Sitting in a boat placed underwater gives the player limitless oxygen

The bug

You can place a boat about 4 blocks underwater sometimes. When you do you can breath forever. Also your partner can jump in and enjoy the submarine view too. Mobs will not target you as well.

How to reproduce

1. Use a structure block to load the structure contained in datapack_MC-127322.zip

   /setblock ~ ~ ~ structure_block{mode:"LOAD",name:"mc-127322:mc-127322",showboundingbox:1}
   

2. Place any type of boat on the lowest water level
3. Ride into the water current
   → Observe that the player doesn't lose oxygen