harryproa : Messages : 5670-5699 of 6681

Hi Rob
that is excellent news - both - you building a Solitarry and the
addition of a new member to your team. I am confident that the building
process of the Solitarry can be documented very well with nice pictures
and youtube or maybe perhaps even with a web cam and server?
Have fun
Heinrich

Reply | Forward | Messages in this Topic (10)

#5698

From: Rob Denney <harryproa@...>
Date: Thu May 7, 2009 2:54 am
Subject:: personal update

proaharry

Offline

G'day,

I am pleased to announce that James Brett
http://www.jbyachtdesigns.co.nz/ has joined forces with me to bounce
ideas off and to take over the drafting of the plans.

I am moving to the Gold Coast (just south of Brisbane on the east
coast of Australia) in July and have contracted with a builder to
build a 15m flat panel Solitarry.  Hopefully this will be less of a
drama than the last one and will allow me to do some racing and
cruising.  If (big if, given my record) it is all done on time, then
Brisbane Gladstone and the solo Transpac next year are on the agenda.

There have also been a couple of serious enquiries from Mini 650
sailors wanting to charter Solitarry's for the Route de Rhum in
November 2010.  The organisers invited me to enter a harryproa, which
was nice, but we are now waiting for them to decide whether they can
alter some of their  trimaran biased rules to allow us to be
competitive.

regards,

Rob

Reply | Forward | Messages in this Topic (10)

#5697

From: Doug Haines <doha720@...>
Date: Wed May 6, 2009 2:41 pm
Subject:: ccamper layout accoms.

doha720

Offline

Following on with gardners sidecar cclone, i may look at moving beams outward to ends further, and setting up a stepped bunk/cooking/seat inside the cabin.

seperating sleeping from cooking etc, and putting legs down off the end of the bunk level down into the cooking level like a seat. from there to sit and cook, write etc. perhaps a fold out desk/board (put laptop on and use mobile broadband.

this looks easy enough with the current bunk floor level staying as the new bunk level and extending forward on way into the space made by moving the beam position forward.

the new lower floor level makes a drop off for your feet, with the stove up on a cross board within reach down the opposite end to the bunk. put stuff under this cross board.

keeps thing in place without moving stuff and may stay hygienic! (not easy ).

the progression on design was also following a new mast in the middle of the lw, which means a new mast step, which could be done as part of an insert into the middle section of a 1m length which thus achieves the desired result of moving beam/bulkheads out further mainly for the purpose of cabin accomodations but incidentally giving a new lw hull length overall of 8.5 or so metres!

rudders on beams are not in a bad spot either.

still may not be able to get too comfortable, distinct improvemnt.

doug

--- On Wed, 6/5/09, Doug Haines <doha720@...> wrote:

From: Doug Haines <doha720@...>
Subject: Re: [harryproa] static moment righting test and speed, plus bonus sail plan tpopic
To: harryproa@...
Date: Wednesday, 6 May, 2009, 7:08 PM

hi again,

perhaps it was closer to 9-9:30 am, which bureau (www.bom.gov. au.....wa. ..perth.. .daily observations. ..melville water), gives average 12knots, gusting to 16/17knots.

so 8,9,10 in 12is good to me. i found it surprising to see what the gps said at first, after so long just knowing that i was going "SLOW", "good" or really GOOd, from feel, wake etc.

what i see as slow is probably a reasonable 5-6 knots, and reasonable speed was actually 7-9 knots, 10 -12 is what i like to get up to when cruising as it seems to be going someplace and passing by coastline rapidly.

the day i went up at 9 knots to lancelin (see video on utube) was probably closer to 10-11 and upwards for a good portion. seeing as i stopped a few times, had to veer around a big offshore construction site? and stop for getting weed off rudders, etc.

this kind of speed is not about breaking records, but the other day i left rottnest and only just got into the fremantle harbuour before the sun went down, the tide got too high or turned and the wind dropped. so its got real world applications even just weekending away.

on a side light - something on the rigs:

the high speeds and low forestay tension reduces the effectiveness of the jib?

therefore uni main is better?

this makes for a big purchase needed on that mainsheet, and shifts CofE of sails backcloser to the rudder, which is not goodd.

assuming schooners suck (personal opinion), where dooes the application to the diffrent haarrries come in.

This is based on chat with Rob, and the Elementarry, solittarry uni rig, and is that going to suit a rapscallion also, but not a visionarry?

doug

--- On Wed, 6/5/09, Doug Haines <doha720@yahoo. co.uk> wrote:

From: Doug Haines <doha720@yahoo. co.uk>
Subject: Re: [harryproa] static moment righting test
To: harryproa@yahoogrou ps.com.au
Date: Wednesday, 6 May, 2009, 6:32 PM

also used gps for halh an hour:

reaches across melville water and back - the port hand marker out in the midlle of the water has the bureaus recording station mounted on it.

The figures for 8:30am are 9knots gusting to 12knots, and for 9am 11 knots gusting to 15knots.

I think I was out there from around 8:30 'till 9am, and the gps reading were giving 6-7 knots inshore starting off, 8-9 knots out in the middle, with a couple of reaches at about 9 knots and gusts shooting speed up over 10,11,12 knots.

Unfortunately rudder turbulence shuts off any acceleration after that, so guesses of potential speed are around 13 knots today and with more wind top speed could be well over 15!

doug

--- On Wed, 6/5/09, Doug Haines <doha720@yahoo. co.uk> wrote:

From: Doug Haines <doha720@yahoo. co.uk>
Subject: [harryproa] static moment righting test
To: harryproa@yahoogrou ps.com.au
Date: Wednesday, 6 May, 2009, 3:13 PM

hi,

got the sidecar up on its side (based on lw hull), with the ww hull sitting up in the air.

It was quite a lift even using halyard to the mast top (me) and lifting/pushing hull (Rob).

got stuck in too tight mast out horizontally with wiggling the wing rotator.

dougg

--- On Wed, 6/5/09, Gardner Pomper <gardner@networknow. org> wrote:

From: Gardner Pomper <gardner@networknow. org>
Subject: Re: [harryproa] Re: Fine tuning design questions
To: harryproa@yahoogrou ps.com.au
Date: Wednesday, 6 May, 2009, 1:41 AM

Hi,

That helps alot. I am looking at 500mm lw and 600mm ww, with
semicircular bottoms and vertical sides, so I can tell from your
numbers that I am not fatter (well, I am, but the hulls aren't) than
yours.

I need to rework my weight calcs. I think the latest pass made a flat
bottom ww hull too deep to use the hull as the floor, so I might as
well go semi-circular if I have to put a floor in anyway.

- Gardner

On Tue, May 5, 2009 at 10:50 AM, Rob Denney <harryproa@gmail. com> wrote:
>
>
> G'day,
>
> No idea, sorry. Lee hull was 600 wide (I had to be able to get
> inside) and had semi circular sections, but I can't remember where it
> floated. ww hull was probably 800 wide, also with semi circular
> sections, but again, no idea where it floated.
>
> regards,
>
> rob
>
> On Tue, May 5, 2009 at 9:36 PM, Gardner Pomper <gardner@networknow. org>
> wrote:
>>
>>
>> I was looking for the waterline beams and the draft of each hull. Are
>> those the numbers you don't remember, or other sailing numbers?
>>
>> - Gardner
>>
>> On Tue, May 5, 2009 at 9:29 AM, Rob Denney <harryproa@gmail. com> wrote:
>>>
>>>
>>> G'day,
>>>
>>> Harrigami managed 15 in 15 on a reach in flat water. I don't remember
>>> any other performance numbers.
>>>
>>> regards,
>>> Rob
>>>
>>> On Tue, May 5, 2009 at 8:27 PM, Gardner Pomper <gardner@networknow. org>
>>> wrote:
>>>>
>>>>
>>>> Rob,
>>>>
>>>> I would like to compare to a known quantity. I know you have sailed
>>>> Harrigami, and said that it sails at wind speed up to about 15 kts, so
>>>> could you give me the figures for it? I know it is a bit smaller, but
>>>> not that much.
>>>>
>>>> I am very happy to hear that John is anxious to quote. I thought he
>>>> might not be ready for the bigger boats yet and I would have a hard
>>>> time getting his attention. I have just been holding off until I sort
>>>> out the final hull shapes, so that the panel drawings that I send will
>>>> have the correct areas on them. Hopefully I will have that ready by
>>>> the end of the week and can send it off.
>>>>
>>>> Thanks, as always, for all the help!
>>>>
>>>> - Gardner
>>>>
>>>> On Tue, May 5, 2009 at 2:05 AM, Rob Denney <harryproa@gmail. com> wrote:
>>>>>
>>>>>
>>>>> G'day,
>>>>>
>>>>> Aroha has 600mm/2' beam clearance, beams are 200 high x 300 wide (8" x
>>>>> 12") waterline beams are 750 and 500mm (30" and 20").
>>>>>
>>>>> I have not sailed on Aroha, so can't comment on the accuracy of these
>>>>> numbers, nor how well it works. I would prefer more lee hull beam
>>>>> clearance,and would see if the beams could be smaller. Probably go
>>>>> with a mostly solid bridgedeck to help with this.
>>>>>
>>>>> Only other change would be to make it from panels, if I was paying for
>>>>> it. John in China is busting to give you a quote. Any idea when you
>>>>> will have something for him?
>>>>>
>>>>> regards,
>>>>>
>>>>> Rob
>>>>>
>>>>> On Mon, May 4, 2009 at 9:13 PM, Gardner Pomper <gardner@networknow. org>
>>>>> wrote:
>>>>>>
>>>>>>
>>>>>> since my design turned out to be practically identical to harry in
>>>>>> length, width and weight, I would like to check against that design.
>>>>>> Can you tell me what the height is above the water for the beams, and
>>>>>> about what the size of the beams is, since I am just using 1 foot
>>>>>> squares for placeholders now?
>>>>>>
>>>>>> Also what is the waterline beam of each hull?
>>>>>>
>>>>>> Would you change any of that is you were redesigning harry now?
>>>>>>
>>>>>> Thanks
>>>>>> - Gardner
>>>>>>
>>>>>> On Monday, May 4, 2009, Rob Denney <harryproa@gmail. com> wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> G'day,
>>>>>>>
>>>>>>> The weight transfer does not happen until the breeze is pretty
>>>>>>> strong,
>>>>>>> and the speed exceeds the hull speed of a short, fat hull very
>>>>>>> quickly. eg, the 33' windward hull on Rare bird has a hull speed
>>>>>>> (1.34 * the waterline length, in feet) of 7.6 knots, which it gets to
>>>>>>> in under 10 knots of breeze, but the windward hull barely lifts at 20
>>>>>>> knots of wind speed when the boat is capable of 15 knots plus, at
>>>>>>> which speed the drag of the short hull would be immense.
>>>>>>>
>>>>>>> regards,
>>>>>>>
>>>>>>> Rob
>>>>>>>
>>>>>>> On Mon, May 4, 2009 at 4:37 PM, jrwells2007
>>>>>>> <jrwells2007@ yahoo.com. au>
>>>>>>> wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>> Rob, I have read somewhere that cats and tris aim for a minimum of
>>>>>>>> 8:1
>>>>>>>> to
>>>>>>>> prevent stern squatting in the manner of a mono-hull. For the ww
>>>>>>>> hull
>>>>>>>> an
>>>>>>>> 8:1
>>>>>>>> would have lower surface area for a given displacement than an 11:1
>>>>>>>> so
>>>>>>>> less
>>>>>>>> resistance at low speeds. At higher speeds some of the displacement
>>>>>>>> of
>>>>>>>> the
>>>>>>>> ww hull would be carried by the lw hull and therefore the greater
>>>>>>>> wave
>>>>>>>> making resistance of 8:1 would be less of a factor. Are there other
>>>>>>>> more
>>>>>>>> important considerations such as drag on the steering?
>>>>>>>>
>>>>>>>> Longer and skinnier is still better for speed probably.
>>>>>>>>
>>>>>>>>>
>>>>>>>>> The longer and skinnier the better, but as long as it does not drop
>>>>>>>>> below 11:1 l:b, you will be fine.
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>
>>>
>>
>
g t;

