[Cats Pajamas]

FUN FACT: In submarine terminology, “zero bubble” means that the bow of the submarine and the stern are level.

https://twitter.com/MajorPatriot/status/1309202107963191297

[Cats Pajamas]

https://twitter.com/RealJamesWoods/status/1309205219423653888
ChinaHijinks Fun for all!!

[Larry - Moe and Curly]

"FUN FACT: In submarine terminology, “zero bubble” means that the bow of the submarine and the stern are level."

19-year old me driving a ballistic missile sub.

The "bubble" is the item I circled in red. If all the instrumentation is out you can still tell what the ship's angle is.