The Flanders U-boat flotillas were

Imperial German Navy The Imperial German Navy or the Imperial Navy () was the navy of the German Empire, which existed between 1871 and 1919. It grew out of the small Prussian Navy (from 1867 the North German Federal Navy), which was mainly for coast defence. Wilhel ...

formations set up to prosecute the

U-boat campaign The U-boat Campaign from 1914 to 1918 was the World War I naval campaign fought by German U-boats against the trade routes of the Allies. It took place largely in the seas around the British Isles and in the Mediterranean. The German Empire r ...

against Allied shipping in the

Western Approaches The Western Approaches is an approximately rectangular area of the Atlantic Ocean lying immediately to the west of Ireland and parts of Great Britain. Its north and south boundaries are defined by the corresponding extremities of Britain. The c ...

(British Home Waters) during the

First World War World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...

. Originally operating as a

flotilla A flotilla (from Spanish, meaning a small ''flota'' (fleet) of ships), or naval flotilla, is a formation of small warships that may be part of a larger fleet. Composition A flotilla is usually composed of a homogeneous group of the same class ...

, it was split in two during the latter part of the war. The Flanders flotilla was constituted in March 1915 at the port of

Bruges Bruges ( , nl, Brugge ) is the capital and largest City status in Belgium, city of the Provinces of Belgium, province of West Flanders in the Flemish Region of Belgium, in the northwest of the country, and the sixth-largest city of the countr ...

in occupied

Belgium Belgium, ; french: Belgique ; german: Belgien officially the Kingdom of Belgium, is a country in Northwestern Europe. The country is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeast, France to th ...

. Commanded by Karl Bartenbach, the force comprised nine UB- and seven UC- type

U-boat U-boats were naval submarines operated by Germany, particularly in the First and Second World Wars. Although at times they were efficient fleet weapons against enemy naval warships, they were most effectively used in an economic warfare role ...

s, small mass-produced coastal types suited for operations in the closed waters of the

Channel Channel, channels, channeling, etc., may refer to: Geography * Channel (geography), in physical geography, a landform consisting of the outline (banks) of the path of a narrow body of water. Australia * Channel Country, region of outback Austral ...

and the

North Sea The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian S ...

. UB boats were prefabricated in Germany and brought in sections to Bruges and assembled. The boats used Zeebrugge and Ostend as exit ports; UC minelayers joined in late 1915. Throughout the campaign the Flotilla grew, though losses also remained high, as the unit bore a considerable proportion of the trade war () around the British coast. During 1916 12 boats were lost; in 1917 this rose to 29 boats, 9 UB- and 20 UC-type. In October 1917 the force was split into two full flotillas and Bartenbach, now a , was made flotilla leader (, FdU). The 1st Flanders Flotilla, under K/L Walther, comprised 8 UB- and 12 UC- boats at its formation. during the next twelve months 10 UB- and 5 UC- boats were lost. With replacements the unit strength in 1918 was 16 UB- and 9 UC- boats. The 2nd Flanders Flotilla, led by K/L Rohrbeck, comprised 12 UB- and 12 UC- boats; 12 Ub- and 4 UC- boats were lost but with replacements its strength in 1918 was 17 UB- and 7 UC- boats. Towards the end of 1918 the base at Bruges was abandoned as the German armies on the Western Front retreated. The surviving boats of the flotillas were surrendered at

Harwich Harwich is a town in Essex, England, and one of the Haven ports on the North Sea coast. It is in the Tendring district. Nearby places include Felixstowe to the north-east, Ipswich to the north-west, Colchester to the south-west and Clacton-on- ...

in November 1918.

Notes

References

* * * {{Uboat U-boat flotillas Military units and formations of the Imperial German Navy Naval units and formations of Germany in World War I