Convoy PQ 18

Convoy PQ 18 was an Arctic convoy of forty Allied freighters from Scotland and Iceland to Arkhangelsk in the Soviet Union in the war against Nazi Germany. The convoy departed Loch Ewe, Scotland on 2 September 1942, rendezvoused with more ships and escorts at Iceland and arrived at Arkhangelsk on 21 September. An exceptionally large number of escorts was provided by the Royal Navy in Operation EV, including the first escort carrier to accompany an Arctic convoy. Detailed information on German intentions was provided by the code breakers at Bletchley Park and elsewhere, through Ultra signals decrypts and eavesdropping on Luftwaffe wireless communications.

The German B-Dienst read some British signals and Luftwaffe used the lull in convoys after Convoy PQ 17 (27 June – 10 July) to prepare a maximum effort with the Kriegsmarine. From 12 to 21 September PQ 18 was attacked by bombers, torpedo-bombers, U-boats and mines, which sank thirteen ships at a cost of forty-four aircraft and four U-boats. The convoy was defended by escort ships and the aircraft of the escort carrier HMS Avenger which used signals intelligence gleaned from Ultra and Luftwaffe wireless frequencies to provide early warning of some air attacks and to attempt evasive routeing of the convoy around concentrations of U-boats. United States Navy Armed Guard and British Naval and Royal Artillery Maritime Regiment gunners were embarked on the freighters to operate anti-aircraft guns and barrage balloons, which made air attacks more difficult and because of inexperience, occasionally wounded men and damaged ships and cargo, with wild shooting.

The convoy handed over its distant escorts and Avenger to the homeward bound Convoy QP 14 near Archangelsk on 16 September and continued with the close escort and local escorts, riding out a storm in the Northern Dvina estuary and the last attacks by the Luftwaffe, before reaching Archangelsk on 21 September. Several ships ran aground in the storm but all were eventually refloated; unloading the convoy took a month. Because of its losses and the transfer in November of its most effective remaining aircraft to the Mediterranean to oppose Operation Torch, the Luftwaffe effort could never be repeated.