Today I noticed that there are quite a few spider cracks on the outside corners of the rear dam of my H15. I have been cleaning up the boat for two days prior to putting her up for sale. I didn't see them when the boat was out in the bright sunlight while I was washing her but today rolled her into my garage to polish and wax the hull. I don't want to spend a lot of money on the repair so can anyone advise an inexpensive method of repairing this problem?