Prop Pitch

[happyhooker2]

I never really had to worry about performance because my big salmon boat has all the power I need. I just bought a new duck hunting boat and wanted to see if I could get a little more top end speed by changing the prop pitch. I installed hydrafoils and have my trim were it should be, do I need to go up in the pitch? I know I have to stay in the 5000-5500 rpm range with the pitch, will going up in pitch help? What about a 4 blade prop? Thanks in advance. Oh yeah the outboard is a 40horse 2 strok Merc.

[waterfoul]

In general, 4 blade of the same pitch will be a tad slower. 4 blade of a greater pitch will be harder to turn. If you are running say, a 19 pitch prop, going up to a 20 or 21 will get you a few mph at less rpm. 2" in pitch =~ 200-300 rpm drop.

What size motor are we talking here, and what kind of boat?

[hitechman]

always been under the impression that a prop with decreased pitch is used on a motor to power a larger boat. For example: my 25hp on my 14 foot boat pushes it well (10 inch diameter with 13 pitch), but I would need to go to a 11-12 inch prop with 11 pitch with this motor to power a heavier pontoon boat.

A decrease in pitch with no increase in diameter will (can) over rev the motor. I have been told to make sure I use a tachometer if I start messing with the props or I could ruin my motor.

Steve