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Gel Coat cracks topside

I recently bought a 1988 J 24 and while I was compounding the hull, I noticed 4 (2 sets of 2) small vertical hairline cracks in the gel coat. It looks like the gel coat got pushed in between two "ribs". The location is aprox mid-ship (starboard side) and are about 6 inches long starting from the the top of the hull. I am confused about these because I do not see an impact area and not sure if I should be concerned about them. I was wondering did the top side have balsa in it (up to the top) and were there "ribs" in the boat? They are not close to the stanchions and there is no evidence of anything (cracks or other repairs) on the inside of the boat. Everything else is solid. Any thoughts would be appreciated.


New Member
Do you have a photo. The J24 has balsa going all the way to the top. Is there any water weeping out of the cracks??
i agree , you could sand the crack out with 600 wet and dry and re gelcoat after the cracks are removed.

I have rebuilt 5 J.s now you can visit www.hiyachtracing.com or www.codeyachtracing.com

contact me if you require more information


Thanks Peter. I have not worked with gel coat so i am a little nervous with grinding the cracks and filling with gel coat. If I mess up, I can always place a sticker over it! Wish me luck!


New Member
many videos on youtube on Gelcoat repairs. You can spray gelcoat with a Prevel and thin it down with acetone. many light coats is better and you need inhibit the air with pva glue. This washes off with water when cured.


New Member
From looking at your photos it appears your boat was once involved in a collision and the old repair is now separating from the original hull. This happens because the repaired area was filled with something that is shrinking at a different rate than the original hull. As long as you have no leaks on the inside of the boat, a simple repair of the gelcoat will work fine. You will have to widen the cracks in the gelcoat all along the repair then refill and refair with West system filler and then put a new coat of gelcoat over it. The work is not as daunting as it sounds. You can order gelcoat to match directly from Waterlines.
Good luck!