Submariners.
Yes, they had crews.
In World War 2 submarines people had many jobs. Some listened to different radio signals, and others watched the sonar. There were also navigators, torpedo loaders and shooters, and preachers. In most submarines there were surgeons.
Yes, that is a German term. Non-Germans call them submarines.
Ships would form a convoy in an attempt to reduce their vulnerability to enemy submarines.
No, not really, submarines were first used successfully in the Civil War.
Why don't you just Google "World War 1 Submarines?"
Submarines changed war. They played a big part of World War I and II.
Yes, submarines were used by the Confederate Navy in the US Civil War.
World War I submarines were primarily used to locate and attack surface cargo and warships.
Before the war, people mainly used ships and boats, therefore, the people with the submarine could destroy these ships.
The TURTLE piloted by Sgt. Lee, American Continental Army 1776.
Submarines were sometimes referred to as submersibles.