planning planing hull?

[previah]

Hi all,

For the school project I have to design a patrol boat with cruising speed 12 kn and maximum speed of 30 kn. In the preliminary design I came up with the waterline length of 41 m. From this It's easy to calculate the displacement speed: 1.34*LWL(feet)^0.5 = 15.5 kn. If I stubborn enough not to lengthen my original length (thus 41 m), is it means that I'm forced to design (semi) planing hull instead of displacement hull?

thanx in advance,
-previah-

PS: I came across in the internet the formula to include the effect of displacement in the hull-speed formula (http://potter-yachters.org/manyways/hullspeed/). With this I can rise the hull speed considerably. But still with LWL = 41m, It can't go faster than 30 kn.

[CDBarry]

Google "kamen" AND "fishmeal" for a planing boat calculation program.

[SailDesign]

CDB - What happened to Fishmeal? I haven't "seen" him around for a while anywhere...
Steve