Hi,

On consideration I think you are right about not designing masts to
break.  It would take a lot of luck to work right - and luck is
usually in short supply in problem situations.

The idea of canting the masts to leeward is an interesting one.  If it
doesn't cause any problems with the mast swinging to leeward because
of the tilt it might be just the solution.

With regard to the weight I have clearly been confused the last few
days.  I am now back to considering my first calculation (which
implied a 29% reduction in weight for a schooner) to be more correct.
  The reason is that for the angle of deflection to be the same, the
ratio L^2/R^2 must be constant.  Which implies that if L is reduced by
  2^.5 then R must be also.

I am not quite sure what to make of the smaller sail area, but I think
it is clear that in any given weather there will be less force on each
mast for the schooner than for the single mast of the sloop.

I look forward to seing the results of your calculations.  I know FEA
costs money, but would it be possible to include an analysis of
exactly the same sail shape to get comparability?  I am not sure how
comparable a jibless schooner is to a balestron sloop from a weight
point of view.  My first thought is that it wouldn't make much
difference, but clearly my first thoughts are not very reliable in
these matters.

Best regards
Herb

--- In harryproa@..., "Rob Denney" <proa@...> wrote:
>
> G'day,
>
> You are right, the angle is more relevant than the amount.   Same
weight is closer to the truth, but still low, I think.  We will be
doing some numbers on a schooner rigged 22m Visionarry which we are
starting early next year.  I will let you know the results.
>
> Designing a mast to break before the boat capsizes is fraught.  It
implies no safety factors and some hard decisions about waves and
payloads.  Then you are sailing along with full sail up, a big gust
hits and you fly a hull.  Ease one sail and the other mast breaks.  I
would prefer to cant both masts to leeward 10 degrees, keep the weight
low in the windward hull and have a chance of self righting from 80
degrees, or more realistically, not be able to capsize this far.
>
>
> regards,
>
> Rob
>
>
>   Oops.
>
>   There is an error in my calculation.
>
>   The weight of each mast is not 1/((2^.5) * (2^.5)) as shown below. It
>   should be 1/((2^.25) * (2^.25)). This is because the luff is being
>   reduced by 2^.5, which means that the reduction in weight is square
>   root (2^.5) = 2^.25.
>
>   So with the schooner sail the weight of the luff portion of the
>   mast is now 1 / ((2^.25) * (2^.25)) = 1/2^.5 = .707. And for two
>   masts it would be 2*.707 = 1.415.
>
>   However the force on each mast is still 1/2 of the force on a unarig,
>   so we can still reduce (I think) the diameter of each mast by 1/2^.5.
>   This gives the total weight as 2/(2^.5)(2^.5) = 1.
>
>   Hopefully this is a bit closer to the truth.
>
>   Also, I was looking at the same angle of deflection - not the distance
>   of deflection, on the assumption that what was relevant was the angle
>   at the top of the mast. The link quoted gives that the angle is
>   proportional to the square of length and radius, whereas distance of
>   deflection is proportional to the cube. Should we be concerned here
>   with angle or distance of deflection?
>
>   One other point, on a cruising boat after a drama with 1 sail up and
>   one down, do we really want to have 1 mast pointing up or 2 masts
>   pointing down? If the former, perhaps the breaking strenght of one
>   mast should be less than the weight of the boat.
>
>   Best regards
>   Herb
>
>   --- In harryproa@..., "Rob Denney" <proa@> wrote:
>   >
>   > G'day,
>   >
>   >
>   >
>   >
>   > Rob I don't mind the schooner rig, in fact on a big boat where a
>   mainsheet winch is required, and if the fore boom of an Easy rig is
>   too high to easily reach, they have a lot going for them. Horses for
>   courses.
>   >
>   > Herb The angle of deflection of a circular thin wall beam is
>   proportional
>   > to the square of the length
>   > ( http://en.wikipedia.org/wiki/Deflection )
>   > and the square of the radius
>   > ( http://en.wikipedia.org/wiki/List_of_moments_of_inertia ).
>   >
>   > R
>   >
>   > The formula for cantilever deflection is
>   >
>   > (Load*length cubed)/8*E*I Therefore it is a cube function of
>   length, not a square. Halve the length, one eight the deflection.
>   >
>   > E is the material properties, I is the 2nd moment of area about
>   the neutral axis. I= pi*radius cubed *wall thickness. The radius is
>   also a cube function, so half the radius, 8 times the deflection.
>   >
>   >
>   > H
>   >
>   > However, each mast now has only 1/2 as much sail area, so the
force on
>   > each mast is 1/2 of what it would be for the single mast.
>   >
>   >
>   >
>   > R
>   >
>   > Yes and no. Each mast has to be strong enough to capsize the
>   boat, as it is possible that only one sail would be fully powered up
>   in a capsize scenario. This does not make each mast as heavy as a
>   single one as to be stiff enough they are already stronger than
>   required. However, depending on bury and other variables, it does
>   make each mast much more than half the weight of a single one. On a
>   harry, the bury will be very similar, although although a higher
>   percentage of the overall length, which reduces the sheer loads
>   somewhat.
>   >
>   >
>   > H
>   >
>   > So I am confused. Is a schooner rig really about 2/3 the weight and
>   > cost of a unarig (ignoring sails), or have I misunderstood
something?
>   >
>   > R
>   >
>   > I would say 3/2 is closer to reality for the weight and cost.
>   >
>   > regards,
>   >
>   > Rob
>   >
>   >
>   >
>   > Best regards
>   > Herb
>   >
>   >
>   >
>   >
>   >
>   >
>   >
>   ----------------------------------------------------------
>   >
>   >
>   > Internal Virus Database is out-of-date.
>   > Checked by AVG Free Edition.
>   > Version: 7.1.394 / Virus Database: 268.14.6/536 - Release Date:
>   11/16/2006
>   >
>
>
>
>
>
>
>
------------------------------------------------------------------------------
>
>
>   Internal Virus Database is out-of-date.
>   Checked by AVG Free Edition.
>   Version: 7.1.394 / Virus Database: 268.14.6/536 - Release Date:
11/16/2006
>

The boat is always going so fast that it is closehauled (;~)
Robert
--- In harryproa@..., "Jim Baltaxe" <jim.baltaxe@...>
wrote:
>
> Huh?
>
> I would imagine that the precise location of the masthead would be
> irrelevant in this respect since the boom will extend much further
to
> leeward, no matter what the angle of the mast.
>
> Which one of us has missed something important here?
>
> Enjoy
>
> Jim Baltaxe
> ITS Desktop Support
> Victoria University of Wellington
> NEW ZEALAND
> (04) 463 5018 or 027 563 5018
>
> I suffer from mental incontinence.
>
> Klein bottle for rent.  Inquire within.
> "If we knew what we were doing, it wouldn't be called research,
would
> it?" -- Albert Einstein
>
>
>
>
> ________________________________
>
>  From: harryproa@...
> [mailto:harryproa@...] On Behalf Of audeojude
>  Sent: Friday, 1 December 2006 1:31 a.m.
>  To: harryproa@...
>  Subject: [harryproa] Re: Schooner v. Unarig
>
>
>
>  I would think that canting the masts to leward would be
fraught
> with
>  problems. I can just see the boat hitting bridge pilings, and
> other
>  sailboats as it goes by. How far out to the side of the boat
> would the
>  top of your mast end up being? You now have effectively
> increased the
>  beam of the boat at the masthead by some ammount.
>
>  --- In harryproa@...
> <mailto:harryproa%40yahoogroups.com.au> , "Rob Denney" <proa@>
wrote:
>  >
>  > G'day,
>  >
>  > You are right, the angle is more relevant than the amount.
> Same
>  weight is closer to the truth, but still low, I think. We will
> be
>  doing some numbers on a schooner rigged 22m Visionarry which
we
> are
>  starting early next year. I will let you know the results.
>  >
>  > Designing a mast to break before the boat capsizes is
fraught.
> It
>  implies no safety factors and some hard decisions about waves
> and
>  payloads. Then you are sailing along with full sail up, a big
> gust
>  hits and you fly a hull. Ease one sail and the other mast
> breaks. I
>  would prefer to cant both masts to leeward 10 degrees, keep
the
> weight
>  low in the windward hull and have a chance of self righting
from
> 80
>  degrees, or more realistically, not be able to capsize this
far.
>
>  >
>  >
>  > regards,
>  >
>  > Rob
>  >
>  >
>  > Oops.
>  >
>  > There is an error in my calculation.
>  >
>  > The weight of each mast is not 1/((2^.5) * (2^.5)) as shown
> below. It
>  > should be 1/((2^.25) * (2^.25)). This is because the luff is
> being
>  > reduced by 2^.5, which means that the reduction in weight is
> square
>  > root (2^.5) = 2^.25.
>  >
>  > So with the schooner sail the weight of the luff portion of
> the
>  > mast is now 1 / ((2^.25) * (2^.25)) = 1/2^.5 = .707. And for
> two
>  > masts it would be 2*.707 = 1.415.
>  >
>  > However the force on each mast is still 1/2 of the force on
a
> unarig,
>  > so we can still reduce (I think) the diameter of each mast
by
> 1/2^.5.
>  > This gives the total weight as 2/(2^.5)(2^.5) = 1.
>  >
>  > Hopefully this is a bit closer to the truth.
>  >
>  > Also, I was looking at the same angle of deflection - not
the
> distance
>  > of deflection, on the assumption that what was relevant was
> the angle
>  > at the top of the mast. The link quoted gives that the angle
> is
>  > proportional to the square of length and radius, whereas
> distance of
>  > deflection is proportional to the cube. Should we be
concerned
> here
>  > with angle or distance of deflection?
>  >
>  > One other point, on a cruising boat after a drama with 1
sail
> up and
>  > one down, do we really want to have 1 mast pointing up or 2
> masts
>  > pointing down? If the former, perhaps the breaking strenght
of
> one
>  > mast should be less than the weight of the boat.
>  >
>  > Best regards
>  > Herb
>  >
>  > --- In harryproa@...
> <mailto:harryproa%40yahoogroups.com.au> , "Rob Denney" <proa@>
wrote:
>  > >
>  > > G'day,
>  > >
>  > >
>  > >
>  > >
>  > > Rob I don't mind the schooner rig, in fact on a big boat
> where a
>  > mainsheet winch is required, and if the fore boom of an Easy
> rig is
>  > too high to easily reach, they have a lot going for them.
> Horses for
>  > courses.
>  > >
>  > > Herb The angle of deflection of a circular thin wall beam
is
>  > proportional
>  > > to the square of the length
>  > > ( http://en.wikipedia.org/wiki/Deflection
> <http://en.wikipedia.org/wiki/Deflection>  )
>  > > and the square of the radius
>  > > ( http://en.wikipedia.org/wiki/List_of_moments_of_inertia
> <http://en.wikipedia.org/wiki/List_of_moments_of_inertia>  ).
>  > >
>  > > R
>  > >
>  > > The formula for cantilever deflection is
>  > >
>  > > (Load*length cubed)/8*E*I Therefore it is a cube function
of
>  > length, not a square. Halve the length, one eight the
> deflection.
>  > >
>  > > E is the material properties, I is the 2nd moment of area
> about
>  > the neutral axis. I= pi*radius cubed *wall thickness. The
> radius is
>  > also a cube function, so half the radius, 8 times the
> deflection.
>  > >
>  > >
>  > > H
>  > >
>  > > However, each mast now has only 1/2 as much sail area, so
> the
>  force on
>  > > each mast is 1/2 of what it would be for the single mast.
>  > >
>  > >
>  > >
>  > > R
>  > >
>  > > Yes and no. Each mast has to be strong enough to capsize
the
>  > boat, as it is possible that only one sail would be fully
> powered up
>  > in a capsize scenario. This does not make each mast as heavy
> as a
>  > single one as to be stiff enough they are already stronger
> than
>  > required. However, depending on bury and other variables, it
> does
>  > make each mast much more than half the weight of a single
one.
> On a
>  > harry, the bury will be very similar, although although a
> higher
>  > percentage of the overall length, which reduces the sheer
> loads
>  > somewhat.
>  > >
>  > >
>  > > H
>  > >
>  > > So I am confused. Is a schooner rig really about 2/3 the
> weight and
>  > > cost of a unarig (ignoring sails), or have I misunderstood
>  something?
>  > >
>  > > R
>  > >
>  > > I would say 3/2 is closer to reality for the weight and
> cost.
>  > >
>  > > regards,
>  > >
>  > > Rob
>  > >
>  > >
>  > >
>  > > Best regards
>  > > Herb
>  > >
>  > >
>  > >
>  > >
>  > >
>  > >
>  > >
>  > ----------------------------------------------------------
>  > >
>  > >
>  > > Internal Virus Database is out-of-date.
>  > > Checked by AVG Free Edition.
>  > > Version: 7.1.394 / Virus Database: 268.14.6/536 - Release
> Date:
>  > 11/16/2006
>  > >
>  >
>  >
>  >
>  >
>  >
>  >
>  >
>  ----------------------------------------------------------
>  >
>  >
>  > Internal Virus Database is out-of-date.
>  > Checked by AVG Free Edition.
>  > Version: 7.1.394 / Virus Database: 268.14.6/536 - Release
> Date:
>  11/16/2006
>  >
>

Jim Baltaxe
ITS Desktop Support
Victoria University of Wellington
NEW ZEALAND
(04) 463 5018 or 027 563 5018 

I suffer from mental incontinence.

