My neighbor has an Advantage Custom 21ft. He uses it for skiing mostly. He likes the hole shots he gets but he says there is not enough top end. It has a stock 350ci with an Alpha One outdrive. I looked at the prop and the last # is 18. I believe that is pitch. Would a 21p still give him a decent hole shot?
ALUMINUM OR STAINLESS ? 3 OR 4 BLADE ? RPM @ WOT?
On similar boats I have seen good performance with 19 pitch Merc. 4 blade.
A 21p 3 blade will give better top end probably but will suffer out of the hole.
The 4 or 5 blade stainless will be the overall way to go.Better hole response,better mid range,much better handling.
Without the info at top it is tuff to give good recommendation . Is the boat full of people and gear most of the time ?
Gotta go stainless. The prop he has is slipping big time.
I would start with a 19 pitch Merc. revolution 4 blade. If the tach. goes over 4800 rpm step up to the 21 pitch revolution.I doubt it will see 4800 but strange things sometime happen.Make sure the tach. is correct.Use a GPS to see the real speed.
Any good prop. shop will let your buddy exchange the prop. if it is not correct.
He should be very happy once he sees the difference that a stainless 4 blade does for the over all performance of his boat.The right prop. is the least expensive upgrade to a boat there is.
Check your local boat shops to see if they have test props you can borrow. They are usually painted blue. That is the advantage of an I/O over a V-drive when it comes to prop testing. You can use your credit card for a deposit and take 2 or 3 props to the lake with you for a day of testing.
I would definetly recomend he test a High Five in a 21 pitch. It gives up a little top speed but handling and acceleration are great.