Captain jack sparrow

I wanna try this to see if it works. When I first saw it I thought "why are they carrying a boat with them? That stupid-ohhhhh" I saw the point...who wants to try this with mee? ^.^

The air in the boat would float them up.

Um, this is impossible because of displacement. The water would fill the boat, period. It's not sealed. In the same way that your goggles get water in them when the seal is not good against your face.