Latest News: Forums Technical Buoyancy Distribution on New Boats

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  • #3377
    Anonymous
    Inactive

    A new builder is a great opportunity to make the boat more attractive to potential Class Association members. One area I hope will be addressed is the buoyancy and capsize performance.

    The Plus S is a dream to right from capsized when compared with most other classes, especially the modern ones with excessive buoyancy that float high on their sides and tend to turn turtle. The Plus S floats low in the water when capsized, which not only means a much-reduced tendency to invert, but also that even an unfit person can climb up on the centreboard; the boat then seems to come upright without a great deal of persuasion. Also, having floorboards, the floor remains dry even when the boat is carrying some water, an important factor for a lot of Wayfarer sailors who relish sailing with dry feet – often not the case with double-bottoms.

    The problems with the Plus S start when upright, when only a long-ish downwind leg in decent wind or a bucket will get rid of the bulk of the water. Also, the self-bailers are working at such a depth and hydrostatic pressure, they have tough time in lighter winds or on the beat clearing water which has entered as spray or through leakage.

    My guess is that the answer is a design which still depends largely on the bow and stern tanks to provide the bulk of the capsized buoyancy but also has a quite shallow double-bottom. The double bottom would not be so deep as to give true static self-draining (deep double-bottoms or excessive buoyancy cause the boat to float high on its side when capsized seem to be the main cause of turtling) but would incorporate bailers set in the double-bottom at the sides of the hull rather than in the bottom of the hull. These would work at less depth and hydrostatic pressure and would thus be more effective at clearing water, and if set in generous wells in the double-bottom (maybe beneath the thwart) would provide collection points for bilge water, keeping the floor dry.

    Wanderer-style flooding side tanks could be provided to avoid the second capsize that sometimes results from trapped water rushing across a double-bottom as the boat is righted, but if the double-bottom were shallow enough, and maybe the bow and stern tanks reduced in size to ensure the boat floats on its side at the same height as the Plus S, this might not be a problem anyway.

    Just think of it, a boat as docile as a Plus S when capsized, but dry in seconds rather than minutes once upright – marvellous!

    #4785
    mudskipper
    Member

    Ease of boat draining is clearly an issue.

    We sail a world, which as justcrew suggests has the self-bailers on the outer edges of the hull, each sits in a fairly deep well. As the boat has a gulley running along each side of the floor the water rushes towards the bailers. We have filled the boat (unintentionally) up to just below the seats, with 4 adults aboard and we managed to get enough way on to drain it dry within a few minutes. In windier conditions once you can get them open and get on the right tack the boat is empty is no time.

    One thing to add is that we also have transom flaps, which are about as much use as a chocolate teapot. The only thing ours have done recently is act as an alternative escape route for the spinnaker pole. So I think a new design which doesn’t bother to include them would be no bad thing.

    #4989
    Anonymous
    Inactive

    Just found this on the Laser 2000 forum:

    I always use masthead buoyancy when sailing alone. Have tried and failed at righting from an inversion, we’re talking 14st jumping up and down on the gunwale and not budging it! On that occasion there was another 14st lump on hand to help out, but because it can fully invert in under half a minute there are no guarantees you could get onto the centreboard in time, ‘specially if you’re using the gennaker.

    Hopefully Mr Morrison will have done a better job on the Wayfarer…

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