The Channel Dash (, Operation Cerberus) was a German naval operation during the Second World War. A (German Navy) squadron, comprising the two s, and , the heavy cruiser and their escorts was evacuated from Brest in Brittany to German ports. Scharnhorst and Gneisenau had arrived in Brest on 22 March 1941 after the success of Operation Berlin in the Atlantic. More raids were planned and the ships were refitted at Brest. The ships were a threat to Allied trans-Atlantic convoys and RAF Bomber Command attacked them from 30 March 1941. Gneisenau was hit on 6 April 1941 and Scharnhorst on 24 July, after dispersal to La Pallice. In late 1941, Adolf Hitler ordered the (OKM; German Navy High Command) to plan an operation to return the ships to German bases, in case of a British invasion of Norway. The short route up the English Channel was preferred to a detour around the British Isles for surprise and air cover by the and on 12 January 1942, Hitler gave orders for the operation.
The British exploited decrypts of German radio messages coded with the Enigma machine, air reconnaissance by the RAF Photographic Reconnaissance Unit (PRU) and agents in France, to watch the ships and report the damage caused by the bombing. Operation Fuller, a joint Royal Navy–RAF contingency plan, was devised to counter a sortie by the German ships against Atlantic convoys, a return to German ports by circumnavigating the British Isles, or a dash up the English Channel. The Royal Navy had to keep ships at Scapa Flow in Scotland in case of a sortie by the from Norway. The RAF had sent squadrons from Bomber and Coastal commands overseas and kept torpedo bombers in Scotland ready for Tirpitz, that limited the number of aircraft available against a dash up the Channel, as did the winter weather which reduced visibility and blocked airfields with snow.
On 11 February 1942, the ships left Brest at (German time) and escaped detection for more than twelve hours, approaching the Strait of Dover without discovery. The provided air cover in (Operation Thunderbolt) and as the ships neared Dover, the British belatedly responded. Attacks by the RAF, Fleet Air Arm, Navy and bombardments by coastal artillery were costly failures but Scharnhorst and Gneisenau were damaged by mines in the North Sea (Scharnhorst was out of action for a year). By 13 February, the ships had reached German ports; Winston Churchill ordered an inquiry into the débâcle and The Times denounced the British fiasco. The judged the operation a tactical success and a strategic failure, because the threat to Atlantic convoys had been sacrificed for a hypothetical threat to Norway. On 23 February, Prinz Eugen was torpedoed off Norway and after being repaired, spent the rest of the war in the Baltic. Gneisenau went into dry dock and was bombed on the night of never to sail again; Scharnhorst was sunk at the Battle of the North Cape on 26 December 1943.
Background
Port of Brest, 1940–1941
German commerce raiding against British north Atlantic convoys was made easier by the capture of Norway and France in 1940. An abortive sortie by the cruiser ended at Brest, at the west end of the Brittany peninsula, on 27 December 1940. After five weeks of attacks by Bomber Command to no effect, the ship put to sea on 1 February 1941, sank numerous ships and returned on 14 February, before sailing to Germany using the roundabout route via the Denmark Strait the next day, reaching Kiel on 28 March. The commerce raids in the north Atlantic during the winter of 1940–1941 by Scharnhorst-class battleships and , the heavy cruisers and Admiral Hipper sank British shipping at a higher rate than German surface ships achieved for the rest of the war. The British reformed 19 Group for Coastal Command in January 1941, which kept watch on the German ships at Brest; Scharnhorst and Gneisenau arrived at the port on 22 March 1941.
British air offensive, 1941
From 10 January to mid-April 1941, Bomber Command aimed of bombs at the ships in Brest harbour. Winston Churchill issued the Battle of the Atlantic directive on 9 March, directing the priority of the British war effort temporarily to counter the German campaign against Atlantic convoys. The RAF photographic reconnaissance unit (1 PRU) discovered Scharnhorst and Gneisenau in port on 28 March. Bomber Command flew about against the ships in Brest, through poor weather over the next two months. Gneisenau needed an engine room overhaul and entered dry dock on 4 April and an unexploded bomb was found between the stocks under the ship. Gneisenau had to be refloated and removed to defuse the bomb. Gneisenau was moored in an exposed position in the roadstead, where it was photographed by a 1 PRU Spitfire on 5 April. A raid was quickly planned with the six Beaufort torpedo bombers at RAF St Eval for an attack at dawn the next day.
Three Beauforts carried bombs to damage the torpedo nets that were presumed to protect the ship and three carried torpedoes. Two of the bombers bogged when taxiing for take-off and the third never found Brest in the thick weather. Two of the torpedo-bombers arrived off Brest, where they were to wait until the nets had been bombed. As dawn arrived the Beaufort flown by Kenneth Campbell attacked and dropped the torpedo as they passed over the mole giving it the maximum distance to arm on its run to its target. There were no torpedo nets and Gneisenau was hit on the starboard side near the after turret; the Beaufort was shot down, killing all on board. The damage to Gneisenau was severe, affecting the starboard propeller shaft bearings and shaft tunnel, causing flooding where the explosion destroyed the watertight integrity of stuffing boxes. Fuel and seawater got into some important compartments and some equipment suffered shock damage. A salvage tug was needed to assist in getting the flooding under control.
