[PCW] fin stabilisers on cats

[Robert Deering]

Tim,

I think I understand your issue now.  When you are beam-to a sea at slow
speed or at rest, when the period of the waves is just right, you experience
a very sharp roll or snap.  Indeed, that is the nature of catamarans.  Every
boat is a compromise.

I don't think a wing/foil will help very much.  But there may be some things
that will:

 - Move your weight down.  If you are storing weight high, move it down into
the hulls.

 - Get skinnier hulls.  Skinny hulls ride deeper in the water, and don't
respond as quickly to passing waves.  The downside is that the boat is more
sensitive to trim issues, and may have more wetted surface, thus poorer
efficiency.

 - Install a mast.  A tall object gives you a greater moment of inertia -
resistance to rotation - and will thus slow down the roll.  And the side
benefit is that you can hoist a bedsheet in case you run out of fuel.  But
you might be confused for a sailboater, and you don't want THAT to happen!

 - Try flopper stoppers.  Though with a cat I suspect they'd have to be
oversized, with excessive drag.

 - Add more weight.  But that of course defeats many of the cat advantages.

Bob Deering
Juneau, Alaska  


On 11/16/09 9:36 PM, "Tim Chrisp" <timchrispb2 at gmail.com> wrote:


> We are not looking for any lift , just limitation of slow or zero speed
> roll.