Building multi-chine sailboat with prefab honey-comb panels.

Discussion in 'Fiberglass and Composite Boat Building' started by DC Landis, Jan 20, 2016.

  1. DC Landis
    Joined: Jan 2016
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    Location: PNW

    DC Landis Junior Member

    Has anyone used cored sandwich panels to build a multi-chine sailboat? Way back when, I did a custom job on a ultra-light racing sailboat. I bought s-glass honey-comb panels from Boeing Surplus for the cockpit sole, worked great. Bought Kevlar honey-comb panels for stringers and 2/3 height bow stiffening frame, worked great.

    Now the need to bend flat cored panels arises, no longer flat easy construction. The extra work would definitely be worth the weight savings. The cored panels, through out the entire build, will save a large sum of weight over the marine ply.

    From what I've heard, read and actually seen, the outside panel laminate is removed. At the chines, enough inside laminate is removed to make a clean bend at the chine. After the bend at the chine, the inside laminate closes back up together. The outside of the hull will be laminated in carbon/epoxy.

    Any real world experience would be great! Double chine, plumb bow, flaired topsides, light and fast.

    Thanks to all who can chip in and share some experience, thanks, DC.
     
  2. rob denney
    Joined: Feb 2005
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    rob denney Senior Member

    First thing is to establish whether the curves are compound or not, If they aren't, then cut away the inner skin and bend. For large diameters, make multiple cuts. For small diameters, remove the core.
    If they are compound, remove the skin from both sides and make a mould (stringers and frames will do) that supports the flat areas away from the bend, then persuade the core into the bend. If it is highly compounded, and the honeycomb deforms, fill it with bog before bending.
    Bow joins tend to be messy. Eaiest is to terminate the panels at a bulkhead a couple of inshes back and make a foam nose piece and glue it on. Doesn't work if the forestay is on the bow. In which case, crush the core for 50-100mm/2-4" to form a rebate on the outside a little thicker than the joining glass. Replace the crushed core with bog and wrap laminate round the bows. Fill the rebate to flush and add bog to shape the entry.
     
  3. gonzo
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    gonzo Senior Member

    Removing skins seems like a hard and expensive way of using a core. You can simply buy the core and then laminate over it. Since they are not compound curves, a mold can be made for the outer skin, then the core is laid on it and the inner laminate over it. Vacuum bagging may be the best method for it.
     
  4. DC Landis
    Joined: Jan 2016
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    DC Landis Junior Member

    Thanks Rob, as far as compound cuves go, there shouldn't be any. The boat was going to be designed for marine-ply construction. I have literally everything I need as far as marine hardware, Kevlar/Mylar sails rig, new standing and running rigging. So I naturally thought, "hey, what the hell let's step it up a notch". So cored panels came to mind. I'm going to make some decisions shortly and the boat will be designed to which ever material I choose.

    I really enjoy hearing from builders who have gotten in the deep recesses of boat building. It continues to amaze me the way builders find the ingenuity to work through such complex challenges. Your description above about using cored panels is one of those complex challenges.

    Thanks for the insight, almost reads like a war story! Cheers, DC.
     
  5. brian eiland
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    brian eiland Senior Member

  6. brian eiland
    Joined: Jun 2002
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    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    Pilgrim Trawler redesign/construction method

    You might find some of discussion of interest, a rather lengthy, and sometimes wandering discussion of building a 40 trawler with a frameless method for the hull, then honeycomb panels for the decks and superstructures. ..simplifies those compound curvature portions of construction.

    Redesigning the Pilgrim 40,...a 'Great Gatsby' style vessel

    http://www.trawlerforum.com/forums/s3/redesigning-pilgrim-40-trawler-canal-boat-11212.html


    Composite Superstructure
    http://www.trawlerforum.com/forums/showpost.php?p=174968&postcount=85

    http://www.trawlerforum.com/forums/showpost.php?p=230808&postcount=291

    http://www.trawlerforum.com/forums/showpost.php?p=174996&postcount=89

    Cabin Superstructure
    http://www.trawlerforum.com/forums/showpost.php?p=179504&postcount=127

    http://www.trawlerforum.com/forums/s3/redesigning-pilgrim-40-trawler-canal-boat-11212-12.html
     

  7. DC Landis
    Joined: Jan 2016
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    Location: PNW

    DC Landis Junior Member

    Thanks Brian,

    That's a ton of info. Makes my project seem very simple, although I am well aware no project is simple.

    Thanks, DC.
     
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