Pontoon stern lift?

Discussion in 'Boat Design' started by jasonvi, Oct 30, 2016.

  1. Barry
    Joined: Mar 2002
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    Barry Senior Member


    I am not sure that I would try to make a square bottom at the bottom. Certainly you will get some lift as the chamfer is just incorrect.
    So you lift the back, that will not really improve the effectiveness of the rest of the pontoons.

    Extend the back at the same diameter,
    then install full length lift strakes almost as per the picture and then ALL, did I say ALL of the length of the pontoons will help carry the weight.

    I would do this in two steps, step one, extend the back , lose the taper and give it a run. You might find this will be enough. Then if it is not, 6 20 foot lengths of an appropriate EXTRUDED angle welded along the pontoons will make that boat fly with 500 hp

    If you just try to make the flat portion square, you will have a transition between round and square that will kick up a lot of spray.

    The strakes, will stop the water from coming up the side of the pontoons for a drier ride
     
  2. ElGringo
    Joined: Mar 2014
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    Location: Amarillo Texas

    ElGringo Senior Member

    While you have it upside down working on those pontoons, you better figure out how to get rid of the center one. When you fix the lift problem in the rear, and have more of the length in the water, then that problem will increase.
     
  3. Barry
    Joined: Mar 2002
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    Barry Senior Member

    www.boatingmag.com/20-best-pontoon-boats

    El Gringo, Not sure why you are wanting to get rid of the third pontoon
    I have tried to attach the link to the top 20 pontoon boats, most with the three toons, if the video does not play the pontoon boats, google, Top 20 Pontoon boats, Boating Magazine and you will see non chamfered tritoons, most with lift strakes running fast with much less hp than you have

    There is absolutely no reason to loose the center toon, none

    Many do not even have lift strakes and I am using the lift strakes term loosely as on a hull that is so narrow and round, the lift strakes will completely change the waterflow and the profile of the wetted hull surface.

    Jasonvi, you will not have an issue of excessive lift on the back of the pontoons.
    Loosing the chamfer will get rid of the bow rise and the strakes will make the boat much more fuel efficient and a dry ride
     
  4. ElGringo
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    Location: Amarillo Texas

    ElGringo Senior Member

    My reason is the amount of horsepower needed to move it. I guess you could make a shipping container move at 35 knots if you had enough power. I will check your link but all the Tri-Toons I have seen had more horsepower than a dozen cars.
     
  5. Barry
    Joined: Mar 2002
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    Barry Senior Member

    My neighbors on both sides have tritoons and I have spent quite a few hours on them. One a 26 with a 250 e-tec. This boat can hit close to 45 (gps) They ski, wakeboard and tube behind it.
    The other has a 300 Yammy, single, and it also flies. He has it out of the water now, I might slip over to see if it has strakes. Last summer, there were 14 people and a significant amount of liquids, and the boat hit plane easy, I would estimate 32 mph easily and I doubt he had it pinned
     
  6. ElGringo
    Joined: Mar 2014
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    Location: Amarillo Texas

    ElGringo Senior Member

    OK Barry you are absolutely correct.
     

  7. jasonvi
    Joined: Oct 2016
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    Location: Michigan USA

    jasonvi Junior Member

    Thanks for all the suggestions. Just to give an update if anyone is searching the threads with a similar issue, I installed lifting strakes on all 3 pontoons and eliminated the chamfers, extending the running surface abaft an additional 6” (simply because of how the aluminum cuts worked out).
    Runs like a champ now, & gets up on plane without difficulty.
    Thanks again for the assistance!
     
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