Reply | Forward | Messages in this Topic (1)

#5696

From: Doug Haines <doha720@...>
Date: Wed May 6, 2009 9:08 am
Subject:: Re: static moment righting test and speed, plus bonus sail plan tpopic

doha720

Offline

hi again,

perhaps it was closer to 9-9:30 am, which bureau (www.bom.gov.au.....wa...perth...daily observations...melville water), gives average 12knots, gusting to 16/17knots.

so 8,9,10 in 12is good to me. i found it surprising to see what the gps said at first, after so long just knowing that i was going "SLOW", "good" or really GOOd, from feel, wake etc.

what i see as slow is probably a reasonable 5-6 knots, and reasonable speed was actually 7-9 knots, 10 -12 is what i like to get up to when cruising as it seems to be going someplace and passing by coastline rapidly.

the day i went up at 9 knots to lancelin (see video on utube) was probably closer to 10-11 and upwards for a good portion. seeing as i stopped a few times, had to veer around a big offshore construction site? and stop for getting weed off rudders, etc.

this kind of speed is not about breaking records, but the other day i left rottnest and only just got into the fremantle harbuour before the sun went down, the tide got too high or turned and the wind dropped. so its got real world applications even just weekending away.

on a side light - something on the rigs:

the high speeds and low forestay tension reduces the effectiveness of the jib?

therefore uni main is better?

this makes for a big purchase needed on that mainsheet, and shifts CofE of sails backcloser to the rudder, which is not goodd.

assuming schooners suck (personal opinion), where dooes the application to the diffrent haarrries come in.

This is based on chat with Rob, and the Elementarry, solittarry uni rig, and is that going to suit a rapscallion also, but not a visionarry?

doug

--- On Wed, 6/5/09, Doug Haines <doha720@...> wrote:

From: Doug Haines <doha720@...>
Subject: Re: [harryproa] static moment righting test
To: harryproa@...
Date: Wednesday, 6 May, 2009, 6:32 PM

also used gps for halh an hour:

reaches across melville water and back - the port hand marker out in the midlle of the water has the bureaus recording station mounted on it.

The figures for 8:30am are 9knots gusting to 12knots, and for 9am 11 knots gusting to 15knots.

I think I was out there from around 8:30 'till 9am, and the gps reading were giving 6-7 knots inshore starting off, 8-9 knots out in the middle, with a couple of reaches at about 9 knots and gusts shooting speed up over 10,11,12 knots.

Unfortunately rudder turbulence shuts off any acceleration after that, so guesses of potential speed are around 13 knots today and with more wind top speed could be well over 15!

doug

--- On Wed, 6/5/09, Doug Haines <doha720@yahoo. co.uk> wrote:

From: Doug Haines <doha720@yahoo. co.uk>
Subject: [harryproa] static moment righting test
To: harryproa@yahoogrou ps.com.au
Date: Wednesday, 6 May, 2009, 3:13 PM

hi,

got the sidecar up on its side (based on lw hull), with the ww hull sitting up in the air.

It was quite a lift even using halyard to the mast top (me) and lifting/pushing hull (Rob).

got stuck in too tight mast out horizontally with wiggling the wing rotator.

dougg

--- On Wed, 6/5/09, Gardner Pomper <gardner@networknow. org> wrote:

From: Gardner Pomper <gardner@networknow. org>
Subject: Re: [harryproa] Re: Fine tuning design questions
To: harryproa@yahoogrou ps.com.au
Date: Wednesday, 6 May, 2009, 1:41 AM

Hi,

That helps alot. I am looking at 500mm lw and 600mm ww, with
semicircular bottoms and vertical sides, so I can tell from your
numbers that I am not fatter (well, I am, but the hulls aren't) than
yours.

I need to rework my weight calcs. I think the latest pass made a flat
bottom ww hull too deep to use the hull as the floor, so I might as
well go semi-circular if I have to put a floor in anyway.

- Gardner

On Tue, May 5, 2009 at 10:50 AM, Rob Denney <harryproa@gmail. com> wrote:
>
>
> G'day,
>
> No idea, sorry. Lee hull was 600 wide (I had to be able to get
> inside) and had semi circular sections, but I can't remember where it
> floated. ww hull was probably 800 wide, also with semi circular
> sections, but again, no idea where it floated.
>
> regards,
>
> rob
>
> On Tue, May 5, 2009 at 9:36 PM, Gardner Pomper <gardner@networknow. org>
> wrote:
>>
>>
>> I was looking for the waterline beams and the draft of each hull. Are
>> those the numbers you don't remember, or other sailing numbers?
>>
>> - Gardner
>>
>> On Tue, May 5, 2009 at 9:29 AM, Rob Denney <harryproa@gmail. com> wrote:
>>>
>>>
>>> G'day,
>>>
>>> Harrigami managed 15 in 15 on a reach in flat water. I don't remember
>>> any other performance numbers.
>>>
>>> regards,
>>> Rob
>>>
>>> On Tue, May 5, 2009 at 8:27 PM, Gardner Pomper <gardner@networknow. org>
>>> wrote:
>>>>
>>>>
>>>> Rob,
>>>>
>>>> I would like to compare to a known quantity. I know you have sailed
>>>> Harrigami, and said that it sails at wind speed up to about 15 kts, so
>>>> could you give me the figures for it? I know it is a bit smaller, but
>>>> not that much.
>>>>
>>>> I am very happy to hear that John is anxious to quote. I thought he
>>>> might not be ready for the bigger boats yet and I would have a hard
>>>> time getting his attention. I have just been holding off until I sort
>>>> out the final hull shapes, so that the panel drawings that I send will
>>>> have the correct areas on them. Hopefully I will have that ready by
>>>> the end of the week and can send it off.
>>>>
>>>> Thanks, as always, for all the help!
>>>>
>>>> - Gardner
>>>>
>>>> On Tue, May 5, 2009 at 2:05 AM, Rob Denney <harryproa@gmail. com> wrote:
>>>>>
>>>>>
>>>>> G'day,
>>>>>
>>>>> Aroha has 600mm/2' beam clearance, beams are 200 high x 300 wide (8" x
>>>>> 12") waterline beams are 750 and 500mm (30" and 20").
>>>>>
>>>>> I have not sailed on Aroha, so can't comment on the accuracy of these
>>>>> numbers, nor how well it works. I would prefer more lee hull beam
>>>>> clearance,and would see if the beams could be smaller. Probably go
>>>>> with a mostly solid bridgedeck to help with this.
>>>>>
>>>>> Only other change would be to make it from panels, if I was paying for
>>>>> it. John in China is busting to give you a quote. Any idea when you
>>>>> will have something for him?
>>>>>
>>>>> regards,
>>>>>
>>>>> Rob
>>>>>
>>>>> On Mon, May 4, 2009 at 9:13 PM, Gardner Pomper <gardner@networknow. org>
>>>>> wrote:
>>>>>>
>>>>>>
>>>>>> since my design turned out to be practically identical to harry in
>>>>>> length, width and weight, I would like to check against that design.
>>>>>> Can you tell me what the height is above the water for the beams, and
>>>>>> about what the size of the beams is, since I am just using 1 foot
>>>>>> squares for placeholders now?
>>>>>>
>>>>>> Also what is the waterline beam of each hull?
>>>>>>
>>>>>> Would you change any of that is you were redesigning harry now?
>>>>>>
>>>>>> Thanks
>>>>>> - Gardner
>>>>>>
>>>>>> On Monday, May 4, 2009, Rob Denney <harryproa@gmail. com> wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> G'day,
>>>>>>>
>>>>>>> The weight transfer does not happen until the breeze is pretty
>>>>>>> strong,
>>>>>>> and the speed exceeds the hull speed of a short, fat hull very
>>>>>>> quickly. eg, the 33' windward hull on Rare bird has a hull speed
>>>>>>> (1.34 * the waterline length, in feet) of 7.6 knots, which it gets to
>>>>>>> in under 10 knots of breeze, but the windward hull barely lifts at 20
>>>>>>> knots of wind speed when the boat is capable of 15 knots plus, at
>>>>>>> which speed the drag of the short hull would be immense.
>>>>>>>
>>>>>>> regards,
>>>>>>>
>>>>>>> Rob
>>>>>>>
>>>>>>> On Mon, May 4, 2009 at 4:37 PM, jrwells2007
>>>>>>> <jrwells2007@ yahoo.com. au>
>>>>>>> wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>> Rob, I have read somewhere that cats and tris aim for a minimum of
>>>>>>>> 8:1
>>>>>>>> to
>>>>>>>> prevent stern squatting in the manner of a mono-hull. For the ww
>>>>>>>> hull
>>>>>>>> an
>>>>>>>> 8:1
>>>>>>>> would have lower surface area for a given displacement than an 11:1
>>>>>>>> so
>>>>>>>> less
>>>>>>>> resistance at low speeds. At higher speeds some of the displacement
>>>>>>>> of
>>>>>>>> the
>>>>>>>> ww hull would be carried by the lw hull and therefore the greater
>>>>>>>> wave
>>>>>>>> making resistance of 8:1 would be less of a factor. Are there other
>>>>>>>> more
>>>>>>>> important considerations such as drag on the steering?
>>>>>>>>
>>>>>>>> Longer and skinnier is still better for speed probably.
>>>>>>>>
>>>>>>>>>
>>>>>>>>> The longer and skinnier the better, but as long as it does not drop
>>>>>>>>> below 11:1 l:b, you will be fine.
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>
>>>
>>
>
g t;

Reply | Forward | Messages in this Topic (1)

#5695

From: Doug Haines <doha720@...>
Date: Wed May 6, 2009 8:32 am
Subject:: Re: static moment righting test

doha720

Offline

also used gps for halh an hour:

reaches across melville water and back - the port hand marker out in the midlle of the water has the bureaus recording station mounted on it.