Klein bottle for rent.  Inquire within.
"If we knew what we were doing, it wouldn't be called research, would it?" -- Albert Einstein

---

From: harryproa@... [mailto:harryproa@...] On Behalf Of audeojude
Sent: Friday, 1 December 2006 1:31 a.m.
To: harryproa@...
Subject: [harryproa] Re: Schooner v. Unarig

I would think that canting the masts to leward would be fraught with
problems. I can just see the boat hitting bridge pilings, and other
sailboats as it goes by. How far out to the side of the boat would the
top of your mast end up being? You now have effectively increased the
beam of the boat at the masthead by some ammount.

--- In harryproa@yahoogroups.com.au, "Rob Denney" <proa@...> wrote:
>
> G'day,
>
> You are right, the angle is more relevant than the amount. Same
weight is closer to the truth, but still low, I think. We will be
doing some numbers on a schooner rigged 22m Visionarry which we are
starting early next year. I will let you know the results.
>
> Designing a mast to break before the boat capsizes is fraught. It
implies no safety factors and some hard decisions about waves and
payloads. Then you are sailing along with full sail up, a big gust
hits and you fly a hull. Ease one sail and the other mast breaks. I
would prefer to cant both masts to leeward 10 degrees, keep the weight
low in the windward hull and have a chance of self righting from 80
degrees, or more realistically, not be able to capsize this far.
>
>
> regards,
>
> Rob
>
>
> Oops.
>
> There is an error in my calculation.
>
> The weight of each mast is not 1/((2^.5) * (2^.5)) as shown below. It
> should be 1/((2^.25) * (2^.25)). This is because the luff is being
> reduced by 2^.5, which means that the reduction in weight is square
> root (2^.5) = 2^.25.
>
> So with the schooner sail the weight of the luff portion of the
> mast is now 1 / ((2^.25) * (2^.25)) = 1/2^.5 = .707. And for two
> masts it would be 2*.707 = 1.415.
>
> However the force on each mast is still 1/2 of the force on a unarig,
> so we can still reduce (I think) the diameter of each mast by 1/2^.5.
> This gives the total weight as 2/(2^.5)(2^.5) = 1.
>
> Hopefully this is a bit closer to the truth.
>
> Also, I was looking at the same angle of deflection - not the distance
> of deflection, on the assumption that what was relevant was the angle
> at the top of the mast. The link quoted gives that the angle is
> proportional to the square of length and radius, whereas distance of
> deflection is proportional to the cube. Should we be concerned here
> with angle or distance of deflection?
>
> One other point, on a cruising boat after a drama with 1 sail up and
> one down, do we really want to have 1 mast pointing up or 2 masts
> pointing down? If the former, perhaps the breaking strenght of one
> mast should be less than the weight of the boat.
>
> Best regards
> Herb
>
> --- In harryproa@yahoogroups.com.au, "Rob Denney" <proa@> wrote:
> >
> > G'day,
> >
> >
> >
> >
> > Rob I don't mind the schooner rig, in fact on a big boat where a
> mainsheet winch is required, and if the fore boom of an Easy rig is
> too high to easily reach, they have a lot going for them. Horses for
> courses.
> >
> > Herb The angle of deflection of a circular thin wall beam is
> proportional
> > to the square of the length
> > ( http://en.wikipedia.org/wiki/Deflection )
> > and the square of the radius
> > ( http://en.wikipedia.org/wiki/List_of_moments_of_inertia ).
> >
> > R
> >
> > The formula for cantilever deflection is
> >
> > (Load*length cubed)/8*E*I Therefore it is a cube function of
> length, not a square. Halve the length, one eight the deflection.
> >
> > E is the material properties, I is the 2nd moment of area about
> the neutral axis. I= pi*radius cubed *wall thickness. The radius is
> also a cube function, so half the radius, 8 times the deflection.
> >
> >
> > H
> >
> > However, each mast now has only 1/2 as much sail area, so the
force on
> > each mast is 1/2 of what it would be for the single mast.
> >
> >
> >
> > R
> >
> > Yes and no. Each mast has to be strong enough to capsize the
> boat, as it is possible that only one sail would be fully powered up
> in a capsize scenario. This does not make each mast as heavy as a
> single one as to be stiff enough they are already stronger than
> required. However, depending on bury and other variables, it does
> make each mast much more than half the weight of a single one. On a
> harry, the bury will be very similar, although although a higher
> percentage of the overall length, which reduces the sheer loads
> somewhat.
> >
> >
> > H
> >
> > So I am confused. Is a schooner rig really about 2/3 the weight and
> > cost of a unarig (ignoring sails), or have I misunderstood
something?
> >
> > R
> >
> > I would say 3/2 is closer to reality for the weight and cost.
> >
> > regards,
> >
> > Rob
> >
> >
> >
> > Best regards
> > Herb
> >
> >
> >
> >
> >
> >
> >
> ----------------------------------------------------------
> >
> >
> > Internal Virus Database is out-of-date.
> > Checked by AVG Free Edition.
> > Version: 7.1.394 / Virus Database: 268.14.6/536 - Release Date:
> 11/16/2006
> >
>
>
>
>
>
>
>
----------------------------------------------------------
>
>
> Internal Virus Database is out-of-date.
> Checked by AVG Free Edition.
> Version: 7.1.394 / Virus Database: 268.14.6/536 - Release Date:
11/16/2006
>

I would think that canting the masts to leward would be fraught with
problems. I can just see the boat hitting bridge pilings, and other
sailboats as it goes by. How far out to the side of the boat would the
top of your mast end up being? You now have effectively increased the
beam of the boat at the masthead by some ammount.

--- In harryproa@yahoogroups.com.au, "Rob Denney" <proa@...> wrote:
>
> G'day,
>
> You are right, the angle is more relevant than the amount. Same
weight is closer to the truth, but still low, I think. We will be
doing some numbers on a schooner rigged 22m Visionarry which we are
starting early next year. I will let you know the results.
>
> Designing a mast to break before the boat capsizes is fraught. It
implies no safety factors and some hard decisions about waves and
payloads. Then you are sailing along with full sail up, a big gust
hits and you fly a hull. Ease one sail and the other mast breaks. I
would prefer to cant both masts to leeward 10 degrees, keep the weight
low in the windward hull and have a chance of self righting from 80
degrees, or more realistically, not be able to capsize this far.
>
>
> regards,
>
> Rob
>
>
> Oops.
>
> There is an error in my calculation.
>
> The weight of each mast is not 1/((2^.5) * (2^.5)) as shown below. It
> should be 1/((2^.25) * (2^.25)). This is because the luff is being
> reduced by 2^.5, which means that the reduction in weight is square
> root (2^.5) = 2^.25.
>
> So with the schooner sail the weight of the luff portion of the
> mast is now 1 / ((2^.25) * (2^.25)) = 1/2^.5 = .707. And for two
> masts it would be 2*.707 = 1.415.
>
> However the force on each mast is still 1/2 of the force on a unarig,
> so we can still reduce (I think) the diameter of each mast by 1/2^.5.
> This gives the total weight as 2/(2^.5)(2^.5) = 1.
>
> Hopefully this is a bit closer to the truth.
>
> Also, I was looking at the same angle of deflection - not the distance
> of deflection, on the assumption that what was relevant was the angle
> at the top of the mast. The link quoted gives that the angle is
> proportional to the square of length and radius, whereas distance of
> deflection is proportional to the cube. Should we be concerned here
> with angle or distance of deflection?
>
> One other point, on a cruising boat after a drama with 1 sail up and
> one down, do we really want to have 1 mast pointing up or 2 masts
> pointing down? If the former, perhaps the breaking strenght of one
> mast should be less than the weight of the boat.
>
> Best regards
> Herb
>
> --- In harryproa@yahoogroups.com.au, "Rob Denney" <proa@> wrote:
> >
> > G'day,
> >
> >
> >
> >
> > Rob I don't mind the schooner rig, in fact on a big boat where a
> mainsheet winch is required, and if the fore boom of an Easy rig is
> too high to easily reach, they have a lot going for them. Horses for
> courses.
> >
> > Herb The angle of deflection of a circular thin wall beam is
> proportional
> > to the square of the length
> > ( http://en.wikipedia.org/wiki/Deflection )
> > and the square of the radius
> > ( http://en.wikipedia.org/wiki/List_of_moments_of_inertia ).
> >
> > R
> >
> > The formula for cantilever deflection is
> >
> > (Load*length cubed)/8*E*I Therefore it is a cube function of
> length, not a square. Halve the length, one eight the deflection.
> >
> > E is the material properties, I is the 2nd moment of area about
> the neutral axis. I= pi*radius cubed *wall thickness. The radius is
> also a cube function, so half the radius, 8 times the deflection.
> >
> >
> > H
> >
> > However, each mast now has only 1/2 as much sail area, so the
force on
> > each mast is 1/2 of what it would be for the single mast.
> >
> >
> >
> > R
> >
> > Yes and no. Each mast has to be strong enough to capsize the
> boat, as it is possible that only one sail would be fully powered up
> in a capsize scenario. This does not make each mast as heavy as a
> single one as to be stiff enough they are already stronger than
> required. However, depending on bury and other variables, it does
> make each mast much more than half the weight of a single one. On a
> harry, the bury will be very similar, although although a higher
> percentage of the overall length, which reduces the sheer loads
> somewhat.
> >
> >
> > H
> >
> > So I am confused. Is a schooner rig really about 2/3 the weight and
> > cost of a unarig (ignoring sails), or have I misunderstood
something?
> >
> > R
> >
> > I would say 3/2 is closer to reality for the weight and cost.
> >
> > regards,
> >
> > Rob
> >
> >
> >
> > Best regards
> > Herb
> >
> >
> >
> >
> >
> >
> >
> ----------------------------------------------------------
> >
> >
> > Internal Virus Database is out-of-date.
> > Checked by AVG Free Edition.
> > Version: 7.1.394 / Virus Database: 268.14.6/536 - Release Date:
> 11/16/2006
> >
>
>
>
>
>
>
>
----------------------------------------------------------
>
>
> Internal Virus Database is out-of-date.
> Checked by AVG Free Edition.
> Version: 7.1.394 / Virus Database: 268.14.6/536 - Release Date:
11/16/2006
>

On Thu, 2006-11-30 at 12:31 +0000, audeojude wrote:
> I would think that canting the masts to leward would be fraught with
> problems. I can just see the boat hitting bridge pilings, and other
> sailboats as it goes by. How far out to the side of the boat would the
> top of your mast end up being? You now have effectively increased the
> beam of the boat at the masthead by some ammount.

Well, that's another reason not to sail monohulls then :) They cant
their masts to leeward all the time and frequently by a lot more than 10
degrees!

Cheers, Dave

I would think that canting the masts to leward would be fraught with
problems. I can just see the boat hitting bridge pilings, and other
sailboats as it goes by. How far out to the side of the boat would the
top of your mast end up being? You now have effectively increased the
beam of the boat at the masthead by some ammount.

