Proper prop size and switching from a 3 to 4 blade

hucka003

Cadet
Joined
Jul 13, 2020
Messages
9
Afternoon everyone, hoping someone can give me their insights on which prop setup I should go with. I have a 1992 Glastron (17') with a 3.0LX Mercruiser, Alpha One. The original prop that came on the boat was a 17P; however the seller also included another prop which I never paid attention to until we ran into some shallow water this year and tore up our original prop pretty bad. I replaced the damaged prop yesterday and noticed that it was a 19P prop. From what I could gather from Glastron, from the manufacturer was a 14 x 21P, however I was reading an old (1991 was the closest I could find) product manual from their site. What prop came with this setup from the manufacturer? Second question, is it worth switching to a 4 blade, to increase the acceleration. Tubing on the 3 blade is fine, but getting me (6'0, 230lb) out of the water on skis (wakeboard is ok) is difficult when you have a couple of passengers in the boat. Not at high elevation, don't really care about top speed, boat at WOT right now runs at about 35-40mph (depending on how rough the lake is), within the manufacturers RPM guidelines on the 17P prop, haven't tested the 19P prop yet. Thanks!
 

WesNewell

Chief Petty Officer
Joined
Jan 3, 2018
Messages
497
if the 17p is within the rpm range, then get another 17P. If it had a hard time pulling a skier up then drop to a 15P and control max rpm with the throttle.
 

Starcraft5834

Lieutenant Commander
Joined
Jun 2, 2013
Messages
1,677
the right prop for your engine should be turning at WOT- 4600-4800 rpms.. 4 blade prop will pull skier up quicker... if your 17p 3 blade gets u 4600-4800.... you'd probably need to drop down 1 for a 4 blade to 16p.. Michigan Match makes 16p 4 blade.. (they did anyway) few years ago
 
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