The two ships laid a series of minefields during their career, though their most significant success came in October 1917, when they attacked a British convoy to Norway.
丽蝇号及牛虻号在服役生涯中曾布设了一系列雷区，但最为成功的行动发生于1917年10月，当时它们受命袭击一支前往挪威的英国护航船队。