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@
>>
>>
>> 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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