--- In harryproa@..., "Rob Denney" <proa@...> wrote:
>
> G'day,
>
> You are right, the angle is more relevant than the amount.   Same
weight is closer to the truth, but still low, I think.  We will be
doing some numbers on a schooner rigged 22m Visionarry which we are
starting early next year.  I will let you know the results.
>
> Designing a mast to break before the boat capsizes is fraught.  It
implies no safety factors and some hard decisions about waves and
payloads.  Then you are sailing along with full sail up, a big gust
hits and you fly a hull.  Ease one sail and the other mast breaks.  I
would prefer to cant both masts to leeward 10 degrees, keep the weight
low in the windward hull and have a chance of self righting from 80
degrees, or more realistically, not be able to capsize this far.
>
>
> regards,
>
> Rob
>
>
>   Oops.
>
>   There is an error in my calculation.
>
>   The weight of each mast is not 1/((2^.5) * (2^.5)) as shown below. It
>   should be 1/((2^.25) * (2^.25)). This is because the luff is being
>   reduced by 2^.5, which means that the reduction in weight is square
>   root (2^.5) = 2^.25.
>
>   So with the schooner sail the weight of the luff portion of the
>   mast is now 1 / ((2^.25) * (2^.25)) = 1/2^.5 = .707. And for two
>   masts it would be 2*.707 = 1.415.
>
>   However the force on each mast is still 1/2 of the force on a unarig,
>   so we can still reduce (I think) the diameter of each mast by 1/2^.5.
>   This gives the total weight as 2/(2^.5)(2^.5) = 1.
>
>   Hopefully this is a bit closer to the truth.
>
>   Also, I was looking at the same angle of deflection - not the distance
>   of deflection, on the assumption that what was relevant was the angle
>   at the top of the mast. The link quoted gives that the angle is
>   proportional to the square of length and radius, whereas distance of
>   deflection is proportional to the cube. Should we be concerned here
>   with angle or distance of deflection?
>
>   One other point, on a cruising boat after a drama with 1 sail up and
>   one down, do we really want to have 1 mast pointing up or 2 masts
>   pointing down? If the former, perhaps the breaking strenght of one
>   mast should be less than the weight of the boat.
>
>   Best regards
>   Herb
>
>   --- In harryproa@..., "Rob Denney" <proa@> wrote:
>   >
>   > G'day,
>   >
>   >
>   >
>   >
>   > Rob I don't mind the schooner rig, in fact on a big boat where a
>   mainsheet winch is required, and if the fore boom of an Easy rig is
>   too high to easily reach, they have a lot going for them. Horses for
>   courses.
>   >
>   > Herb The angle of deflection of a circular thin wall beam is
>   proportional
>   > to the square of the length
>   > ( http://en.wikipedia.org/wiki/Deflection )
>   > and the square of the radius
>   > ( http://en.wikipedia.org/wiki/List_of_moments_of_inertia ).
>   >
>   > R
>   >
>   > The formula for cantilever deflection is
>   >
>   > (Load*length cubed)/8*E*I Therefore it is a cube function of
>   length, not a square. Halve the length, one eight the deflection.
>   >
>   > E is the material properties, I is the 2nd moment of area about
>   the neutral axis. I= pi*radius cubed *wall thickness. The radius is
>   also a cube function, so half the radius, 8 times the deflection.
>   >
>   >
>   > H
>   >
>   > However, each mast now has only 1/2 as much sail area, so the
force on
>   > each mast is 1/2 of what it would be for the single mast.
>   >
>   >
>   >
>   > R
>   >
>   > Yes and no. Each mast has to be strong enough to capsize the
>   boat, as it is possible that only one sail would be fully powered up
>   in a capsize scenario. This does not make each mast as heavy as a
>   single one as to be stiff enough they are already stronger than
>   required. However, depending on bury and other variables, it does
>   make each mast much more than half the weight of a single one. On a
>   harry, the bury will be very similar, although although a higher
>   percentage of the overall length, which reduces the sheer loads
>   somewhat.
>   >
>   >
>   > H
>   >
>   > So I am confused. Is a schooner rig really about 2/3 the weight and
>   > cost of a unarig (ignoring sails), or have I misunderstood
something?
>   >
>   > R
>   >
>   > I would say 3/2 is closer to reality for the weight and cost.
>   >
>   > regards,
>   >
>   > Rob
>   >
>   >
>   >
>   > Best regards
>   > Herb
>   >
>   >
>   >
>   >
>   >
>   >
>   >
>   ----------------------------------------------------------
>   >
>   >
>   > Internal Virus Database is out-of-date.
>   > Checked by AVG Free Edition.
>   > Version: 7.1.394 / Virus Database: 268.14.6/536 - Release Date:
>   11/16/2006
>   >
>
>
>
>
>
>
>
------------------------------------------------------------------------------
>
>
>   Internal Virus Database is out-of-date.
>   Checked by AVG Free Edition.
>   Version: 7.1.394 / Virus Database: 268.14.6/536 - Release Date:
11/16/2006
>

I was pondering the effect of closing the gap between the sail and
the deck to improve efficiency and whether it is worth the extra
hassle. There is supposed to be quite a large improvement( according
theoretically to Tom speer recently on proa file and practically to
the bewoulf site and sailboard sailors) so I thought it was probably
worth the effort of setting up the deck of the lw hull and the rig to
accomodate this. Unfortunately this would make it harder to offset
the mast 10 degrees for the self righting. On scheme I considered was
to have a battened extension below the boom that was pulled over to
the hull by a string to the sheet, thus sealing the gap.I am assuming
the extra bouyancy of the wingmasts makes it easier to avoid going
right over, and therefore wouldn't need quite such a large offset
  Robert
PS
I figure the shorter masts of the schooner rigs reduces some of the
whipping that can occur from boat movement in waves. Makes up to some
extent for the single rigs extra height and clearer air. I was
wondering if the height of the schooner rig should be set as the
equivalent in capsizing moment to the single mast for given
conditions rather than equivalent area. This would make them a little
taller and heavier but with less loss of light wind performance ---
In harryproa@..., "Rob Denney" <proa@...> wrote:
>
> G'day,
>
> You are right, the angle is more relevant than the amount.   Same
weight is closer to the truth, but still low, I think.  We will be
doing some numbers on a schooner rigged 22m Visionarry which we are
starting early next year.  I will let you know the results.
>
> Designing a mast to break before the boat capsizes is fraught.  It
implies no safety factors and some hard decisions about waves and
payloads.  Then you are sailing along with full sail up, a big gust
hits and you fly a hull.  Ease one sail and the other mast breaks.  I
would prefer to cant both masts to leeward 10 degrees, keep the
weight low in the windward hull and have a chance of self righting
from 80 degrees, or more realistically, not be able to capsize this
far.
>
>
> regards,
>
> Rob
>
>
>   Oops.
>
>   There is an error in my calculation.
>
>   The weight of each mast is not 1/((2^.5) * (2^.5)) as shown
below. It
>   should be 1/((2^.25) * (2^.25)). This is because the luff is being
>   reduced by 2^.5, which means that the reduction in weight is
square
>   root (2^.5) = 2^.25.
>
>   So with the schooner sail the weight of the luff portion of the
>   mast is now 1 / ((2^.25) * (2^.25)) = 1/2^.5 = .707. And for two
>   masts it would be 2*.707 = 1.415.
>
>   However the force on each mast is still 1/2 of the force on a
unarig,
>   so we can still reduce (I think) the diameter of each mast by
1/2^.5.
>   This gives the total weight as 2/(2^.5)(2^.5) = 1.
>
>   Hopefully this is a bit closer to the truth.
>
>   Also, I was looking at the same angle of deflection - not the
distance
>   of deflection, on the assumption that what was relevant was the
angle
>   at the top of the mast. The link quoted gives that the angle is
>   proportional to the square of length and radius, whereas distance
of
>   deflection is proportional to the cube. Should we be concerned
here
>   with angle or distance of deflection?
>
>   One other point, on a cruising boat after a drama with 1 sail up
and
>   one down, do we really want to have 1 mast pointing up or 2 masts
>   pointing down? If the former, perhaps the breaking strenght of one
>   mast should be less than the weight of the boat.
>
>   Best regards
>   Herb
>
>   --- In harryproa@..., "Rob Denney" <proa@> wrote:
>   >
>   > G'day,
>   >
>   >
>   >
>   >
>   > Rob I don't mind the schooner rig, in fact on a big boat where a
>   mainsheet winch is required, and if the fore boom of an Easy rig
is
>   too high to easily reach, they have a lot going for them. Horses
for
>   courses.
>   >
>   > Herb The angle of deflection of a circular thin wall beam is
>   proportional
>   > to the square of the length
>   > ( http://en.wikipedia.org/wiki/Deflection )
>   > and the square of the radius
>   > ( http://en.wikipedia.org/wiki/List_of_moments_of_inertia ).
>   >
>   > R
>   >
>   > The formula for cantilever deflection is
>   >
>   > (Load*length cubed)/8*E*I Therefore it is a cube function of
>   length, not a square. Halve the length, one eight the deflection.
>   >
>   > E is the material properties, I is the 2nd moment of area about
>   the neutral axis. I= pi*radius cubed *wall thickness. The radius
is
>   also a cube function, so half the radius, 8 times the deflection.
>   >
>   >
>   > H
>   >
>   > However, each mast now has only 1/2 as much sail area, so the
force on
>   > each mast is 1/2 of what it would be for the single mast.
>   >
>   >
>   >
>   > R
>   >
>   > Yes and no. Each mast has to be strong enough to capsize the
>   boat, as it is possible that only one sail would be fully powered
up
>   in a capsize scenario. This does not make each mast as heavy as a
>   single one as to be stiff enough they are already stronger than
>   required. However, depending on bury and other variables, it does
>   make each mast much more than half the weight of a single one. On
a
>   harry, the bury will be very similar, although although a higher
>   percentage of the overall length, which reduces the sheer loads
>   somewhat.
>   >
>   >
>   > H
>   >
>   > So I am confused. Is a schooner rig really about 2/3 the weight
and
>   > cost of a unarig (ignoring sails), or have I misunderstood
something?
>   >
>   > R
>   >
>   > I would say 3/2 is closer to reality for the weight and cost.
>   >
>   > regards,
>   >
>   > Rob
>   >
>   >
>   >
>   > Best regards
>   > Herb
>   >
>   >
>   >
>   >
>   >
>   >
>   >
>   ----------------------------------------------------------
>   >
>   >
>   > Internal Virus Database is out-of-date.
>   > Checked by AVG Free Edition.
>   > Version: 7.1.394 / Virus Database: 268.14.6/536 - Release Date:
>   11/16/2006
>   >
>
>
>
>
>
>
> --------------------------------------------------------------------
----------
>
>
>   Internal Virus Database is out-of-date.
>   Checked by AVG Free Edition.
>   Version: 7.1.394 / Virus Database: 268.14.6/536 - Release Date:
11/16/2006
>

