The primer is the coat that does the protecting; everything above it is wear surface and cosmetics. On a hull, primer selection comes down to substrate, preparation level and where on the vessel it goes.
Steel hulls
Two pack epoxy anticorrosives are the standard. For full repaints over blasted steel to Sa 2.5, high build grades at 100 to 150 microns per coat build the barrier fast. For maintenance over power tool prepared steel, surface tolerant epoxies grip where a full blast is impossible, at some cost in ultimate life. Our marine hull primer page covers the standard schemes.
Aluminium hulls
Aluminium needs two things: thorough abrasion or sweep blasting with aluminium safe abrasive, and strict avoidance of copper contamination. Never apply a copper based antifouling directly onto aluminium; galvanic corrosion will eat the hull. The correct stack is epoxy primer, sealer coat, then an antifouling rated for aluminium.
Above versus below the waterline
Below water, the primer is overcoated with a tie coat and antifouling. Above water, the same epoxy chalks in Dubai sun within months if left as a finish, so it is overcoated with a UV stable polyurethane topside paint. The epoxy does not care about the sun once covered.
Compatibility rules
Overcoating windows matter with epoxies: past the window, the surface must be abraded for the next coat to grip. In UAE temperatures windows shorten, so plan coats within days, not weeks.
MENA Industrial Supplies quotes primer and full scheme from Dubai stock the same day, with TDS and MSDS included.