Boom Location

Discussion in 'Sailboats' started by SailingAustin, May 8, 2013.

  1. SailingAustin
    Joined: May 2013
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    Location: Austin, TX

    SailingAustin New Member

    I'm shopping for a mid-80s Hunter 25.5. On one I'm looking at, the owner moved the boom about 8 inches lower on the mast to fit a larger sail.

    What's your opinion on (a) the sailing safety/performance with the new mainsail geometry and (b) having six more holes in the mast at the new gooseneck location?

    I test sailed the boat in 8-10 kts and the rig seems solid - nothing unusual happened.

    More boat info....
    86 Hunter 25.5
    4500 lb displacement
    shoal draft keel
    masthead rig

    Many thanks!
    Steve
     
  2. Petros
    Joined: Oct 2007
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    Location: Arlington, WA-USA

    Petros Senior Member

    the boom is no weaker than when the boom was mounted in the old location. the hole weakens the mast the same amount whether there is a screw or pop rivet in it or not. In fact the highest streesed point is now moved down to the new gooneck location, so this area will have less stress than before. The mast is just fine, as long as the holes are filled with sealant to prevent moisture and corrosion.

    Lowering the boom should not only improve the sail area, but also improve the efficiency of the sail by bringing it closer to the cabin top. Tests have shown there is some "end plate" effect that benefits the sail the lower the boom is located to the cabin top. Your only issue is of the boom is lowered enough to be a hazard to unsuspecting crew or guests if you gibe or not paying attention when tacking.

    Good luck with the purchase.
     
  3. SailingAustin
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    SailingAustin New Member

    Thanks

    Thanks, Petros, for the reply.

    I had not thought about filling in those old holes - good idea.

    The boom is not super-low, but I'll warn everyone to watch their heads just in case.

    Cheers,
    Steve
     
  4. messabout
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    Location: Lakeland Fl USA

    messabout Senior Member

    Politely question the reason for lowering the boom. The difference in sail area would not amount to much and the foot is not the most effective place to add sail area. It might make a tiny advantage if competing with identical boats. OR.....did the owner do that to accommodate a bargain priced main that happened to have an 8 inch longer luff....Or was the original main luff stretched that much? Must be a reason for such a mod. Before you buy, CYOAF
     
  5. troy2000
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    troy2000 Senior Member

    I think he answered your question in the original post: "the owner moved the boom about 8 inches lower on the mast to fit a larger sail."
     
  6. messabout
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    messabout Senior Member

    Troy; yes he wanted to fit a larger sail. But for what reason? To get more sail area? An eight inch panel 15 feet long would result in only 10 sq ft of main. Useful, maybe, in light air on a run. Doubtful that it would matter much on a windward leg except for a very skilled and attentive skipper. It would be interesting to discover the reasoning behind this modification.
     
  7. michael pierzga
    Joined: Dec 2008
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    Location: spain

    michael pierzga Senior Member

    When you lower a boom you change the Boom Vang geometry. The smaller the boom vang angle , the more highly loaded the vang, the boom and its goosenecks
     
  8. troy2000
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    troy2000 Senior Member

    Probably because it was a sail he already had, for one reason or another. I doubt he'd have had one custom-made for the extra inches....

    But anything's possible. I'm just speculating, and filling the silence until we get an answer from the OP.
     
    Last edited: May 13, 2013
  9. messabout
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    Location: Lakeland Fl USA

    messabout Senior Member

    Good point Michael. It may not be serious depending on the location of the vang ends and the attendent trig. If the vang is a short one it will matter.
     
  10. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    [​IMG]

    The Hunter has more than sufficient room to lower the boom 8" and still rig a vang. Even with the "pop top" open . . .
     
  11. SailingAustin
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    SailingAustin New Member

    Hey, guys. Thanks for the interest and the good replies! (I was away for 10 days crewing for a friend in the Florida Keys).

    Yep, the previous owner found a sail that was a little too big so he just lowered the boom.

    Steve
     

  12. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    The extra few feet of area isn't going to hurt a thing . . . have fun . . .
     
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