Why not just get a gallon of gel-coat. Clean the surface, put a little tooth in with a sander. Vacuum and then roll on gel-coat and sprinkle on a nonslip substance..... You would need to do it inside now,,,,,,and it would help if it was warmer... I have re-done my outer sides and bottom that way -- turned out great. A gallon only weighs about 3 pounds or so.. Good luck,,,,,but you will need a shed for whatever you do.