boat resistance

[plain_sailing]

A friend of mine is aiming to build a 10 m motorboat and he asked me if I could calculate the effective horsepower of the boat in order to choose the appropriate engine.
Does anybody know which is the best method to find boat's resistance knowing only the main dimensions, the lines and the service speed.
I don't have time to make a model and test it.

Thank u in advance.

[Eric Sponberg]

You can get some guidance from Dave Gerr's book, the Propeller Handbook. We naval architects generally use speed-and-power software, but it costs a few thousand dollars. However, I have used Gerr's book with success for checks and balances, or to do a preliminary, off-the-cuff kind of calculation.

Eric

[water addict]

Also, look at other 10m boats of similar design and find out what they have.