I'm trying to figure out how much force is required to move a 300/350lb object across the top of water and maintain a certain velocity. My goal is to do a minimum of 20mph but depending on the size of the engine and weight considerations 30-35mph would be ideal. From some of my research I realized water has 3 different drag coefficients until you are planing on the waters surface. 300lbs and 30mph converted and if I've applied f=ma right then: f=136.078kgx13.4112m/s^2 f=136.078x179.860 f=24474.98908N converted to 5502.196lbs of force required to accelerate to 30mph. This doesn't take into account drag created by water. I would say that obviously that much force is not required to maintain that velocity. So I suppose the question should be, how much force is required to maintain 30mph in a fluid environment?