Need recommendations

[Marley marl]

Happy 4th fellow iboats crew. I have a 24ft Starcraft that's I converted to a tritoon. I also have lifting strakes installed on center room and the outside of the outer toons. It is powered with a 1988 Mercury 150 blackmax. I know I'm over proped. With only me onboard I get 5000 rpm at wot. With 5 adults I get about 4400. What would be the best pitch prop for me?ive heard 4 blades are the way to go because it gives more bite. I'm not necessarily looking for high top end speed but would like optimal performance. I will usually have atleast 5-6 riders and pulling tube.

 

[Maclin]

What pitch is the prop you are running now?

 

[Marley marl]

I'm running a 17p 3 blade 14 1/2 dia

 

[Sea Rider]

What's the max wot rpm range for that OB ? If always will be boating with + 6 up, need to prop it right for OB to achieve at least middle wot rpm range. Could send current prop to a prop shop and have it re pitched to a 15 pitch and see what happens, definitely more wot rpm increase, but a 3 blade 13 pitch prop will do a much better job.

Happy Boating

 

[Marley marl]

5000 to 5600 rpm is the max range

 

[Marley marl]

Would a 4 blade give me more bite and control?

 

[jimmbo]

5000 to 5600 rpm is the max range

I thought it was 5000 - 5500

 

[89retta]

I would drop down to 15" prop either 4 or 3 blade

 

[ahicks]

Tough call 3 blad alum. vs a 4 blade or SS prop with your setup. Smaller engines on a conventional pontoon that will never see anything over 25mph have little to gain and will be hard to justify. Tri-toon with a 150, well, maybe you might. 4 blade should give more bite getting a tube on top, but could cost you on top end. We've got some smaller tri-toons (18-20') on our lake with 150+ power that scoot pretty good. Looks like they're hitting 30mph pretty easily. Thinking SS props on those might be much easier to justify.

Bottom line, nothing is set in stone here. Thinking a lot of different props will do well.

 

[Sea Rider]

With five passengers up OB is 1200 wot revs down, if rule of thumb applies will need to go 6 less pitch to a 3 blade 11 pitch for OB to run to it's max wot range. Will have oustanding hole shot, good end speed and nice fuel comsumption. If wanting running at middle of its wot range will need 3 less pitch, all is pure speculation theory, must be tested on water.

That's the issue of boating lightly and then heavily loaded, weight kills wot rpm. With a prop that revs to max wot range with 5 up will overrev badly with you alone. Personally don't buy this 4 blade prop gripping better issue, it's all related to the water bed height prop spins in to achieve proper forward prop thrust, worse if OB sits too high on transom.

Did you know that a prop is a push-pull device, how can it perform right with insufficient amout of water surrounding prop.

Happy Boating

 

[Marley marl]

Thanks everyone for their thoughts and advice