What's the difference

antique fisherman

Petty Officer 3rd Class
Joined
Feb 10, 2010
Messages
85
What kind of performance or anything else would be realized between a 3 blade and a 4 blade prop with the same diameter and pitch?
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: What's the difference

Basically a a 3 blade will have good overall performance.
a 4 blade will have better low to midrange performance.Better hole shot,
stay on plane with less power,more control at the dock,resists ventilation,
allows higher mount of an outboard. Often prescribed for pontoons with ventilation(cavitation)issues.Usually will out perform a 3 blade on a pontoon.Only draw back is a possible slight reduction of top end.
 

45Auto

Commander
Joined
May 31, 2002
Messages
2,842
Re: What's the difference

Basic myth is that more blade area (4 blade) gives less slip therefore better acceleration, but the increased blade area also causes more drag therefore slightly less top speed.

Sometimes it works that way, sometimes it doesn't.

Reality is that on a pleasure boat, hull form and drag due to boat loading will have more effect on prop performance than the number of blades.
 

antique fisherman

Petty Officer 3rd Class
Joined
Feb 10, 2010
Messages
85
Re: What's the difference

Thank you guys, I've never had a 4 blade. I have to buy one, so I was wondering about them.
 
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