This topic has been covered a bunch in the past too and I have written much about it. Not all two part paints are considered great for topside use (hull sides) for longevity, color and gloss and abrasion resistance. Two part linear polyurethanes are. 2 part epoxies are not, because they don't hold up to sun very well. Awlgrip makes a hard two part linear polyurethane paint that can be sprayed or brushed. It is very hard after it cures that it cannot be easily repaired, but is very abrasion resistant, and color and gloss retention are excellent. Awlcraft, a more recent 2 part linear polyurethane paint is "softer" than Awlgrip, but has the same color selection (good). Because it is softer scratches can be repaired long after the application date. But, while it is excellent paint, it is not as abrasion existent as the original, but also because it is more VOC compliant is used more widely today. The Interlux two part urethane paint is good - especially for the DIY boater, but color selection is limited. It is formulated for rolling and tipping. Well, more to write, but I have already written it and so you can delve back for more info.