CE/CLP Bolger June Bug

Discussion in 'Boat Design' started by A N Other, Jul 10, 2010.

  1. A N Other
    Joined: Jul 2010
    Posts: 2
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    Location: Flint Michigan

    A N Other New Member

    I am about to build my second Phil Bolger June Bug. This one will have no built in seats, as we only use her for sailing; we will have stools as on my Teal for occasional rowing. We often sail without the lee board in very shallow water. With her plumb sides and three bottom skids, she sails pretty well, even (modestly) to windward. She does however have quite a lee helm and its hard to get the bow through the wind with or without the lee board. In light air it's often impossible and we end up tacking by doing a 270 (or so).

    Looking at the drawing and the old hull. the CE is about 6" behind the CLP, with or without the board. On an old thread on this forum, a designer said the CE should be about 10% to 12% of waterline length ahead of the CLP. Ted Brewer's site makes a similar reference. I suspect the lee board and mast location on the June Bug (it may be seen on the Instant Boats site) are matters of convenience. Bolger designed the boat as a tender first and added his 59 square foot rig for sailing as an afterthought. The mast partner lashes down to the front oar locks to make it removable. We permanently mounted the mast partner on ours and decked the boat over from the bow to the partner.

    I would appreciate knowledgable comment on whether there is anything to be gained by moving the mast 14" or so forward, or anything lost. Moving the leeboard would put it around the curvature of the hull and increase drag substantially. Also, that wouldn't help in sailing without the board. THX.
  2. Perm Stress
    Joined: Sep 2009
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    Location: Lithuania

    Perm Stress Senior Member

    As you already have a boat, use her as test bed: lash temporary the mast on different positions, progressively moving it aft, until boat will develop unacceptable weather helm. then move the mast back forward until weather helm is acceptable and boat tack well. this will be your position of mast for newbuild.

    As for CE/CLR calculations and their relative positions, please remeber, that:
    *both CE and CLR do NOT coincide with real location of physical force,
    *CE of sails is assumed with sails on Center-line, what is never the case in practice.
    * etc. etc...

    Therefore, any geometrical CE/CLR calculations, recomended relative positions are only useful for that certain type of boat they are derived from. Example for narrow keelboats and beamy dingies of same rig recomended lead will be completely different. for different rigs also.

    In your case, when you have a "prototype" at hand, most reliable (and fun) way is to go for experiments.

    Good luck and keep us informed. :)
  3. A N Other
    Joined: Jul 2010
    Posts: 2
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    Location: Flint Michigan

    A N Other New Member

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