DownBubble

Factual Questions
1

I hear this alot in submarine movies… what does DownBubble mean?

2

http://www.maritime.org/dsphrase.htm

I’m sure a submariner will be along soon to explain why.

3

WAG: They use a calibrated spirit level to tell how much up or down they’re tilted. So tilting the boat makes the little bubble move along the scale.