The figures for 8:30am are 9knots gusting to 12knots, and for 9am 11 knots gusting to 15knots.

I think I was out there from around 8:30 'till 9am, and the gps reading were giving 6-7 knots inshore starting off, 8-9 knots out in the middle, with a couple of reaches at about 9 knots and gusts shooting speed up over 10,11,12 knots.

Unfortunately rudder turbulence shuts off any acceleration after that, so guesses of potential speed are around 13 knots today and with more wind top speed could be well over 15!

doug

--- On Wed, 6/5/09, Doug Haines <doha720@...> wrote:

From: Doug Haines <doha720@...>
Subject: [harryproa] static moment righting test
To: harryproa@...
Date: Wednesday, 6 May, 2009, 3:13 PM

hi,

got the sidecar up on its side (based on lw hull), with the ww hull sitting up in the air.

It was quite a lift even using halyard to the mast top (me) and lifting/pushing hull (Rob).

got stuck in too tight mast out horizontally with wiggling the wing rotator.

dougg

--- On Wed, 6/5/09, Gardner Pomper <gardner@networknow. org> wrote:

From: Gardner Pomper <gardner@networknow. org>
Subject: Re: [harryproa] Re: Fine tuning design questions
To: harryproa@yahoogrou ps.com.au
Date: Wednesday, 6 May, 2009, 1:41 AM

Hi,

That helps alot. I am looking at 500mm lw and 600mm ww, with
semicircular bottoms and vertical sides, so I can tell from your
numbers that I am not fatter (well, I am, but the hulls aren't) than
yours.

I need to rework my weight calcs. I think the latest pass made a flat
bottom ww hull too deep to use the hull as the floor, so I might as
well go semi-circular if I have to put a floor in anyway.

- Gardner

On Tue, May 5, 2009 at 10:50 AM, Rob Denney <harryproa@gmail. com> wrote:
>
>
> G'day,
>
> No idea, sorry. Lee hull was 600 wide (I had to be able to get
> inside) and had semi circular sections, but I can't remember where it
> floated. ww hull was probably 800 wide, also with semi circular
> sections, but again, no idea where it floated.
>
> regards,
>
> rob
>
> On Tue, May 5, 2009 at 9:36 PM, Gardner Pomper <gardner@networknow. org>
> wrote:
>>
>>
>> I was looking for the waterline beams and the draft of each hull. Are
>> those the numbers you don't remember, or other sailing numbers?
>>
>> - Gardner
>>
>> On Tue, May 5, 2009 at 9:29 AM, Rob Denney <harryproa@gmail. com> wrote:
>>>
>>>
>>> G'day,
>>>
>>> Harrigami managed 15 in 15 on a reach in flat water. I don't remember
>>> any other performance numbers.
>>>
>>> regards,
>>> Rob
>>>
>>> On Tue, May 5, 2009 at 8:27 PM, Gardner Pomper <gardner@networknow. org>
>>> wrote:
>>>>
>>>>
>>>> Rob,
>>>>
>>>> I would like to compare to a known quantity. I know you have sailed
>>>> Harrigami, and said that it sails at wind speed up to about 15 kts, so
>>>> could you give me the figures for it? I know it is a bit smaller, but
>>>> not that much.
>>>>
>>>> I am very happy to hear that John is anxious to quote. I thought he
>>>> might not be ready for the bigger boats yet and I would have a hard
>>>> time getting his attention. I have just been holding off until I sort
>>>> out the final hull shapes, so that the panel drawings that I send will
>>>> have the correct areas on them. Hopefully I will have that ready by
>>>> the end of the week and can send it off.
>>>>
>>>> Thanks, as always, for all the help!
>>>>
>>>> - Gardner
>>>>
>>>> On Tue, May 5, 2009 at 2:05 AM, Rob Denney <harryproa@gmail. com> wrote:
>>>>>
>>>>>
>>>>> G'day,
>>>>>
>>>>> Aroha has 600mm/2' beam clearance, beams are 200 high x 300 wide (8" x
>>>>> 12") waterline beams are 750 and 500mm (30" and 20").
>>>>>
>>>>> I have not sailed on Aroha, so can't comment on the accuracy of these
>>>>> numbers, nor how well it works. I would prefer more lee hull beam
>>>>> clearance,and would see if the beams could be smaller. Probably go
>>>>> with a mostly solid bridgedeck to help with this.
>>>>>
>>>>> Only other change would be to make it from panels, if I was paying for
>>>>> it. John in China is busting to give you a quote. Any idea when you
>>>>> will have something for him?
>>>>>
>>>>> regards,
>>>>>
>>>>> Rob
>>>>>
>>>>> On Mon, May 4, 2009 at 9:13 PM, Gardner Pomper <gardner@networknow. org>
>>>>> wrote:
>>>>>>
>>>>>>
>>>>>> since my design turned out to be practically identical to harry in
>>>>>> length, width and weight, I would like to check against that design.
>>>>>> Can you tell me what the height is above the water for the beams, and
>>>>>> about what the size of the beams is, since I am just using 1 foot
>>>>>> squares for placeholders now?
>>>>>>
>>>>>> Also what is the waterline beam of each hull?
>>>>>>
>>>>>> Would you change any of that is you were redesigning harry now?
>>>>>>
>>>>>> Thanks
>>>>>> - Gardner
>>>>>>
>>>>>> On Monday, May 4, 2009, Rob Denney <harryproa@gmail. com> wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> G'day,
>>>>>>>
>>>>>>> The weight transfer does not happen until the breeze is pretty
>>>>>>> strong,
>>>>>>> and the speed exceeds the hull speed of a short, fat hull very
>>>>>>> quickly. eg, the 33' windward hull on Rare bird has a hull speed
>>>>>>> (1.34 * the waterline length, in feet) of 7.6 knots, which it gets to
>>>>>>> in under 10 knots of breeze, but the windward hull barely lifts at 20
>>>>>>> knots of wind speed when the boat is capable of 15 knots plus, at
>>>>>>> which speed the drag of the short hull would be immense.
>>>>>>>
>>>>>>> regards,
>>>>>>>
>>>>>>> Rob
>>>>>>>
>>>>>>> On Mon, May 4, 2009 at 4:37 PM, jrwells2007
>>>>>>> <jrwells2007@ yahoo.com. au>
>>>>>>> wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>> Rob, I have read somewhere that cats and tris aim for a minimum of
>>>>>>>> 8:1
>>>>>>>> to
>>>>>>>> prevent stern squatting in the manner of a mono-hull. For the ww
>>>>>>>> hull
>>>>>>>> an
>>>>>>>> 8:1
>>>>>>>> would have lower surface area for a given displacement than an 11:1
>>>>>>>> so
>>>>>>>> less
>>>>>>>> resistance at low speeds. At higher speeds some of the displacement
>>>>>>>> of
>>>>>>>> the
>>>>>>>> ww hull would be carried by the lw hull and therefore the greater
>>>>>>>> wave
>>>>>>>> making resistance of 8:1 would be less of a factor. Are there other
>>>>>>>> more
>>>>>>>> important considerations such as drag on the steering?
>>>>>>>>
>>>>>>>> Longer and skinnier is still better for speed probably.
>>>>>>>>
>>>>>>>>>
>>>>>>>>> The longer and skinnier the better, but as long as it does not drop
>>>>>>>>> below 11:1 l:b, you will be fine.
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>
>>>
>>
>
g t;

Reply | Forward | Messages in this Topic (2)

#5694

From: Doug Haines <doha720@...>
Date: Wed May 6, 2009 5:13 am
Subject:: static moment righting test

doha720

Offline

hi,

got the sidecar up on its side (based on lw hull), with the ww hull sitting up in the air.

It was quite a lift even using halyard to the mast top (me) and lifting/pushing hull (Rob).

got stuck in too tight mast out horizontally with wiggling the wing rotator.

dougg

--- On Wed, 6/5/09, Gardner Pomper <gardner@...> wrote:

From: Gardner Pomper <gardner@...>
Subject: Re: [harryproa] Re: Fine tuning design questions
To: harryproa@...
Date: Wednesday, 6 May, 2009, 1:41 AM

Hi,

That helps alot. I am looking at 500mm lw and 600mm ww, with
semicircular bottoms and vertical sides, so I can tell from your
numbers that I am not fatter (well, I am, but the hulls aren't) than
yours.

I need to rework my weight calcs. I think the latest pass made a flat
bottom ww hull too deep to use the hull as the floor, so I might as
well go semi-circular if I have to put a floor in anyway.