This is why I was wondering aboutthe idea of  leaning the mast over
without lifting it to deck level first. Maybe there is a method but
it escapes me,
  Robert--- In harryproa@..., Doug Haines <doha720@...>
wrote:
>
> I don't like messing with the basis of your strength, ie. the hull.
>
>   Doug
>
> Robert <cateran1949@...> wrote:
>           I actually meant for leaning the masts over. Lean a mast
over at 45
> degrees with the bottom still inside the hull and it will need
almost
> an extra 50% larger hole. Lay it almost flat and you need a large
slot
> Robert--- In harryproa@..., Doug Haines <doha720@>
> wrote:
> >
> > Robert,
> >
> > You mean for retro installing the centre mast tube in the hull?
> > See pics of Elementatty can see carbon black round where hole was
> cut (under single ruddder/mast of photos in yahoo discussion group.
> >
> > Doug
> >
> > Robert <cateran1949@> wrote:
> > Just wondering how big a hole is needed in the deck,
> > RObert--- In harryproa@..., Doug Haines <doha720@>
> > wrote:
> > >
> > > Hi,
> > >
> > > I went to Rob Denny's house in Swanbourne yesterday and looked
> > and talked. He does well without a proper shed, though the double
> > garage is pretty good.
> > > Elementarry stuff I liked were the newest version of the rudder
> > (single on a slide from one end to the other), that kicks up if
> hit,
> > this is good engineering, because you can't raise the rudder up,
> like
> > to see how it works on the water.
> > >
> > > I liked the wing mast made from a single peice of this
> > honeycombed stuff of plastic I thimk it is the polycore at $20 a
> sqm
> > (6mm thick size).
> > >
> > > Hinging for me is best by leaving the mast as usual with a bit
> > more space at the bottom and making a tabernacle if you can call
it
> > that up over the bottom stem. This should include a removable 4th
> > side and 3 permanent sides so you can let the mast swing down
when
> > you take the 4th side off. Seemed pactical enough with carbon and
> > squaring the stem to fit the tabernacle sides.
> > >
> > > Doug
> > >
> > > Robert <cateran1949@> wrote:
> > > Should be possible. Have to offset the masts slightly so
> > they don't
> > > interfere with each other as they lean towards the centre of
the
> lw
> > > hull.For going under bridges, you wouldn't have to remove the
> masts
> > > but simply leave them tilted,
> > > RObert --- In harryproa@..., Dave Howorth
> > > <Dave.Howorth@> wrote:
> > > >
> > > > On Fri, 2006-11-24 at 04:27 +0000, Robert wrote:
> > > > > -What I thought about earlier is to have a hinged sleeve.
> Lift
> > > the
> > > > > mast till it is out of the hull but still in the sleeve and
> > then
> > > you
> > > > > can lay it flat with control,
> > > > > Robert
> > > >
> > > > If it can be managed, perhaps it would be simpler to hinge
the
> > mast
> > > tube
> > > > itself. I.e. the mast is supported by a tube between deck and
> > keel,
> > > and
> > > > this tube has a hinge at deck level.
> > > >
> > > > When upright, the tube can be supported on three sides
> (windward,
> > > > leeward and a bow) by permanent structure bonded into the
hull.
> > The
> > > > fourth side can be supported by a wedge dropped into place
> after
> > the
> > > > mast is swung upright, with the wedge itself supported by
> further
> > > > permanent structure.
> > > >
> > > > Then there's no need to lift the mast vertically at all, and
no
> > > need to
> > > > align a 'sleeve' and a 'tube' when inserting the mast.
Dropping
> > the
> > > mast
> > > > goes as follows:
> > > > (1) Pull halyard out to bow on same side as wedge, and secure
> to
> > > hold
> > > > mast.
> > > > (2) Lift out wedge.
> > > > (3) Slacken halyard and rotate mast until it is level (or
> nearly
> > > so).
> > > > (4) Pull mast out of tube.
> > > >
> > > > Raising is the reverse.
> > > >
> > > > Cheers, Dave
> > > >
> > >
> > >
> > >
> > >
> > >
> > > Send instant messages to your online friends
> > http://uk.messenger.yahoo.com
> > >
> >
> >
> >
> >
> >
> >
> > ---------------------------------
> > The all-new Yahoo! Mail goes wherever you go - free your email
> address from your Internet provider.
> >
>
>
>
>
>
>  Send instant messages to your online friends
http://uk.messenger.yahoo.com
>

Oops.

There is an error in my calculation.

The weight of each mast is not 1/((2^.5) * (2^.5)) as shown below. It
should be 1/((2^.25) * (2^.25)). This is because the luff is being
reduced by 2^.5, which means that the reduction in weight is square
root (2^.5) = 2^.25.

So with the schooner sail the weight of the luff portion of the
mast is now 1 / ((2^.25) * (2^.25)) = 1/2^.5 = .707. And for two
masts it would be 2*.707 = 1.415.

However the force on each mast is still 1/2 of the force on a unarig,
so we can still reduce (I think) the diameter of each mast by 1/2^.5.
This gives the total weight as 2/(2^.5)(2^.5) = 1.

Hopefully this is a bit closer to the truth.

Also, I was looking at the same angle of deflection - not the distance
of deflection, on the assumption that what was relevant was the angle
at the top of the mast. The link quoted gives that the angle is
proportional to the square of length and radius, whereas distance of
deflection is proportional to the cube. Should we be concerned here
with angle or distance of deflection?

One other point, on a cruising boat after a drama with 1 sail up and
one down, do we really want to have 1 mast pointing up or 2 masts
pointing down? If the former, perhaps the breaking strenght of one
mast should be less than the weight of the boat.

Best regards
Herb

--- In harryproa@yahoogroups.com.au, "Rob Denney" <proa@...> wrote:
>
> G'day,
>
>
>
>
> Rob I don't mind the schooner rig, in fact on a big boat where a
mainsheet winch is required, and if the fore boom of an Easy rig is
too high to easily reach, they have a lot going for them. Horses for
courses.
>
> Herb The angle of deflection of a circular thin wall beam is
proportional
> to the square of the length
> ( http://en.wikipedia.org/wiki/Deflection )
> and the square of the radius
> ( http://en.wikipedia.org/wiki/List_of_moments_of_inertia ).
>
> R
>
> The formula for cantilever deflection is
>
> (Load*length cubed)/8*E*I Therefore it is a cube function of
length, not a square. Halve the length, one eight the deflection.
>
> E is the material properties, I is the 2nd moment of area about
the neutral axis. I= pi*radius cubed *wall thickness. The radius is
also a cube function, so half the radius, 8 times the deflection.
>
>
> H
>
> However, each mast now has only 1/2 as much sail area, so the force on
> each mast is 1/2 of what it would be for the single mast.
>
>
>
> R
>
> Yes and no. Each mast has to be strong enough to capsize the
boat, as it is possible that only one sail would be fully powered up
in a capsize scenario. This does not make each mast as heavy as a
single one as to be stiff enough they are already stronger than
required. However, depending on bury and other variables, it does
make each mast much more than half the weight of a single one. On a
harry, the bury will be very similar, although although a higher
percentage of the overall length, which reduces the sheer loads
somewhat.
>
>
> H
>
> So I am confused. Is a schooner rig really about 2/3 the weight and
> cost of a unarig (ignoring sails), or have I misunderstood something?
>
> R
>
> I would say 3/2 is closer to reality for the weight and cost.
>
> regards,
>
> Rob
>
>
>
> Best regards
> Herb
>
>
>
>
>
>
>
----------------------------------------------------------
>
>
> Internal Virus Database is out-of-date.
> Checked by AVG Free Edition.
> Version: 7.1.394 / Virus Database: 268.14.6/536 - Release Date:
11/16/2006
>

---

Internal Virus Database is out-of-date.
Checked by AVG Free Edition.
Version: 7.1.394 / Virus Database: 268.14.6/536 - Release Date: 11/16/2006

Oops.

There is an error in my calculation.

The weight of each mast is not 1/((2^.5) * (2^.5)) as shown below.  It
should be 1/((2^.25) * (2^.25)).  This is because the luff is being
reduced by 2^.5, which means that the reduction in weight is square
root (2^.5) = 2^.25.

So with the schooner sail the weight of the luff portion of the
  mast is now 1 / ((2^.25) * (2^.25)) = 1/2^.5 = .707.  And for two
masts it would be 2*.707 = 1.415.

However the force on each mast is still 1/2 of the force on a unarig,
so we can still reduce (I think) the diameter of each mast by 1/2^.5.
  This gives the total weight as 2/(2^.5)(2^.5) = 1.

Hopefully this is a bit closer to the truth.

Also, I was looking at the same angle of deflection - not the distance
of deflection, on the assumption that what was relevant was the angle
at the top of the mast.  The link quoted gives that the angle is
proportional to the square of length and radius, whereas distance of
deflection is proportional to the cube. Should we be concerned here
with angle or distance of deflection?

One other point, on a cruising boat after a drama with 1 sail up and
one down, do we really want to have 1 mast pointing up or 2 masts
pointing down?  If the former, perhaps the breaking strenght of one
mast should be less than the weight of the boat.

Best regards
Herb




--- In harryproa@..., "Rob Denney" <proa@...> wrote:
>
> G'day,
>
>
>
>
>   Rob I don't mind the schooner rig, in fact on a big boat where a
mainsheet winch is required, and if the fore boom of an Easy rig is
too high to easily reach, they have a lot going for them.  Horses for
courses.
>
>   Herb The angle of deflection of a circular thin wall beam is
proportional
>   to the square of the length
>   ( http://en.wikipedia.org/wiki/Deflection )
>   and the square of the radius
>   ( http://en.wikipedia.org/wiki/List_of_moments_of_inertia ).
>
>   R
>
>   The formula for cantilever deflection is
>
>   (Load*length cubed)/8*E*I  Therefore it is a cube function of
length, not a square.  Halve the length, one eight the deflection.
>
>   E is the material properties, I is the 2nd moment of area about
the neutral axis.  I= pi*radius cubed *wall thickness.  The radius is
also a cube function, so half the radius, 8 times the deflection.
>
>
>   H
>
>   However, each mast now has only 1/2 as much sail area, so the force on
>   each mast is 1/2 of what it would be for the single mast.
>
>
>
>   R
>
>   Yes and no.  Each mast has to be strong enough to capsize the
boat, as it is possible that only one sail would be fully powered up
in a capsize scenario.  This does not make each mast as heavy as a
single one as to be stiff enough they are already stronger than
required.  However, depending on bury and other variables, it does
make each mast much more than half the weight of a single one.  On a
harry, the bury will be very similar, although although a higher
percentage of the overall length, which reduces the sheer loads
somewhat.
>
>
>   H
>
>   So I am confused. Is a schooner rig really about 2/3 the weight and
>   cost of a unarig (ignoring sails), or have I misunderstood something?
>
>   R
>
>   I would say 3/2 is closer to reality for the weight and cost.
>
>   regards,
>
>   Rob
>
>
>
>   Best regards
>   Herb
>
>
>
>
>
>
>
------------------------------------------------------------------------------
>
>
>   Internal Virus Database is out-of-date.
>   Checked by AVG Free Edition.
>   Version: 7.1.394 / Virus Database: 268.14.6/536 - Release Date:
11/16/2006
>

 

Rob I don't mind the schooner rig, in fact on a big boat where a mainsheet winch is required, and if the fore boom of an Easy rig is too high to easily reach, they have a lot going for them.  Horses for courses.

Herb The angle of deflection of a circular thin wall beam is proportional
to the square of the length
( http://en.wikipedia.org/wiki/Deflection )
and the square of the radius
( http://en.wikipedia.org/wiki/List_of_moments_of_inertia ).

R

The formula for cantilever deflection is

(Load*length cubed)/8*E*I  Therefore it is a cube function of length, not a square.  Halve the length, one eight the deflection.

E is the material properties, I is the 2nd moment of area about the neutral axis.  I= pi*radius cubed *wall thickness.  The radius is also a cube function, so half the radius, 8 times the deflection.


H

However, each mast now has only 1/2 as much sail area, so the force on
each mast is 1/2 of what it would be for the single mast.

 

R

Yes and no.  Each mast has to be strong enough to capsize the boat, as it is possible that only one sail would be fully powered up in a capsize scenario.  This does not make each mast as heavy as a single one as to be stiff enough they are already stronger than required.  However, depending on bury and other variables, it does make each mast much more than half the weight of a single one.  On a harry, the bury will be very similar, although although a higher percentage of the overall length, which reduces the sheer loads somewhat. 

H

So I am confused. Is a schooner rig really about 2/3 the weight and
cost of a unarig (ignoring sails), or have I misunderstood something?

R

I would say 3/2 is closer to reality for the weight and cost.

regards,

Rob

 

Best regards
Herb

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----- Original Message -----

From: pkeck2

To: harryproa@...

Sent: Wednesday, November 29, 2006 1:44 AM

Subject: [harryproa] trailering elementarry

Rob,

When you trailer elementarry, does the trailer handle funny because the
load is unevenly distributed? Any comments on this?

Thanks,
Phil

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Hi All,

I have been reading Rob's comments that schooners are more hassle and
heavier than sloops, which seem entirely reasonable. But I wondered
how much? So after a bit of searching I found the following
surprising results, which also seem reasonable.

