How can I repair the gelcoat on my boat?

Depends on where the damage is and what type of damage. Most chandlers stock gelcoat repair kits and small vials of pigment to colour match. Follow the instructions on the box. If the damage is close to or below the waterline, don't forget to apply gelcoat sealer (International or 3M) to prevent osmosis prior to applying your antifouling paint.  more