Yann Quenet, Baluchon

Discussion in 'Sailboats' started by skyl4rk, Oct 4, 2020.

  1. skyl4rk
    Joined: Aug 2006
    Posts: 47
    Likes: 8, Points: 8, Legacy Rep: 21
    Location: Lake Michigan

    skyl4rk Junior Member

  2. sharpii2
    Joined: May 2004
    Posts: 1,986
    Likes: 151, Points: 63, Legacy Rep: 611
    Location: Michigan, USA

    sharpii2 Senior Member

    Thanks for showing us this, Skyl4rk.

    The more I see of this boat, the more I am impressed.

    Starting with the keel.

    For a fin-keel with a bulb on it, this one is quite clever. It is attached to the hull with two metal flanges, which in turn are bolted to the hull. It is held on by bolts which pass through the first flange, the keel fin (which appears to be a steel plate), then through the second flange.

    The structural advantages I see in this arrangement are:

    1.) the bolts, which hold the flanges on, are spaced relative widely apart transversely. They are also some distance from the weld joint on the flanges. This allows some freedom of movement for the whole structure to flex, without causing leaks.

    2.) The plate-fin itself will be able to flex far better Than a thicker airfoil section fin would, which would tend to keep shock bending loads away from the hull/keel joint. This in my view allows for a more resilient structure than what is found with a more typical bulb-keel arrangement.

    The rig is interesting, as it is a simple Bermuda main with virticle battens, so the sail can wrap around the mast.

    A possible drawback of this type of rig is that, when the sail is reefed, the CE of the sail moves forward. This can cause a dangerous lee helm right when good balance is needed most.

    I have often thought of this problem, a have chosen a gaff or lug rig for a single-sail boat to avoid it.

    The solution this builder/designer appears to have chosen, is to move the keel forward relative to the mast. This creates worse weather helm under full sail, but is easily cured by reducing sail when the wind freshens.

    Forgoing a boom makes reefing operations simpler. Using a whisker pole to hold the clew out is also quite clever. No boom in the way, and it can be deployed at convenience.

    The hull seems to de designed to prevent nose-diving while running down big waves.
    Dolfiman likes this.
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