History glossary
U-boats
German submarines used to attack enemy and merchant shipping during the First World War.
- Category
- Military technology
- Region
- Atlantic and European waters
- Date range
- First World War
What it means
U-boats were German submarines. In the First World War, Germany used them to challenge British sea power and blockade Britain by sinking merchant shipping. Unrestricted submarine warfare meant attacking ships without warning, including neutral vessels. This strategy helped push the United States into the war in 1917.
