Ouch. Not to worry. The hardest part really, is getting your hands on some genuine Parker gelcoat. I have made this repair many time as I used to accidentally hit a sea turtle once or twice a month when I had a faster heavier boat.
Essentially, the the repair simply involves putting back the gelcoat that the pipe removed, sanding the added gelcoat smooth (even w/the existing gelcoat) with a sanding block/600 grit wet or dry (wet), then buffing with 1500+ rpm buffer w/wool bonnet with 3m finesse it II. After you have sanded and buffed and the repair is undetectable, finish by hand with some marine teflon polish or good quality marine wax to seal the repair area.
You are lucky that the damage is on the bottom because there likely isn't any fading and the new gelcoat will match perfectly. Good luck.
