I think you are right. I seem to remember that he dropped the rode with a buoy attached. Not that rare an event; I have even done it. Could be a case of the anchor holding too well (well probably not), likely jammed under a rock. Those can be very hard to get out without a diver at times.
Heading back to Lake Ontario for this summer. Relatively few stops along the way from Grenada. Martinique, Guadeloupe, St. Martin (must have something to do with the French food), then Bermuda, New England and up the Hudson/Erie Canal. We were going to go via Newfoundland and Labrador but June remembered that one of the kids is getting married this summer - details, details!