What condition is the original paint in? Is the color consistent, no damage and just needs to be shined up? Or does it have nicks, scratches or is it in need of repair in places?

Awlgrip, Imron are two Polyurethanes I'm familar with and they are excellent as one stage or one part paints. Two stage normally means a base coat (color) and a top coat (Clear). Now if your boat is like the first part of my question(just needs to be shined up) then you could sand the boat with like 600 grit and have it clearcoated with Imron. Like new finish. Or if you want to do a little fairing and repairs refinish it with one stage awlgrip or Imron.

Find someone in your area that deals with or uses these paints and ask them. Many Automotive paint suppliers carry Imron. Look for one that has Dupont products. Ask them who uses it in the area and go talk to them. Don't confuse Poly-urethanes with urethanes. Two very different animals.