The proper term is "Underway Submerged".
Underwater volcanoes are called submarine volcanoes. They form in a similar way as their continental counterparts, that is close to plate boundaries.
That is the correct spelling for "submarine" (underwater, or underwater vehicle).
the name of a boat that goes underwater is called a SUBMARINE.
An underwater volcano is called a submarine volcano.
As regards torpedoes or missiles, yes, the submarine has weapons that can be launched underwater.
The proper term is "Underway Submerged"
a under water boat hmm... titanic (kidding) submarine
This is an old and a common term. The torpedo has been used since the first submarine's were used in war time.
It's often called a trench.
A valley that is underwater.
A submarine
A valley underwater is called a submarine canyon. These can form through a variety of geological processes, such as erosion by underwater currents or the collapse of underwater sediment. Submarine canyons can be important habitats for a diverse range of marine life.