I repainted my 16 foot tinner this past spring. I took it to bare metal (wire wheel then sanded it to even everything out), wipped it down with a 50/50 mix of vinagre an water, then used self etching primer (from walmart), then painted it with Ultra Flat OD Green Krylon Camouflage paint. Sounds simpe enough but believe me it was a long drawn out process.
Biggest thing I can tell you is to make sure there is absolutely no oil/ grease/ hand or finger prints/ other crap on the surface before it is primmed and painted. You will spend more time preping the boat for paint than actually painting it. Follow the directions on the cans of primer and paint.
The paint has held up extremely well.
Best 5$ you can spend is on an aerosol trigger, it clips ontop of the spray can and lets you apply the paint evenly. Feel free to message me if yo have any questions along the way.