Catamaran problem with hullspeed

Hello,
I'm Marc and I have a Thecnical Naval Engineur, I'm a new user of boatdesign.net, (I dont speak English very much, sorry).
I have a problem with hullspeed, Which method I have user with analize the speed? (the ship is a small catamaran Length:25m Beam 9m)

My version of hullspeed is 3.5.
Thanks.

 

The simplest method determines the hull speed potential of most hulls by multiplying the square root of the wateline length by 1.34 to get knots per hour, but planing and wave-piercing hulls aren't as simple.
Catamarans are usually faster than this, but how much faster will depend on hull design and means of propulsion.
Probably your best estimate will be gotten by finding another design that is very similar.
What do you mean that your version of hull speed is 3.5? 3.5 what?

 

Marc
I expect that only the slender body function will yield an accurate result. Most of the regression based models are not set up to give reliable results with slender hulls. (If it has the Kaper series then this is OK for slender hulls as well)

If you have Michlet it will give a reliable answer providing the hulls are indeed slender and operating in displacement mode. If you do not have Michlet then I can give you an accurate answer to check against the Hullspeed result.

Rick W

 

Try to use Molland/Insel regression for catamarans, though not availavle in HullSpeed but can be done 'by hand'.