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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