GP14 Sailing Forums Forum Foot-straps – Securing to Hull

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    • #9425
      Simon
      Participant

      Hi, I have a fairly old all glass GP with 3 pairs of transverse floors lightly glassed into the hull on which floorboards are screwed. Currently foot-straps are anchored at the front of the centre-board case, wrapped around thwarts and anchored to a fore/aft rib running to the transom. The issue is that the straps are too high for hiking comfortably upwind….I have long legs! I’d like to move the straps from the thwart to an anchor point on the floor immediately under the thwart. My question: How to beef up the floor/hull joint sufficiently to handle helm (110kg) and crew (75kg) hiking hard in wind/waves. Advice much appreciated!

    • #9426
      Oliver Shaw
      Moderator

      I suspect that Steve White will be the best expert for the detail on this,  but I am not sure whether he uses this Forum.   If he doesn’t come in on this,  try the GP14 Owners Online Community.

       

      However building up a mount direct to the hull should be viable,  and with a sufficient number of layers of GRP and spread over a reasonable area it should be massively strong.   My own preference is for woven glass mat or rovings,  or woven glass tape rather than chopped strand mat,  because I understand it is stronger.

       

      A few other points:

       

      1. Use epoxy,  absolutely not polyester.    Polyester (which is what was used in the original build of your boat) is fine for original construction,  laminating up wet on wet,  but it does not have good adhesion to existing solid substrates,  not even to cured polyester.   Epoxy,  by contrast,   offers possibly the best adhesion you can obtain;   and as a bonus it is stronger than polyester.   Unfortunately it is also more expensive,  but a standard 1kg pack will probably not break the bank,  and is probably more than sufficient for the job.

       

      2.  Clean up the substrate first,  fairly brutally if necessary;   an angle grinder works fine for this.   Then remove all dust,  and clean off any remaining dust and other residue with acetone.

       

      3.  Be very strict about measuring out the correct ratio of quantities,  and insist on dry and warm conditions for doing the job.   Personally I measure by weight,  and some years ago I bought myself a cheap electronic  kitchen balance for this specific purpose.    But don’t make the mistake which I originally made,  of putting your mixing tin direct onto the balance,  and then afterwards cleaning off any splashes on the display window with solvent;  it will just craze the window,  and write off the balance.    Now,  on my second cheap electronic kitchen balance(!),  I first put the balance inside a transparent polythene bag;   then any splashes remain on the outside of the bag.

       

      4.   Most important;  wear eye protection when handling the hardener.   Eye injuries due to splashes of hardener into the eye are very rare,  but at least in the case of polyester hardener it was reported in the seventies that they can be progressive and irreversible,  potentially leading to blindness.   It is not worth the risk.   I don’t know whether this also applies to epoxy,  but I choose to play safe just in case.

       

      The rest is just basic fibreglassing techniques.

       

      Hope this helps,

       

       

      Oliver

    • #9438
      Simon
      Participant

      Hi Oliver, Many thanks for the fast and comprehensive feedback. Much appreciated! I am thinking of layering up epoxy and woven glass over a section of the floors (wood core, lightly glassed to hull) and hull then bolting through an eye onto the floor to attach the foot-straps to. I am wondering about the best approach to the layering ie., how many layers? Whether to vary layer lengths to give a “stepped” lay-up? And how wide/long to make the lay-up to secure the floor to the hull and take the strain of the foot-straps? Maybe even wood triangle shaped fillet block on either side of the floor might improve strength and resist pull of toe-straps?

      As you suggest, maybe good to run it by Steve White.

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