Hydro fin

Discussion in 'Boats, Blinds, & Gadgets Forum' started by Canadian hitman, Jun 5, 2021.

  1. Canadian hitman

    Canadian hitman Senior Refuge Member

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    Anybody ever use a hydro fin on their outboard?? Does it help with porpoising?

    90 hp 2 stroke Yamaha on a Bankes Freedom and it porpoises when up on plane.
     
  2. duckbuster5901

    duckbuster5901 Elite Refuge Member

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    I tryed one on a small outboard and it worked but you,ll loose a couple mile per hr top end usually. Does pop them on top quickly. Power trim & tilt on that 90 adjusted right should alleviate your issue I would think.
     
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  3. GUNNERX2

    GUNNERX2 Elite Refuge Member

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    My son put one on his 50 Yamaha to tame a 1548 Express. Worked very well.
     
  4. HaydenHunter

    HaydenHunter Elite Refuge Member

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    Bought a 2012 Merc 50 HP tiller OB used, with one on it. Left it on there. Hard to tell what would happen if I took it off.
     
  5. bird junkie

    bird junkie Elite Refuge Member

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    They get a boat up on plane fast.
     
  6. Tuleman

    Tuleman Elite Refuge Member

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    Agree with all the above.
    With one exception: it did not reduce my top speed.
    In fact, it increased it. Without the 'hydrofoil' bolted to the vent plate, my little boat would start to porpose as it approached top speed. This required that I back off the throttle a tad to keep things under control. With the 'hydrofoil' bolted on, I can run wide open throttle and get that last couple of mph out it.
    It also, as others have said, gets the boat up on plane much more quickly and easily.
     
  7. oleww

    oleww Elite Refuge Member

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    Might help. That’s a fiberglass boat? That fin helps underpowered or high drag boats like a pontoon.

    if it’s set up right, the fin should be out the water on plane.
     
  8. Aunt Betty

    Aunt Betty Elite Refuge Member Supporting Member

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    Porpoising is a trim issue. Im just guessing but try lowering the tilt one notch or fiddle with your power trim or whatever you do to adjust trim.
     
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  9. Tuleman

    Tuleman Elite Refuge Member

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    My little marsh boat is overpowered, if anything. (original hull rated for 8hp, had a 20, then a new 25, now a new 15, on it. By new, I mean prop-rated hp)
    If my 'foil were out of the water on plane, it would not be much help in controlling porpoising.
    I suppose you set 'em up so that they do what you want them to do...?
     
  10. oleww

    oleww Elite Refuge Member

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    OP has a 90hp outboard.
     

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