Planing hull inclines to the left

Discussion in 'Boat Design' started by Akeswins, Jul 23, 2018.

  1. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    Well, we have seen the "funny cars" at the drag races, this one appeared to have potential as a "funny boat".
    fallguy likes this.

  2. Akeswins
    Joined: Jun 2005
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    Location: Sardegna Italy

    Akeswins Naval Architect

    the reason was just an excess of lift in the aft sections, putting down the bow so decreasing the dynamic stability , and then the propeller torque did its job. But we were speaking of few degrees, not enough to put the outer flap above the water or to be visible enough to be recognizable as "funny".

    2 boats had same behavior, then others with updated hulls hadn't that issue. After that , also the first 2 have been updated. No, the hull didn't twist , just was inclining a bit .

    The solution was quite simple to do but not as simple to find, since the CG , pressure center and other parameters , + the effective trim angle theorically were ok.
    Trim "fishtail " fixed tabs indeed were simply the continuation of hull , or in other words, the hull originally was longer to achieve the "theorically" correct trim angle. Instead the trim angle is correct the same without.
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