Tritoon center log not parallel

Discussion in 'Hydrodynamics and Aerodynamics' started by kenfyoozed, Nov 9, 2024.

  1. kenfyoozed
    Joined: Mar 2005
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    kenfyoozed Junior Member

    My tritoon had an accident in where the center toon needed to be replaced. It was done so at the factory. Never felt that the boat was the same after the accident. Performance didn’t seem the same. That may have been because it could have had a different prop but I can’t confirm that. I was looking at the hydrofoils and needed to measure between the pontoons to get an overall width. In doing so I have found the center pontoon is not square to the outside pontoons. I know a tritoon isn't supposed to great on performance but I want as much from my boat as possible

    So would having that much of a pontoon skewed diagonally that much be an issue? I feel like it would hinder my top end performance which is what I have always felt was lacking.

    The boat is out of warranty as is the repair, I’m sure since it happened in 2019. I had no reason to measure or check it until now. I’m sure I have no recourse at this point.
    I love the boat but it’s sad the amount of money that I pay for insurance and that insurance paid out to fix this and it seems it wasn’t done properly.

    These are the actual measurements between the strakes of the center pontoon and the outside pontoons.
    Port Bow = 435mm
    Starboard Bow = 454mm
    Port Stern = 452mm
    Starboard Stern = 430 mm

    Factory is telling me that this is nothing to worry about. It would not hurt any performance. is this true or would not being parallel cause drag?

    Thanks
     
  2. messabout
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    messabout Senior Member

    Pontoons need to be parallel. If not, some unwelcome drag will be the inevitable result. The people who told you that it does not matter, are sadly mistaken or....... I am trying to be polite here.....form your own conclusion.

    At low speeds the disadvantage will not amount to much. As speed increases the problem will increase , probably in an exponential way. That is to say that the drag may theoretically be X amount of drag at 12 knots but four times that amount at 24 knots.
     
  3. kenfyoozed
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    kenfyoozed Junior Member

    Messabout, that's the way I see it as well. I am running 4oknots at WOT, trying to hit 44konts +. I feel this is hindering my efforts. Is there a way to calculate the drag?
     
  4. revintage
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    revintage Senior Member

    How long is the waterline of your tritoon?
     
  5. kenfyoozed
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    kenfyoozed Junior Member

    outside pontoons are 25' and the center pontoon is just over 26'
     
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  6. BlueBell
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    BlueBell . . . _ _ _ . . . _ _ _

    This is a very strange situation without adequate explanation.

    Sell it and buy a new pontoon boat that goes 44 knots, your target.
     
  7. kenfyoozed
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    kenfyoozed Junior Member

    This boat did 44knots before the accident. I’ve been trying to find out why it hasn’t since, although lazily. We cruise around 20 knots and pull water sports at 15-17knots. So WOT isn’t needed all the time. I’m sure I’ve now found the issue but the factory is telling me it’s not an issue.

    I liken this to the door gaps not being even on a car after it’s repaired. Yes the doors may open but it’s not fixed correctly.

    I would like to prove this is or isn’t an issue. I’m taking the factory’s word because if it is an issue they loose more money fixing it. Of course they will say it’s not an issue.

    what further explanation points could I provide?
     
  8. baeckmo
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    baeckmo Hydrodynamics

    I find it hard to believe that the actual angle difference of about 0,15 degree would cause any measurable difference. Have you checked the center distances between the outer hulls, and what is the speed difference from before? I'd look for other issues, most probably a difference in weight, weight distribution, or somewhere in the propulsion dept.
     
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  9. kenfyoozed
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    kenfyoozed Junior Member

    Weight is the same. Speed difference from before is -3mpg. Went from 50mph to 47mph. I have not checked to make sure of the squareness of the outside pontoons to each other. That is next on the list.

    thank you for the degree calc.
     
  10. BlueBell
    Joined: May 2017
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    BlueBell . . . _ _ _ . . . _ _ _

    And let's not leave out the propeller question from the original post...
    We know with zero certainty if it's even the same prop.
    And it's been in an "accident" so anything and everything could be different from before.

    Your measurement numbers don't add-up.
    They total ~9m beam.
    How can a 26' pontoon boat be 9m wide??
    Also 44 knots WOT is ridiculous for a pontoon boat.

    More questions than answers.

    What are the diagonal measurements on the hull?
    Corner to corner.
     
  11. BlueBell
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    BlueBell . . . _ _ _ . . . _ _ _

    This boat has hydrofoils?
    No wonder it goes 40 knots!
     
  12. kenfyoozed
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    kenfyoozed Junior Member

    no, this boat does not have hydrofoils. Yes it will do 40 kn. Some say that that is crazy speed for a pontoon or tritoon, but these are not the boats that your grandfather knew.

    Not sure how you got to a 9 m beam.
    So to clear matters up the outside pontoons are 25 foot long. The center pontoon is 26 foot long. The outside pontoons are 25 inches in diameter while the center pontoon is 27 inches in diameter.

    yes, you are correct. I cannot confirm what the original prop was on my first motor. But in calling the dealership, the manufacturer of the boat and the manufacturer of the outboard they all agree that it would have had the same size propeller.

    it is possible that the outside pontoons are not squared to each other, but I will not be able to measure that until the rain stops. And that looks like it may not happen for another four or five days as soon as I can get those measurements I will let everyone know.
     

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  13. kenfyoozed
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    kenfyoozed Junior Member

    I am looking to add a hydrofoil which would allow this boat to reach 50+ knots
     
  14. BlueBell
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    BlueBell . . . _ _ _ . . . _ _ _

    Good luck!
     

  15. kenfyoozed
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    kenfyoozed Junior Member

    Thank you.

    the measurements I posted…. Did I use the wrong abbreviations for millimeter as mm?

    The strakes are not at the widest part of the pontoon. Only a couple of inches from the bottom of each pontoon. Full width is about 8.5’.
     
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