When I started into the r/c boating world, I also had the thinking of, being around and building full size boats, the little boats should be a walk in the park. My first hull was perfect to scale, not one defect, I was all smiles until I put that bad boy in the water. It ran great until I tried to make that first turn, look like a tornada reached down on it.
Main Entry: horse·pow·er
Pronunciation: 'hors-"pau(-&)r
Function: noun
1 : the power that a horse exerts in pulling
2 : a unit of power equal in the U.S. to 746 watts and nearly equivalent to the English gravitational unit of the same name that equals 550 foot-pounds of work per second(lift 550lbs one foot in one second)
If we used only the HP to weight ratio, the full size boat should run alot faster than 140+mph, the truth is there is too many more factors that must be added in. ex: 30" boat with a 2hp engine has a speed of 40mph(just a given speed) does that mean if you was to replace that engine with one that has 4hp, the boat will have a speed of 80mph? Would be nice if it did. Or if you replaced the 30" boat with a 15" boat(also 1/2 of the weight) that it would have a speed of 80mph? Also would be nice if it would work that way. The main thing that I'm trying to say is a boat that is perfectly scaled down from the full size will not have the near the preformance that it could have.