I got off the boat and it whizzed forward several feet, ending up inside some blocks. Wouldn't be so bad except I had a turtle still in it. Tried rescuing it, but had trouble. Took several block "breaks" at the back end to get them to actually break, no luck on the front end. No matter how much digging I did, blocks just reappeared in their places. The turtle seemed oddly fine irregardless, probably because it being broken so it wasn't suffocating (it was all black. Boat was too at first). At one point while trying to break blocks, the game minimized (nothing else had interfered. It just happened).

Easy fix though. I just exited to main menu and re-entered, and found myself back in the boat that was back in its position where I dismounted. Turtle fine. Few feet away were the drops of the blocks I managed to break.