Wood''s got a good point and even different areas of the boat fades differently enough that one color mixed for the side may not match the stern. I have a 1994 Crownline so I'd be interested to know if there is a way to find out your boat's colors but I'd only think of it as a starting point. My off-white color is called Moonstone, maybe that is what you have. The link below has some good videos on gelcoat, including color matching, it might give you some ideas. There is an outfit that makes color matched gelcoat, can't remember the name but it's mentioned in one of the videos. Iboats has several Crownline colors, I know it's tough to match on a PC screen but it might help you decide which color it is; I suspect they are reselling colors from the company I can't remember the name of. Again, it would be a good starting point but to really get it close you'll need some other tints to dial it in and even then the pros use different grades of sandpaper to slowly blend it in to the surrounding area and other techniques. The trick is more in fooling the eye because you will never get a 100% perfect match. Would love to see some pictures of your work and the results.