A number of years ago I read the book Adrift: Seventy-six Days Lost at Sea by Steve Callahan. A sailor who was sailing across the Atlantic when one night he awoke to find his boat sinking. He had just a few minutes to get into the life raft he had on board and spent the next several months at sea before being rescued. He never did find out what his boat had hit that caused his boat to sink. On a online cruising forum in a discussion of why boats sink I read this:
"When we were in the river system off Brazil ... we had huge logs coming down at speed ... river was doing about 5 knots ... if one of those hit us..."
I was reminded of something I saw on the beach of eastern Long Island a few years ago. A large eight foot long log had washed up on the beach and was rolling around in the surf. It look like Mahogany or some other exotic tropical wood. As it rolled around in the surf I wondered how far it had journeyed before it landed on the beach. Perhaps as far away as Brazil.