Carbon Bowsprit

Discussion in 'Boat Design' started by BobBill, Nov 10, 2015.

  1. BobBill
    Joined: Oct 2009
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    Location: Minnesotan wakes up daily, in SE MN, a good start,

    BobBill Senior Member

    Advice on attaching portion of salvaged windsurfer mast to Hobie 18 hull as short bowsprit for below outrigger project.

    Sprit will be used to support jib only and prefer not to insert into hull.

    I noted some very interesting work here, but very little regarding attaching the carbon tube to the hull on the port or outside.

    My hope is to run the tube just below the port bow deck flange and attach there in some way.
     

    Attached Files:

  2. upchurchmr
    Joined: Feb 2011
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    upchurchmr Senior Member

    The Hobie 18 is a foam sandwich construction.
    If you put bolts thru the sandwich area there will not be enough glass to support the load without beefing up the laminate in that area.
    The best way is to cut out the inner skin (very very thin), fill in the space with glass / epoxy, then glass over that with a fairly thick laminate - tapering out from the center.
     
  3. BobBill
    Joined: Oct 2009
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    Location: Minnesotan wakes up daily, in SE MN, a good start,

    BobBill Senior Member

    Mr. Upchurch. Thanks.

    I had figured to remove foam and fill void with epoxy, but but boat is assembled and would have to disassemble (PIA) hulls from beams/akas to do that. (Wish I had had a trailer and grabbed your Tornado...)

    I did think of "strapping the spar on," using carbon tow or strips under/along edge, begin from small holes in hull into foam under the flange, epoxying in place first, then adding the spar and wrapping or bringing the carbon tow around the spar to other side of deck, wet of course, to cure, but seems so iffy!

    Most other ways seem to require taking boat apart...I suppose I could run under deck out the bow, but big job...

    I am trying to avoid flipping the thing as much as possible. The spar is but 6-feet loa.

    This is really last design install. Boat needs to play before I can't.

    Thanks again.
     
  4. BobBill
    Joined: Oct 2009
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    BobBill Senior Member

    Mr. Upchurch...your comments got me thinking and over and over it went...I might, in the spring...sort of do as you suggest, sorta, by removing outer skin along area for the sprit, remove the inner foam and seal, then fill with epoxy carbon matrix paste, and press the carbon spar into the area and let cure...only thing is its permanence, in case of problems. I do have time to mull it over...
     
  5. JRD
    Joined: May 2010
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    Location: New Zealand

    JRD Senior Member

    BB, this is how I attached a prod for my dinghy a couple of years ago. This one is designed to retract into a void under the fore deck. Here are some photos of how the sleeve was supported. You will see that the sleeve is open at each end and otherwise sealed into the deck to avoid leaks. It has survived a 25 knot squall with the kite up, which is more than can be said for the driver :rolleyes:

    You could make your sprit removable by glassing in a blind sleeve that allows you to plug it in and tie or pin it into place while rigging. The same approach would work for a permanent sprit, you would just need to seal the end. Feel free to let me know if you would like any further details on this approach.

    NS - Copy.JPG

    WP_000635.jpg

    WP_000225.jpg

    WP_000224.jpg
     

  6. BobBill
    Joined: Oct 2009
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    Location: Minnesotan wakes up daily, in SE MN, a good start,

    BobBill Senior Member

    Now that is interesting...I have closed deck, but give me a few days to cogitate, will get back to you and thanks much...very kewl!
     
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