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.