 As the Eastern approaches to the English Channel were defended by NORECHAN and BENECHAN, PLYMCHAN's task was to prevent Soviet Navy submarines from entering the Western side of the channel.Therefore, PLYMCHAN had a large number of anti-submarine warships at its disposal, which would operate where Channel and Atlantic Ocean intersect.PLYMCHAN would have operated alongside the French Navy, which was not integrated into NATO's command structures.