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.

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.

During the lull, Admiral John Tovey concluded that the Home Fleet had been of no great protection to convoys beyond Bear Island, midway between Spitsbergen and the North Cape.

[6] The British Government Code and Cypher School (GC&CS) based at Bletchley Park housed a small industry of code-breakers and traffic analysts.

In 1941, B-Dienst read signals from the Commander in Chief Western Approaches informing convoys of areas patrolled by U-boats, enabling the submarines to move into "safe" zones.

Two Hampdens ran out of fuel and force-landed in Russia, one a write-off; one aircraft arrived over the Kola Inlet during an air raid and was shot down into the sea by Russian fighters.

[g] The summer melt of the polar ice cap meant that the convoy could sail north of Bear Island, considerably lengthening the journey and to conserve fuel, destroyer attacks on U-boats were limited to 90 minutes' duration.

[h] A Distant Covering Force (Vice Admiral Bruce Fraser) with the battleships HMS Anson and Duke of York, the cruiser Jamaica and five short-range destroyers, was to sail from Akureyri on the north Icelandic coast.

[21] On 24 June, a British minesweeper based at Kola was sunk by Ju 87 Stuka dive-bombers and on 16 August, Admiral Scheer conducted Unternehmen Wunderland, a sortie against Russian ships thought to be sailing along the route north of Siberia.

Ju 88 bombers were to divert the defenders with medium and dive bombing attacks as the torpedo-bombers approached out of the twilight, flying in line abreast at wave-top height to evade radar, the convoy being silhouetted against the lighter sky, then dropping their torpedoes at the same time.

The convoy was reported by U-456 and on 6 September, a Focke-Wulf Fw 200 Condor long-range reconnaissance aircraft had observed Avenger and the Close Escort Force at Seidisfiord in Iceland.

The Cruiser Covering Force had sailed independently to a position west of Bear Island and the group carrying supplies bound for the Norwegian weather station at Barentsburg was off Svalbard, using Convoy PQ 18 to divert the Luftwaffe.

[31] The convoy received Ultra information on the latest U-boat positions from the Admiralty and Swordfish aircraft were on anti-submarine patrol by 4:00 a.m., dodging a BV 138 and a Ju 88, which were faster and better armed.

They came in low on the starboard bow of the convoy and seemed to fill the whole horizon.They swept in, thirty or forty of them, about twenty feet above sea level, disregarding completely the escort screen.

The torpedo-bombers approached so close to the sea that machine-guns and even the low-angle BL 4.7-inch guns Mk I on some of the destroyers could be brought to bear, ...a pall of smoke hung like a curtain out on the starboard flank...criss-crossed by the bright red tracers and punctuated by the flashes of the shell bursts.

[36]Some of the anti-aircraft fire was poorly aimed and spent rounds from the ships on the left flank hit those on the right, wounding gunners, damaging cargoes and holing lifeboats.

At the head of one of the left flank columns, Empire Beaumont was hit, set on fire and the crew rescued; John Penn was torpedoed in the engine room, three men were killed and the ship was sunk by gunfire from the escorts.

More aircraft were seen mining the water ahead of the convoy, which made a sharp turn to port until 8:15 p.m. Fifteen minutes later, as night fell, twelve He 115s attacked from the south-west but were deterred by the anti-aircraft barrage.

)[38] Colthurst decided that the Sea Hurricanes henceforth would fly standing patrols of 25 minutes duration each, to ensure that some were always available to break up Goldene Zange formations, even if they were too slow and ill-armed to inflict many losses.

[41] The German surface force at Narvik had been alerted when the convoy was first sighted and on 10 September sailed north to Altafjord to begin Unternehmen Doppelschlag (Operation Double Hit).

The move was sighted by the two British submarines on patrol and HMS Tigris made an abortive torpedo attack on Admiral Scheer, erroneously reporting the ship as Tirpitz.

(The RAF donated the remaining Hampdens and Spitfires to the Soviet Air Force (Voyenno-Vozdushnye Sily, VVS) and the crews returned to Britain on the cruiser HMS Argonaut and two destroyers on 28 October).

The weather deterioration continued into the evening and as the destroyer Meteor returned to its station after dropping back to refuel, a depth-charge attack was made on a "suspicious object".

Soon after dawn, the first Catalina from Russia arrived, allowing the Swordfish crews to cease their anti-submarine patrols and at 9:00 a.m. the convoy turned south, running into mist and rising winds.

There were constant U-boat alarms and at one point, mines were seen amidst the freighters, leading to the convoy gunners engaging anything seen afloat, to the detriment of seals in the sea, men, superstructure and cargo on other ships.

Campfire, aground, was full of explosives; the captain ordered the crew to abandon and make for Modyugski Island, which was achieved despite the storm and on 21 September, in better weather, the master and several volunteers re-boarded.

For the rest of 20 September, the ships waited for the storm to abate and as the winds fell in the afternoon, twelve Ju 88 bombers appeared through the cloud at 3:40 p.m. and attacked, achieving only several near-misses.

[57] The Germans failed to prevent the convoy reaching Russia and their losses, particularly in trained pilots, were severe, reducing the ability of the Luftwaffe to repeat its anti-convoy operation.

[58] In November, Luftflotte 5, the German air command in Norway and Finland, was ordered to transfer its Ju 88 and He 111 torpedo-bombers to the Mediterranean against Operation Torch, a decision which the British received through Ultra intercepts.

Only the Heinkel 115 floatplanes, suitable for torpedo attacks on stragglers and some Ju 87 dive-bombers remained in Norway, along with a few long-range reconnaissance aircraft to observe for the surface and U-boat forces.