast looks very whippy or flexing
alot with the sail ? Also the bow seemed to be almost over powered? or
riding very low in the water for the sea state and wind strength? Just
curious.

Todd

#2073 From: "Rob Denney" <proa@...>
Date: Wed Nov 1, 2006 1:18 pm
Subject:: Re: Re: masts
proaharry
Offline Offline
Send Email Send Email
 
G'day,
 
You are right (and I am wrong) about 2 masts vs one.  The stiffness and the strength are different, and it is the strength which needs to be enough to tip the boat over on either mast of a schooner.  I will redo some of my calculations for the bigger boats.
 
Not so sure about the load attachments to test the mast, but no doubt if there are 5 attachments to the top half and it tips the boat over, the mast will not break in normal use.    
 
Re carbon tow at $30/kg.  The actual mast is made up of about 60% carbon and 40% resin.  The resin costs about $13 per kg so the actual mast cost is considerably less.  There is also a lot less wastage than with a wooden mast, which also needs glassing for protection, but this adds nothing to the stiffness.
 
regards,
 
Rob
----- Original Message -----
From: Robert
Sent: Wednesday, November 01, 2006 11:41 AM
Subject: [harryproa] Re: masts

-I would have thought that with the safety factor needed for gusts
and wave actions it wouldn't need quite that level of load spreading.
The mast has to be able to handle gusts while in a wave trough at the
same time as being jerked around by chop. I would have thought that
just a spread load for the top half would be enough., especially as
that is where the moments are. By the way, working on the figures for
loadings on masts makes me more impressed by the Visionarry mast.

