JMG

I only have very little knowledge on props but after reading many threads here and consulting the Merc prop selector I think I have pretty much narrowed prop pitch to 21". I just can't decide which type of prop is right.....

Current (previous owner's) setup is a 19p Mirage prop which I can spin 4700 to 4800 RPM and only get 42 MPH. Prop is probably out of whack.
I read that 88 Scarabs came with 23p Mirage props, but my boat has been repowered with a 330 HP 7.4 L engine. I don't know I can turn a 23" Mirage plus fast enough?

Main question is, would you use a Mirage Plus, or a Rev 4 or even a Bravo I Prop with this Hull. I have been searching the forum and the web and could not find a clear answer. I feel I should get around 50 MPH, yet acceleration and cruise seem more important than top speed to me.

Your help is greatly appreciated.

sbslinde

I have the same boat. 454 Mag 365hp. I have a 21p and 23p Mirage props. The 23p would take a while to get on plane and blow out in turns. The 21p would get on plane better but still blow out in turns. Max speed 51mph 5200 rpm. I purchased a 22p Bravo 1 and the boat got on plane great and the prop would stay hooked up in turns. Lost some top end though. 48mph 4800 rpm.

Hope this helps.

sea6

Try a smaller diameter. Will spin up a little more. my motor was a 468 with an alleged 525 hp and I ran a 23p 3 blade to 5200 for 70 mph. Please tell me you haven't taken off the cool a$$ tubing over the air intake. That makes the boat. imo.

JMG

It helps a lot, thank you!

So the 4 blade props seem to have an advandage with this boat
Do you think a Revolution 4 would be a candidate?
Looking at your real world numbers I'm afraid I'm short on power for a Bravo 1 prop....
Your Engine has more power and a substantially higher RPM limit than mine, I should aim for 4400 - 4500 RPM I believe, so maybe not enough power to spin a bravo 1?
Taking into account sea6's reply below maybe a 21p or even a 19p Revolution 4 could work well?



Absolutely agree with you , the grilles are there, I would never remove them...

sbslinde

Bblades suggested using a Rev 4 prop to me a couple of years ago. I would say worth a try.

Grilles still on.

JMG

I'll try a Rev 4 then.
I'll see if I can locate a good used one that someone would ship overseas. Otherwise I'll bite the bullet and buy new.
It will be a while since the boating season has not started yet in Switzerland. I'll let you know how things turn out.
Many thanks!

cgpsu309

When does the boating season start in Switzerland?

JMG

I see You are in Ohio, climate is similar here. So normally around mid April.