Formula to calc HP requirements of pontoon

[rduval]

Hi:

I'm a layman and have been tearing my hair out with various formulas...

Can someone either point me to some formulas or software or tell me the HP required to propel a vessel on a pair 40ft x 2ft diameter round pontoons (50% submerged) at hull speed, 10 knots, 15, knots, 20 & 25 (I know there's a lot of factors but just approximately)?

I have a 40ft houseboat that does 5.5kn with a 120hp engine. I want to get more speed but I'm knot sure how much HP I will ahve to throw at it to achieve reasonable increases.

Thanks much in advance for any help

Rick

[Jango]

HP with respect to speed is exponential, if nothing else changes. Twice the Speed requires 4 times the power. A 50% increase requires 1.5 squared or 2 1/4 the power etc.
Hope this helps, Jango

[george allard]

Go to www.pithpontoons.com

[Ike]

HP = volume of the pontoons in cubic feet X the pontoon length in feet / pontoon diameter in inches