it's appropriately called the dive alarm.
a diver
A submarine is an undersea boat, or submersible.
The Nautilus was Fulton's submarine.
Below
plunger is a fitting name for submarine because , it is under the water
this word is an adjective meaning "under the sea". submarine is the word shortened from the term "submarine boat".
The H. L. Hunley was the name of the Confederate submarine that was the first combat submarine to sink an enemy ship.
The Confederate submarine 'H L Hunley' was the first submarine to sink an enemy ship
Submersible.
Nautilus.
Underseaboat.
A submarine