What is the best, (or any) method for checking for rot below the floor? I have found no soft spots, or any evidence of rot in this 1966 fiberglass boat. but, all of the paint on the floor is cracked and some exposed to weather. This boat sat outside for years under a tarp. I sanded down the rear portion of the floor to the wood, and it looked OK, but how do I know the water hasn't found itw way into the stringers or below the floor. I really don't want to remove the floor if I don't have to?