This is a common repair, when the boat is not attached to the trailer when backing down the boat ramp! We received two of these in one week. The first was quite bad with the hull laminate requiring re-building to bring it back to spec. The bung hole needed to be set using a piece of poly pipe as a mould.
The second boat was not as badly damaged but still needed glassing to the area below the bung hole, with cosmetic repairs to the keel and planing strake. To get to the keel the boat was slid half off the trailer and chocked.