The angle of deflection of a circular thin wall beam is proportional
to the square of the length
( http://en.wikipedia.org/wiki/Deflection )
and the square of the radius
( http://en.wikipedia.org/wiki/List_of_moments_of_inertia ).

If we take a unarig and reduce it in area by 1/2, we will reduce the
length of the luff by 1/square root(2). But to obtain the same angle of
deflection for a given force, while maintaining the same wall
thickness and material, we must also reduce the radius of the mast by
1/square root(2). So with the schooner sail the weight of the luff
portion of the
mast is now 1 / (square root(2) * square root(2)) = 1/2. That seems
reasonable because there are now two masts instead of one.

However, each mast now has only 1/2 as much sail area, so the force on
each mast is 1/2 of what it would be for the single mast. The
surprising thing is that now each schooner mast is
1 / (square root(2) * square root(2) * square root(2)) = 1/(2 * square
root(2)).
So the total weight of both masts is
2/(2 * square root(2)) = 70.7%
of the single masted rig.

If we assume that the bury, boom and deck to boom distance also reduce
in proportion (which would certainly be true for boom and bury) then
the weight (and presumably material costs) of the total schooner rig
is 70.7% of the single masted rig.

Actually, it would be a bit less than that because the schooner is
shorter than the unarig, so the force on each mast of the schooner
would be less than 1/2 of the unarig. After some more searching I
found that the wind speed increases with the 7th root of height and
the force on the sail with the square of the wind speed. So the
weight of the schooner rig would now be (70.7%^(2/7))^.5 = 67.3%, but
that difference is so small it hardly seems worth bothering about.

So I am confused. Is a schooner rig really about 2/3 the weight and
cost of a unarig (ignoring sails), or have I misunderstood something?

Best regards
Herb

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

Rob,

When you trailer elementarry, does the trailer handle funny because the
load is unevenly distributed?  Any comments on this?

Thanks,
Phil

Hi All,

I have been reading Rob's comments that schooners are more hassle and
heavier than sloops, which seem entirely reasonable.  But I wondered
how much?  So after a bit of searching I found the following
surprising results, which also seem reasonable.

The angle of deflection of a circular thin wall beam is proportional
to the square of the length
( http://en.wikipedia.org/wiki/Deflection )
and the square of the radius
( http://en.wikipedia.org/wiki/List_of_moments_of_inertia ).

If we take a unarig and reduce it in area by 1/2, we will reduce the
length of the luff by 1/square root(2).  But to obtain the same angle of
deflection for a given force, while maintaining the same wall
thickness and material, we must also reduce the radius of the mast by
1/square root(2).  So with the schooner sail the weight of the luff
portion of the
mast is now 1 / (square root(2) * square root(2)) = 1/2.  That seems
reasonable because there are now two masts instead of one.

However, each mast now has only 1/2 as much sail area, so the force on
each mast is 1/2 of what it would be for the single mast.  The
surprising thing is that now each schooner mast is
1 / (square root(2) * square root(2) * square root(2)) = 1/(2 * square
root(2)).
So the total weight of both masts is
2/(2 * square root(2)) = 70.7%
of the single masted rig.

If we assume that the bury, boom and deck to boom distance also reduce
in proportion (which would certainly be true for boom and bury) then
the weight (and presumably material costs) of the total schooner rig
is 70.7% of the single masted rig.

Actually, it would be a bit less than that because the schooner is
shorter than the unarig, so the force on each mast of the schooner
would be less than 1/2 of the unarig.  After some more searching I
found that the wind speed increases with the 7th root of height and
the force on the sail with the square of the wind speed.  So the
weight of the schooner rig would now be (70.7%^(2/7))^.5 = 67.3%, but
that difference is so small it hardly seems worth bothering about.

So I am confused.  Is a schooner rig really about 2/3 the weight and
cost of a unarig (ignoring sails), or have I misunderstood something?

Best regards
Herb

I actually meant for leaning the masts over. Lean a mast over at 45
degrees with the bottom still inside the hull and it will need almost
an extra 50% larger hole. Lay it almost flat and you need a large slot
Robert--- In harryproa@yahoogroups.com.au, Doug Haines <doha720@...>
wrote:
>
> Robert,
>
> You mean for retro installing the centre mast tube in the hull?
> See pics of Elementatty can see carbon black round where hole was
cut (under single ruddder/mast of photos in yahoo discussion group.
>
> Doug
>
> Robert <cateran1949@...> wrote:
> Just wondering how big a hole is needed in the deck,
> RObert--- In harryproa@yahoogroups.com.au, Doug Haines <doha720@>
> wrote:
> >
> > Hi,
> >
> > I went to Rob Denny's house in Swanbourne yesterday and looked
> and talked. He does well without a proper shed, though the double
> garage is pretty good.
> > Elementarry stuff I liked were the newest version of the rudder
> (single on a slide from one end to the other), that kicks up if
hit,
> this is good engineering, because you can't raise the rudder up,
like
> to see how it works on the water.
> >
> > I liked the wing mast made from a single peice of this
> honeycombed stuff of plastic I thimk it is the polycore at $20 a
sqm
> (6mm thick size).
> >
> > Hinging for me is best by leaving the mast as usual with a bit
> more space at the bottom and making a tabernacle if you can call it
> that up over the bottom stem. This should include a removable 4th
> side and 3 permanent sides so you can let the mast swing down when
> you take the 4th side off. Seemed pactical enough with carbon and
> squaring the stem to fit the tabernacle sides.
> >
> > Doug
> >
> > Robert <cateran1949@> wrote:
> > Should be possible. Have to offset the masts slightly so
> they don't
> > interfere with each other as they lean towards the centre of the
lw
> > hull.For going under bridges, you wouldn't have to remove the
masts
> > but simply leave them tilted,
> > RObert --- In harryproa@yahoogroups.com.au, Dave Howorth
> > <Dave.Howorth@> wrote:
> > >
> > > On Fri, 2006-11-24 at 04:27 +0000, Robert wrote:
> > > > -What I thought about earlier is to have a hinged sleeve.
Lift
> > the
> > > > mast till it is out of the hull but still in the sleeve and
> then
> > you
> > > > can lay it flat with control,
> > > > Robert
> > >
> > > If it can be managed, perhaps it would be simpler to hinge the
> mast
> > tube
> > > itself. I.e. the mast is supported by a tube between deck and
> keel,
> > and
> > > this tube has a hinge at deck level.
> > >
> > > When upright, the tube can be supported on three sides
(windward,
> > > leeward and a bow) by permanent structure bonded into the hull.
> The
> > > fourth side can be supported by a wedge dropped into place
after
> the
> > > mast is swung upright, with the wedge itself supported by
further
> > > permanent structure.
> > >
> > > Then there's no need to lift the mast vertically at all, and no
> > need to
> > > align a 'sleeve' and a 'tube' when inserting the mast. Dropping
> the
> > mast
> > > goes as follows:
> > > (1) Pull halyard out to bow on same side as wedge, and secure
to
> > hold
> > > mast.
> > > (2) Lift out wedge.
> > > (3) Slacken halyard and rotate mast until it is level (or
nearly
> > so).
> > > (4) Pull mast out of tube.
> > >
> > > Raising is the reverse.
> > >
> > > Cheers, Dave
> > >
> >
> >
> >
> >
> >
> > Send instant messages to your online friends
> http://uk.messenger.yahoo.com
> >
>
>
>
>
>
>
> ---------------------------------
> The all-new Yahoo! Mail goes wherever you go - free your email
address from your Internet provider.
>

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

I actually meant for leaning the masts over. Lean a mast over at 45
degrees with the bottom still inside the hull and it will need almost
an extra 50% larger hole. Lay it almost flat and you need a large slot
Robert--- In harryproa@..., Doug Haines <doha720@...>
wrote:
>
> Robert,
>
>   You mean for retro installing the centre mast tube in the hull?
>   See pics of Elementatty can see carbon black round where hole was
cut (under single ruddder/mast  of photos in yahoo discussion group.
>
>   Doug
>
> Robert <cateran1949@...> wrote:
>           Just wondering how big a hole is needed in the deck,
> RObert--- In harryproa@..., Doug Haines <doha720@>
> wrote:
> >
> > Hi,
> >
> > I went to Rob Denny's house in Swanbourne yesterday and looked
> and talked. He does well without a proper shed, though the double
> garage is pretty good.
> > Elementarry stuff I liked were the newest version of the rudder
> (single on a slide from one end to the other), that kicks up if
hit,
> this is good engineering, because you can't raise the rudder up,
like
> to see how it works on the water.
> >
> > I liked the wing mast made from a single peice of this
> honeycombed stuff of plastic I thimk it is the polycore at $20 a
sqm
> (6mm thick size).
> >
> > Hinging for me is best by leaving the mast as usual with a bit
> more space at the bottom and making a tabernacle if you can call it
> that up over the bottom stem. This should include a removable 4th
> side and 3 permanent sides so you can let the mast swing down when
> you take the 4th side off. Seemed pactical enough with carbon and
> squaring the stem to fit the tabernacle sides.
> >
> > Doug
> >
> > Robert <cateran1949@> wrote:
> > Should be possible. Have to offset the masts slightly so
> they don't
> > interfere with each other as they lean towards the centre of the
lw
> > hull.For going under bridges, you wouldn't have to remove the
masts
> > but simply leave them tilted,
> > RObert --- In harryproa@..., Dave Howorth
> > <Dave.Howorth@> wrote:
> > >
> > > On Fri, 2006-11-24 at 04:27 +0000, Robert wrote:
> > > > -What I thought about earlier is to have a hinged sleeve.
Lift
> > the
> > > > mast till it is out of the hull but still in the sleeve and
> then
> > you
> > > > can lay it flat with control,
> > > > Robert
> > >
> > > If it can be managed, perhaps it would be simpler to hinge the
> mast
> > tube
> > > itself. I.e. the mast is supported by a tube between deck and
> keel,
> > and
> > > this tube has a hinge at deck level.
> > >
> > > When upright, the tube can be supported on three sides
(windward,
> > > leeward and a bow) by permanent structure bonded into the hull.
> The
> > > fourth side can be supported by a wedge dropped into place
after
> the
> > > mast is swung upright, with the wedge itself supported by
further
> > > permanent structure.
> > >
> > > Then there's no need to lift the mast vertically at all, and no
> > need to
> > > align a 'sleeve' and a 'tube' when inserting the mast. Dropping
> the
> > mast
> > > goes as follows:
> > > (1) Pull halyard out to bow on same side as wedge, and secure
to
> > hold
> > > mast.
> > > (2) Lift out wedge.
> > > (3) Slacken halyard and rotate mast until it is level (or
nearly
> > so).
> > > (4) Pull mast out of tube.
> > >
> > > Raising is the reverse.
> > >
> > > Cheers, Dave
> > >
> >
> >
> >
> >
> >
> > Send instant messages to your online friends
> http://uk.messenger.yahoo.com
> >
>
>
>
>
>
>
> ---------------------------------
>  The all-new Yahoo! Mail goes wherever you go - free your email
address from your Internet provider.
>

