Hey there is this movie that I loved when I was a little kid and for the life of me can't remember what it is called all I can remember is there is a floating bed in it and they go under water and a man a women and kids all travel on this bed through the whole movie. It is a really old movie.

Perhaps, Bed Knobs and Broomsticks: Bedknobs and Broomsticks (1971) - IMDb

That's it thank you..

Glad I could help.