Do not leave boats in the water. Put them in a box.

Birds can land on a boat and the AI gets confused and the boat will literally fly off thinking it is the bird. <honestly I really want to see this, it is a known issue>

Not only that but if you teleport near it you can actually flip it over and it will destroy itself, if you don't have a bench around close enough the parts will despawn.

Just don't leave boats out at all, it is asking for trouble.