Effects of Raising Mast Or Reducing Leach

Discussion in 'Sailboats' started by wesley Sherman, Nov 8, 2020.

  1. wesley Sherman
    Joined: Jan 2020
    Posts: 43
    Likes: 7, Points: 8
    Location: New York

    wesley Sherman Junior Member

    I am wondering what the effects would be on my Alberg 30 By raising the boom. 7", I realize I would have to have new sails made which I have to anyway. Hazard a guess the center of effort would raise enough to make the boat heel a lot more? a little ? not noticeable?

    Would Raising the end of the boom 6-8" and cutting a triangle from leach to the gooseneck and leaving the foot the same be a better idea? not sure what that would do. Would it possibly not affect the center of effort as much and make the boat not heel more.

    I am remembering right the sails drive is more affected by the Luff rather than the Leach. So taking nothing from the Luff and just a bit from the Leach would be better.

    Also would cutting this triangle from Leach to gooseneck affect the heel of the making it less? Alberg is stiffer at a sharp heel.

    Please be kind in your responses I am not all that skilled in sail changes.

    Thank you
     
    Last edited: Nov 8, 2020
  2. bajansailor
    Joined: Oct 2007
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    Location: Barbados

    bajansailor Marine Surveyor

    I guess you want to have more headroom in the cockpit, re the possibility of the boom bashing you on the head?
    I would be inclined to leave the gooseneck / mainsail foot where it is, and raise the clew by cutting out a triangle wedge as you suggest.
    By doing this you only lose half the amount of low down sail area, compared to if you simply raise the boom.
    And if you raise the boom, then you would need to re-position the gooseneck, which would probably be rather complicated.
     
  3. Blueknarr
    Joined: Aug 2017
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    Location: Colorado

    Blueknarr Senior Member

    I concur with Bajansailer. Leave the tack alone and raise the foot.
    If your current sail has reef points. Give it a test run by only using the leach reef point. It will be more than you intend but will also magnify any performance issues.
     
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  4. wesley Sherman
    Joined: Jan 2020
    Posts: 43
    Likes: 7, Points: 8
    Location: New York

    wesley Sherman Junior Member

    Thank you Bajan and Blue, I don't have new sails yet. The old ones are in a bunch of bags in the shop. My boat is under a tent undergoing a full gut and refit.
     

  5. latestarter
    Joined: Jul 2010
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    Location: N.W. England

    latestarter Senior Member

    I can not give you advice on the aerodynamics or practicalities just on the physics of your comment above.
    Assuming you are not raising the head of the sail to keep the sail area the same, removing part of the sail will reduce the heel.
    Although the centre of effort will rise it is more than offset by the reduction in sail area.
    With it being at the foot of the sail the effect will be small.
    Looked at another way, all of the existing sail is causing the yacht to heel, removing any part of the sail will tend to reduce heel not increase it.
     
    bajansailor likes this.
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