1) Weapons countermeasure 
Foxer was the codename for a British built acoustic decoy, used to confuse German acoustic homing torpedoes like the G7es torpedo during the Second World War. A US version codenamed FXR was deployed in 1943. A Canadian version was also built called the CAT (Counter-Acoustic Torpedo). It was replaced in US service by the Fanfare noisemaker. The dev...