When drilling into fiberglass the proper tool is a must. This is a brad point drill and it will create a clean, no chip hole in gelcoat provided you use a few tricks.
The main trick is to always start the drill in reverse! This trick also works well with hole saws. By starting in reverse it allows the outer cutting edges of the drill to cut cleanly through the gelcoat. Once through the gelcoat you can then switch the drill to forward and complete the hole without chipping any gelcoat off the surface.