Last Saturday Marge and I anchored in Potter Cove on Prudence Is., RI. There was a large power boat about 25 yards to port. Two other power boats came up and rafted with him. There was a bunch of kids on board who got in the three dinghies and prodeeded to buzz 'round and 'round our boat, doing "wheelies" etc. This went on for over three hours without stop, and finally after dinner at 7:30pm Marge called out to them to "knock-it-off". They went back to their boats. As we got into our dinghy for the final doggie run, the father came over, very belligerent saying that we had made his 10 year old son cry, and how dare we, and that if we didn't like the noise we should move. While we were ashore the teenage son started going around our boat yelling and screaming at the top of his lungs. When we got back the father called out "I hope you have a nice quiet evening!"I was nervous about this guy at this point. The whole gang was drinking heavily, and so I hauled the dinghy up on to the bow because I had the feeling that something was up, and we might wake up to find no dinghy, or at least a dinghy with a hole in it. One boat left.We went to bed at 10pm. Ten minutes later I felt a bump against the stern and all sorts of noise blared forth right behind the stern. I looked out and there were the two boats with their sterns to us, dinghies astern with the outboards running, about six feet from my stern. There was music blaring and they were yelling at the tops of their voices. The outboard motors were making a LOT of noise. Obvious payback!We went up and asked them politely to stop, at which time they said that we had drifted on to them (there was virtually no wind, and we hadn't budged an inch). I pulled in 20 ft of chain, and watched - they slowly "drifted" right on to our stern again. I asked them what the hell they were doing, and they said they weren't doing anything - it was me that was drifting all over the cove. Funny that they were the only boats in the cove pointing stern to the light wind!Marge and I were a bit scared - these people were quite drunk and obviously intent on intimidation, and so we decided to move. We did, moved about 200 yards. The problem was that in re-anchoring in the dark I somehow got my left hand under the chain, the boat lurched and I got my hand squashed under the chain. It hurt like crazy all night, so we left at first light and I went to the ER to find that the pinky was fractured in a couple of places, it's now in a temporary splint and I have to see a hand specialist on Thursday.We got the name of one boat, but no hailing port, and could not see any name or registration on the other two.The question is - what is the best way to deal with a situation like this? Should I have called the Coast Guard? I didn't want to do anything to escalate the situation... There are some scary people out there!Derek