My calculations though, don't come out as two una rigs weighing that
much more than a single rig of the same area when the extra stiffness
required for  working sail area of the taller rig are considered. Add
30% to the top of the mast with the same taper and there is nothing
left to attach a halliard to.  The short masts need to have enough
strength each to be able to lift the ww hull and therefore the bottom
2m need to be about the same, but only need to have enough stiffness
to carry half that load of working sail. I am not sure how much extra
weight is needed to give that stiffness for the taller mast or
whether it is a natural consequence of the materials stiffness to
strength ratio. If the latter I can see the extra 30-40% weight of
the two mast set up. I see the main advantage of a single rig is
catching cleaner air in light conditons, rather than weight.
regards,
robert
-- In harryproa@..., "Rob Denney" <proa@i...> wrote:
>
> G'day,
>
> Not that easy as the pulling load has to be evenly distributed
along the mast.  Needs a lot of pulleys so that the single load can
be dissipated to minimum 10 points along the mast. 
>
> regards,
>
> Rob----- Original Message -----
>   From: Robert
>   To: harryproa@...
>   Sent: Tuesday, October 31, 2006 4:38 PM
>   Subject: [harryproa] Re: masts
>
>
>   Easy enough to check if the masts are strong enough. Load them up
by
>   trying to lift the ww hull with a 100kg weight sitting on it.
>   I was looking at the characteristics of quality bamboo section
and it
>   looks considerable better than glass weight for weight with 4GPa
>   youngs modulus and a breaking strain of 30kg/mm 2. It may be
worth
>   considering for cheap masts. I am considering it myself for
skinning
>   cores in areas where exra stiffness is wanted without the expense
of
>   carbon. Hope carbon becomes more easily available and cheaper as
it
>   is by far the best material.
>   Robert
>   -- In harryproa@..., "Robert" <cateran1949@y...>
wrote:
>   >
>   > --- In harryproa@..., Doug Haines <doha720@y...>
>   wrote:
>   > >
>   > > Hi,
>   > >   
>   > >   Just meant swinging around on the water, like anchored in
the
>   sea
>   > breeze comes in 20knots.
>   > >   
>   > >   I was wondering about general ideas about swinging around
>   coming
>   > from experienced multihullers out there. Like when you anchor a
>   > bigger boat out further where the wind is. What about two
anchors
>   30
>   > degrees apart?
>   > >   
>   > >   Mast is same as boat - kiri strip and glass.
>   > >   I've tapered the tops to half dimensions. There is a round
pole
>   > up a metre and a half into the mast that slots in the hull. I
hope
>   it
>   > is all not going to break.
>   > >   Obviously it is heavy but is cheaper.
>   > >   
>   > >   Doug
>   > >   
>   > >   
>   > >  
>   > > Myriam & Youri <wangka@s...> wrote:
>   > >        
>   > >
>   > >     v\:* {behavior:url(#default#VML);}  o\:* {behavior:url
>   > (#default#VML);}  w\:* {behavior:url(#default#VML);}  .shape
>   > {behavior:url(#default#VML);}        st1\:*{behavior:url
>   > (#default#ieooui) }                Dear Doug,
>   > >   
>   > >   
>   > >     Dear Wangkas,
>   > >
>   > >     
>   > >
>   > >     Nice pictures and all, but where is a finished sailing
boat?
>   > >               We know it takes a long time, but sometimes we
have
>   > other worries on our minds . like carbon spars for classical
yachts
>   > where we have to sort out two boats, masts, booms, sprits,
poles
>   > etc,  we have to make molds and plugs for rudders, keels and
bulbs,
>   .
>   > for the carbon parts we are achieving and testing  a
construction
>   > method VAPM (vacuum assisted pressure molding that gives us
>   autoclave
>   > quality laminates (not only on the voids ratio but also on the
>   > compression side) in our pressure molds( compression +-5 Bars)
>   which
>   > can produce one piece parts, which is not possible by standard
>   > autoclave procedures. We are also currently testing a method
for
>   > direct CNC mold cutting for parts construction .
>   > >
>   > >     Also, what do you hope to acheive with around beam?
>   > >
>   > >      They are not only rounded in length but also elliptical
in
>   > section and will be constructed VAPM. less windage, better
stress
>   > distribution, less wave interference .
>   > >
>   > >     Thanks again for your mast section, it is coming
together.
>   > >               We are glad, how are you going to construct
it ? .
>   > >
>   > >     The boat really swings around at the moment without masts
up
>   > and I wonder if it can be helped? More a question for the
cruising
>   > boaters - do you plan doing cruising Elementarries?
>   > >               What do you mean with swinging around ? I
suspect
>   we
>   > will but that depends on the interest shown . for the moment we
>   have
>   > some asks for quotes from France, Switzerland and Germany .
>   > >   
>   > >   
>   > >   Best regards,
>   > >   
>   > >   
>   > >   Myriam & Youri
>   > >   Wangka bvba
>   > >   Belgium
>   > >   
>   > >   e-mail. info@w...
>   > >   web. www.wangkaboats.eu
>   > >   
>   > >   
>   > >   
>   > >
>   > >     
>   > >
>   > >     yaendenboom <wangka@s...> wrote:
>   > >
>   > >     Dear people,
>   > >
>   > > Our site has been updated.
>   > > We kindly invite you to have a look at:
>   > >     www.wangkaboats.eu
>   > >
>   > > Suggestions and criticism is welcome at:
>   > >     info@w...
>   > >
>   > > Thank you very much,
>   > >
>   > > Myriam & Youri
>   > > Wangka bvba
>   > > Belgium
>   > >
>   > >
>   > >
>   > >
>   > >
>   > >
>   > >
>   > >   
>   > >    Send instant messages to your online friends
>   > http://uk.messenger.yahoo.com 
>   > >
>   > > 
>   > >
>   > >  Send instant messages to your online friends
>   > http://uk.messenger.yahoo.com
>   > >
>   >
>
>
>
>   
>
>
> --------------------------------------------------------------------
----------
>
>
>   Internal Virus Database is out-of-date.
>   Checked by AVG Free Edition.
>   Version: 7.1.385 / Virus Database: 268.11.5/426 - Release Date:
8/23/2006
>




Internal Virus Database is out-of-date.
Checked by AVG Free Edition.
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