How do you reduce Slapping on a Catamaran?

Question

Is there a way to reduce the slapping effect of waves between the hulls of a 26ft catamaran? More weight? Less weight?Distribution of payload? Please don't say buy a monohull!

Answer 1

It can be reduced by a course or speed change.

Answer 2

I always try to get the skipper (love multis but don't have one, myself) to tow the inflatable between the hulls where this is annoying. And, mostly it isn't, anyway.

(Use springs, or fwd & aft painters to keep it nicely in position, so it doesn't, itself, 'slap' from side-to-side, against the hulls; and experiment with position in any given seaway - mainly fwd/aft - to allow for tacking.)

It will smooth out the turbulence between the hulls, but create some small drag - it will do this anyway, if you are just towing it, though I appreciate, most leave the inflatable on-deck, partially inflated.

Give it a try and let me know how you get on.

Clear sailing and have a really nice season.

Answer 3

I owned a 26-foot multi-hull for quite some time.   In that size range, it will be difficult to prevent swells from slamming under the bridgedeck.      Weight will negatively affect the performance on a multi-hull much more than on a monohull, so do everything you can to keep the weight to a minimum.   Also play with moving some of the weight for or aft and see if this helps.    Make sure you are not sailing over-powered.   This will also increase the slapping, and it's easy to do since you don't get the heeling feedback you do in a monohull.

Some of these things may help, but at 26-feet, expect to continue to experience slapping under the hulls and bridgedeck when you have any seas.

Answer 4

This is where people go wrong when buying a catamaran, as they should check to see what clearance it has between the two hauls, to the water. The higher the clearance the less likely it will slap.

Answer 5

I hired mother-in-law to make it a trimaran - worked a treat!