'FZ' was a British naval undertaking associated with the passage of the JW.59 outbound convoy to ports in the northern USSR (15/25 August 1944).

JW.59 was the first Arctic convoy of the season after the period of uninterrupted daylight during the middle of the year, and departed Liverpool on 15 August with 33 merchant ships, one rescue ship and 11 Lend-Lease submarine chasers being transferred by the US Navy to the Soviet navy to encourage a more active Soviet involvement in anti-submarine operations off the Kola inlet. The covering force comprised the light cruiser Jamaica, escort carriers Vindex and Striker, and destroyers Caprice, Marne, Meteor, Milne and Musketeer, and close cover was provided by the 20^th and 22^nd Escort Groups with the destroyers Keppel and Whitehall, frigate Loch Dunvegan, sloops Cygnet, Kite, Mermaid and Peacock, and corvettes Bluebell, Camellia, Charlock, Honeysuckle and Oxlip.

An innovation reflecting the appreciation that the aircraft carrier was the most important single anti-submarine ship involved in convoy support operations was the fact that Vice Admiral F. H. G. Dalrymple-Hamilton, commanding the entire operation, flew his flag in the escort carrier Vindex rather than a cruiser.

The former British battleship Royal Sovereign, which was being transferred to the USSR for service as Arkhangyel''sk, departed from Scapa Flow on 17 August with a British escort, and the elderly battleship was met by eight Russian-manned ex-US destroyers at sea, overtook the convoy to the west of Bjørnøya, and then went straight through to the Kola inlet.

Vice Admiral Sir Henry Moore, second in command of the Home Fleet, took the main strength of the Home Fleet to sea on 18 August to carry out the 'Goodwood' (ii) attack on the German battleship Tirpitz during the convoy’s passage. He had with him the battleship Duke of York, the fleet carriers Indefatigable (flagship of Rear Admiral R. R. McGrigor), Formidable and Furious, the heavy cruisers Berwick and Devonshire of the 1^st Cruiser Squadron, and 14 destroyers. A second force consisted of the escort carriers Trumpeter and Nabob and heavy cruiser Kent, escorted by a group of frigates on loan from Admiral Sir Max Horton’s Western Approaches Command, while two fleet oilers sailed separately under the charge of four corvettes. This force served, in effect, as the distant cover for 'FZ'.

The JW.59 convoy steamed to the east during the period of 'Goodwood' (ii) and enjoyed a comparatively uneventful passage. The weather was unusually favourable, and this and the continuous daylight enabled the escort carriers to work their aircraft almost continuously. The U-boats, of which nine were on patrol in the Barents Sea, were given no chance to approach within striking distance, and the convoy suffered no losses. However, on 21 August the sloop Kite was hit by two torpedoes from Kapitänleutnant Ulrich Pietsch’s U-344 and sank immediately, leaving a mere nine survivors.

Kite, and also Bickerton of the main force which had been scuttled after being severely damaged on 22 August by Oberleutnant Hans-Jürgen Sthamer’s U-354, were not long unavenged, for later on 22 August Vindex's Fairey Swordfish anti-submarine aircraft sank Pietsch’s U-344 with air-dropped depth charges, and two days later ships of the 20^th Escort Group accounted for Sthamer’s U-354.

The corresponding homebound convoy was RA.59A of nine ships, and this had an almost unopposed passage. Only one U-boat was sighted, and this was Kapitänleutnant Wolfgang Borger’s U-394, which was destroyed after attacks by Swordfish aircraft of Vindex and a 12-hour hunt by the 20^th Escort Group.