Dinghy 13 ft with bi-convex sections option

Discussion in 'Sailboats' started by Dolfiman, Apr 22, 2019.

  1. Dolfiman
    Joined: Aug 2017
    Posts: 755
    Likes: 360, Points: 63
    Location: NICE (France)

    Dolfiman Senior Member

    I have investigated this option in the idea to enlarge the beam overall (to maximize the righting moment from the helmsman in hiking position) while maintaining at minima the beam at waterline (to maintain low the drag) but with offering more managable stability (especially during tack or gybe manoeuvers by rough seas). For user with less kills and/or seaching a more easy but still fun dinghy.
    The convexity can be more or less accentuated, here attached I have chosen a medium shape, for a comparison with a convex-concav one (a more common design) built at same beam overall and with exactly the same immerged hull waterlines.
    The main result is about the stability when the "payload" (i.e. the helmsman) is temporarly in the center of the dinghy : the bi-convex option can offer a greater tolerance.
    The main unknowns are about the behaviour at speed on waves :
    - the bi-convex leeward side can act as a spray rail (less wetty for the crew), can add some dynamic lift when heel is 10° or over.
    - … but at the cost of some extra drag, of some slam occurrences,
    Thanks in advance for your comments.

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