Spent another day on my back in tight space preparing hull for bottom paint, grinding and gel coating. A few days away from painting bottom. Unfortunately I did too good a job of cleaning water line prior to discovering that most reasonably priced bottom paints are not white (color of hull). I bought gray so I need to identify and tape waterline before going back in water. I realize line will depend on equipment, but any suggestion for locating and taping line on O'Day 19. Now I wish I had sprung extra money for white bottom paint. Thanks for any suggestions.