The US helped France in world war 1 with submarines in the Atlantic.
Why don't you just Google "World War 1 Submarines?"
Sonar was used widely in World War II in an effort to locate enemy submarines. It wasn't as sophisticated as it is today, but it did help. Actual numbers are difficult to come by, but sonar was effective in the successful attacks on several submarines.
World War I submarines were primarily used to locate and attack surface cargo and warships.
Submarines changed war. They played a big part of World War I and II.
Yes
Submarines were sometimes referred to as submersibles.
Yes, German submarines were very effective in both world wars. The Germans built excellent submarines and still do.
2,200,000 Soldiers 97 Warships 40 Submarines.
Atlantic Ocean.
Steel plates.
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