I am going to airbrush some stuff when I paint my boat and I need to sandwich it between two clear coats. The base coat will be a 2 part polyurethane like interlux perfection or dupont imron. I will be spraying the paint. I am not sure what type of clear coat to use. Is there a good marine clear coat, or will an automotive clear work. I want a clear that will last and that is really hard. It needs to work with a polyurethane paint, and it will be below the waterline. The boat will be trailered after use and will never be in the water for more than two days.