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Prop Selection - 3 Blade or 4 Blade Prop for Egret 189 w/ Yamaha 4 Stroke F150

HeartNShoalHeartNShoal Posts: 937 Officer
I've read the pros and cons of 3 blade vs. 4 blade props. Seems like you get a long list of benefits with the 4 blade prop, listed below, for giving up 1 mph or 2 mph of top speed.

Based on everything I have read I am going to get a 4-blade, whatever configuration Frank recommends. Am I on the right track?

4-Blade Prop Performance Traits:

planes the boat faster
keeps the boat on plane at a slower speed
gives improved mid-range speed at the same RPM
provides quicker acceleration
has better holding power in rough seas
is less likely to ventilate in sharp turns
offers better low-speed handling
is not as fast on top end

Replies

  • trponhuntertrponhunter Posts: 249 Deckhand
    I think you'll give up more than 1 mph - but someone on the forum should have first hand experience with this and can chime in. Also, to me the top end is not what is really important, it's what your cruise speed is and at what rpm's - this is where I focus, as it's what I do 90% of the time. For what it's worth, my old bird had a 150 etec on it and cruised around 40mph at 4200 rpm's - top end was about 50 or so. Fuel economy usually falls apart over 4000 rpm's or so - check the engine reports. My personal focus is I want the best cruise at as close to 4000 rpm's as possible, for good fuel economy. If you prop for the low end of the recommended rpm range, you will generally increase your cruise speed, and to the best of my knowledge, a 3 blade will usually provide better cruise speed.
    *Previous - 2000 Egret 189 carbon w/ vmax 150 - twin rotating prop
    *Previous - 2008 Egret 189 carbon w/ ETEC 150
    *Previous 2010 Beavertail Vengence w/ETEC 90
    *Current - 2015 Beavertail BTV w/ Suzuki 90
  • mastercastermastercaster Posts: 1,259 Officer
    Expect 2-4 MPH loss with a normal 4 blade.

    Most hulls benefit from a 4 blade, especially at higher weight loads, I've always felt the benefits far out-weigh the loss of speed.

    My hull (not an Egret) unfortunately needs as much bow lift as possible, even the most bow-lifting 4 blade doesn't work out with it. I really dislike the feel of a 3 blade.
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