Submarines were sometimes referred to as submersibles.
the U boats..
During World War 2, it is reported that over 2,000 variants of Japanese Submarines were used during World War 2. Out of this, it is estimated that 10,000s were likely to be used during WW2.
The British lost 76 submarines during WWII.
U-Boat , ULTRA ,U-boat, the name for German submarines during World War 2
The submarines were either called "submarines" or "U-boats." The German submarine was called the "U-boat"
Germany called there submarines U boats
submarines
An estimation of about 600 subs were operated during the war.
The early SS and the newer GATO Class diesel submarines.
ASDIC
More than you can afford
Britain, France, Germany, Italy and USA all used submarines during WW1