Boats don't float when placed underwater

When placing a boat on top of the water, it floats fine. However, it does not float when placed underwater. and will be impossible to enter.

Steps to reproduce:

1. Create a "Water World" super flat world
2. give yourself water breathing, night vision, and a boat
3. place the boat

the boat will not float

EDIT: duplicates MC-89944 ; accidentally published instead of pressing cancel