Bought a boat with a HUGE prop

[Mudshack]

My buddy just bought a 1992 Dyna-Trak with a Yamaha 150 ProV (less than 100hrs). The prop the PO has on this boat is HUGE! It is a stainless steel 3 screw with 24M pitch. What does this mean. I say this is huge because it looks like they took the trim tab off in order for this prop to fit.

I don't know much about boats....just learning. But most pitches I have seen talked about are 17-19. What can we expect with this 24M?

 

[steelespike]

Re: Bought a boat with a HUGE prop

If the boat is light and fast I think 60+ may be possible. But the motor needs to be able to rev close to its rated wot(wide open throttle)
rpm of 5,500. The Trim tab may be removed due to extreme rake.with the high pitch the diameter may actually be slightly smaller
than those with less pitch.
If your new to boating be very careful at those kinds of speeds. Wear a pfd(personal flotation device)
And a kill switch lanyard. Check" you tube' titles like "boat crash"
Its amazing how quick the slightest move will kill.

 

[Mudshack]

Re: Bought a boat with a HUGE prop

Thanks for the advice steelespike. Actually, we always wear PFD when moving. And usually when fishing too. And we are not looking for speed. We have been fishing/tubing in a tracker flatbottom with 45hp. Just want enough juice to get up out of the hole with skiier or boarder.

I will check to see if we can get the boat to cruise around 5500rpm. That is good advice. We take it out on the water tomorrow for it's first test spin.

 

[Texasmark]

Re: Bought a boat with a HUGE prop

Gear boxes on engines of that size can be 2:1 (engine 2, prop 1) down to like 1.75:1. With that sized engine and that gearbox, a 24P is built for pushing a BB at high speeds as steel mentioned. It's probably ported to help it get out of the hole and after that the high pitch makes it go fast.

If you want to play with water toys, you need to reduce your pitch as you questioned. Getting the numbers right for your engine and your desires will probably take more than one try, so do yourself a favor: Get involved with a dealer that loans props. Tell him what you are wanting to do and take a few out and run them. Just ensure you run them in clean water and take them off as soon as you have your numbers....so he can resell for new what you didn't use. You will pay more for it, but will be satisfied and remember sir, the money will be long gone and all you will have left is the satisfaction with your rig!!!!! Aw shucks. Grin.

My 2c,
Mark