Apply Primer

Apply two coats of Primer

I recommend using System Three Yacht Primer. It is a great two part epoxy primer with easy water clean up. Apply two coats of primer over the entire bottom surface and sides. Once cured, fill any low spots and other obvious fills with lightweight epoxy putty. Sand all the surfaces and fair as needed. Once the area is fair, apply another 2 or 3 coats of primer and flip the boat right side up again. Repeat all the primer steps on the rest of the boat.