It never hurts to do a pressure test on the area. Can you see strands of glass fibers sticking out around the damaged area? Is the area caved in? If the answer to both of these questions is "no", then I would just clean it up with some 150-200 grit sand paper, wipe the area down with acetone, and patch the gelcoat. If your boat hull is white, you could use marine tex to fill the scratch. After it hardens, it can be sanded very smooth and looks o.k. Later, when you have more scratches to fill, you can buy a gelcoat patch kit and do them all at the same time. If you have a digital camera, you could post some close-up pics, which would make it easier to determine the best course of action. Good luck! -Matt