Re: guestion on pitch vs diameter
It is difficult to compare exactly since prop design varies. However a larger diameter prop will generally have more blade area and less pitch than a smaller diameter prop. This results in more thrust on heavy displacement hulls like pontoons.
SO: for a hypothetical example. On a 'toon with a medium sized engine you might use a 14 inch diameter 13 inch pitch prop for 5000 RPM at wide open throttle. The same engine on a planing hull might use a 13 inch diameter 15 pitch prop of the same manufacturer and design and turn the same RPM yet achieve a much higher speed.
A half inch increase in diameter should load the engine down similar to a 1 inch increase in pitch. But, of course, this depends upon the engine, hull, and expected use.
