Prop Question but with Plenty of Info to Help

[cptbraine40]

Boat: Mariah Talari 221 (22ft long and weight with beer and gear about 3500lb)
Open Bowrider Boat
Engine: Mercruiser 5.7 Carb (250hp)
Outdrive: Alpha One Gen II (1.47 Gear Ratio)
Current Prop: Solas Rubex (Aluminum) 4 Blade 17" Pitch
Current WOT RPM/Speed: 4300-4400 43-46mph (GPS). Trimmed up

Thinking of moving to a Solas Rubex (Stainless Steel) 4-Blade 15" pitch to accomplish 3 things

1. Get the RPMs close to the 4800 number
2. Better performance with hole shot and mid-range cruising
3. More top speed than current set up (since current prop only hitting 4300-4400 rpm)

What is everyone's thoughts about this? Good move. Dumb move.

 

[jimmbo]

If you want more top speed, deep six the four blade. Try a 18 Mercury Enertia 3 blade. Enertia has very good holeshot, good top end, and a very solid bite on the water.

 

[cptbraine40]

If I went from a 17 pitch 4 blade to a 18" pitch 3-blade, how would that impact my RPM. Going up in pitch would lower my RPM but going from a 4 blade to a 3 would raise it some.

 

[jimmbo]

I would say the increase in pitch is less load than the extra blade was. That was why I increased the pitch. I run an Enertia. Great prop. My boat is a 18.5 ft. VP 5.7 260hp 1.51:1 gears, I run a 20 in @ 4700 - 4800 rpm. About 2300 ft above sea level


Best thing to do is make friends with a dealer or his partsman. Borrow a few different props, with the intent to BUY one, then see what works best. It might cost a few more bucks than buying online, but it will end up being much cheaper in the long run.

 

[cptbraine40]

Thanks for the advice Jimmbo, appreciate it sir

 

[jimmbo]

I edited my post as you were posting