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.
>
>
> 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.
> 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.
>>>
>>>
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>>> 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.
>>>>
>>>>
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>>
>
>
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