Just wondering how big a hole is needed in the deck,
RObert--- In harryproa@yahoogroups.com.au, Doug Haines <doha720@...>
wrote:
>
> Hi,
>
> I went to Rob Denny's house in Swanbourne yesterday and looked
and talked. He does well without a proper shed, though the double
garage is pretty good.
> Elementarry stuff I liked were the newest version of the rudder
(single on a slide from one end to the other), that kicks up if hit,
this is good engineering, because you can't raise the rudder up, like
to see how it works on the water.
>
> I liked the wing mast made from a single peice of this
honeycombed stuff of plastic I thimk it is the polycore at $20 a sqm
(6mm thick size).
>
> Hinging for me is best by leaving the mast as usual with a bit
more space at the bottom and making a tabernacle if you can call it
that up over the bottom stem. This should include a removable 4th
side and 3 permanent sides so you can let the mast swing down when
you take the 4th side off. Seemed pactical enough with carbon and
squaring the stem to fit the tabernacle sides.
>
> Doug
>
> Robert <cateran1949@...> wrote:
> Should be possible. Have to offset the masts slightly so
they don't
> interfere with each other as they lean towards the centre of the lw
> hull.For going under bridges, you wouldn't have to remove the masts
> but simply leave them tilted,
> RObert --- In harryproa@yahoogroups.com.au, Dave Howorth
> <Dave.Howorth@> wrote:
> >
> > On Fri, 2006-11-24 at 04:27 +0000, Robert wrote:
> > > -What I thought about earlier is to have a hinged sleeve. Lift
> the
> > > mast till it is out of the hull but still in the sleeve and
then
> you
> > > can lay it flat with control,
> > > Robert
> >
> > If it can be managed, perhaps it would be simpler to hinge the
mast
> tube
> > itself. I.e. the mast is supported by a tube between deck and
keel,
> and
> > this tube has a hinge at deck level.
> >
> > When upright, the tube can be supported on three sides (windward,
> > leeward and a bow) by permanent structure bonded into the hull.
The
> > fourth side can be supported by a wedge dropped into place after
the
> > mast is swung upright, with the wedge itself supported by further
> > permanent structure.
> >
> > Then there's no need to lift the mast vertically at all, and no
> need to
> > align a 'sleeve' and a 'tube' when inserting the mast. Dropping
the
> mast
> > goes as follows:
> > (1) Pull halyard out to bow on same side as wedge, and secure to
> hold
> > mast.
> > (2) Lift out wedge.
> > (3) Slacken halyard and rotate mast until it is level (or nearly
> so).
> > (4) Pull mast out of tube.
> >
> > Raising is the reverse.
> >
> > Cheers, Dave
> >
>
>
>
>
>
> Send instant messages to your online friends
http://uk.messenger.yahoo.com
>

Just wondering how big a hole is needed in the deck,
  RObert--- In harryproa@..., Doug Haines <doha720@...>
wrote:
>
> Hi,
>
>   I went to Rob Denny's house in Swanbourne yesterday and looked
and talked. He does well without a proper shed, though the double
garage is pretty good.
>   Elementarry stuff I liked were the newest version of the rudder
(single on a slide from one end to the other), that kicks up if hit,
this is good engineering, because you can't raise the rudder up, like
to see how it works on the water.
>
>   I liked the wing mast made from a single peice of this
honeycombed stuff of plastic I thimk it is the polycore at $20 a sqm
(6mm thick size).
>
>   Hinging for me is best by leaving the mast as usual with a bit
more space at the bottom and making a tabernacle if you can call it
that up over the bottom stem. This should include a removable 4th
side and 3 permanent sides so you can let the mast swing down when
you take the 4th side off. Seemed pactical enough with carbon and
squaring the stem to fit the tabernacle sides.
>
>   Doug
>
> Robert <cateran1949@...> wrote:
>           Should be possible. Have to offset the masts slightly so
they don't
> interfere with each other as they lean towards the centre of the lw
> hull.For going under bridges, you wouldn't have to remove the masts
> but simply leave them tilted,
> RObert --- In harryproa@..., Dave Howorth
> <Dave.Howorth@> wrote:
> >
> > On Fri, 2006-11-24 at 04:27 +0000, Robert wrote:
> > > -What I thought about earlier is to have a hinged sleeve. Lift
> the
> > > mast till it is out of the hull but still in the sleeve and
then
> you
> > > can lay it flat with control,
> > > Robert
> >
> > If it can be managed, perhaps it would be simpler to hinge the
mast
> tube
> > itself. I.e. the mast is supported by a tube between deck and
keel,
> and
> > this tube has a hinge at deck level.
> >
> > When upright, the tube can be supported on three sides (windward,
> > leeward and a bow) by permanent structure bonded into the hull.
The
> > fourth side can be supported by a wedge dropped into place after
the
> > mast is swung upright, with the wedge itself supported by further
> > permanent structure.
> >
> > Then there's no need to lift the mast vertically at all, and no
> need to
> > align a 'sleeve' and a 'tube' when inserting the mast. Dropping
the
> mast
> > goes as follows:
> > (1) Pull halyard out to bow on same side as wedge, and secure to
> hold
> > mast.
> > (2) Lift out wedge.
> > (3) Slacken halyard and rotate mast until it is level (or nearly
> so).
> > (4) Pull mast out of tube.
> >
> > Raising is the reverse.
> >
> > Cheers, Dave
> >
>
>
>
>
>
>  Send instant messages to your online friends
http://uk.messenger.yahoo.com
>

Hi All

I just found this on multihull boatbuilders list:

> The ostensible purpose [of partial lifting foils] is to moderate the
tendency
> of narrow multihulls to pitch as they travel through the water, as I
understand
> it, and also they serve as fences at the bottom of the rudder, acting
to
> increase the functional aspect ratio. Both of these would be helpful
to me,
> since the little cat I'm building is designed to be as hassle-free and
> idiot-proof as possible. To that end, my rudders are fixed and of low
> aspect ratio.

An example of this is found on  Darryl Barretts Formula 14 cat.
http://www.catsailor.com/bb_files/78311-P6100003.JPG

Would this be useful on the Single Rudder version of Elementarry? The
pitching control may be taken care of by hull shape as Rob has pointed
out before, but the effective aspect ratio might be worthwhile.
Enjoy

Jim Baltaxe
ITS Desktop Support
Victoria University of Wellington
NEW ZEALAND
(04) 463 5018 or 027 563 5018

I suffer from mental incontinence.

Klein bottle for rent.  Inquire within.
"If we knew what we were doing, it wouldn't be called research, would
it?" -- Albert Einstein

 

----- Original Message -----

From: Doug Haines

To: harryproa@yahoogroups.com.au

Sent: Sunday, November 26, 2006 12:44 PM

Subject: Re: [harryproa] Sunday E/NE tending W/NW, Moderate

G'Day,

 

More sailing experience now shows a few points that are better than others.

1) I broke the rudder off the beam where the gudgeons are glassed on, too little contact area and too much torque due to the two gudgeons spaced so close together on the beam.

 

r

Try to build them up above and below the beam if you can.  Spreads the load, and it is easier to attache to the flat top and bottom of the beam.

 

Will probably fix it back on with extra glass, but in future hope to improve on current design with Rob's single system though I have'nt had a close look at and don't know exactly how it all works, I turst Rob's designing, to get it sorted right.

 

r

The system I have on my boat worked well last summer.  Using lines as tracks, instead of timber should make it a lot more forgiving. 

 

2)I find the two mainsails a little complicated to watch and angle in to the wind, and steer too. It may be a good challenge to a pair of keen sailors but,  I'm not really that experienced sort of go on the feel somewhere between luffing up and too hard on, and see where the speed is. This sort of tuning is not so easy wih the two mainsails. I therefore suppose I might make the centre mast tube and bulkheads as Rob did by cutting a big hole in the side of the lw hull to retro-fit. I can use one of my current masts in that centre spot.

However there are a couple more issues on the mast/sails:

 

3)To get around Perth, up Rivers under bridges the masts need to swing down. I think this is fairly straight forward not adding too much extra bulk down around about boom height to make a hingewith pins or some fixing. The mast overall would need too be lighter than my wood/glass, too heavy too lift without excess effort. So a single mast in the centre with a hinge and light enough to drop and raise up so foam and carbon I suppose.

 

r

The wedge in front works, but is cumbersome, particularly with big wakes from powerboats.  I would make it telescope if 5m is the limit and you are building a new mast anyway.

 

4) Another issue is that I found that the mainsail only ( called cat rig or una rig ?), would not swing around sometimes its a bit complicated but I wonder if the easy or ballestron rig would be easier to turn because you can sheet to both ends? I'm not sure about this I'll look for some internet diagrams or look at Harryproa galleries.

 

r

cat rig (USA) una rig (UK) The only times I used a sheet to the front of the ballestron boom was when I had a spinnaker up.     If the sheet is to the lee hull it should be pretty easy to move the boom.  If it isn't,  then a turning block on the beam should give enough angle.

 

Incidently for cruising with two mainsails, lowering/raising sails out on the water you can't reach the aft boom end as it is lying far back over the stern. I.e. an easy rig would be easier to reach especially if ever wanting to reef offshore. I neede to jump in and walk down the back to tie on the clew (is that the back corner of the sail?) and your sail falls into the water a bit. The front sail/mast is easy to reach standing on the deck and netting.

 

r

Easiest, driest and safest is to drop them both completely, tie in the reefs standing on the tramp, the rehoist them.

 

I don't know about the dynamics but why the small jib on the easy rig wouldn't be better performance I don't know.

 

r

Luff tension is hard to get.  Not a worry on a cruiser.  The boom gets in the way a bit as well.

 

I occasionally wanted to push the boom back round through the wind and this would be easier with the balancing jib.

 

5) Definitely need a small outboard (2hp) on a bracket near the ww hull ( so the boom won't bang into it, and easier to reach for helmsman, and out of way of rudder). One direction only needed, opposite end that used for anchoring keeping things tidier.

 

r

Not too far from the lee hull or maneuvering gets tricky.  Make sure it lifts up high enough to clear waves coming from the wrong direction.

 

Anyhow good fun sailing the proa this morning, good 8-12 knots I think, I think above improvements will be safe enough to venture in confidence out offshore, up and down the coast.

 

r

Excellent.  Feel free to borrow my gps as I won't be using it for awile.

 

regards,

 

rob

.

---

Internal Virus Database is out-of-date.
Checked by AVG Free Edition.
Version: 7.1.394 / Virus Database: 268.14.6/536 - Release Date: 11/16/2006

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

Should be possible. Have to offset the masts slightly so they don't
interfere with each other as they lean towards the centre of the lw
hull.For going under bridges, you wouldn't have to remove the masts
but simply leave them tilted,
RObert --- In harryproa@yahoogroups.com.au, Dave Howorth
<Dave.Howorth@...> wrote:
>
> On Fri, 2006-11-24 at 04:27 +0000, Robert wrote:
> > -What I thought about earlier is to have a hinged sleeve. Lift
the
> > mast till it is out of the hull but still in the sleeve and then
you
> > can lay it flat with control,
> > Robert
>
> If it can be managed, perhaps it would be simpler to hinge the mast
tube
> itself. I.e. the mast is supported by a tube between deck and keel,
and
> this tube has a hinge at deck level.
>
> When upright, the tube can be supported on three sides (windward,
> leeward and a bow) by permanent structure bonded into the hull. The
> fourth side can be supported by a wedge dropped into place after the
> mast is swung upright, with the wedge itself supported by further
> permanent structure.
>
> Then there's no need to lift the mast vertically at all, and no
need to
> align a 'sleeve' and a 'tube' when inserting the mast. Dropping the
mast
> goes as follows:
> (1) Pull halyard out to bow on same side as wedge, and secure to
hold
> mast.
> (2) Lift out wedge.
> (3) Slacken halyard and rotate mast until it is level (or nearly
so).
> (4) Pull mast out of tube.
>
> Raising is the reverse.
>
> Cheers, Dave
>

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

----- Original Message -----

From: Doug Haines

To: harryproa@...

Sent: Sunday, November 26, 2006 12:44 PM

Subject: Re: [harryproa] Sunday E/NE tending W/NW, Moderate

G'Day,

 

More sailing experience now shows a few points that are better than others.

1) I broke the rudder off the beam where the gudgeons are glassed on, too little contact area and too much torque due to the two gudgeons spaced so close together on the beam.

 

r

Try to build them up above and below the beam if you can.  Spreads the load, and it is easier to attache to the flat top and bottom of the beam.

 

Will probably fix it back on with extra glass, but in future hope to improve on current design with Rob's single system though I have'nt had a close look at and don't know exactly how it all works, I turst Rob's designing, to get it sorted right.

 

r

The system I have on my boat worked well last summer.  Using lines as tracks, instead of timber should make it a lot more forgiving. 

 

2)I find the two mainsails a little complicated to watch and angle in to the wind, and steer too. It may be a good challenge to a pair of keen sailors but,  I'm not really that experienced sort of go on the feel somewhere between luffing up and too hard on, and see where the speed is. This sort of tuning is not so easy wih the two mainsails. I therefore suppose I might make the centre mast tube and bulkheads as Rob did by cutting a big hole in the side of the lw hull to retro-fit. I can use one of my current masts in that centre spot.

