Hole in the bow as frontsail padeye???

Discussion in 'Multihulls' started by Cat2Fold, Oct 7, 2012.

  1. Cat2Fold
    Joined: May 2012
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    Location: Felt, Idaho

    Cat2Fold Junior Member

    Hello mighty forum,
    I am wanting to install an attachment point for a large furling frontsail on my biplane rigged catamaran as far forward on the bow as possible.
    I just came across this Mod70 Trimaran hole in the bow style and thought that it seems easy enough and stronger than any sort of padeye with a backing plate.
    Plus, I can get it further forward on the bow than anything else I can mount and have access to mount.
    Just drill a 3/4" hole (or so) through the bows a couple of inches in and down from the top and front edges, hog out some foam, fill with epoxy putty, and smooth it out?
    Attach the furler with some dyneema loops, and go sailing?
    :?::confused::?:
    Thanks,
    Big B

    [​IMG]
     
  2. auscat
    Joined: Jan 2010
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    Location: Airlie Beach

    auscat Junior Member

    I think you will find there is a huge amount of carbon unis over the top off that "hole".Your average bow has no need of that sort of strength but if you drill a hole you will see pretty quickly how thick the glass is.In that pic you can also see some kind of a ferrel there to spread the load and stop point loading the rope.Looks easy but there is more too it mate,dont go ripping your bow off.
     
  3. Corley
    Joined: Oct 2009
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    Location: Melbourne, Australia

    Corley epoxy coated

    probably best to have a chat to Kurt and see what he reckons about the bow structure and whether it's up to coping with those sorts of loadings IIRC a lot of these boats have a composite nose piece made of foam or balsa your composite chainplate may have to attach to the bulkhead behind to get adequate area to spread the load. In general composite chainplates are a bit like an iceberg the attachment point is the tip but the unis normally run down into the hull over a large area or over most of a bulkhead to carry the load into the structure. Your biplane rigs are freestanding? So that probably will have an impact on the design of the composite forestay attachment as well. I do agree though that the soft padeyes are worth the trouble and a much better solution.
     
  4. cavalier mk2
    Joined: Mar 2010
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    Location: Pacific NW North America

    cavalier mk2 Senior Member

    I like the idea too but agree that carbon must be tying things together inside as well as over the deck and stem. I'd think the hole should be curved upwards on the top edge so the dyneema pulls as a loop instead of bearing on the holes top "corners".
     
  5. Cat2Fold
    Joined: May 2012
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    Location: Felt, Idaho

    Cat2Fold Junior Member

    What is a better option?
    A stainless padeye would need a pretty big backing plate to be stronger than the hole brought the bow. The backing plate in effect is only pulling on the relatively flat surface of deck, where as the hole through the bow is essentially pulling up on a C-channel (the deck surface along with the two walls). If I drill the hole low enough to leave a solid 2-3" of meat above the top of the hole, I can't imagine a stronger way to do it.
    I do have a note sent to Kurt Hughes now, we'll see what he says.
    Sorry for my clear ignorance when it comes to boat design. I come from a background of custom home building, and gut instinct engineering.
    Thanks for the responses!

    Big B
     
  6. Cat2Fold
    Joined: May 2012
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    Location: Felt, Idaho

    Cat2Fold Junior Member

    Just heard back from Kurt.
    He says ideal would be to put a fiberglass tube in the hole, epoxy it in and ease the edges.
    I'll poke around the boat when I get to Mexico and go from there.
     
  7. Charly
    Joined: Dec 2009
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    Location: st simons island ga

    Charly Senior Member

    Hey Cat2Fold,
    Sure would like to see some photos if you do it. I am considering the same kind of thing in my beach cat build for a bridle arrangement.
     
  8. Corley
    Joined: Oct 2009
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    Location: Melbourne, Australia

    Corley epoxy coated

    How do you find the bi rig arrangement in terms of handling? Any problems with tacking or sails being shadowed on certain points of sail?
     
  9. Cat2Fold
    Joined: May 2012
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    Location: Felt, Idaho

    Cat2Fold Junior Member

    The boat sails very easily and tacks very well. I basically single hand with my girlfriend on board. I often sail right to where I drop the hook. And I love to sail off the hook.
    She sails (and tacks) quite well with only one sail up.
    I have a free flying jib that I used some last year in Mexico. It works well for pointing and close reaching. I'm adding a furler that can be used with either the jib or my new used drifter for light wind work. I like running the front sail on the leeward hull. Mostly so the sheets are outside the living area. If the winds are up over 10-15, the two mainsails generally work well enough by themselves. I am cruising with the boat and only doing fun, easy races.
    In and around a beam reach, the windward sail will blanket the leeward, but it is easily fixed by easing the windward sheet until the leeward sail fills again.
    Easy peasy lemon squeezy.
     

  10. HASYB
    Joined: Jun 2011
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    Location: The Netherlands

    HASYB Senior Member

    Hi Cat2fold,

    I have the same kind off holes in the ama's of my tri; like Kurt suggested with fiberglass tube.
    Just some practical advice, don't make them too small. Mine are ± 25-30 mm and wish they were a bit bigger.
    Just for ease of handling and the occasional extra rope.

    cheers,
     
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