- Gardner

On Tue, May 5, 2009 at 10:50 AM, Rob Denney <harryproa@gmail. com> wrote:
>
>
> G'day,
>
> No idea, sorry. Lee hull was 600 wide (I had to be able to get
> inside) and had semi circular sections, but I can't remember where it
> floated. ww hull was probably 800 wide, also with semi circular
> sections, but again, no idea where it floated.
>
> regards,
>
> rob
>
> On Tue, May 5, 2009 at 9:36 PM, Gardner Pomper <gardner@networknow. org>
> wrote:
>>
>>
>> I was looking for the waterline beams and the draft of each hull. Are
>> those the numbers you don't remember, or other sailing numbers?
>>
>> - Gardner
>>
>> On Tue, May 5, 2009 at 9:29 AM, Rob Denney <harryproa@gmail. com> wrote:
>>>
>>>
>>> G'day,
>>>
>>> Harrigami managed 15 in 15 on a reach in flat water. I don't remember
>>> any other performance numbers.
>>>
>>> regards,
>>> Rob
>>>
>>> On Tue, May 5, 2009 at 8:27 PM, Gardner Pomper <gardner@networknow. org>
>>> wrote:
>>>>
>>>>
>>>> Rob,
>>>>
>>>> I would like to compare to a known quantity. I know you have sailed
>>>> Harrigami, and said that it sails at wind speed up to about 15 kts, so
>>>> could you give me the figures for it? I know it is a bit smaller, but
>>>> not that much.
>>>>
>>>> I am very happy to hear that John is anxious to quote. I thought he
>>>> might not be ready for the bigger boats yet and I would have a hard
>>>> time getting his attention. I have just been holding off until I sort
>>>> out the final hull shapes, so that the panel drawings that I send will
>>>> have the correct areas on them. Hopefully I will have that ready by
>>>> the end of the week and can send it off.
>>>>
>>>> Thanks, as always, for all the help!
>>>>
>>>> - Gardner
>>>>
>>>> On Tue, May 5, 2009 at 2:05 AM, Rob Denney <harryproa@gmail. com> wrote:
>>>>>
>>>>>
>>>>> G'day,
>>>>>
>>>>> Aroha has 600mm/2' beam clearance, beams are 200 high x 300 wide (8" x
>>>>> 12") waterline beams are 750 and 500mm (30" and 20").
>>>>>
>>>>> I have not sailed on Aroha, so can't comment on the accuracy of these
>>>>> numbers, nor how well it works. I would prefer more lee hull beam
>>>>> clearance,and would see if the beams could be smaller. Probably go
>>>>> with a mostly solid bridgedeck to help with this.
>>>>>
>>>>> Only other change would be to make it from panels, if I was paying for
>>>>> it. John in China is busting to give you a quote. Any idea when you
>>>>> will have something for him?
>>>>>
>>>>> regards,
>>>>>
>>>>> Rob
>>>>>
>>>>> On Mon, May 4, 2009 at 9:13 PM, Gardner Pomper <gardner@networknow. org>
>>>>> wrote:
>>>>>>
>>>>>>
>>>>>> since my design turned out to be practically identical to harry in
>>>>>> length, width and weight, I would like to check against that design.
>>>>>> Can you tell me what the height is above the water for the beams, and
>>>>>> about what the size of the beams is, since I am just using 1 foot
>>>>>> squares for placeholders now?
>>>>>>
>>>>>> Also what is the waterline beam of each hull?
>>>>>>
>>>>>> Would you change any of that is you were redesigning harry now?
>>>>>>
>>>>>> Thanks
>>>>>> - Gardner
>>>>>>
>>>>>> On Monday, May 4, 2009, Rob Denney <harryproa@gmail. com> wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> G'day,
>>>>>>>
>>>>>>> The weight transfer does not happen until the breeze is pretty
>>>>>>> strong,
>>>>>>> and the speed exceeds the hull speed of a short, fat hull very
>>>>>>> quickly. eg, the 33' windward hull on Rare bird has a hull speed
>>>>>>> (1.34 * the waterline length, in feet) of 7.6 knots, which it gets to
>>>>>>> in under 10 knots of breeze, but the windward hull barely lifts at 20
>>>>>>> knots of wind speed when the boat is capable of 15 knots plus, at
>>>>>>> which speed the drag of the short hull would be immense.
>>>>>>>
>>>>>>> regards,
>>>>>>>
>>>>>>> Rob
>>>>>>>
>>>>>>> On Mon, May 4, 2009 at 4:37 PM, jrwells2007
>>>>>>> <jrwells2007@ yahoo.com. au>
>>>>>>> wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>> Rob, I have read somewhere that cats and tris aim for a minimum of
>>>>>>>> 8:1
>>>>>>>> to
>>>>>>>> prevent stern squatting in the manner of a mono-hull. For the ww
>>>>>>>> hull
>>>>>>>> an
>>>>>>>> 8:1
>>>>>>>> would have lower surface area for a given displacement than an 11:1
>>>>>>>> so
>>>>>>>> less
>>>>>>>> resistance at low speeds. At higher speeds some of the displacement
>>>>>>>> of
>>>>>>>> the
>>>>>>>> ww hull would be carried by the lw hull and therefore the greater
>>>>>>>> wave
>>>>>>>> making resistance of 8:1 would be less of a factor. Are there other
>>>>>>>> more
>>>>>>>> important considerations such as drag on the steering?
>>>>>>>>
>>>>>>>> Longer and skinnier is still better for speed probably.
>>>>>>>>
>>>>>>>>>
>>>>>>>>> The longer and skinnier the better, but as long as it does not drop
>>>>>>>>> below 11:1 l:b, you will be fine.
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>
>>>
>>
>
gt;

Reply | Forward | Messages in this Topic (2)

#5693

From: Gardner Pomper <gardner@...>
Date: Tue May 5, 2009 3:41 pm
Subject:: Re: Re: Fine tuning design questions

gardnerpomper

Offline

Hi,

That helps alot. I am looking at 500mm lw and 600mm ww, with
semicircular bottoms and vertical sides, so I can tell from your
numbers that I am not fatter (well, I am, but the hulls aren't) than
yours.

I need to rework my weight calcs. I think the latest pass made a flat
bottom ww hull too deep to use the hull as the floor, so I might as
well go semi-circular if I have to put a floor in anyway.

- Gardner

On Tue, May 5, 2009 at 10:50 AM, Rob Denney <harryproa@...> wrote:
>
>
> G'day,
>
> No idea, sorry. Lee hull was 600 wide (I had to be able to get
> inside) and had semi circular sections, but I can't remember where it
> floated. ww hull was probably 800 wide, also with semi circular
> sections, but again, no idea where it floated.
>
> regards,
>
> rob
>
> On Tue, May 5, 2009 at 9:36 PM, Gardner Pomper <gardner@...>
> wrote:
>>
>>
>> I was looking for the waterline beams and the draft of each hull. Are
>> those the numbers you don't remember, or other sailing numbers?
>>
>> - Gardner
>>
>> On Tue, May 5, 2009 at 9:29 AM, Rob Denney <harryproa@...> wrote:
>>>
>>>
>>> G'day,
>>>
>>> Harrigami managed 15 in 15 on a reach in flat water. I don't remember
>>> any other performance numbers.
>>>
>>> regards,
>>> Rob
>>>
>>> On Tue, May 5, 2009 at 8:27 PM, Gardner Pomper <gardner@...>
>>> wrote:
>>>>
>>>>
>>>> Rob,
>>>>
>>>> I would like to compare to a known quantity. I know you have sailed
>>>> Harrigami, and said that it sails at wind speed up to about 15 kts, so
>>>> could you give me the figures for it? I know it is a bit smaller, but
>>>> not that much.
>>>>
>>>> I am very happy to hear that John is anxious to quote. I thought he
>>>> might not be ready for the bigger boats yet and I would have a hard
>>>> time getting his attention. I have just been holding off until I sort
>>>> out the final hull shapes, so that the panel drawings that I send will
>>>> have the correct areas on them. Hopefully I will have that ready by
>>>> the end of the week and can send it off.
>>>>
>>>> Thanks, as always, for all the help!
>>>>
>>>> - Gardner
>>>>
>>>> On Tue, May 5, 2009 at 2:05 AM, Rob Denney <harryproa@...> wrote:
>>>>>
>>>>>
>>>>> G'day,
>>>>>
>>>>> Aroha has 600mm/2' beam clearance, beams are 200 high x 300 wide (8" x
>>>>> 12") waterline beams are 750 and 500mm (30" and 20").
>>>>>
>>>>> I have not sailed on Aroha, so can't comment on the accuracy of these
>>>>> numbers, nor how well it works. I would prefer more lee hull beam
>>>>> clearance,and would see if the beams could be smaller. Probably go
>>>>> with a mostly solid bridgedeck to help with this.
>>>>>
>>>>> Only other change would be to make it from panels, if I was paying for
>>>>> it. John in China is busting to give you a quote. Any idea when you
>>>>> will have something for him?
>>>>>
>>>>> regards,
>>>>>
>>>>> Rob
>>>>>
>>>>> On Mon, May 4, 2009 at 9:13 PM, Gardner Pomper <gardner@...>
>>>>> wrote:
>>>>>>
>>>>>>
>>>>>> since my design turned out to be practically identical to harry in
>>>>>> length, width and weight, I would like to check against that design.
>>>>>> Can you tell me what the height is above the water for the beams, and
>>>>>> about what the size of the beams is, since I am just using 1 foot
>>>>>> squares for placeholders now?
>>>>>>
>>>>>> Also what is the waterline beam of each hull?
>>>>>>
>>>>>> Would you change any of that is you were redesigning harry now?
>>>>>>
>>>>>> Thanks
>>>>>> - Gardner
>>>>>>
>>>>>> On Monday, May 4, 2009, Rob Denney <harryproa@...> wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> G'day,
>>>>>>>
>>>>>>> The weight transfer does not happen until the breeze is pretty
>>>>>>> strong,
>>>>>>> and the speed exceeds the hull speed of a short, fat hull very
>>>>>>> quickly. eg, the 33' windward hull on Rare bird has a hull speed
>>>>>>> (1.34 * the waterline length, in feet) of 7.6 knots, which it gets to
>>>>>>> in under 10 knots of breeze, but the windward hull barely lifts at 20
>>>>>>> knots of wind speed when the boat is capable of 15 knots plus, at
>>>>>>> which speed the drag of the short hull would be immense.
>>>>>>>
>>>>>>> regards,
>>>>>>>
>>>>>>> Rob
>>>>>>>
>>>>>>> On Mon, May 4, 2009 at 4:37 PM, jrwells2007
>>>>>>> <jrwells2007@...>
>>>>>>> wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>> Rob, I have read somewhere that cats and tris aim for a minimum of
>>>>>>>> 8:1
>>>>>>>> to
>>>>>>>> prevent stern squatting in the manner of a mono-hull. For the ww
>>>>>>>> hull
>>>>>>>> an
>>>>>>>> 8:1
>>>>>>>> would have lower surface area for a given displacement than an 11:1
>>>>>>>> so
>>>>>>>> less
>>>>>>>> resistance at low speeds. At higher speeds some of the displacement
>>>>>>>> of
>>>>>>>> the
>>>>>>>> ww hull would be carried by the lw hull and therefore the greater
>>>>>>>> wave
>>>>>>>> making resistance of 8:1 would be less of a factor. Are there other
>>>>>>>> more
>>>>>>>> important considerations such as drag on the steering?
>>>>>>>>
>>>>>>>> Longer and skinnier is still better for speed probably.
>>>>>>>>
>>>>>>>>>
>>>>>>>>> The longer and skinnier the better, but as long as it does not drop
>>>>>>>>> below 11:1 l:b, you will be fine.
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>
>>>
>>
>
>

#5692

From: Rob Denney <harryproa@...>
Date: Tue May 5, 2009 2:50 pm
Subject:: Re: Re: Fine tuning design questions

proaharry

Offline

G'day,

No idea, sorry.  Lee hull was 600 wide (I had to be able to get
inside) and had semi circular sections, but I can't remember where it
floated.  ww hull was probably 800 wide, also with semi circular
sections, but again, no idea where it floated.