However there are a couple more issues on the mast/sails:

 

3)To get around Perth, up Rivers under bridges the masts need to swing down. I think this is fairly straight forward not adding too much extra bulk down around about boom height to make a hingewith pins or some fixing. The mast overall would need too be lighter than my wood/glass, too heavy too lift without excess effort. So a single mast in the centre with a hinge and light enough to drop and raise up so foam and carbon I suppose.

 

r

The wedge in front works, but is cumbersome, particularly with big wakes from powerboats.  I would make it telescope if 5m is the limit and you are building a new mast anyway.

 

4) Another issue is that I found that the mainsail only ( called cat rig or una rig ?), would not swing around sometimes its a bit complicated but I wonder if the easy or ballestron rig would be easier to turn because you can sheet to both ends? I'm not sure about this I'll look for some internet diagrams or look at Harryproa galleries.

 

r

cat rig (USA) una rig (UK) The only times I used a sheet to the front of the ballestron boom was when I had a spinnaker up.     If the sheet is to the lee hull it should be pretty easy to move the boom.  If it isn't,  then a turning block on the beam should give enough angle.

 

Incidently for cruising with two mainsails, lowering/raising sails out on the water you can't reach the aft boom end as it is lying far back over the stern. I.e. an easy rig would be easier to reach especially if ever wanting to reef offshore. I neede to jump in and walk down the back to tie on the clew (is that the back corner of the sail?) and your sail falls into the water a bit. The front sail/mast is easy to reach standing on the deck and netting.

 

r

Easiest, driest and safest is to drop them both completely, tie in the reefs standing on the tramp, the rehoist them.

 

I don't know about the dynamics but why the small jib on the easy rig wouldn't be better performance I don't know.

 

r

Luff tension is hard to get.  Not a worry on a cruiser.  The boom gets in the way a bit as well.

 

I occasionally wanted to push the boom back round through the wind and this would be easier with the balancing jib.

 

5) Definitely need a small outboard (2hp) on a bracket near the ww hull ( so the boom won't bang into it, and easier to reach for helmsman, and out of way of rudder). One direction only needed, opposite end that used for anchoring keeping things tidier.

 

r

Not too far from the lee hull or maneuvering gets tricky.  Make sure it lifts up high enough to clear waves coming from the wrong direction.

 

Anyhow good fun sailing the proa this morning, good 8-12 knots I think, I think above improvements will be safe enough to venture in confidence out offshore, up and down the coast.

 

r

Excellent.  Feel free to borrow my gps as I won't be using it for awile.

 

regards,

 

rob

.

---

Internal Virus Database is out-of-date.
Checked by AVG Free Edition.
Version: 7.1.394 / Virus Database: 268.14.6/536 - Release Date: 11/16/2006

Should be possible. Have to offset the masts slightly so they don't
interfere with each other as they lean towards the centre of the lw
hull.For going under bridges, you wouldn't have to remove the masts
but simply leave them tilted,
  RObert --- In harryproa@..., Dave Howorth
<Dave.Howorth@...> wrote:
>
> On Fri, 2006-11-24 at 04:27 +0000, Robert wrote:
> > -What I thought about earlier is to have a hinged sleeve. Lift
the
> > mast till it is out of the hull but still in the sleeve and then
you
> > can lay it flat with control,
> >  Robert
>
> If it can be managed, perhaps it would be simpler to hinge the mast
tube
> itself. I.e. the mast is supported by a tube between deck and keel,
and
> this tube has a hinge at deck level.
>
> When upright, the tube can be supported on three sides (windward,
> leeward and a bow) by permanent structure bonded into the hull. The
> fourth side can be supported by a wedge dropped into place after the
> mast is swung upright, with the wedge itself supported by further
> permanent structure.
>
> Then there's no need to lift the mast vertically at all, and no
need to
> align a 'sleeve' and a 'tube' when inserting the mast. Dropping the
mast
> goes as follows:
> (1) Pull halyard out to bow on same side as wedge, and secure to
hold
> mast.
> (2) Lift out wedge.
> (3) Slacken halyard and rotate mast until it is level (or nearly
so).
> (4) Pull mast out of tube.
>
> Raising is the reverse.
>
> Cheers, Dave
>

On Fri, 2006-11-24 at 04:27 +0000, Robert wrote:
> -What I thought about earlier is to have a hinged sleeve. Lift the
> mast till it is out of the hull but still in the sleeve and then you
> can lay it flat with control,
>  Robert

If it can be managed, perhaps it would be simpler to hinge the mast tube
itself. I.e. the mast is supported by a tube between deck and keel, and
this tube has a hinge at deck level.

When upright, the tube can be supported on three sides (windward,
leeward and a bow) by permanent structure bonded into the hull. The
fourth side can be supported by a wedge dropped into place after the
mast is swung upright, with the wedge itself supported by further
permanent structure.

Then there's no need to lift the mast vertically at all, and no need to
align a 'sleeve' and a 'tube' when inserting the mast. Dropping the mast
goes as follows:
(1) Pull halyard out to bow on same side as wedge, and secure to hold
mast.
(2) Lift out wedge.
(3) Slacken halyard and rotate mast until it is level (or nearly so).
(4) Pull mast out of tube.

Raising is the reverse.

Cheers, Dave

Sorry,
I meant mast bearings. I think I must be going troppo in the heat and
humidity,
Robert

--- In harryproa@yahoogroups.com.au, Doug Haines <doha720@...> wrote:
>
> Rudder Bearings, I thought we were talking about the mast?
>
>
> Robert <cateran1949@...> wrote:
> A cylinder that sits on top of the hull over the rudder
bearings,
> just big enough for the base of the mast to slide in and out of and
> enough depth to provide a measure of control when stepping or
> unstepping the mast,
> regards,,
> robert--- In harryproa@yahoogroups.com.au, Doug Haines <doha720@>
> wrote:
> >
> > Which bit is the sleeve?
> >
> > Robert <cateran1949@> wrote: Sorry, I wasn't very
> clear. The sleeve has a hinge at its base.
> > Robert
> > --- In harryproa@yahoogroups.com.au, Doug Haines <doha720@> wrote:
> > >
> > > How can you hinge the mast part that is in the tube?
> > >
> > > Robert <cateran1949@> wrote: -What I thought about
> > earlier is to have a hinged sleeve. Lift the
> > > mast till it is out of the hull but still in the sleeve and
then
> > you
> > > can lay it flat with control,
> > > Robert
> > >
> > > -- In harryproa@yahoogroups.com.au, Doug Haines <doha720@>
wrote:
> > > >
> > > > Hi,
> > > >
> > > > I think it is a cruising necessity to hinge masts on a small
> > > cruiser. I don't see why it couldn't be done on the
Elementarry.
> > > > Been thinking about it, would also like a bracket/pod that
tkes
> a
> > > 2hp outboard, then your bridges, adverse tides, moorings are
more
> > > like regular cruising situations.
> > > > To me its not a day sailing, its as long as possible.
> > > >
> > > > Doug
> > > >
> > > > Rob Denney <proa@> wrote:
> > > > G'day,
> > > >
> > > > Good thinking. I am building 2 x 6m/20' pieces, joined at the
> > > mast, with all the external carbon added after it is joined.
The
> > > removable ends will be built seperately. Could just as easily
> join
> > > it at the beams.
> > > >
> > > > KSS would not allow the one join oval sections, nor the
> squashed
> > > cones.
> > > >
> > > > Glassing part of the Polycore is not a good idea, as you
damage
> > > the scrim when you sand it to get a key for subsequent layers.
> > > Welding on a piece of scrim may work, or if it is an inside
> curve,
> > > bog should do the trick.
> > > >
> > > > regards,
> > > >
> > > > Rob
> > > >
> > > >
> > > > ----- Original Message -----
> > > > From: Robert
> > > > To: harryproa@yahoogroups.com.au
> > > > Sent: Thursday, November 23, 2006 11:38 AM
> > > > Subject: [harryproa] Conoc sections
> > > >
> > > >
> > > > Been thinking of Harry bows on the lw hull. The sections
> > > forward of the
> > > > rudders could be built using the squashed cone idea. If the
the
> > > centre
> > > > section of the lw hull with all its fiddly bits with the
> rudders
> > > and
> > > > mast bearings could be built separately and the bows added on
> > later
> > > it
> > > > could be built in a much smaller space and making it much
> easier
> > to
> > > > work on those fiddly bits. This a fairly natural place to
have
> a
> > > change
> > > > of curvature and needs a bit of fairing anyway with the
rudder
> > > > reinforcing. The fact that the hulls could be fair to well
> above
> > > the
> > > > water line suggest that hulls could be built using a KSS
> process
> > > with
> > > > no cutting or shutting below the waterline.
> > > > I was wondering about the problems of bending the halfglassed
> > > polyprop
> > > > and whether the joins could be made where you want the panels
> to
> > be
> > > > near flat and pre tape them with glass tape. Or possibly weld
a
> > > strip
> > > > of scrim over the joint
> > > > Robert
> > > >
> > > >
> > > >
> > > >
> > > > ---------------------------------
> > > >
> > > > No virus found in this incoming message.
> > > > Checked by AVG Free Edition.
> > > > Version: 7.1.394 / Virus Database: 268.14.6/536 - Release
Date:
> > > 11/16/2006
> > > >
> > > >
> > > >
> > > >
> > > > Send instant messages to your online friends
> > > http://uk.messenger.yahoo.com
> > > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > ---------------------------------
> > > Try the all-new Yahoo! Mail . "The New Version is radically
> easier
> > to use" – The Wall Street Journal
> > >
> >
> >
> >
> >
> >
> > 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

Sorry,
I meant mast bearings. I think I must be going troppo in the heat and
humidity,
  Robert

--- In harryproa@..., Doug Haines <doha720@...> wrote:
>
> Rudder Bearings, I thought we were talking about the mast?
>
>
> Robert <cateran1949@...> wrote:
>           A cylinder that sits on top of the hull over the rudder
bearings,
> just big enough for the base of the mast to slide in and out of and
> enough depth to provide a measure of control when stepping or
> unstepping the mast,
> regards,,
> robert--- In harryproa@..., Doug Haines <doha720@>
> wrote:
> >
> > Which bit is the sleeve?
> >
> > Robert <cateran1949@> wrote: Sorry, I wasn't very
> clear. The sleeve has a hinge at its base.
> > Robert
> > --- In harryproa@..., Doug Haines <doha720@> wrote:
> > >
> > > How can you hinge the mast part that is in the tube?
> > >
> > > Robert <cateran1949@> wrote: -What I thought about
> > earlier is to have a hinged sleeve. Lift the
> > > mast till it is out of the hull but still in the sleeve and
then
> > you
> > > can lay it flat with control,
> > > Robert
> > >
> > > -- In harryproa@..., Doug Haines <doha720@>
wrote:
> > > >
> > > > Hi,
> > > >
> > > > I think it is a cruising necessity to hinge masts on a small
> > > cruiser. I don't see why it couldn't be done on the
Elementarry.
> > > > Been thinking about it, would also like a bracket/pod that
tkes
> a
> > > 2hp outboard, then your bridges, adverse tides, moorings are
more
> > > like regular cruising situations.
> > > > To me its not a day sailing, its as long as possible.
> > > >
> > > > Doug
> > > >
> > > > Rob Denney <proa@> wrote:
> > > > G'day,
> > > >
> > > > Good thinking. I am building 2 x 6m/20' pieces, joined at the
> > > mast, with all the external carbon added after it is joined.
The
> > > removable ends will be built seperately. Could just as easily
> join
> > > it at the beams.
> > > >
> > > > KSS would not allow the one join oval sections, nor the
> squashed
> > > cones.
> > > >
> > > > Glassing part of the Polycore is not a good idea, as you
damage
> > > the scrim when you sand it to get a key for subsequent layers.
> > > Welding on a piece of scrim may work, or if it is an inside
> curve,
> > > bog should do the trick.
> > > >
> > > > regards,
> > > >
> > > > Rob
> > > >
> > > >
> > > > ----- Original Message -----
> > > > From: Robert
> > > > To: harryproa@...
> > > > Sent: Thursday, November 23, 2006 11:38 AM
> > > > Subject: [harryproa] Conoc sections
> > > >
> > > >
> > > > Been thinking of Harry bows on the lw hull. The sections
> > > forward of the
> > > > rudders could be built using the squashed cone idea. If the
the
> > > centre
> > > > section of the lw hull with all its fiddly bits with the
> rudders
> > > and
> > > > mast bearings could be built separately and the bows added on
> > later
> > > it
> > > > could be built in a much smaller space and making it much
> easier
> > to
> > > > work on those fiddly bits. This a fairly natural place to
have
> a
> > > change
> > > > of curvature and needs a bit of fairing anyway with the
rudder
> > > > reinforcing. The fact that the hulls could be fair to well
> above
> > > the
> > > > water line suggest that hulls could be built using a KSS
> process
> > > with
> > > > no cutting or shutting below the waterline.
> > > > I was wondering about the problems of bending the halfglassed
> > > polyprop
> > > > and whether the joins could be made where you want the panels
> to
> > be
> > > > near flat and pre tape them with glass tape. Or possibly weld
a
> > > strip
> > > > of scrim over the joint
> > > > Robert
> > > >
> > > >
> > > >
> > > >
> > > > ---------------------------------
> > > >
> > > > No virus found in this incoming message.
> > > > Checked by AVG Free Edition.
> > > > Version: 7.1.394 / Virus Database: 268.14.6/536 - Release
Date:
> > > 11/16/2006
> > > >
> > > >
> > > >
> > > >
> > > > Send instant messages to your online friends
> > > http://uk.messenger.yahoo.com
> > > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > ---------------------------------
> > > Try the all-new Yahoo! Mail . "The New Version is radically
> easier
> > to use" – The Wall Street Journal
> > >
> >
> >
> >
> >
> >
> > Send instant messages to your online friends
> http://uk.messenger.yahoo.com
> >
>
>
>
>
>
>  Send instant messages to your online friends
http://uk.messenger.yahoo.com
>

