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69962RE: [bolger] Booms strength

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  • John Trussell
    Nov 16, 2013

      Leigh,

       

      I have owned several balanced lug boats. In order to achieve any windward performance, it is necessary to maintain a tight luff. This is accomplished by applying tension to a downhaul attached to the boom. If the sail is loose footed, the stress of the downhaul tends to bend the boom and make the sail fuller. Consequently, the boom needs to be stiff and on small boats, I use a plank boom. Rigging any boom involves some cost and labor. While I have no experience with Martha Janes, I would hate to go to the expense of building a boom and finding it was unsatisfactory. Therefore, I would be inclined to use the stiffest tubing I could find. If you look around, you might find a section of an old aluminum mast which would work.

       

      You might also want to consider using stainless pop rivets rather than aluminum for attaching hardware.

       

      Have fun.

       

      JohnT

       


      From: bolger@yahoogroups.com [mailto: bolger@yahoogroups.com ] On Behalf Of Leigh
      Sent: Saturday, November 16, 2013 9:55 AM
      To: Bolger Group
      Subject: [bolger] Booms strength

       

       

      I'm busy refitting a Martha Jane and need to replace the boom. It's about 17ft and I'm likely to make it from aluminum tube, simpler and lighter than making a fir boom. So do I need to use Schedule 40 pipe or will tube be stiff enough? If so what diameter would one use? I'm thinking about 2 1/2 to 3 inch should be fine.

      Leigh Ross

      484 464 1575 C
      610 624 1730 H

      www.unicornkayaks.com

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