for a small boat that has small value, perhaps using latex paint may work, for a while...
but unless you are maticulous in your prep, it may stay in place a few months.
In HS shop we used to try the different paints and coatings on steel, glass and fiberglass samples....just to see how they held up. On glass and fiberglass you could almost peel it off with your finger nail.
YMMV, but unless it was an absolute last chance - I would stick with marine paints, proper prep and undercoating.