Classic

Rob Denney <proa@....au> wrote:

Sorry, Sunday is out as we are spending the weekend doing classical music at a winery at Margaret River.

 

regards,

 

Rob

----- Original Message -----

From: Doug Haines

To: harryproa@yahoogroups.com.au

Sent: Friday, November 24, 2006 6:02 PM

Subject: [harryproa] Sunday E/NE tending W/NW, Moderate

Ideal forecast for Sunday.

Come down to Manduah Rob if you can.

Anytime I'll take a mobile: 0406309440.

 

Doug

Doug Haines <doha720@yahoo.co.uk> wrote:

How can you hinge the mast part that is in the tube?

Robert <cateran1949@yahoo.co.uk> wrote:

-What I thought about earlier is to have a hinged sleeve. Lift the
mast till it is out of the hull but still in the sleeve and then you
can lay it flat with control,
Robert

-- In harryproa@yahoogroups.com.au, Doug Haines <doha720@...> wrote:
>
> Hi,
>
> I think it is a cruising necessity to hinge masts on a small
cruiser. I don't see why it couldn't be done on the Elementarry.
> Been thinking about it, would also like a bracket/pod that tkes a
2hp outboard, then your bridges, adverse tides, moorings are more
like regular cruising situations.
> To me its not a day sailing, its as long as possible.
>
> Doug
>
> Rob Denney <proa@...> wrote:
> G'day,
>
> Good thinking. I am building 2 x 6m/20' pieces, joined at the
mast, with all the external carbon added after it is joined. The
removable ends will be built seperately. Could just as easily join
it at the beams.
>
> KSS would not allow the one join oval sections, nor the squashed
cones.
>
> Glassing part of the Polycore is not a good idea, as you damage
the scrim when you sand it to get a key for subsequent layers.
Welding on a piece of scrim may work, or if it is an inside curve,
bog should do the trick.
>
> regards,
>
> Rob
>
>
> ----- Original Message -----
> From: Robert
> To: harryproa@yahoogroups.com.au
> Sent: Thursday, November 23, 2006 11:38 AM
> Subject: [harryproa] Conoc sections
>
>
> Been thinking of Harry bows on the lw hull. The sections
forward of the
> rudders could be built using the squashed cone idea. If the the
centre
> section of the lw hull with all its fiddly bits with the rudders
and
> mast bearings could be built separately and the bows added on later
it
> could be built in a much smaller space and making it much easier to
> work on those fiddly bits. This a fairly natural place to have a
change
> of curvature and needs a bit of fairing anyway with the rudder
> reinforcing. The fact that the hulls could be fair to well above
the
> water line suggest that hulls could be built using a KSS process
with
> no cutting or shutting below the waterline.
> I was wondering about the problems of bending the halfglassed
polyprop
> and whether the joins could be made where you want the panels to be
> near flat and pre tape them with glass tape. Or possibly weld a
strip
> of scrim over the joint
> Robert
>
>
>
>
> ---------------------------------
>
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.1.394 / Virus Database: 268.14.6/536 - Release Date:
11/16/2006
>
>
>
>
> Send instant messages to your online friends
http://uk.messenger.yahoo.com
>

---

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

---

Internal Virus Database is out-of-date.
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Version: 7.1.394 / Virus Database: 268.14.6/536 - Release Date: 11/16/2006

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

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

A cylinder that sits on top of the hull over the rudder bearings,
just big enough for the base of the mast to slide in and out of and
enough depth to provide a measure of control when stepping or
unstepping the mast,
regards,,
robert--- In harryproa@yahoogroups.com.au, Doug Haines <doha720@...>
wrote:
>
> Which bit is the sleeve?
>
> Robert <cateran1949@...> wrote: Sorry, I wasn't very
clear. The sleeve has a hinge at its base.
> Robert
> --- In harryproa@yahoogroups.com.au, Doug Haines <doha720@> wrote:
> >
> > How can you hinge the mast part that is in the tube?
> >
> > Robert <cateran1949@> wrote: -What I thought about
> earlier is to have a hinged sleeve. Lift the
> > mast till it is out of the hull but still in the sleeve and then
> you
> > can lay it flat with control,
> > Robert
> >
> > -- In harryproa@yahoogroups.com.au, Doug Haines <doha720@> wrote:
> > >
> > > Hi,
> > >
> > > I think it is a cruising necessity to hinge masts on a small
> > cruiser. I don't see why it couldn't be done on the Elementarry.
> > > Been thinking about it, would also like a bracket/pod that tkes
a
> > 2hp outboard, then your bridges, adverse tides, moorings are more
> > like regular cruising situations.
> > > To me its not a day sailing, its as long as possible.
> > >
> > > Doug
> > >
> > > Rob Denney <proa@> wrote:
> > > G'day,
> > >
> > > Good thinking. I am building 2 x 6m/20' pieces, joined at the
> > mast, with all the external carbon added after it is joined. The
> > removable ends will be built seperately. Could just as easily
join
> > it at the beams.
> > >
> > > KSS would not allow the one join oval sections, nor the
squashed
> > cones.
> > >
> > > Glassing part of the Polycore is not a good idea, as you damage
> > the scrim when you sand it to get a key for subsequent layers.
> > Welding on a piece of scrim may work, or if it is an inside
curve,
> > bog should do the trick.
> > >
> > > regards,
> > >
> > > Rob
> > >
> > >
> > > ----- Original Message -----
> > > From: Robert
> > > To: harryproa@yahoogroups.com.au
> > > Sent: Thursday, November 23, 2006 11:38 AM
> > > Subject: [harryproa] Conoc sections
> > >
> > >
> > > Been thinking of Harry bows on the lw hull. The sections
> > forward of the
> > > rudders could be built using the squashed cone idea. If the the
> > centre
> > > section of the lw hull with all its fiddly bits with the
rudders
> > and
> > > mast bearings could be built separately and the bows added on
> later
> > it
> > > could be built in a much smaller space and making it much
easier
> to
> > > work on those fiddly bits. This a fairly natural place to have
a
> > change
> > > of curvature and needs a bit of fairing anyway with the rudder
> > > reinforcing. The fact that the hulls could be fair to well
above
> > the
> > > water line suggest that hulls could be built using a KSS
process
> > with
> > > no cutting or shutting below the waterline.
> > > I was wondering about the problems of bending the halfglassed
> > polyprop
> > > and whether the joins could be made where you want the panels
to
> be
> > > near flat and pre tape them with glass tape. Or possibly weld a
> > strip
> > > of scrim over the joint
> > > Robert
> > >
> > >
> > >
> > >
> > > ---------------------------------
> > >
> > > No virus found in this incoming message.
> > > Checked by AVG Free Edition.
> > > Version: 7.1.394 / Virus Database: 268.14.6/536 - Release Date:
> > 11/16/2006
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A cylinder that sits on top of the hull over the rudder bearings,
just big enough for the base of the mast to slide in and out of and
enough depth to provide a measure of control when stepping or
unstepping the mast,
  regards,,
  robert--- In harryproa@..., Doug Haines <doha720@...>
wrote:
>
> Which bit is the sleeve?
>
> Robert <cateran1949@...> wrote:          Sorry, I wasn't very
clear. The sleeve has a hinge at its base.
> Robert
> --- In harryproa@..., Doug Haines <doha720@> wrote:
> >
> > How can you hinge the mast part that is in the tube?
> >
> > Robert <cateran1949@> wrote: -What I thought about
> earlier is to have a hinged sleeve. Lift the
> > mast till it is out of the hull but still in the sleeve and then
> you
> > can lay it flat with control,
> > Robert
> >
> > -- In harryproa@..., Doug Haines <doha720@> wrote:
> > >
> > > Hi,
> > >
> > > I think it is a cruising necessity to hinge masts on a small
> > cruiser. I don't see why it couldn't be done on the Elementarry.
> > > Been thinking about it, would also like a bracket/pod that tkes
a
> > 2hp outboard, then your bridges, adverse tides, moorings are more
> > like regular cruising situations.
> > > To me its not a day sailing, its as long as possible.
> > >
> > > Doug
> > >
> > > Rob Denney <proa@> wrote:
> > > G'day,
> > >
> > > Good thinking. I am building 2 x 6m/20' pieces, joined at the
> > mast, with all the external carbon added after it is joined. The
> > removable ends will be built seperately. Could just as easily
join
> > it at the beams.
> > >
> > > KSS would not allow the one join oval sections, nor the
squashed
> > cones.
> > >
> > > Glassing part of the Polycore is not a good idea, as you damage
> > the scrim when you sand it to get a key for subsequent layers.
> > Welding on a piece of scrim may work, or if it is an inside
curve,
> > bog should do the trick.
> > >
> > > regards,
> > >
> > > Rob
> > >
> > >
> > > ----- Original Message -----
> > > From: Robert
> > > To: harryproa@...
> > > Sent: Thursday, November 23, 2006 11:38 AM
> > > Subject: [harryproa] Conoc sections
> > >
> > >
> > > Been thinking of Harry bows on the lw hull. The sections
> > forward of the
> > > rudders could be built using the squashed cone idea. If the the
> > centre
> > > section of the lw hull with all its fiddly bits with the
rudders
> > and
> > > mast bearings could be built separately and the bows added on
> later
> > it
> > > could be built in a much smaller space and making it much
easier
> to
> > > work on those fiddly bits. This a fairly natural place to have
a
> > change
> > > of curvature and needs a bit of fairing anyway with the rudder
> > > reinforcing. The fact that the hulls could be fair to well
above
> > the
> > > water line suggest that hulls could be built using a KSS
process
> > with
> > > no cutting or shutting below the waterline.
> > > I was wondering about the problems of bending the halfglassed
> > polyprop
> > > and whether the joins could be made where you want the panels
to
> be
> > > near flat and pre tape them with glass tape. Or possibly weld a
> > strip
> > > of scrim over the joint
> > > Robert
> > >
> > >
> > >
> > >
> > > ---------------------------------
> > >
> > > No virus found in this incoming message.
> > > Checked by AVG Free Edition.
> > > Version: 7.1.394 / Virus Database: 268.14.6/536 - Release Date:
> > 11/16/2006
> > >
> > >
> > >
> > >
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