The sea was cast resin, kind of tan color, so the paint job was some effort. After the shades of blue and blue green (airbrushing), I applied several coats of a clear gloss polyurethane from a spray can. Can't remember the brand, but they advertise it as a heavy/thick version. Then, I applied a bit of acrylic gel medium to create bow and stern wake, brush painted white.
Ordinarily I put the waves down by brushing all the waves with the acrylic gel medium. This was the first time I had a wavy sea to work with. I did all the sea- er- lake painting before gluing the ship to the water. The guy who made the water left a flat area the size of the ship.