I don't know if it broke, but my boat just disappeared...right in the middle of a HUGE ocean. What sucked the most is my BH was completely out of energy at the time. It took a very long time to get him on shore.
I was sailing along, then I switched to another BH (he was in need of sleep) for a few moments. When I got back to my seafarer, he was floating around and no boat in sight. Go figure.