Re: painting aluminum hull
Rustoleum will stick from a rattle can but, it will cost you a fortune. ezmobee painted his first Starcraft that way and he might chime in.
For an initial paint job over aluminum (not painted before) you will need to lightly scuff it up, treat the metal with a wipe down of alodine then prime with zinc chromate (a light coating will work) and then paint.
Rustoleum works great and is the cheapest.
Single stage polyurethane marine paints work great too.
Or go high end with a two part marine epoxy...... people have even used regular automotive paints with great success.
Any of those paints will last and look good for a LONG time and if it is a trailered boat even longer.
Rustoleum advantage is the ability to do touch ups cheap.
The secret is in the prep