Initial attempt

Admiral Hipper departed Kiel bound for the Atlantic on 24 September 1940. She put in at Kristiansand in Norway to repair a broken cooling pump, and sailed again on 27 September. Admiral Hipper suffered an engine room fire the next day while sailing to the west of Stavanger. Both turbines had to be shut down to allow her crew to fight the fire, leaving the ship adrift for four hours. The damage from the fire forced the abandonment of the sortie.^[9][16]

The cruiser arrived back at Kiel on 30 September, and proceeded to Hamburg on 2 October for repairs. These were completed on 28 October.^[17] During this period Admiral Scheer departed Germany on 23 October 1940 for what proved to be a successful raid into the Atlantic and Indian Oceans that lasted until 1 April 1941.^[11][18]

Breakout into the Atlantic

Once the repairs were completed Admiral Hipper underwent training in the Baltic Sea from 29 October until 18 November. She then loaded ammunition and supplies for a long range operation into the Atlantic. This sortie, code named Operation Nordseetour (German: "North Sea Tour"), was more ambitious than that which had been planned for September.^[17] The goal of the operation was to attack Allied convoys in the North Atlantic.^[19] The cruiser was not to attack ships sailing independently.^[20] Consistent with standing practices for German surface raiders, the orders for the operation required Meisel to not engage enemy forces that were superior or equal to his ship.^[21]

At this time the German B-Dienst signals intelligence service was providing raiders with general information about the locations of Allied ships. The service was generally unable to pass on actionable intelligence though, as it could not decrypt intercepted Royal Navy radio messages. In particular, the Germans lacked information on the dates Allied convoys sailed and the routes they took.^[22] Each raider embarked a B-Dienst detachment that was responsible for monitoring Allied radio signals and using direction finding techniques to locate convoys and warships.^[23]

The cruiser set out again from Brunsbüttel on 30 November.^[17] She had been spotted there by a Royal Air Force reconnaissance aircraft the previous day, but the British did not realise that her presence at the port meant she was about to sail.^[24] Admiral Hipper was escorted by four torpedo boats for the first stage of the voyage. She refuelled from a tanker at a fjord near Bergen in Norway on 1 December before proceeding north. Meisel wanted a period of bad weather to help hide his ship from British patrols while passing Allied occupied Iceland, and he operated to the south of Jan Mayan island for the next several days. During this period, the cruiser refuelled from the tanker Adria on 2, 3 and 5 December.^[17] After the weather worsened, Admiral Hipper passed through the Denmark Strait that separated Greenland and Iceland on the night of 6/7 December. She was not detected by the British.^[17][25]

After entering the Atlantic, Admiral Hipper proceeded to the waters off southern Greenland to rendezvous with the tanker Friedrich Breme. It took several days to locate the tanker, during which Admiral Hipper's crew experienced extreme cold and a hurricane force storm.^[17]

Attack on Convoy WS 5A

Once refuelling was complete, Admiral Hipper began searching for convoys on the key route between Halifax in Canada and the United Kingdom.^[17] She patrolled to the south of the routes taken by convoys though, and did not encounter any.^[20] The crew endured another hurricane level storm, the cruiser's starboard engine failed and she ran dangerously low on fuel at one point.^[17][26] Admiral Hipper refuelled again from Friedrich Breme on 16 and 20 December.^[17] On 20 December Meisel decided to conclude the operation, and set course for Brest in occupied France.^[26]

Admiral Hipper detected multiple ships with her radar at 8:45 pm on 24 December while sailing 700 miles (1,100 km) west of Cape Finisterre in Spain.^[26] This was Convoy WS 5A, which had sailed from the United Kingdom carrying 40,000 soldiers and large quantities of supplies on board 20 ships.^[26] The WS convoys were special convoys that carried troops and supplies from the United Kingdom to Egypt and Asia on board fast ships. They were assigned powerful escort forces.^[27] Five of the ships were travelling with the convoy in the North Atlantic before entering the Mediterranean Sea to form part of an Operation Excess convoy that would carry supplies to Malta and Greece.^[28]

