Gelcoat problem on new boat: cracks, yellowing & pores

Discussion in 'Boat Design' started by MCNav, Mar 10, 2011.

  1. MCNav
    Joined: Mar 2011
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    Location: Med

    MCNav New Member

    I purchased a new “boat show” 34ft cabin cruiser in late 2009. The boat rests in salt water in the Med throughout the year however it has been well taken care of. The hull is rinsed down with fresh water after every run, washed weekly with boat soap and polished & waxed twice a year.

    Numerous problems are starting to appear more and more frequent on the gel coat (photos attached):
    - a yellowing on the surface of the hull in certain parts
    - multiple areas full of tiny ‘pore-like’ holes
    - most importantly surface cracks & fissures on the super structure in different parts of the boat

    All three issues are concerning but the cracks are very troubling. The boat is due for the annual haul out during which I am planning on having the submerged part analyzed for cracks and fissures as well checking the depth of the surface fissures on the super structure.

    Several people I spoke with have said the issues are an indicator of a poor quality gel coat (too much styrene for the yellowing, bad paint job for the small holes, and poor quality gel coat and boat structure design problems for the cracks).

    I’d like to get the board members’ opinions on the source and possible causes of the pores, yellowing and most importantly the cracks. Are these issues normal for a 2 year old boat that is well maintained???

    What solution from the shipyard would acceptable to fix these problems and prevent future ones? I would expect that for a boat that is less than 2 years old and still in Warranty, that any serious shipyard would fix the aforementioned at their expense.

    Attached Files:

  2. DCockey
    Joined: Oct 2009
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    DCockey Senior Member

  3. powerabout
    Joined: Nov 2007
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    powerabout Senior Member

    ask who made the chemicals
  4. Alik
    Joined: Jul 2003
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    Alik Senior Member

    Cracks could be indicator of stress areas. How fast is the boat, in which conditions operated?
  5. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    It should still be under warranty.
  6. Alik
    Joined: Jul 2003
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    Alik Senior Member

    We had similar gelcoat cracking issues on one of boats built to our designs. As it was found that boat was in commercial service and was carrying 30+ passengers instead of 20 per licence.

    So we know one side of problem - there are cracks. Not enough info to make any conclusions...

  7. Jeremy Harris
    Joined: Jun 2009
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    Jeremy Harris Senior Member

    Although not boat related, I had a GRP bodied specialist car many years ago that had identical looking gel coat cracks to yours. They appeared around 18 months after manufacture and were mainly on flat panel areas and sharp corners. The worst affected areas were the relatively flat bonnet (hood) panel and the front corners of the doors.

    After a great deal of investigation the cause was put down to the gel coat being applied too thickly to the mould and the underlying glass lay-up being too flexible in places (essentially insufficient bracing or support from a core). The panels were flexing and the gel coat, being both too thick and brittle, cracked wherever the surface stresses were too great. The big radial crack areas were a result of vibration "tin canning" the panel in and out on the road. They looked exactly like the radial cracks you have.

    In my case there was no warranty (the company had ceased trading) and I had to get the problem fixed myself. The initial fix that was recommended to me was to grind out all the cracks to a V shape, fill the bottom of the V with glass reinforced resin bridging filler then use gel coat touch up to mask the repairs. This was a complete and utter failure. Within three months most of the cracks were back, just as bad as before and the gel coat touch up looked pretty dreadful, even after flatting off and polishing. What was worse was that there was evidence that moisture had penetrated right down into the lay-up in places.

    The final repair was both drastic and costly. The affected areas were ground off with a gel coat peeler, right down to the start of the layup, a layer of thin glass cloth was laminated over the whole area, followed by filling, sanding, priming and painting the whole car. The hollow bracing under the flat panel areas was filled with PU foam, to help stiffen up the flat panel areas a little. This proved to be a good fix, that lasted for several years with no sign of the problem recurring and no indication that the car had ever been repaired so extensively.

    I hope for your sake that you have a good warranty, because the thought of doing such extensive remedial work on a 34ft GRP boat would make my wallet tremble with fear.................

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