> Rule of thumb for a boat motor is 1hp for each 40-50lbs of weight. For a planing hull, maybe? Displacement hulls (sailboats, trawlers, etc) don't need (and

> Rule of thumb for a boat motor is 1hp for each 40-50lbs of weight. For a planing hull, maybe? Displacement hulls (sailboats, trawlers, etc) don't need (and can't make use of) much hp. It doesn't take much to get to hull speed, and basically no amount of power will make it go significantly faster. For example my 8000lb sailboat has an 18hp engine (~440lb/hp) and it could easily reach hull speed with a smaller engine in most conditions.