Why not give hulls 'negative camber' on a cat?

[Ward]

Im just curious why on a catamaran, the hulls, looking head on have paralell centerlines. Why not tilt them inwards (the tops of them) just a bit? Since a catamaran is going to be listing during sail, the hull that its riding on would then be vertical in the water. Im sure there's probably some reason they're not made this way though, otherwise someone would have already done it

I work on cars alot, and i know that an easy way to make a car handle better is to give the front tires negative camber, where the tops of them are farther inboard than the bottoms. During a hard turn, when the car leans a bit, the inside wheel will be vertical and have more tire touching the ground. Would this not benefit a catamaran any?

[Pieetry]

maby when u sheet the sheets althe way in its going to make hte main be above centerline, ass everything is oriented around the direction the hull is going

[SailDesign]

Many (most?) fast cats have canted centreboards, which gives the same effect, so to speak. Since the section of the hulls is close to circular, the heel won't matter much, as they should be sailed pretty flat (one hull flying, but only just, to keep the sail as upright as poss)

Steve Baker

[tspeer]

The A-class cats have been using canted hulls for some time, and some cruising cats have canted hulls. Trimarans also use canted hulls for the amas. It's actually a common practice these days.

[Ward]

Hmm, I guess they only run a couple degrees of camber then, because from all the racing cats I've seen in pictures, they just look paralell. they must only run a couple degrees.

[SailDesign]

15 degrees on the last A-Class I worked on.....

For example this cat posted in the gallery by b_rodwell: http://www.boatdesign.net/gallery/sh....php?photo=168

[SailDesign]

Guest says "For example this cat posted in the gallery by b_rodwell:.........."
Except that his centreboards are vertical, where I would have expected them to follow the hull cant.

[robl]

A Class cats have used canted hulls for many years. Some have been up to 15deg. but most have now settled on around 5deg. the downside to using canted hulls is that when both hulls are in the water they present an assymetrical shape, which can be slow.