regards,

rob

On Tue, May 5, 2009 at 9:36 PM, Gardner Pomper <gardner@...> wrote:
>
>
> I was looking for the waterline beams and the draft of each hull. Are
> those the numbers you don't remember, or other sailing numbers?
>
> - Gardner
>
> On Tue, May 5, 2009 at 9:29 AM, Rob Denney <harryproa@...> wrote:
>>
>>
>> G'day,
>>
>> Harrigami managed 15 in 15 on a reach in flat water. I don't remember
>> any other performance numbers.
>>
>> regards,
>> Rob
>>
>> On Tue, May 5, 2009 at 8:27 PM, Gardner Pomper <gardner@...>
>> wrote:
>>>
>>>
>>> Rob,
>>>
>>> I would like to compare to a known quantity. I know you have sailed
>>> Harrigami, and said that it sails at wind speed up to about 15 kts, so
>>> could you give me the figures for it? I know it is a bit smaller, but
>>> not that much.
>>>
>>> I am very happy to hear that John is anxious to quote. I thought he
>>> might not be ready for the bigger boats yet and I would have a hard
>>> time getting his attention. I have just been holding off until I sort
>>> out the final hull shapes, so that the panel drawings that I send will
>>> have the correct areas on them. Hopefully I will have that ready by
>>> the end of the week and can send it off.
>>>
>>> Thanks, as always, for all the help!
>>>
>>> - Gardner
>>>
>>> On Tue, May 5, 2009 at 2:05 AM, Rob Denney <harryproa@...> wrote:
>>>>
>>>>
>>>> G'day,
>>>>
>>>> Aroha has 600mm/2' beam clearance, beams are 200 high x 300 wide (8" x
>>>> 12") waterline beams are 750 and 500mm (30" and 20").
>>>>
>>>> I have not sailed on Aroha, so can't comment on the accuracy of these
>>>> numbers, nor how well it works. I would prefer more lee hull beam
>>>> clearance,and would see if the beams could be smaller. Probably go
>>>> with a mostly solid bridgedeck to help with this.
>>>>
>>>> Only other change would be to make it from panels, if I was paying for
>>>> it. John in China is busting to give you a quote. Any idea when you
>>>> will have something for him?
>>>>
>>>> regards,
>>>>
>>>> Rob
>>>>
>>>> On Mon, May 4, 2009 at 9:13 PM, Gardner Pomper <gardner@...>
>>>> wrote:
>>>>>
>>>>>
>>>>> since my design turned out to be practically identical to harry in
>>>>> length, width and weight, I would like to check against that design.
>>>>> Can you tell me what the height is above the water for the beams, and
>>>>> about what the size of the beams is, since I am just using 1 foot
>>>>> squares for placeholders now?
>>>>>
>>>>> Also what is the waterline beam of each hull?
>>>>>
>>>>> Would you change any of that is you were redesigning harry now?
>>>>>
>>>>> Thanks
>>>>> - Gardner
>>>>>
>>>>> On Monday, May 4, 2009, Rob Denney <harryproa@...> wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> G'day,
>>>>>>
>>>>>> The weight transfer does not happen until the breeze is pretty strong,
>>>>>> and the speed exceeds the hull speed of a short, fat hull very
>>>>>> quickly. eg, the 33' windward hull on Rare bird has a hull speed
>>>>>> (1.34 * the waterline length, in feet) of 7.6 knots, which it gets to
>>>>>> in under 10 knots of breeze, but the windward hull barely lifts at 20
>>>>>> knots of wind speed when the boat is capable of 15 knots plus, at
>>>>>> which speed the drag of the short hull would be immense.
>>>>>>
>>>>>> regards,
>>>>>>
>>>>>> Rob
>>>>>>
>>>>>> On Mon, May 4, 2009 at 4:37 PM, jrwells2007 <jrwells2007@...>
>>>>>> wrote:
>>>>>>>
>>>>>>>
>>>>>>> Rob, I have read somewhere that cats and tris aim for a minimum of
>>>>>>> 8:1
>>>>>>> to
>>>>>>> prevent stern squatting in the manner of a mono-hull. For the ww hull
>>>>>>> an
>>>>>>> 8:1
>>>>>>> would have lower surface area for a given displacement than an 11:1
>>>>>>> so
>>>>>>> less
>>>>>>> resistance at low speeds. At higher speeds some of the displacement
>>>>>>> of
>>>>>>> the
>>>>>>> ww hull would be carried by the lw hull and therefore the greater
>>>>>>> wave
>>>>>>> making resistance of 8:1 would be less of a factor. Are there other
>>>>>>> more
>>>>>>> important considerations such as drag on the steering?
>>>>>>>
>>>>>>> Longer and skinnier is still better for speed probably.
>>>>>>>
>>>>>>>>
>>>>>>>> The longer and skinnier the better, but as long as it does not drop
>>>>>>>> below 11:1 l:b, you will be fine.
>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>
>>>>
>>>
>>
>>
>

#5691

From: Gardner Pomper <gardner@...>
Date: Tue May 5, 2009 1:36 pm
Subject:: Re: Re: Fine tuning design questions

gardnerpomper

Offline

I was looking for the waterline beams and the draft of each hull. Are
those the numbers you don't remember, or other sailing numbers?

- Gardner

On Tue, May 5, 2009 at 9:29 AM, Rob Denney <harryproa@...> wrote:
>
>
> G'day,
>
> Harrigami managed 15 in 15 on a reach in flat water. I don't remember
> any other performance numbers.
>
> regards,
> Rob
>
> On Tue, May 5, 2009 at 8:27 PM, Gardner Pomper <gardner@...>
> wrote:
>>
>>
>> Rob,
>>
>> I would like to compare to a known quantity. I know you have sailed
>> Harrigami, and said that it sails at wind speed up to about 15 kts, so
>> could you give me the figures for it? I know it is a bit smaller, but
>> not that much.
>>
>> I am very happy to hear that John is anxious to quote. I thought he
>> might not be ready for the bigger boats yet and I would have a hard
>> time getting his attention. I have just been holding off until I sort
>> out the final hull shapes, so that the panel drawings that I send will
>> have the correct areas on them. Hopefully I will have that ready by
>> the end of the week and can send it off.
>>
>> Thanks, as always, for all the help!
>>
>> - Gardner
>>
>> On Tue, May 5, 2009 at 2:05 AM, Rob Denney <harryproa@...> wrote:
>>>
>>>
>>> G'day,
>>>
>>> Aroha has 600mm/2' beam clearance, beams are 200 high x 300 wide (8" x
>>> 12") waterline beams are 750 and 500mm (30" and 20").
>>>
>>> I have not sailed on Aroha, so can't comment on the accuracy of these
>>> numbers, nor how well it works. I would prefer more lee hull beam
>>> clearance,and would see if the beams could be smaller. Probably go
>>> with a mostly solid bridgedeck to help with this.
>>>
>>> Only other change would be to make it from panels, if I was paying for
>>> it. John in China is busting to give you a quote. Any idea when you
>>> will have something for him?
>>>
>>> regards,
>>>
>>> Rob
>>>
>>> On Mon, May 4, 2009 at 9:13 PM, Gardner Pomper <gardner@...>
>>> wrote:
>>>>
>>>>
>>>> since my design turned out to be practically identical to harry in
>>>> length, width and weight, I would like to check against that design.
>>>> Can you tell me what the height is above the water for the beams, and
>>>> about what the size of the beams is, since I am just using 1 foot
>>>> squares for placeholders now?
>>>>
>>>> Also what is the waterline beam of each hull?
>>>>
>>>> Would you change any of that is you were redesigning harry now?
>>>>
>>>> Thanks
>>>> - Gardner
>>>>
>>>> On Monday, May 4, 2009, Rob Denney <harryproa@...> wrote:
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> G'day,
>>>>>
>>>>> The weight transfer does not happen until the breeze is pretty strong,
>>>>> and the speed exceeds the hull speed of a short, fat hull very
>>>>> quickly. eg, the 33' windward hull on Rare bird has a hull speed
>>>>> (1.34 * the waterline length, in feet) of 7.6 knots, which it gets to
>>>>> in under 10 knots of breeze, but the windward hull barely lifts at 20
>>>>> knots of wind speed when the boat is capable of 15 knots plus, at
>>>>> which speed the drag of the short hull would be immense.
>>>>>
>>>>> regards,
>>>>>
>>>>> Rob
>>>>>
>>>>> On Mon, May 4, 2009 at 4:37 PM, jrwells2007 <jrwells2007@...>
>>>>> wrote:
>>>>>>
>>>>>>
>>>>>> Rob, I have read somewhere that cats and tris aim for a minimum of 8:1
>>>>>> to
>>>>>> prevent stern squatting in the manner of a mono-hull. For the ww hull
>>>>>> an
>>>>>> 8:1
>>>>>> would have lower surface area for a given displacement than an 11:1 so
>>>>>> less
>>>>>> resistance at low speeds. At higher speeds some of the displacement of
>>>>>> the
>>>>>> ww hull would be carried by the lw hull and therefore the greater wave
>>>>>> making resistance of 8:1 would be less of a factor. Are there other
>>>>>> more
>>>>>> important considerations such as drag on the steering?
>>>>>>
>>>>>> Longer and skinnier is still better for speed probably.
>>>>>>
>>>>>>>
>>>>>>> The longer and skinnier the better, but as long as it does not drop
>>>>>>> below 11:1 l:b, you will be fine.
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>
>>>
>>
>
>

#5690

From: Rob Denney <harryproa@...>
Date: Tue May 5, 2009 1:29 pm
Subject:: Re: Re: Fine tuning design questions

proaharry

Offline

G'day,

Harrigami managed 15 in 15 on a reach in flat water.  I don't remember
any other performance numbers.

