Gelcoat Crack
 

I have a small 1 1/2" crack in the gelcoat near the bottom right corner near my bedroom slide. It looks like someone tried to seal it before, but it has worn off. I would just like to coat it with something to keep any moisture out and keep it from getting worse.
Ideally would like something that would flatten out. I don't want a big wad of sealer. That wouldn't look very nice.

Thanks for any tips you may have.

I suspect that you do not have Gel coat, although you definetly have a crack in your fiberglass. The best thing you can do is fix it properly. The crack, as in a windshield will continue over time to become longer. Putting a stop to it is in order and I would do it by taking a drill at the very end(just a tiny bit beyond) and drill a small hole. Then I would take my dremel tool and grove the crack like a small V along the length of it. I would use west systems or a similar product and follow the directions on how to repair the crack. After the repair is completed go to NAPA or a similar operation that can match the color of your project and have them mix up some and put it in a spray can. Paint and walk away happy and satisfied. Our you can get a tube of caulk and apply as best you can and then walk until you need to reapply the caulk.

As said you need to grind that out and apply a good epoxy filler. I use the following Marine Tex, epoxy resin, adhesives, silicone grease, engine treatment, cleaner, repair, bond, fill, seal, fiberglass, aluminum, plastics, Starboard, wood

I've seen so many crack around slide outs.
But if some people don't want to fix it with gelcoat, etc., we sore a straight line in the direction it's going, get a piece of trim to match the rest, putty it and secure/seal it up.