Durability of Piranha and other composite props?

Discussion in 'Props' started by liki, May 19, 2011.

  1. liki
    Joined: Nov 2008
    Posts: 220
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    Location: Finland

    liki Senior Member

    I have an old 35hp 2-stroke Evinrude that (once again) needs a new propeller. 10x15" was a bit too much, I think I will return to 10x13", but ... After again another 120 EUR spent into a new propeller, I now have some questions on the composite propeller that I wish somebody could answer.

    a) What is the risk to damage the actual hub in a ground impact?
    b) How easily the blades are rendered totally useless making it impossible to limp back to port?
    c) Is it possible to survive a minor impact at near idle speed with damage to only one blade?
    d) Will the blades survive stopping the engine by running aground into a mud bottom?

    We are often fishing in very muddy waters with mud and rocks and just last time totalled the propeller by running into waters less than 1 feet deep. Bottom visibility was less than 15cm at worst, and I wonder would a composite propeller wind up as an even more expensive option compared with an aluminium one? Maybe we should just be more careful and stop the engine further. :)
     
  2. Stumble
    Joined: Oct 2008
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    Location: New Orleans

    Stumble Senior Member

    Liki,

    I tried a pair on my fishing boat, running out of the mouth of the Mississippi river (muddy, debris strewn). The first day we headed out we got 10 miles before 2 of the blades. Relaced them with spares, and went fishing for the day. On the way back in we snapped 4 blades (twin engine boat). This used up all the spares we had but were able to get some more from a local chandlery. We also put the old props back on the boat.

    The second day we fished the marshes, and within an hour had broken an additional 3 blades, and switched back to standard props.

    To answer your questions:

    a) We destroyed a lot of blades, but the hub was always fine. The product worked as intended in breaking off before damage could occur

    b) They were either ok, or disentegrated. None of the blades we broke could have limped anywhere.

    c) Maybe, but we never experienced it

    d) Not in my experience.

    I have fished these same waters for years, and have at most had minor dings to a metal prop, one weekend with the composites and I went back to metal. If the water is clear with few obstructions I might be ilwling to give them another try, but in areas where the water is murky, and there is a lot of floating junk it isn't worth it.
     
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  3. liki
    Joined: Nov 2008
    Posts: 220
    Likes: 12, Points: 18, Legacy Rep: 114
    Location: Finland

    liki Senior Member

    Thanks a lot for that information. Sounds much like I should consider staying with Al props; The waters are pretty free of floating junk but minor hits with a rock or running aground into mud are likely to happen every time we go fishing.
     

  4. Stumble
    Joined: Oct 2008
    Posts: 1,901
    Likes: 71, Points: 48, Legacy Rep: 739
    Location: New Orleans

    Stumble Senior Member

    Ya, they are interesting, and the thought was it would make swapping pitch easier, but in out waters there is just too much debris. On Wednesday we were out and I had the option of hitting a 20 foot oak tree of heading through a pool of light flotsam.... But that is here.
     
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