Extending bow sprit?

Discussion in 'Sailboats' started by Pylasteki, Apr 21, 2008.

  1. Pylasteki
    Joined: Apr 2008
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    Pylasteki Junior Member

    Hi guys,

    I'm curious about these extending bow sprits that are used on some of the new racing boats.

    I'd like to take my spinnaker pole, and build some chocks for it on deck with a line running to a bow eye, and be able put a drifter waaaay out front in the very light winds.

    Anyone seen something like that?

    Thanks,

    Zach
     
  2. alan white
    Joined: Mar 2007
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    alan white Senior Member

    Yes, the sprits are commonly epoxy/carbon fiber, easy to build using a styrene foam core that can be melted out using acetone afterwards (or you could leave it in----- now who's gonna come up with one with a bugle end that the sail can be sucked right into?). You need a mounting plan, meaning two points, one at the bow and one inboard a few feet. Those sleeves must be bonded strongly to the boat. No whisker stays are required though you might have them for security.
    Aluminum would also work, though not as strong per weight (but ultra simple).

    Alan
     
  3. Meanz Beanz
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    Meanz Beanz Boom Doom Gloom Boom

    I have seen Tornados Cats that have this setup, half the pole is a pipe large enough to hold the kite.
     
  4. Meanz Beanz
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    Meanz Beanz Boom Doom Gloom Boom

    Like this but all carbon and a bit slicker looking.
     

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  5. alan white
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    alan white Senior Member

    It's as if they could see into the future when I invented it!
     
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  6. Pylasteki
    Joined: Apr 2008
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    Pylasteki Junior Member

    Boy do I ever know that feeling. :D

    Looks cool!

    Anyone have a picture of the deck chocks? At the moment I'm thinking a block of wood and a hole saw of the proper diameter and then cutting them in half.
     
  7. Meanz Beanz
    Joined: Jun 2007
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    Meanz Beanz Boom Doom Gloom Boom

    That would be an easy way and quick. If weight is an issue I would be tempted to laminate them up in grp or carbon epoxy.
     
  8. Paul B

    Paul B Previous Member


    The chocks are under a HUGE load, with the forward one trying to pull up off the deck and shear to the side at the same time. The aft one is being driven into the deck and shearing sideways as well. A pc of wood is not going to do it.

    I did this setup on my boat last year. I machined the chocks from 6061 and lined them with teflon tape to make the carbon pole slide easily and not react with the aluminum.

    I would not use an aluminum pole if you plan to have much of an extension. Carbon is the only way to go.
     

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  9. Meanz Beanz
    Joined: Jun 2007
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    Meanz Beanz Boom Doom Gloom Boom

    Not sure he was talking about that kind of chock, "cutting them in half" suggests a std deck pole chock.
     
  10. Pylasteki
    Joined: Apr 2008
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    Location: North Carolina

    Pylasteki Junior Member

    I'm thinking a laminated hunk of marine ply about 6 inches long (Drill one side, flip and drill the other) and cut it in half, then mounting a cleat on each side using a piece of vectran or other low stretch cord to lash it down. Spent a little time pondering a cup glassed into the front of the cabintop for the aft end, but the extension would be short for the deck space. If I go that route I'll spend some time to design a chock that'll dual purpose an anchor roller.

    I'd prefer it pop loose if I stuff the bow in a wave rather than rip my deck in two, and be quick to convert from whisper pole to bow sprit and back to keep from wrapping anything up at anchor, and save on dockage for loa.

    That carbon pole and aluminum chock look cool! How quick does it unbutton? Assuming it does, with the height of the bow light.
     
  11. kenJ
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    kenJ Senior Member


  12. Pylasteki
    Joined: Apr 2008
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    Location: North Carolina

    Pylasteki Junior Member

    Very cool... Pre-made kits.

    Little bit steep, so I think I'll end up making my own. :D
     
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