Gneisenau went back into dry dock; on the night of it was hit by four bombs and had two near misses. One of the hits did not explode but the others killed 75 crewmen, jammed 'B' turret and distorted the armoured deck near it, made about a third of the crew quarters uninhabitable by fire and blast damage, destroyed the kitchens and bakery and affected some gunnery control systems. The damage to Gneisenau led the Seekriegsleitung (SKL) to raise the question of the suitability of Brest for heavy surface units; Raeder disagreed and wanted more air defences instead. Scharnhorst was not damaged but the bomb hits on the docks delayed its refit, which included a substantial overhaul of its machinery; the boiler superheater tubes had a manufacturing defect that had plagued the ship throughout Operation Berlin. Repairs had been expected to take ten weeks but delays, exacerbated by British mine laying in the vicinity, caused them to miss (Operation Rhine Exercise). The sortie by and Prinz Eugen into the North Atlantic went ahead and Bismarck was sunk; Prinz Eugen returned to Brest on 1 June. Hitler ordered that capital ships must operate with much greater caution, that severely limited the freedom of action of the German surface fleet.
During the summer the new RAF heavy bombers attacked Gneisenau, Prinz Eugen and Scharnhorst. Prinz Eugen was hit on the night of and put out of action. The sailing on 21 July of Scharnhorst to La Pallice forestalled a surprise attack by Bomber Command. Scharnhorst was attacked by six Stirling bombers on the evening of 23 July and German fighters shot down one bomber. The attack on Brest took place in daylight on 24 July, with a loss of La Pallice was bombed again by fifteen Halifaxes. The formation was met by and anti-aircraft fire (); five bombers were shot down and five seriously damaged; Scharnhorst was hit five times. While returning to Brest containing of seawater, Scharnhorst was attacked by a Beaufort but shot it down before it could drop its torpedo. By late July 1941, the bombing left the three large ships in Brest undergoing extensive repairs. Lützow had been seriously damaged by a torpedo on 13 June; Admiral Scheer and Admiral Hipper were undergoing maintenance in German shipyards, was still working up and Bismarck had been sunk. British code breakers had contributed to the destruction of the German supply-ship network in the Atlantic that supported surface ship actions against Allied convoys.
From 28 March to the end of July, of bombs were dropped in Bomber Command, which also sent sorties, with another Coastal Command, laying off Brest; the British lost three being mine layers. For the next two months, Bomber Command made frequent small attacks, then attacked on the night of followed by on the night of Frequent small attacks were resumed and about were flown from July to December. At the start of the month, the Brest Group was made the Bomber Command priority again and from 11 December, bombing and mine laying took place nightly. When Prinz Eugen was found out of dry dock on 16 December, a attack was made on the night of followed by a day operation by bombers on the afternoon of 18 December, escorted by ten fighter squadrons. Gneisenau was slightly damaged and dock gates were smashed, stranding Scharnhorst for a month, for the loss of six bombers. Attacks continued all month and another day raid by Halifaxes was made on 30 December. From 1 August to 31 December, of high explosive and of incendiaries were dropped, eleven heavy bombers were shot down and considerable damage was inflicted on the docks and the town but none of the ships were hit again. Gneisenau was damaged on the evening of 6 January; 37 per cent of Bomber Command sorties between 10 December and 20 January 1942 were flown against the ships at Brest.
Ultra
Ultra was the code name used by British military intelligence for signals intelligence obtained by breaking German radio and teleprinter communications, including signals encrypted by Enigma, a German electro-mechanical rotor cipher machine. The decryption was carried out at the Government Code and Cypher School at Bletchley Park and the information was passed on to operational commands. From May 1941, Bletchley could read the Enigma Home Waters setting used by surface ships with few failures or interruptions, which combined with the PRU and reports from agents kept watch on the ships at Brest. By April 1941, the British knew that the three ships had been hit but not the extent of the damage.
From 16 to 23 December, Enigma decrypts showed that the gunners of the ships were on the Baltic, conducting gunnery training. Next day, the Admiralty warned that an attempt to break out was likely. On 25 January 1942, the ships were photographed in the harbour and two short periods in dry dock by two ships were seen. From the end of January to early February, torpedo boats, minesweepers and destroyers joined the big ships; together with news that the battleship Tirpitz in Norway had moved to the south, this led the Admiralty to issue an appreciation on 2 February that the three ships were going to attempt to sail up the channel and sent the signal Executive Fuller, the order to begin the operation to prevent the German Fleet from breaking into the North Atlantic. Next day Enigma and RAF photographic reconnaissance (PR) found that the number of German ship reinforcements from Brest to the Hook of Holland had risen to seven destroyers, ten torpedo-boats, more than and many smaller craft.
Norway Hypothesis