I've done over 20 jons, painted and fully modded. Here is the easiest route.
1. Take everything off the boat, wash it.
2. Apply stripper in the shade, let it do the work. Remove old paint with plastic putty knife or pressure washer.
3. Sand with orbital sander, 220 grit. Make sure surface is smooth, sand to metal. (this is the longest processes and the most critical for a good adhesion and nice appearance.) Make sure the entire boat is roughen up by sanding.
4. Pour undiluted vinegar over the sanded area, keep metal wet for 5-10 minutes, this is the etching process, removes oxidization, rinse with water. (Be ready to paint after this step). Let dry, move into shade, let metal cool to touch.
5. Paint in shade!!!. Easiest stuff to use is Duralux Aluminium Boat Paint. This paint doesn't require you to prime, which is a huge step to remove when painting aluminum! 2 coats should be good.
6. Let dry 24hrs, then cure it by parking it in full sun, use the "fingernail scratch test". Scratch in a spot with your fingernail, if paint doesn't have a mark the paint is fully cured. If it leaves a mark then cure longer.
You can use a ultra smooth foam roller to apply, lead with a wet edge. Use foam brushes for areas rollers won't reach.
Xylene can be used to thin it from spraying purposes and for clean up. This stuff once cured is tough and can handle abuse. PAINT