The ships were built by
Germaniawerft (F 1 – F 6),
Kiel,
Blohm & Voss (F 7, F 8) and Wilhelmshaven dockyard (F 9, F 10). They entered service between 1936 and 1939. Similar in size to the
Type 35 and
Type 37 torpedo-boats, the ships were originally conceived as fast fleet or convoy escort ships that could also perform
anti-submarine and
minesweeping work. They were also used as a test bed class for a new high-pressure steam power plant intended for use in
destroyers. As a class, they were overloaded and over-engined, which contributed to severe hull stress and very poor sea-keeping characteristics; these flaws were partially remedied by extensive rebuilds between 1938 and 1940. The power plants likewise proved to be prone to frequent breakdowns, and most of the ships were removed from operational service during the later years of the war after machinery failures meant the ships spent more time in repair than in use. ==Use and administration==