Prop Question?

[kkahmann]

I just bought a 17ft Crestliner with a 115hp Merc 4-cycle and it came with an A45 17p aluminum prop. I got a chance to get a Stainless Steel Prop but it is 19 pitch. What effect will the change in pitch have to do with performance--more pulling power? Higher speed?

[delcecchi]

The higher pitch prop will be somewhat slower out of the hole. What it does at top speed is unknown. It depends on the boat and how much stuff you have. The ideal is to be somewhere in the WOT range of RPM for the motor at top speed for your boat. The only way to know is to try it.

[TR21HP]

If your current prop is over revving at top speed a 19 pitch prop will probably work but if your motor doesn't have enough power to get the rev up high enough you will not only not get any benefit but you could damage the motor. As Del said the only way to see is to take it out, but as I said before if the 17" you have on there now isn't maxing out don't bother trying the 19.

[delcecchi]

That is a good point. The thing you need to do first is take the boat out and see what RPM you get at WOT with the 17 prop.

The current Merc 115 4stroke has a max RPM at WOT of 5800 to 6400. If you hit 6400 or there abouts with the 17 prop, then give the 19 a try. One or the other prop will put you in the recommended 5800 to 6400 range. If you will be normally having several people and their gear, lean towards the 17 if you are in doubt.

These days the difference between SS and Aluminum isn't that much.