regards,
Rob

On Tue, May 5, 2009 at 8:27 PM, Gardner Pomper <gardner@...> wrote:
>
>
> Rob,
>
> I would like to compare to a known quantity. I know you have sailed
> Harrigami, and said that it sails at wind speed up to about 15 kts, so
> could you give me the figures for it? I know it is a bit smaller, but
> not that much.
>
> I am very happy to hear that John is anxious to quote. I thought he
> might not be ready for the bigger boats yet and I would have a hard
> time getting his attention. I have just been holding off until I sort
> out the final hull shapes, so that the panel drawings that I send will
> have the correct areas on them. Hopefully I will have that ready by
> the end of the week and can send it off.
>
> Thanks, as always, for all the help!
>
> - Gardner
>
> On Tue, May 5, 2009 at 2:05 AM, Rob Denney <harryproa@...> wrote:
>>
>>
>> G'day,
>>
>> Aroha has 600mm/2' beam clearance, beams are 200 high x 300 wide (8" x
>> 12") waterline beams are 750 and 500mm (30" and 20").
>>
>> I have not sailed on Aroha, so can't comment on the accuracy of these
>> numbers, nor how well it works. I would prefer more lee hull beam
>> clearance,and would see if the beams could be smaller. Probably go
>> with a mostly solid bridgedeck to help with this.
>>
>> Only other change would be to make it from panels, if I was paying for
>> it. John in China is busting to give you a quote. Any idea when you
>> will have something for him?
>>
>> regards,
>>
>> Rob
>>
>> On Mon, May 4, 2009 at 9:13 PM, Gardner Pomper <gardner@...>
>> wrote:
>>>
>>>
>>> since my design turned out to be practically identical to harry in
>>> length, width and weight, I would like to check against that design.
>>> Can you tell me what the height is above the water for the beams, and
>>> about what the size of the beams is, since I am just using 1 foot
>>> squares for placeholders now?
>>>
>>> Also what is the waterline beam of each hull?
>>>
>>> Would you change any of that is you were redesigning harry now?
>>>
>>> Thanks
>>> - Gardner
>>>
>>> On Monday, May 4, 2009, Rob Denney <harryproa@...> wrote:
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> G'day,
>>>>
>>>> The weight transfer does not happen until the breeze is pretty strong,
>>>> and the speed exceeds the hull speed of a short, fat hull very
>>>> quickly. eg, the 33' windward hull on Rare bird has a hull speed
>>>> (1.34 * the waterline length, in feet) of 7.6 knots, which it gets to
>>>> in under 10 knots of breeze, but the windward hull barely lifts at 20
>>>> knots of wind speed when the boat is capable of 15 knots plus, at
>>>> which speed the drag of the short hull would be immense.
>>>>
>>>> regards,
>>>>
>>>> Rob
>>>>
>>>> On Mon, May 4, 2009 at 4:37 PM, jrwells2007 <jrwells2007@...>
>>>> wrote:
>>>>>
>>>>>
>>>>> Rob, I have read somewhere that cats and tris aim for a minimum of 8:1
>>>>> to
>>>>> prevent stern squatting in the manner of a mono-hull. For the ww hull
>>>>> an
>>>>> 8:1
>>>>> would have lower surface area for a given displacement than an 11:1 so
>>>>> less
>>>>> resistance at low speeds. At higher speeds some of the displacement of
>>>>> the
>>>>> ww hull would be carried by the lw hull and therefore the greater wave
>>>>> making resistance of 8:1 would be less of a factor. Are there other
>>>>> more
>>>>> important considerations such as drag on the steering?
>>>>>
>>>>> Longer and skinnier is still better for speed probably.
>>>>>
>>>>>>
>>>>>> The longer and skinnier the better, but as long as it does not drop
>>>>>> below 11:1 l:b, you will be fine.
>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>
>>
>

#5689

From: Rob Denney <harryproa@...>
Date: Tue May 5, 2009 1:00 pm
Subject:: Re: Re: Aroha sailing to New Zealand Any News?

proaharry

Offline

G'day,

No news.  No confirmation they have actually left for NZ, either.    I
spoke to NZ customs who know nothing.  Will try Aus customs and see if
they have any news.

regards,

Rob

#5688

From: Gardner Pomper <gardner@...>
Date: Tue May 5, 2009 12:27 pm
Subject:: Re: Re: Fine tuning design questions

gardnerpomper

Offline

Rob,

I would like to compare to a known quantity. I know you have sailed
Harrigami, and said that it sails at wind speed up to about 15 kts, so
could you give me the figures for it? I know it is a bit smaller, but
not that much.

I am very happy to hear that John is anxious to quote. I thought he
might not be ready for the bigger boats yet and I would have a hard
time getting his attention. I have just been holding off until I sort
out the final hull shapes, so that the panel drawings that I send will
have the correct areas on them. Hopefully I will have that ready by
the end of the week and can send it off.

Thanks, as always, for all the help!

- Gardner

On Tue, May 5, 2009 at 2:05 AM, Rob Denney <harryproa@...> wrote:
>
>
> G'day,
>
> Aroha has 600mm/2' beam clearance, beams are 200 high x 300 wide (8" x
> 12") waterline beams are 750 and 500mm (30" and 20").
>
> I have not sailed on Aroha, so can't comment on the accuracy of these
> numbers, nor how well it works. I would prefer more lee hull beam
> clearance,and would see if the beams could be smaller. Probably go
> with a mostly solid bridgedeck to help with this.
>
> Only other change would be to make it from panels, if I was paying for
> it. John in China is busting to give you a quote. Any idea when you
> will have something for him?
>
> regards,
>
> Rob
>
> On Mon, May 4, 2009 at 9:13 PM, Gardner Pomper <gardner@...>
> wrote:
>>
>>
>> since my design turned out to be practically identical to harry in
>> length, width and weight, I would like to check against that design.
>> Can you tell me what the height is above the water for the beams, and
>> about what the size of the beams is, since I am just using 1 foot
>> squares for placeholders now?
>>
>> Also what is the waterline beam of each hull?
>>
>> Would you change any of that is you were redesigning harry now?
>>
>> Thanks
>> - Gardner
>>
>> On Monday, May 4, 2009, Rob Denney <harryproa@...> wrote:
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> G'day,
>>>
>>> The weight transfer does not happen until the breeze is pretty strong,
>>> and the speed exceeds the hull speed of a short, fat hull very
>>> quickly. eg, the 33' windward hull on Rare bird has a hull speed
>>> (1.34 * the waterline length, in feet) of 7.6 knots, which it gets to
>>> in under 10 knots of breeze, but the windward hull barely lifts at 20
>>> knots of wind speed when the boat is capable of 15 knots plus, at
>>> which speed the drag of the short hull would be immense.
>>>
>>> regards,
>>>
>>> Rob
>>>
>>> On Mon, May 4, 2009 at 4:37 PM, jrwells2007 <jrwells2007@...>
>>> wrote:
>>>>
>>>>
>>>> Rob, I have read somewhere that cats and tris aim for a minimum of 8:1
>>>> to
>>>> prevent stern squatting in the manner of a mono-hull. For the ww hull an
>>>> 8:1
>>>> would have lower surface area for a given displacement than an 11:1 so
>>>> less
>>>> resistance at low speeds. At higher speeds some of the displacement of
>>>> the
>>>> ww hull would be carried by the lw hull and therefore the greater wave
>>>> making resistance of 8:1 would be less of a factor. Are there other more
>>>> important considerations such as drag on the steering?
>>>>
>>>> Longer and skinnier is still better for speed probably.
>>>>
>>>>>
>>>>> The longer and skinnier the better, but as long as it does not drop
>>>>> below 11:1 l:b, you will be fine.
>>>>
>>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>
>

#5687

From: Mike Crawford <jmichael@...>
Date: Tue May 5, 2009 11:32 am
Subject:: Re: Can you cut a carbon mast in half, then repair it?

jmichaelcraw...

Offline

That's interesting. I was thinking it would make more sense to cut it 39 feet from the bottom, so the join will be in an area of low stress.

Perhaps halfway is a good compromise: lower stress, and in an area where the bend is less important.

- Mike

Daniel wrote:

Why cut the mast in half?

Why not cut it 39 feet from the top?
This will put the join closer to the bottom of the mast where not so much bend is needed

deepee
OZ

Reply | Forward | Messages in this Topic (24)

#5686

From: "Daniel" <deepee58@...>
Date: Tue May 5, 2009 11:00 am
Subject:: Re: Can you cut a carbon mast in half, then repair it?

deepee58rabaul

Offline

Why cut the mast in half?

Why not cut it 39 feet from the top?
This will put the join closer to the bottom of the mast where not so much bend
is needed

deepee
OZ

Reply | Forward | Messages in this Topic (24)

#5685

From: "Paul Bowker" <paul.lis.bowker@...>
Date: Tue May 5, 2009 10:53 am
Subject:: Re: Aroha sailing to New Zealand Any News?

taikaha

Offline

--- In harryproa@..., "Paul Bowker" <paul.lis.bowker@...> wrote:
>
> --- In harryproa@..., Doug Haines <doha720@> wrote:
> >
> > good weather this week compared to last few weeks.
> > real intense lows were�hanging around in the tasman sea.
> > how�far is it?
> > doug�
> >
> > --- On Wed, 29/4/09, Rob Denney <harryproa@> wrote:
> >
> >
> > From: Rob Denney <harryproa@>
> > Subject: [harryproa] Aroha sailing to New Zealand
> > To: harryproa@...
> > Date: Wednesday, 29 April, 2009, 3:11 PM
> >
> >
> >
> >
> >
> >
> >
> >
> > G'day,
> >
> > Apparently Aroha (12m harry) woth Bain and Gomati onboard have left Coffs
Harbour en route for Whangerei on the east coast of New Zealand.�
> >
> > More details if/when I get them.
> >
> > regards,
> > Rob
> >
>  Have to look out for them, suggest post on Proafile too.
> Just had some really ugly weather, but know of someone who came across the
ditch 2 weeks ago with more calms than they wanted and took well over 2 weeks
from Brisbane to Opua, I was told they were  hungry when they got to NZ.
>
> Would love to see Aroha.
>
> Regards
>
> Paul
> Rawene NZ
>

#5684

From: Doug Haines <doha720@...>
Date: Tue May 5, 2009 10:42 am
Subject:: Re: Re: Fine tuning design questions

doha720

Offline

hi robert,

i have gone up through the top of a big wave and come down with a little bit of a slap, but really nothing much. lw hull that is. ww never gets out much.

V front would lose that buoyat response!

doug

--- On Mon, 4/5/09, Robert <cateran1949@...> wrote:

From: Robert <cateran1949@...>
Subject: [harryproa] Re: Fine tuning design questions
To: harryproa@...
Date: Monday, 4 May, 2009, 8:50 PM

When doing calculations of surface area, I found that with the displacement of Harrys, from about 12:1 to about 16:1 for the ww hulll there was not a great difference in surface area. It doesn't need much power to start getting into displacement speeds for the ww hull and so an 8:1 would give a fair bit of drag at those intermediate speeds before there was significant weight transfer. It is hard to set up a shunting sailing boat for planing and not go to too much form drag at lower speeds without having significant moveable ballast, though I am looking at having a slight flare back from the bows a bit to get a little lift when going through chop. This allows a bit more room in the hulls while keeping the waterline skinny. I would not go below 12:1 myself.
I can't see any advantage of rocker with a shunting vessel with two rudders. It means a fatter or deeper hull overall, more susceptibility to hobbyhorsing, and greater bow depression when pushing hard. It may be worth rounding the forefoot slightly to reduce damage and I am looking at a v for the last 8% to handle coming off the top of a wave and slamming down in fairly extreme conditions and reverse stem to make working through heavy chop that little bit easier--- In harryproa@yahoogrou ps.com.au, "jrwells2007" <jrwells2007@ ...> wrote:
>
> Rob, I have read somewhere that cats and tris aim for a minimum of 8:1 to prevent stern squatting in the manner of a mono-hull. For the ww hull an 8:1 would have lower surface area for a given displacement than an 11:1 so less resistance at low speeds. At higher speeds some of the displacement of the ww hull would be carried by the lw hull and therefore the greater wave making resistance of 8:1 would be less of a factor. Are there other more important considerations such as drag on the steering?
>
> Longer and skinnier is still better for speed probably.
>
>
> >
> > The longer and skinnier the better, but as long as it does not drop
> > below 11:1 l:b, you will be fine.
>

#5683

From: Rob Denney <harryproa@...>
Date: Tue May 5, 2009 6:05 am
Subject:: Re: Re: Fine tuning design questions

proaharry

Offline

G'day,

Aroha has 600mm/2' beam clearance, beams are 200 high x 300 wide (8" x
12") waterline beams are 750 and 500mm (30" and 20").

