Leaking fibreglass rowing boat/dinghy

Discussion in 'Fiberglass and Composite Boat Building' started by valvebounce, Nov 21, 2015.

  1. valvebounce
    Joined: Dec 2010
    Posts: 536
    Likes: 11, Points: 18, Legacy Rep: 124
    Location: manchester uk

    valvebounce Senior Member

    I acquired a 10ftX5ft beam dinghy,it has no osmosis but has had what seems to be a bit of rough handling.
    It has the odd fibreglass patch here and there which hasn't been completely fibreglassed in on the inside of the boat.
    I turned the boat keel up on stands and went over it with a fine tooth comb.
    I patched and sanded it then put two coats of paint on it.
    I was satisfied the hull was externally sound.
    Before I completed the internal fibreglassing I took it out on the river,It started to let water in through one of the badly seated internal fibreglass patches.I examined the hull externally and could find no breaks.
    If we shifted our weight slightly to starboard it stopped leaking.We were using an outboard,but when just floating the leak was a lot less.
    I thought of filling the boat with water so as to detect the leak externally,but suspect the loose fibreglass patch will act as a non-return valve and close the gap.
    It would be a simple job to fibreglass over the leak internally and stop the leak,but it would bother me that I had not found where the water was getting in.
    Has anybody had a similar problem,or any suggestions?
    "V"
     
  2. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    Is it a cored hull?
     
  3. valvebounce
    Joined: Dec 2010
    Posts: 536
    Likes: 11, Points: 18, Legacy Rep: 124
    Location: manchester uk

    valvebounce Senior Member

    Hi Gonzo,
    No,it's not a cored hull.The fibreglass is quite thick and the boat is quite heavy.It has a very robust keel,with two outer keel/runners.
    It handles very well using the oars,and will turn in it's own length no problem.
    It has flotation chambers in the bow and stern,also in the middle seat.
    The gunnels are quite robust also.
    The stability is excellent.
    "V"
     
  4. SukiSolo
    Joined: Dec 2012
    Posts: 1,270
    Likes: 25, Points: 0, Legacy Rep: 271
    Location: Hampshire UK

    SukiSolo Senior Member

    Remove the entire rotten repair and redo it properly. Scarf in the new glass, I tend to do it from the outside but it should not matter. If you need a former, melamine coated hardboard will do or a sheet of polythene, maybe a chopping board curved to suit.
    Personally I would not feel comfortable with a sizeable 'repair' indicating it might pop out anytime...;)
     
  5. valvebounce
    Joined: Dec 2010
    Posts: 536
    Likes: 11, Points: 18, Legacy Rep: 124
    Location: manchester uk

    valvebounce Senior Member

    Hi SS,
    There is no rot or osmosis,the boat is built like a tank.I think the old guy I got it off went OTT with his glassing.
    If I start pulling patches I think it might be like a painted over Jigsaw.
    I think what I will do is,tap a slim wedge under the the edge of the leaky seam,then fill it with water over the height of the leak,maybe add a bit of kids powder paint as a dye,then see where the leak is on the outside.
    If I had completed the renovation on the inside before I tried it,I would have
    glassed over it anyway.
    I painted the outside with two part epoxy paint and then white.Each coat took a couple of days to harden,but the result was a tough flexible finish.
    I intend to renovate the inside,and give it two coats of two part epoxy paint.
    The epoxy dries to a buff colour,which should look ok in contrast with the outer.
    I have replaced the oarlocks with larger cast ones,I bought some aluminium oars and customised the shoulders to suit.All in all,it's quite a pleasing boat.
    I have a nice little 5hp Yamaha that fits on it very nicely.
    "V"
     
  6. SukiSolo
    Joined: Dec 2012
    Posts: 1,270
    Likes: 25, Points: 0, Legacy Rep: 271
    Location: Hampshire UK

    SukiSolo Senior Member

    This indicates the bond is rubbish, so redo it properly. The danger is the entire patch will fall out so matter how sound it is in itself. It has not bonded to the original moulding properly. Hope that makes sense now.

    I'm well aware that is not good news but polyesyter basic repairs are fast and you'll be done in a day. Just chisel it out and get good clean glass at a good angle say 1:5 to 1:8 to scarf the new material in.
     

  7. valvebounce
    Joined: Dec 2010
    Posts: 536
    Likes: 11, Points: 18, Legacy Rep: 124
    Location: manchester uk

    valvebounce Senior Member

    Better to be safe than sad then.
    I've got all the materials etc,I have a 14ft ship to shore launch/speed boat project partly done.I have replaced all the timbers on it,including the transom, stringers and gunnels,plus the upper and lower futtocks.I sheeted it up to do the dinghy.
     
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