Skull and Bones

This achievement has the distinction of being one of the more fun achievements to unlock. Ramming is good stuff. It’s brute force, it disregards your own safety, and it does good damage to other ships. All you need to do is sail at top speed into another vessel – preferably, right into their flank. It’s especially satisfying to do this toward the end of a battle, when your opponent is weakened, so that your ram downs them. In any event, keep ramming as a valued tactic in your arsenal, and you should unlock this achievement very easily. It will take a while, but it isn't actually difficult to get.