Prop - pitch - size - duh?????

[fish-n-dive]

Ok, I'm hanging myself out here but could someone please give a simple explination about prop pitch; ie what pitch causes what to happen etc, and what effect does a different size prop cause.

I've got a 40hp Mercury Lightning pushing a Quintrex 4.2 Dory and was thinking of changing to a S/S prop.

Cheers, 8-)

[Jekyll]

Pitch represents the distance travelled for one revolution of the prop.

Imagine your propeller was immersed in a really thick fluid, like honey. For a 17" pitch prop, one revolution of the prop would theoretically move the boat forward 17". In the real world its something less than that, since you have to factor slippage into the equation.

The higher the pitch, the faster you go. The higher the pitch, the slower your acceleration.

[Spaniard_King]

Pitch is the amount a propellor will move forward with 1 full rotation of the propellor

increasing pitch will drop WOT rpm and decreasing pitch will increase rpm, you boat should reach within 2-300rpm of the manufacturers recommended full rpm to be proped correctly for good engine performance

Garry