Any simple fix?

About two weeks ago I painted the inside of my boat. I used a Rust Oleum self etching primer about 2 coats and then 2 coats of Rust Oleum from spray cans. It has sat in the sun the past week but yet in some places the paint is still soft and able to be scratched off with a finger nail. Would putting another coat or two from spray cans over the existing paint cause it to harden up? Should I buy brush on Rust Oleum and put a thicker coat of paint on? Any help would be great...

what was it cleaned with prior to paint, and how long did the primer cure? some paints cannot topcoat some types of primers. Laquer vs enamel etc. and sometimes not shaking enough prior to spray will leave wanted consequences.

Screw it all - just go fishing!

You can give it a few more days and see if it sets up ..... but more than likely you will need to strip the area and start over. Sounds like something isn't adhering properly. Maybe the primer to the hull, or maybe the paint to the primer.

Before priming, make sure the aluminum is really clean (but not too smooth - scratch it up a bit) and wiped down with paint thinner or some other alcohol based solvent. Then tack cloth it off. Then spray primer. I usually let the primer dry just until its tacky, then apply the top coats. You could let the primer dry completely, rough it up with some sand paper, and then apply the top coat.