Standard West Marine Gelcoat. Get some Acetone too. You might need some styrene to thin it a little to spray it. Practice on a piece of wood. Here's a list:

1. Spray bottle
2. Mold Release
3. Gelcoat
4. 3 mil plastic sheeting
5. Tape.
6. Color agent for gelcoat if needed.
7. Preval sprayer (available at West Marine)
8. Acetone to clean the sprayer.

Turn it upside down
Sand it to get a smooth finish 100-220 grit.
Tape it off with the plastic and tape that you don't want sprayed. Overlap a little.
Spray it with possibly a little styrene to thin it.
Spray 3 coats about 20 minutes apart.
After the last coat sits for about 15 minutes spray the whole thing with Mold release.
Let it sit for 24 hours.
Wash off the mold release and start sanding. Start with 220 and work your way to 600 or so wet with a long board.
You can finish with a 3M product. I forget the name.

Mike Hill