Convoy WS 5A's escort comprised the heavy cruiser HMS Berwick as well as the light cruisers HMS Bonaventure and Dunedin.^[20] Only Dunedin was fitted with radar.^[29] The light cruiser HMS Naiad had also formed part of the escort until 24 December.^[30] The aircraft carriers HMS Argus and Furious were sailing with the convoy to transport land-based aircraft to West Africa. As their flight decks were crowded with these aircraft, the two carriers could only fly off five of their own aircraft.^[27]

Meisel wrongly believed that he had found one of the weakly escorted OB convoys that sailed from the United Kingdom to Africa and decided to attack it at dawn the next day. His radar was unable to distinguish escorts from cargo vessels.^[27] Still, when in the darkness Admiral Hipper detected a large ship at the rear of the convoy, the Germans thought it was an escorting armed merchant cruiser. Preferring to weaken the escort before attacking the convoy in the morning, Meisel decided to attack with torpedoes which will not give away their presence since the British will think they were under U-Boat attack.^[31] Admiral Hipper fired three torpedoes at the convoy at 1:53 am on 25 December, but none hit.^[26]

The German sailors spotted the convoy to the west at 6:03 am on Christmas Day. Weather conditions were poor, with a strong wind, heavy seas, limited visibility and rain squalls.^[12] Berwick was among the first ships to be sighted, and other escorts were soon spotted. Meisel turned his ship towards the British heavy cruiser. The attack plan was to approach unsuspected as close as possible, to be able to attack the ship with a 3 torpedo fan shot from the rear torpedo launcher. But fire was opened on her with his 203-millimetre guns from a range of 6,000 yards (5,500 m) at 6:39 am, before the torpedoes were launched. As a result, the torpedo launcher was blocked by the blast of the guns and the launch had to aborted. Similarly the launching of 3 torpedoes from the forward launcher was botched when the secondary armament opened fire on the other escorts.^[32] While the British had not spotted Admiral Hipper, Berwick's crew were at dawn action stations when the engagement began. They returned fire at Admiral Hipper from 6:41 am, and the light cruisers changed course to join the fight. During this period Admiral Hipper's secondary armament fired at the transports, damaging Empire Trooper and Arabistan.^[21][29] Two men were killed on Empire Trooper.^[29]

In line with his orders to not engage equal or superior forces, Meisel sought to end the battle. He believed that the British light cruisers were destroyers, and turned to port to evade a possible torpedo attack. Admiral Hipper's rear turrets continued to fire at Berwick, and her secondary armament engaged the light cruisers.^[21]

Meisel was able to break contact at 6:43 am but was sighted by Berwick again at 6:47 am.^[33] At this time the British cruiser was on a parallel course approximately 8,000 yards (7,300 m) to the port of Admiral Hipper.^[21] Berwick opened fire, and Admiral Hipper fired back.^[33] At 7:05 am a 203-millimetre shell disabled one of Berwick's gun turrets, and she was hit below the waterline soon afterwards. Rain squalls then allowed Miesel to evade the British at 7:14 am by sailing north west.^[21][33] The British cruisers rejoined the convoy.^[33] Convoy WS 5A's ships had been ordered to scatter at 6:50 am, and it proved difficult to reassemble them.^[20][33] Admiral Hipper did not suffer any damage in this engagement and Berwick required repairs that took six months to complete.^[21]

Following the battle Admiral Hipper returned to a course bound for Brest. The ship was continuing to experience engine problems and was running low on fuel.^[21] At 10:00 am on 25 December, Admiral Hipper's crew sighted the cargo ship Jumma sailing by itself. She was sunk by a single salvo from the cruiser's 203-millimetre guns and two torpedoes. None of Jumma's crew of 111 survived.^[17] Admiral Hipper docked at Brest on 27 December.^[21] This made her the first major German warship to arrive at a port in occupied France.^[20] Royal Air Force Coastal Command aircraft had attempted to locate Admiral Hipper as she approached Brest, but did not spot her.^[30]