I have not sailed on Aroha, so can't comment on the accuracy of these
numbers, nor how well it works.  I would prefer more lee hull beam
clearance,and would see if the beams could be smaller.  Probably go
with a mostly solid bridgedeck to help with this.

Only other change would be to make it from panels, if I was paying for
it.  John in China is busting to give you a quote.  Any idea when you
will have something for him?

regards,

Rob

On Mon, May 4, 2009 at 9:13 PM, Gardner Pomper <gardner@...> wrote:
>
>
> since my design turned out to be practically identical to harry in
> length, width and weight, I would like to check against that design.
> Can you tell me what the height is above the water for the beams, and
> about what the size of the beams is, since I am just using 1 foot
> squares for placeholders now?
>
> Also what is the waterline beam of each hull?
>
> Would you change any of that is you were redesigning harry now?
>
> Thanks
> - Gardner
>
> On Monday, May 4, 2009, Rob Denney <harryproa@...> wrote:
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> G'day,
>>
>> The weight transfer does not happen until the breeze is pretty strong,
>> and the speed exceeds the hull speed of a short, fat hull very
>> quickly. eg, the 33' windward hull on Rare bird has a hull speed
>> (1.34 * the waterline length, in feet) of 7.6 knots, which it gets to
>> in under 10 knots of breeze, but the windward hull barely lifts at 20
>> knots of wind speed when the boat is capable of 15 knots plus, at
>> which speed the drag of the short hull would be immense.
>>
>> regards,
>>
>> Rob
>>
>> On Mon, May 4, 2009 at 4:37 PM, jrwells2007 <jrwells2007@...>
>> wrote:
>>>
>>>
>>> Rob, I have read somewhere that cats and tris aim for a minimum of 8:1 to
>>> prevent stern squatting in the manner of a mono-hull. For the ww hull an
>>> 8:1
>>> would have lower surface area for a given displacement than an 11:1 so
>>> less
>>> resistance at low speeds. At higher speeds some of the displacement of
>>> the
>>> ww hull would be carried by the lw hull and therefore the greater wave
>>> making resistance of 8:1 would be less of a factor. Are there other more
>>> important considerations such as drag on the steering?
>>>
>>> Longer and skinnier is still better for speed probably.
>>>
>>>>
>>>> The longer and skinnier the better, but as long as it does not drop
>>>> below 11:1 l:b, you will be fine.
>>>
>>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>

#5682

From: Doug Haines <doha720@...>
Date: Tue May 5, 2009 4:11 am
Subject:: Re: Re: Fine tuning design questions

doha720

Offline

Hi hi,

the other day on a pleasant reach in moderte 10-12 knots (maybe more) I dumped off the aft sheet and noticed the boat fall down on it's ww hull. Obviously I was getting a good deal of 'rise'. El camper ww hull is fatter than Harry length/beam by a lot. Can't remember the figure.

I always wonder if this is a draw back in design, i.e. should be a thinner ww hull. I guess the deesign is as thin as it could be made without going longer.

doug

--- On Mon, 4/5/09, Rob Denney <harryproa@...> wrote:

From: Rob Denney <harryproa@...>
Subject: Re: [harryproa] Re: Fine tuning design questions
To: harryproa@...
Date: Monday, 4 May, 2009, 10:17 PM

G'day,

The weight transfer does not happen until the breeze is pretty strong,
and the speed exceeds the hull speed of a short, fat hull very
quickly. eg, the 33' windward hull on Rare bird has a hull speed
(1.34 * the waterline length, in feet) of 7.6 knots, which it gets to
in under 10 knots of breeze, but the windward hull barely lifts at 20
knots of wind speed when the boat is capable of 15 knots plus, at
which speed the drag of the short hull would be immense.

regards,

Rob

On Mon, May 4, 2009 at 4:37 PM, jrwells2007 <jrwells2007@ yahoo.com. au> wrote:
>
>
> Rob, I have read somewhere that cats and tris aim for a minimum of 8:1 to
> prevent stern squatting in the manner of a mono-hull. For the ww hull an 8:1
> would have lower surface area for a given displacement than an 11:1 so less
> resistance at low speeds. At higher speeds some of the displacement of the
> ww hull would be carried by the lw hull and therefore the greater wave
> making resistance of 8:1 would be less of a factor. Are there other more
> important considerations such as drag on the steering?
>
> Longer and skinnier is still better for speed probably.
>
>>
>> The longer and skinnier the better, but as long as it does not drop
>> below 11:1 l:b, you will be fine.
>
>

#5681

From: Gardner Pomper <gardner@...>
Date: Mon May 4, 2009 1:13 pm
Subject:: Re: Fine tuning design questions

gardnerpomper

Offline

since my design turned out to be practically identical to harry in
length, width and weight, I would like to check against that design.
Can you tell me what the height is above the water for the beams, and
about what the size of the beams is, since I am just using 1 foot
squares for placeholders now?

Also what is the waterline beam of each hull?

Would you change any of that is you were redesigning harry now?

Thanks
- Gardner

On Monday, May 4, 2009, Rob Denney <harryproa@...> wrote:
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>       G'day,
>
> The weight transfer does not happen until the breeze is pretty strong,
> and the speed exceeds the hull speed of a short, fat hull very
> quickly.  eg, the 33' windward hull on Rare bird has a hull speed
> (1.34 * the waterline length, in feet) of 7.6 knots, which it gets to
> in under 10 knots of breeze,  but the windward hull barely lifts at 20
> knots of wind speed when the boat is capable of 15 knots plus, at
> which speed the drag of the short hull would be immense.
>
> regards,
>
> Rob
>
> On Mon, May 4, 2009 at 4:37 PM, jrwells2007 <jrwells2007@...> wrote:
>>
>>
>> Rob, I have read somewhere that cats and tris aim for a minimum of 8:1 to
>> prevent stern squatting in the manner of a mono-hull. For the ww hull an 8:1
>> would have lower surface area for a given displacement than an 11:1 so less
>> resistance at low speeds. At higher speeds some of the displacement of the
>> ww hull would be carried by the lw hull and therefore the greater wave
>> making resistance of 8:1 would be less of a factor. Are there other more
>> important considerations such as drag on the steering?
>>
>> Longer and skinnier is still better for speed probably.
>>
>>>
>>> The longer and skinnier the better, but as long as it does not drop
>>> below 11:1 l:b, you will be fine.
>>
>>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>

#5680

From: Rob Denney <harryproa@...>
Date: Mon May 4, 2009 12:17 pm
Subject:: Re: Re: Fine tuning design questions

proaharry

Offline

G'day,

The weight transfer does not happen until the breeze is pretty strong,
and the speed exceeds the hull speed of a short, fat hull very
quickly.  eg, the 33' windward hull on Rare bird has a hull speed
(1.34 * the waterline length, in feet) of 7.6 knots, which it gets to
in under 10 knots of breeze,  but the windward hull barely lifts at 20
knots of wind speed when the boat is capable of 15 knots plus, at
which speed the drag of the short hull would be immense.

regards,

Rob

On Mon, May 4, 2009 at 4:37 PM, jrwells2007 <jrwells2007@...> wrote:
>
>
> Rob, I have read somewhere that cats and tris aim for a minimum of 8:1 to
> prevent stern squatting in the manner of a mono-hull. For the ww hull an 8:1
> would have lower surface area for a given displacement than an 11:1 so less
> resistance at low speeds. At higher speeds some of the displacement of the
> ww hull would be carried by the lw hull and therefore the greater wave
> making resistance of 8:1 would be less of a factor. Are there other more
> important considerations such as drag on the steering?
>
> Longer and skinnier is still better for speed probably.
>
>>
>> The longer and skinnier the better, but as long as it does not drop
>> below 11:1 l:b, you will be fine.
>
>

#5679

From: "Robert" <cateran1949@...>
Date: Mon May 4, 2009 10:50 am
Subject:: Re: Fine tuning design questions

cateran1949

Offline

When doing calculations of surface area, I found that with the displacement of
Harrys, from about 12:1 to about 16:1 for the ww hulll there was not a great
difference in surface area. It doesn't need much power to start getting into
displacement speeds for the ww hull and so an 8:1 would give a fair bit of drag
at those intermediate speeds before there was significant weight transfer. It is
hard to set up a shunting sailing boat for planing and not go to too much form
drag at lower speeds without having significant moveable ballast, though I am
looking at having a slight flare back from the bows a bit to get a little lift
when going through chop. This allows a bit more room in the hulls while keeping
the waterline skinny. I would not go below 12:1 myself.
  I can't see any advantage of rocker with a shunting vessel with two rudders. It
means a fatter or deeper hull overall, more susceptibility to hobbyhorsing, and
greater bow depression when pushing hard. It may be worth rounding the forefoot
slightly to reduce damage and I am looking at a v for the last 8% to handle
coming off the top of a wave and slamming down in fairly extreme conditions and
reverse stem to make working through heavy chop that little bit easier--- In
harryproa@..., "jrwells2007" <jrwells2007@...> wrote:
>
> Rob, I have read somewhere that cats and tris aim for a minimum of 8:1 to
prevent stern squatting in the manner of a mono-hull. For the ww hull an 8:1
would have lower surface area for a given displacement than an 11:1 so less
resistance at low speeds. At higher speeds some of the displacement of the ww
hull would be carried by the lw hull and therefore the greater wave making
resistance of 8:1 would be less of a factor. Are there other more important
considerations such as drag on the steering?
>
> Longer and skinnier is still better for speed probably.
>
>
> >
> > The longer and skinnier the better, but as long as it does not drop
> > below 11:1 l:b, you will be fine.
>

#5678

From: "jrwells2007" <jrwells2007@...>
Date: Mon May 4, 2009 8:37 am
Subject:: Re: Fine tuning design questions

jrwells2007

Offline

Rob, I have read somewhere that cats and tris aim for a minimum of 8:1 to
prevent stern squatting in the manner of a mono-hull. For the ww hull an 8:1
would have lower surface area for a given displacement than an 11:1 so less
resistance at low speeds. At higher speeds some of the displacement of the ww
hull would be carried by the lw hull and therefore the greater wave making
resistance of 8:1 would be less of a factor. Are there other more important
considerations such as drag on the steering?

Longer and skinnier is still better for speed probably.


>
> The longer and skinnier the better, but as long as it does not drop
> below 11:1 l:b, you will be fine.

#5677

From: Rob Denney <harryproa@...>
Date: Mon May 4, 2009 3:35 am
Subject:: Re: Fine tuning design questions

proaharry

Offline

G'day,

here is fine.� Answers follow questions
>
> 1) What is the "best" beam clearance for a harry-sized boat? I figure
> 2' min and 3' max. The higher, the more force on the rudders. The
> lower, the more wave impact. What do you think?

