[quote=klozhald][quote=Dogboy]I would say that some modern catamaran hull shapes have flatter bottoms to help lift the hull and reduce wetted surface at speed. I would not necessarily call that planing though[/quote]
It is a blend of even [i]more[/i] factors. Scientific design has made catamaran hulls thinner, the bow attack angle more aggressive, the after portions flatter, and with more buoyancy up front. This allows easier knifing through the water, either over a wave or through it, and the buoyancy helps keep you from pointing your hulls down while powered up. Up is up. and down is down. The hulls [i]will[/i] go where you aim them.
Additionally, while cats can't plane in the same way a flat-bottomed Laser can, they do heel, and most cat designs present a better profile to the water when heeled. When the heel increases to flying a hull, you have now reduced the friction on your cat's wetted surface by about 45%, which gives a grand improvement to your boat speed. This is why racers are always trying to get the windward hull "just kissing" the water.
I agree with Dogboy about cats not truly planing. Catamarans [b]do[/b] utilize a blend of hydrodynamic design and physics elements, along with technique, to make the best of their unique situation.[/quote]
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