Geoffrey, been there, done that, got the T-shirt. I too had to scrap, wire brush and clean the inside of my V22. I then put two coats of ZINSSER primer stain killer on. Then rolled two more coats of the porch paint, white on. Got to say it has made a huge difference inside the boat. Also have to say the boat has not been in the water so the hull has not flexed which would test adhesion. The stuff is shiny and hard as nails. Good luck.