I use Meguire's gold on our Ranger gel coat. Seems to work OK.
Hammer

 

Talo-You probably already know this but waxing your boat will make it faster. Less friction when going thru the water.

 

Faster? ;D ;D ;D

And it will make it shinny too! Good wax protect the metal, paint, and fiberglass from oxidation and fading (uv inhibitors). This Collinite stuff is supposed last all year even in harsh environments.