The next day he was promoted to captain and appointed commander of the German destroyer force (Führer der Zerstörer), succeeding Commodore Bonte, who had been killed on 10 April in the first Battle of Narvik.

Bey then commanded the destroyer screen protecting the ships of the Brest Group (Scharnhorst, Gneisenau, Prinz Eugen) during Operation Cerberus (the “Channel Dash”) in February 1942.

Promoted to Konteradmiral (Rear Admiral), on 1 March 1943, Bey on 26 December led a task force consisting of the battleship Scharnhorst and the destroyers Z29, Z30, Z33, Z34 and Z38 out of the Altafjord in Operation Ostfront.

The first and only surface sortie ordered by Grand Admiral Karl Dönitz, Bey's objective was to intercept the Allied Convoy JW 55B en route to Murmansk.

Poor weather, heavy seas and inadequate Luftwaffe reconnaissance prevented Bey from initially locating the convoy, so he detached his destroyers to fan out and assist in the search.