Warning this article contains material that may be offensive if you think painting is more fun than boating. Marine paint cost several times as much as house paint of similar composition. I worked for a major chemical company that also made paint and knew that their paint that made the most money and on which they spent the most on research was house paint.
Houses are out in the weather all year-no winter cover or inside storage.
Their owners expect to repaint them infrequently, such as every ten years or so. They also expect a good paint job will require little preparation before repainting. Back then the only house paints were oil paints, so my yacht was painted with top quality oil-based house paint. All paints consist of binders or resins, pigments, solvents, and additives. The binder forms the film that sticks to the boat and holds the pigment there.