Pontoon Transom

Discussion in 'Boat Design' started by 54d18, Nov 28, 2012.

  1. 54d18
    Joined: Nov 2012
    Posts: 3
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    Location: Northern Ontario Canada

    54d18 New Member

    Hi, I just stumbled onto this site, very interesting, and quite a
    coincidence as I have been planning to build a new transom for
    my pontoon boat and would like to try to achieve more lift from
    the transom. I've read about the "Pontoon Waterglide" kit that
    mounts overtop of the existing transom and would like to build
    a new one with the same concept, I have at my disposal an
    aluminum fabrication shop that can do almost anything.
    One of things that I need to know is what angle to set the back at
    and also what angle the bottom should be at. The kit from PW is
    said to be 10' long so I will start at that legth but am not sure how
    agressive to be with the slope.


  2. hoytedow
    Joined: Sep 2009
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    Location: North of Cuba

    hoytedow Carbon Based Life Form

    Welcome, 54d18.
    Check your engine manual for the optimal transom tilt angle. It is usually lies between 12 and 15 degrees, but varies by manufacturer.
  3. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    I use 15 degrees on mounts without power tilt and trim, 12 on those with.
  4. 54d18
    Joined: Nov 2012
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    Location: Northern Ontario Canada

    54d18 New Member

    OK, after a computer re-format and Xmas holidays over, I'm back.

    The basic idea that I am shooting for is like a mini Jonboat 24" wide
    with 6" strakes on both sides slightly dipped down, about 2 deg.
    The flat bottom part would be between 6-8' with a slope forward
    to make the overall length about 10'. The angle of the slope
    I am not sure of yet, I will look at it when on the bench.

    Any opinions would be appreciated...

  5. messabout
    Joined: Jan 2006
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    Location: Lakeland Fl USA

    messabout Senior Member

    It seems to me that you are referring to the addition of some horizontal platework that will function as a planing surface at or near the transoms of the pontoons. If that is the case then there are a whole bunch of variables. One of them is operating speed versus angle of incidence of the flat planes.

    If your pontoons are tubular, as I suspect they might be, then the addition of "planing fins" will probably help. Getting the right angles the first time may be a bit of a problem. Could you dream up a method that would allow you to attach the fins in such a way as to be adjustable in the angular direction? Two degrees may be right for one size engine but not for another size and horsepower.

    If you are to use a small engine and are happy with displacement speeds then the fins will not be advisable at all. All they would do is increase drag.

  6. 54d18
    Joined: Nov 2012
    Posts: 3
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    Location: Northern Ontario Canada

    54d18 New Member

    The basic concept which I am going on is the same as
    the "Pontoon Waterglide," their product is an aftermarket
    sort of saddle that fits over the existing transom.
    As mentioned, the angle of incidence will be a trial and error,
    I plan to achieve this adjustability with shims between the
    underside of the deck and the new transom.

    I am still toying with the actual construction plans,
    I hope to have aquired all the materials and get started
    in the early spring.

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