Latest News: Forums Technical mk1 grp foredeck repair

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  • #4439

    Here’s some pictures of damage to the foredeck on my newly obtained mk1 grp. I’m not overly familiar with these boats, and have never sailed a sloop with a spinnaker before. I’m wondering what might have caused the damage and have come up with these theories…

    over chocking of the mast (As I won’t be racing do I need to chock the mast?)
    incorrect installation of the cleats. I assume these are for the spinnaker.

    There is evidence of a botched repair/strengthening on the underside, which I intend to cut out and repair properly when we get some half decent weather.

    Tips welcome!

    #10825
    admin
    Member

    Mine is a Mark 2 but I am sure the Mk 1 is similar and the striking thing I but notice is that your GRP tabernacle is missing! It has been replaced with timber and through those penny washers and screws the timber is providing the structural support to the rear of the foredeck. The attached image is of my tabernacle, which you can see is in GRP laminated to the centreboard moulding and the underside of the deck.

    The pattern of cracks and stress fractures on yours suggests (to me at least) that at some stage the GRP tabernacle sides have been removed and then the deck subjected to some vertical load near the edge, perhaps someone stepping onto the fore deck to take a mooring? Crunch. Perhaps the timber sides were added after the damage occured to strengthen the deck. The GRP tabernacle has three sides, your timber one only has two, maybe there is sufficient movement between timber and deck to continue to propagate the cracking.

    You still have the basic shape of the deck edge so you might be able to grind away the gelcoat and repair the outside cosmetically using epoxy and woven cloth (not chopped strand and polyester), and filler which you will need to protect from UV by painting it or varnishing over the repair. You then need to beef up the deck structure underneath, I would suggest you use formers to create “top-hat” sections to give the repair some depth overlaid with 5 or so layers of cloth and epoxy. I use foam obtained from cfs glassfibre (http://www.cfsnet.co.uk/) to make formers.

    I suppose the timber is doing the appropriate job of providing support and if you cannot obtain glassfibre sides to the tabernacle, (maybe Porters have spare ones?), then doing a better job of fixing the timber would be ok, your solution should however not leave those screws and washers which I suspect will damage your mast, at least scratching the anodizing and at worst introducing a point load at the point of maximum stress.

    #10830
    Swiebertje
    Participant

    With the boat upside down on some saw horses or tables it should not be difficult to glass/epoxy the tabernacle to the underside of the deck and, in the process, re-enforcing the deck. As Mike said, remove the bolts (screws?), they will damage your mast over time. Then with the boat upright, sand away some of the gel coat and replace it with two pot filler and paint for better looks. Then, some day, paint the whole deck and the repair will be totally invisible.

    #10843

    Guys, thanks for taking the time to reply.

    I find it hard to believe that there was a grp tabernacle, there is no sign of a previous grp attachment anywhere else. Also I did notice that the clearance around the mast at the foredeck (where the damage is) is much greater on mine than on the MK2 that I had a “familiarisation” lesson in, the mast would have to bend a hell of a lot to hit the screw heads. Even so I will certainly bear that clearance in mind when repairing.

    However, as the boat is over 30 years old, anything could have happened to it!

    The plot thickens……

    Tony

    #10845
    Dave Barker
    Keymaster

    Tony,

    I don’t know whether Porters website is up to date, but it mentions availability of both GRP and alloy tabernacles. But to be honest you could probably retain the wooden components you already have.

    The only other thing I would add is to suggest that perhaps rather than glass the deck to the tabernacle, I would glass some battens/bearers to the underside of the deck “outside” the tabernacle and glue & screw the tabernacle to the new battens, so spreading any load. I am no expert however! Good luck with it…

    #10846

    A quick update,

    I’ve just spoken to Ian Porter at Ian Porter sales. He couldn’t have been more helpful.

    Mk1 grp boats have a 5/8″ mahogany tabernacle, bolted with 3 off 1/4″ or 6mm through bolts to the foredeck. Phew, looks like the repair should be just a case of beefing it up with fibre glass under the foredeck.

    Tony

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