Higher mounted/longer boom.

Discussion in 'Sailboats' started by Mychael, Oct 23, 2008.

  1. Mychael
    Joined: Apr 2006
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    Mychael Mychael

    Come next year I'll be completely renewing the standing rigging and mast on my boat, this will allow me the opportunity to make changes if they are feasible and practical.

    It's always been an annoyance that my boom is set relatively low, too low for a tent and if you stand in the cockpit you risk getting a boom in the teeth.

    To just mount it higher would mean loosing to much size in the main but could this be offset by getting a new boom that was longer as well as set higher?

    I need a new main anyway so could have whatever I wanted made.

    Thoughts?

    Mychael
     
  2. rwatson
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    rwatson Senior Member

    Longer foot, lower sail means loss in sailing performance.

    This sounds like a small boat as you are talking about boom tents, in which case maybe you just need to raise the base of the mast by a couple of feet.

    You will need longer shrouds, but all the other fittings can stay the same
     
  3. Mychael
    Joined: Apr 2006
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    Mychael Mychael

    Keel stepped mast.. Boat is 26ft. Just want a tent for when working on the boat for some sun shade and to keep some bird **** out of the cockpit.

    Mychael
     
  4. Paul B

    Paul B Previous Member

    What is the Aspect Ratio of the main? Fractional or Masthead?

    Most modern sloop rigs don't go to a lower aspect ration than about 2.4. If you can raise the boom the amount required and lengthen the boom the amount you like and retain this aspect ratio you should be OK.
     
  5. Mychael
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    Mychael Mychael

    Masthead rig. I'm afraid I don't actually know the aspect ratio, I'll try to find that out from the sailmaker. He has drawings of the original sailplan.

    Mychael
     
  6. Omeron
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    Omeron Senior Member

    One of the biggest constraints usually is the backstay clearance, if you are not changing the mast and lengthening the boom. Unless ofcourse you have a backstayless rig, and or ready to give up some of the mainsail roach.
     
  7. Hansen Aerosprt
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    Hansen Aerosprt Junior Member

    AR => Span Squared / Area

     
  8. Paul B

    Paul B Previous Member

    I was referring to geometric AR (span/chord > 2.4), not aerodynamic aspect ratio.
     
  9. Mychael
    Joined: Apr 2006
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    Mychael Mychael

    That's what I figured. We need to do some precise measurements to see how far we can go. Certainly would loose some roach.
    Guess it really depends how much we can gain at the bottom with a longer boom.

    Mychael
     

  10. diwebb
    Joined: Jun 2008
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    diwebb Senior Member

    Hi,
    if the problem is just the clearance for the boom tent, why not just mount the gooseneck fitting on a short length of heavy track. Then you could raise it when the boom tent is in place and adjust it back again for sailing. You could also put in an upwards reef if there is sufficient clearance between the backstay and boom end. This would give added headroom clearance below the boom when required, yet still allow for the full sail area in lighter winds.

    All the best with the project.
    David
     
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