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  1. #1
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    Propeller Education Desired

    Assuming all things are equal; same 17' Hydrostream boat, same 150 hp Mercury motor, but 2 different props.
    The first prop is a 19 pitch (3-blade) and the second is a 19 pitch (4-blade). What differences in performance could be expected.

    Also, I have a Switzer IO with a 5.7 / 350 ci (260 hp) using a high-5 prop. It performs very well and I have never tried any other prop. Should I play around with other props. The boat does 68 mph and gets there very quickly holeshot-wise.
    It does 68 with just me and 1/4 tank of gas. It will do 65 with 4 people and a big cooler.

    Thanks for any offered opinions.
    Swivomatically,

    The Pic

  2. #2
    Join Date
    Jan 2015
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    Wisconsin
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    Still are way too many variables at play for a simple answer. If I remember correctly, all things being the same ie rake, cup, blade surface area, the less blades the faster top end. But less blades would mean more vibration, higher speed to stay on plane, and not as good of a grip in corners.

    I have a Checkmate trimate with 1990 140 looper and run a Raker 24pitch 3blade hits 60mph. A Renegade 21p 4b runs 55mph. And an OMC, I believe STV, maybe an SRT, but 17p 3b makes about 45. All of those are at 6000 rpm, motor will not spin any higher. The 24 breaks over slow but once it does, hang on. The 21 breaks over good, and hang on after that. The 17 will literally launch the boat out of the water, it is fun.

    Yes, I would definitely try other props. I bought the Raker off of Craigslist in mint condition, for $100 delivered within a half mile of my door. That was the asking price I did not beat them down. The Renegade was from Ebay, just under $200 and then a different thrust washer was another $20. In about 8 out of 10 condition. The OMC 3 blade came with the boat, different motor, and it is maybe a 4 out of 10. Each prop has a different use and work good for what I use them for. A little over lap, but definitely worth the time to switch them out.

  3. #3
    Join Date
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    Props are like money, the more the merrier! I like the chopper I just tried on my stream it lifts and holds very well. 26p big ear but its a 200 it might be too much for the 150 although ya never know til ya try. I had a 22p small ear that I unloaded in a trade deal I wanted to try on my 135. I tried a few props 24 too much, 21-23 it liked. I believe the four blade is designed to hold more weight and locks the boat up soundly loading the prop so its easier to control, something like that I read here. I havent tried a 4 blade yet. Ran a high five once on an IO for a couple summers eons ago on a close friends boat, meh didnt do much for me
    Hydrostream dreamin

  4. #4
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    Lake Coochiching, Ontario
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    Try any prop you can borrow. Don't be afraid to buy used props, you can always sell them. I keep saying that and props keep accumulating in my crawl space, but that's just me.

  5. #5
    Join Date
    Feb 2014
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    Missouri
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    Blade -+ 100-200 rpm
    1” diameter -+ 100-200rpm
    1” pitch -+ 100-200rpm
    cup -+ 100-200 rpm (not rated though you will see heavy or light )
    aluminum - ss -+ 100-200 rpm ( ss is heavier so tougher to turn )

    thats just an average as the attitude of the boat also changes

    for example with say a merc trophy plus 21 vs a 23 their close so expect the 23 to be 200-400 rpm slower; throw in the boat lifting better it may not be any less rpm. Switch that 21 tp for a spitfire expect to gain 1-200 for diameter 1-200 for loos of cup and 1-200 for going aluminum so 300-600 rpm gain but expect mor slip and such

    In the end unless you know a boat you ran several props on it’s all guessing. But you can expect safe performance with the go to props.

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