Dark topsides colours
Single part Urethanes look good for only bout 2 years then turn chalky. 2 part Urethanes last a lot longer. 2 part application is easy if you have two people rolling and tipping. Do an article archive search on Sailnet to read Don Caseys method of 2 pat application that results ''almost'' in a ''sprayed-look; finish.
Changing to dark colors can be a problem. Unless the boat has an extra thick matting layer under the gelcoat you risk further heat curing the gelcoat with the result of ''print-through'' of the structural roving, etc. layers. Go through any boat yard and carefully look at any old boat that has been painted a dark color - usually you will see lots of perceptable ''bumps'' all over the hull - thats ''print-through''. With a dark hull the thermal stresses will cause the styrene to further cure and that causes the surface ''wrinkling''. .... plus dark colored boats are hotter-then-hell inside during the summer. They ARE beautiful, especially the contrast of the dark hull and light cabin tops ..... but unfortunately you usually only own ONE dark hulled boat in your lifetime.
Painting a boat is a very last resort as once you paint there is no going back. Usually most gelcoat can be wet sanded and buffed back to show-room quality with a little bet of effort - thats how they do it when the boat is pulled from its mold !!! If you have gouges and scrapes these can be repaired by local gelcoat ''artists''. Always better to try to restore the gelcoat .... as paint (no matter what kind of paint) .... is always at risk to lift and peel when long term wetted.