Need help with prop selection

kwoolard

Chief Petty Officer
Joined
Feb 9, 2003
Messages
420
I currently have a 235WA cuddy cabin Sea Pro with 5.7L-250hp Alpha One sterndrive(1.47:1 ratio).

My current performance numbers with gps are:

2 People, 60 gallons of gas, gear = WOT 4500 rpms @ 39 mph, Cruise 3400 rpms @ 32 mph
4 People, 125 gallons of gas, gear = WOT 4100 rpms @ 35 mph, Cruse 3400 rpms @ 28 mph

When I bought the boat it was propped with a 3 blade SS 19" prop which only gave me a WOT of 4000 rpms but at 40 mph. I switched to a 3 blade Aluminum 15" prop (15-1/2 x 15 Quicksilver Black Diamond), which is what the current performance numbers are based on.

My question is, with a recommended WOT for my engine at 4400-4800 is my current prop setup OK? Should I drop in pitch or is there a different style 15" prop that would increase my rpms and keep me in the same speed range?

Thanks,
Keith
 

kwoolard

Chief Petty Officer
Joined
Feb 9, 2003
Messages
420
Re: Need help with prop selection

Anybody have any suggestions? Should I drop down to a 14" prop and maybe add some cup to it to increase my top end?
 
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