A bit more to it than max and min (boat weight, cabin and cockpit set
up, beam location), but basically yes.  The rudders can easily be made
stronger, the wave impact will be a pain every time it happens.

>
> 2) Does a bit of rocker help? If I am going to go with carved foam for
> the "front" 25% of the hull, I could give the hull a little rocker as
> easiliy as not. Would that help turning? If so, should I then lengthen
> the ww hull to give it a better length/beam ratio?

My boats tend to lean forward and sit on rocker, so I don't use it.
Will help turning, but with to rudders, you don't need help.
>
> 3) I have drawn the ww and lw hull with as small a beam as I think I
> can get away with.. 20" for ww and 12" for lw. Increasing that beam a
> little will give me a better walkway in the ww hull and easier access
> into the lw hull. If I increase to 22" ww and 18" lw, will I be giving
> up significant speed?

The longer and skinnier the better, but as long as it does not drop
below 11:1 l:b, you will be fine.
>
> 4) I read in your harrigami papers that you put a bulkhead 26" back
> and (I think) carved the last 2 feet of bow out of foam. Is that the
> recommended procedure, or do I bring the foam sandwich forward as far
> as possible and just round off the bow?

The carved foam was originally a strip plank trick, but it makes an
excellent fender, so I would go with it.  No other reason for not
extending the panels forward.
>
> 5) Cutouts for hatches - do I cut these out of the foam before
> infusion, or do I make solid panels and then cut the hatches into it
> after assembling the panels into a boat?

Should be able to make the hatches and the bulkheads in one hit,
ensuring they are a perfect match.  Taper the edges and they will not
need a flange.
>
> 6) How do I know if the sail plan I drew up will really work? Is this
> calculated, or do you just have an "eye" for it? I am particularly
> referring to the use of the screacher on the extended jib boom.

Lots of calculations, but too many variables, the trickiest being the
size and "fall off" of the mainsail roach.  Make balance part of the
criteria for the sailmaker.  Until he gets it, he doesn't get paid.

regards,
Rob
>
> Thanks,
>
> - Gardner
>
>

#5676

From: Gardner Pomper <gardner@...>
Date: Mon May 4, 2009 3:00 am
Subject:: Fine tuning design questions

gardnerpomper

Offline

Hi Rob,

I am not sure if I should post questions to you on my design via
private email, or the forum. Since there aren't any specific structure
or finance questions, I thought I would try here.

1) What is the "best" beam clearance for a harry-sized boat? I figure
2' min and 3' max. The higher, the more force on the rudders. The
lower, the more wave impact. What do you think?

2) Does a bit of rocker help? If I am going to go with carved foam for
the "front" 25% of the hull, I could give the hull a little rocker as
easiliy as not. Would that help turning? If so, should I then lengthen
the ww hull to give it a better length/beam ratio?

3) I have drawn the ww and lw hull with as small a beam as I think I
can get away with.. 20" for ww and 12" for lw. Increasing that beam a
little will give me a better walkway in the ww hull and easier access
into the lw hull. If I increase to 22" ww and 18" lw, will I be giving
up significant speed?

4) I read in your harrigami papers that you put a bulkhead 26" back
and (I think) carved the last 2 feet of bow out of foam. Is that the
recommended procedure, or do I bring the foam sandwich forward as far
as possible and just round off the bow?

5) Cutouts for hatches - do I cut these out of the foam before
infusion, or do I make solid panels and then cut the hatches into it
after assembling the panels into a boat?

6) How do I know if the sail plan I drew up will really work? Is this
calculated, or do you just have an "eye" for it? I am particularly
referring to the use of the screacher on the extended jib boom.

Thanks,

- Gardner

#5675

From: "Peter Southwood" <peter.southwood@...>
Date: Sat May 2, 2009 6:45 am
Subject:: Re: reeply to doug onproas and everglades challenge

pbsouthwood

Offline

In this context a physical constraint of the course which prevents boats with cetain characteristics from getting through.

A filter for removing solids of a certain size from a fluid is a reasonable analogy. The filter blocks all the solids with dimensions larger than the size of the holes. Similarly the race course has places where the depth is restricted for significant distances, this fliters out deeper vessels and lets the shallow ones through, then there are bridges, which only allow boats through which are not permanently higher than the bridge clearance. This filters out tall rigs which can not be lowered in some way. Narrow watercourses impose a width restriction, etc..

Hope this helps,

Peter

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

From: john h wright

To: harryproa@...

Sent: Saturday, May 02, 2009 6:21 AM

Subject: Re: [harryproa] reeply to doug onproas and everglades challenge

filter?

--- On Sat, 2/5/09, carlos Solanilla <carlosproacarlos@yahoo.com> wrote:

From: carlos Solanilla <carlosproacarlos@yahoo.com>
Subject: [harryproa] reeply to doug onproas and everglades challenge
To: harryproa@yahoogroups.com.au
Date: Saturday, 2 May, 2009, 4:19 AM

Doug

The EC is best done on a very low draft boat, preferably flat hull. The filters will limit your width to 9 ft; the first filter will force you to step your mast due to about 5 ft clearance, the second filter will force you to row, paddle or yuloh for about 2 miles as well to avoid big oyster banks and thread your boat into cannals surrounded by mudpits that will swallow you above the knees if you jump out. The third filter is a maze of mangrove islands where small cannals let you in and out but any wrong move willhave you stuck in the mud.

Overall is 300 miles - for most of the races there is plenty of winds (Except this year) thanks to a series of cold fronts. It should take about 5 days to do it if your boat survives all the above and some nasty steep chop in the waves as well as some interesting approaches to the coast line

The "perfect" boat so far is a tornado equiped by local olympic sailors who knows the are very well and do not mind staying awake for 3 days

____________________________________________________________
Earn a degree in Criminal Justice and work as a Police officer. Click here for more info.

No virus found in this incoming message.
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#5674

From: john h wright <jhargrovewright2@...>
Date: Sat May 2, 2009 4:21 am
Subject:: Re: reeply to doug onproas and everglades challenge

jhargrovewri...

Offline

filter?

--- On Sat, 2/5/09, carlos Solanilla <carlosproacarlos@yahoo.com> wrote:

From: carlos Solanilla <carlosproacarlos@yahoo.com>
Subject: [harryproa] reeply to doug onproas and everglades challenge
To: harryproa@yahoogroups.com.au
Date: Saturday, 2 May, 2009, 4:19 AM

Doug

The EC is best done on a very low draft boat, preferably flat hull. The filters will limit your width to 9 ft; the first filter will force you to step your mast due to about 5 ft clearance, the second filter will force you to row, paddle or yuloh for about 2 miles as well to avoid big oyster banks and thread your boat into cannals surrounded by mudpits that will swallow you above the knees if you jump out. The third filter is a maze of mangrove islands where small cannals let you in and out but any wrong move willhave you stuck in the mud.

Overall is 300 miles - for most of the races there is plenty of winds (Except this year) thanks to a series of cold fronts. It should take about 5 days to do it if your boat survives all the above and some nasty steep chop in the waves as well as some interesting approaches to the coast line

The "perfect" boat so far is a tornado equiped by local olympic sailors who knows the are very well and do not mind staying awake for 3 days

____________________________________________________________
Earn a degree in Criminal Justice and work as a Police officer. Click here for more info.

#5673

From: Doug Haines <doha720@...>
Date: Sat May 2, 2009 1:57 am
Subject:: Re: reeply to doug onproas and everglades challenge

doha720

Offline

filter?

--- On Sat, 2/5/09, carlos Solanilla <carlosproacarlos@...> wrote:

From: carlos Solanilla <carlosproacarlos@...>
Subject: [harryproa] reeply to doug onproas and everglades challenge
To: harryproa@...
Date: Saturday, 2 May, 2009, 4:19 AM

Doug

The EC is best done on a very low draft boat, preferably flat hull. The filters will limit your width to 9 ft; the first filter will force you to step your mast due to about 5 ft clearance, the second filter will force you to row, paddle or yuloh for about 2 miles as well to avoid big oyster banks and thread your boat into cannals surrounded by mudpits that will swallow you above the knees if you jump out. The third filter is a maze of mangrove islands where small cannals let you in and out but any wrong move willhave you stuck in the mud.

Overall is 300 miles - for most of the races there is plenty of winds (Except this year) thanks to a series of cold fronts. It should take about 5 days to do it if your boat survives all the above and some nasty steep chop in the waves as well as some interesting approaches to the coast line

The "perfect" boat so far is a tornado equiped by local olympic sailors who knows the are very well and do not mind staying awake for 3 days

#5672

From: Michael Gehl <mike@...>
Date: Fri May 1, 2009 6:57 pm
Subject:: Re: reeply to doug onproas and everglades challenge

rattus32

Offline

I also heard that one of the more promising techniques to dealing with sticking in the mud was to wear snowshoes (!) in the water to prevent sinkage...

Mike

On May 1, 2009, at 12:19 PM, carlos Solanilla wrote:

Doug

The EC is best done on a very low draft boat, preferably flat hull. The filters will limit your width to 9 ft; the first filter will force you to step your mast due to about 5 ft clearance, the second filter will force you to row, paddle or yuloh for about 2 miles as well to avoid big oyster banks and thread your boat into cannals surrounded by mudpits that will swallow you above the knees if you jump out. The third filter is a maze of mangrove islands where small cannals let you in and out but any wrong move willhave you stuck in the mud.

Overall is 300 miles - for most of the races there is plenty of winds (Except this year) thanks to a series of cold fronts. It should take about 5 days to do it if your boat survives all the above and some nasty steep chop in the waves as well as some interesting approaches to the coast line

The "perfect" boat so far is a tornado equiped by local olympic sailors who knows the are very well and do not mind staying awake for 3 days

#5671

From: carlos Solanilla <carlosproacarlos@...>
Date: Fri May 1, 2009 6:19 pm
Subject:: reeply to doug onproas and everglades challenge

carlosproaca...

Offline

Doug

The EC is best done on a very low draft boat, preferably flat hull. The filters will limit your width to 9 ft; the first filter will force you to step your mast due to about 5 ft clearance, the second filter will force you to row, paddle or yuloh for about 2 miles as well to avoid big oyster banks and thread your boat into cannals surrounded by mudpits that will swallow you above the knees if you jump out. The third filter is a maze of mangrove islands where small cannals let you in and out but any wrong move willhave you stuck in the mud.

Overall is 300 miles - for most of the races there is plenty of winds (Except this year) thanks to a series of cold fronts. It should take about 5 days to do it if your boat survives all the above and some nasty steep chop in the waves as well as some interesting approaches to the coast line

The "perfect" boat so far is a tornado equiped by local olympic sailors who knows the are very well and do not mind staying awake for 3 days

#5670

From: Doug Haines <doha720@...>
Date: Thu Apr 30, 2009 3:35 pm
Subject:: Re: sails...balance- rudder

doha720

Offline