I found this 2 feet down at the beach in the wet sand. My best guess is that it's part of a compass (or gauge) gimbal off a boat. The brass ring wasn't attached, but, was in the same hole. It seems to fit on the side of the tube. The pointed end seems to be solid, but, I haven't been able to see if it's removable yet. The other end unthreads from the tube and has 3 set screws. Any other ideas or confirmation of my guess?