Designing a weak/failure point in a leeboard

Discussion in 'Boat Design' started by Ikenzu, Oct 15, 2007.

  1. Ikenzu
    Joined: Oct 2007
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    Location: Windsor, CT, USA

    Ikenzu Junior Member

    I am working on making an outrigger sailing canoe and plan to put on an approx. 3' leeboard that will attach somehow to the side of the 17' canoe. I am wondering if anyone has any ideas on how to engineer a failure point into the leeboard system so that in the event of a collision, the leeboard doesn't rip off and damage the hull. It would seem to me that it should not be in the blade but in the connection from the blade to the hull. I thought you could design it so that if you hit something, the blade would pop right off and would have a little cord attached to it so you don't have to pull a U-turn to go back and get it.

    Any thoughts?
  2. GTO
    Joined: Jul 2007
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    Location: Alabama

    GTO Senior Member

    Try this site for info:

    (first site I came too with a search on leeboard design)

    You could just use the classic leeboard. Strakes (or battens) along the sides of the canoe to give the board the correct angle to the waters flow, then pass a rope, with a stop knot on the leeboard end, thru it, attach the other end of the rope to a center point at the bottom of the canoe.

    To use, simply flip the leeboard from one side to the other. The rope is the free pivot point and would no doubt absorb any side impacts safely, while allowing a fore/aft pivot during forward impacts.

    I have a 16' Windsprint that I built with a pivoting leeboard. I don't think you really have anything to worry about impact wise, except around the launch ramp maybe.
  3. lewisboats
    Joined: Oct 2002
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    Location: Iowa

    lewisboats Obsessed Member


    Here's what I folds up if you hit uses a rubber bungee to pull it down and forward.

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

    messabout Senior Member

    Do it the way GTO says. You will find that rope and stopper knot system on many boats. Bolger uses it regularly. It is simple, effective, and cheap.

  5. Ikenzu
    Joined: Oct 2007
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    Location: Windsor, CT, USA

    Ikenzu Junior Member

    GTO's approach sounds good. I will give it a try. Thanx guys.
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