TotalBoat Aluminum Boat Paint is a unique, corrosion-resistant polyurethane specially formulated for aluminum boats, and it requires no primer. But anodized aluminum is slick and non-porous, so if you apply paint to it as is, the paint won't stick. You have to remove the anodized coating first.
To remove the anodized aluminum coating, we recommended the following for maximum adhesion of the paint to bare aluminum:
Sand the surface with 220-320 grit sandpaper.
Remove sanding residue.
Apply TotalBoat Aluminum Boat Etch Wash, as directed.
Within 1 hour of aluminum surface prep, apply TotalBoat Aluminum Boat Paint, as directed.