Dude, that has worn through the gelcoat. You need to repair that. Do asearch for a how-to on gelcoat. It doesn't look that hard, but if you have the money to spend you can probably get it done professionally for about $300. If you do get it fixed, I would quit beaching it or spring for the keel guard. It is a strip that can be put on the keel for protection when you beach it.