When riding a boat, it is frequently the case that the boat is destroyed and the cause is not clear. When riding a boat through a swamp, it is possible to sail through lily pads unaffected, but then collide with apparently invisible lily pads. Careful observation of both behaviors leads me to believe the boat is detecting collisions at a different location than it is being rendered. (The relationship between the visually apparent location of the boat and the player's view is normal.)

In one instance, as I approached a shore, my boat stopped, unable to move, more than 16 blocks off shore. I got out of the boat, and I was placed on the land I had been approaching. When I swam out to the boat's apparent location, I could not get in, nor could I destroy it with an axe, nor could I collide with it to move it. I stood on top of the boat, saved and exited, and reloaded the game, and found that the boat was now much closer to shore and I was dropped into the water.