Kerry,
Thanks for that rule of thumb. In the case of my 24' pontoon, the beam is 8' but the tubes are 2' diameter so the center to center distance is 6' and the distance between them is only 4'. I guess that means they will interact to some degree.
Also, thanks to luv2bsailin for the link. Between the information on that site and all the further links it contains, I will be able to answer all my questions and then some.
Pat
--- In electricboats@yahoogroups.com, "Kerry Thomas" <kjthomas@...> wrote:
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> Hi
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> Rules of thumb.
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> The distance between hulls is more than a third of the hull length, on a cat, they probably will not interact significantly. If the distance between is less than a quarter, they certainly will.
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> Other factors apply of course. Hulls with lower LB ratio, fatter, are more likely to interact, for example.
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> Some plan-ing power boats are designed so the hulls work together.
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> Displacement catamaran designers usually try to get the hulls far enough apart so interaction is minimal.
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> From: electricboats@yahoogroups.com [mailto:electricboats@yahoogroups.com] On Behalf Of Michael Mccomb
> Sent: Monday, 12 September 2011 9:51 a.m.
> To: electricboats@yahoogroups.com
> Subject: Re: [Electric Boats] Dual Hull Question
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> i know that there are few potential problems with catamarans and apparently these are not hard to get into if one isn't familiar enough while trying to do a design.... there is such a thing as hull interference and if you build the exact wrong hulls and then place them at the exact wrong distance the cat is severely speed compromised... the other big deal is bridge deck clearance above the water, too high and you get too much windage along with some instability and too low you get a lot of pounding from below... i've noticed that they pretty much always show cats in lake surface like conditions
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> _____
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> From: luv2bsailin <luv2bsailin@...>
> To: electricboats@yahoogroups.com
> Sent: Sunday, September 11, 2011 4:34 PM
> Subject: Re: [Electric Boats] Dual Hull Question
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> They will interact to some degree. A quick Google search brings up a whole bunch of material on the subject, though it will take some studying to digest it. This might be a good place to start:
> http://www.wavewalk.com/COMPARISON.html (check out the links at the end)
>
> Jim
>
> --- In electricboats@yahoogroups.com <mailto:electricboats%40yahoogroups.com> , Ned Farinholt <nedfarinholt@> wrote:
> >
> > I have not studied catamarans so I cannot help you with that.
> > Ned
> >
> > On Sep 8, 2011, at 2:26 PM, greenpjs04 wrote:
> >
> > > Hi Ned,
> > > Thanks for the reply. I'll take a look at the reference you provided. You are confirming what I thought about narrow hulls being capable of higher speed, but I am still interested in what happens when two of them are in parallel. Do they interact in some way that matters or do they essentially become two separate racing skulls?
> > >
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