I have used latex type house paint on several boats. It works fine and is cheap. You probably do not want to leave the boat in the water for long periods of time. I have left myne in the water for a week or more. It seems prety tough as far as abrasion goes too. It is very easy to repair and match.

I do feel I get a better finish with marine grade paints though. The latex can be kind of rubbery (what do you want from 100% latex). I may get a better finish with marine paint because I am better at using brushing additives and thiner. The latex is difficult to get coverage with darker colors. I used a high build primer and still had marking pen construction lines show through.