SM U-35 was the most successful submarine of World War I by merchant shipping tonnage sunk.
Commissioned into the Imperial German Navy in 1914, U-35 operated mainly in the Mediterranean under commanders including Waldemar Kophamel and Lothar von Arnauld de la Perière. Its patrols used Germany’s unrestricted submarine warfare campaign against Allied and neutral shipping.
U-35 sank more than 200 vessels, totaling over half a million gross register tons, making it one of the most effective warships of any type in the conflict. Many targets were stopped and sunk after their crews were given time to abandon ship, although the campaign still generated major controversy.
U-35 is sometimes confused with U-9, which became famous for sinking three British cruisers in one action in 1914, or with U-48, the leading German submarine of World War II. U-35 survived the war and was surrendered in 1918.