U-boat Campaign (World War I)
U-Boat Campaign Part of the Naval Theatre of World War I A German postcard depicting the U-boat SM U-20 sinking RMS Lusitania Date 28 July 1914 – 11 November 1918 (4 years, 3 months and 2 weeks) Location Atlantic Ocean, North Sea, Mediterranean Sea, Black Sea Result Allied Victory Belligerents Royal Navy Royal Canadian Navy French Navy Regia Marina United States Navy Imperial Japanese Navy Brazilian Navy Imperial Russian Navy Royal Romanian Navy Kaiserliche Marine Austro-Hungarian Navy Bulgarian Navy Commanders and leaders Lord Fisher Sir Henry Jackson Sir John Jellicoe Sir Rosslyn Wemyss Hugo von Pohl Gustav Bachmann Henning von Holtzendorff Reinhard Scheer Strength ? surface vessels 366 Q-ships 351 U-boats Casualties and losses 5,000 merchant ships sunk [1] 15,000 merchant sailors killed 104 warships sunk [2] 42 warships damaged 61 Q-ships sunk [3] 217 U-boats lost to all causes 5,000 sailors killed v t e Theatres of World War I European Western Front...