Operation Catechism

From early 1942, Tirpitz posed a significant threat to the Allied convoys transporting supplies through the Norwegian Sea to the Soviet Union. Stationed in fjords on the Norwegian coast, the battleship was capable of overwhelming the close-escort forces assigned to the Arctic convoys or breaking out into the North Atlantic. To counter this threat, the Allies needed to keep a powerful force of warships with the British Home Fleet, and capital ships accompanied most convoys part of the way to the Soviet Union.

Tirpitz was repeatedly attacked by British forces over several years. RAF heavy bombers made four unsuccessful raids on the battleship between January and April 1942 while she was stationed at Fættenfjord. From March 1943, Tirpitz was based at Kaafjord in the far north of Norway. During Operation Source on 22 September, she was severely damaged by explosives placed on her hull by Royal Navy personnel who had used midget submarines to penetrate Kaafjord. On 3 April 1944, aircraft flying from Royal Navy aircraft carriers attacked Tirpitz during Operation Tungsten and inflicted further damage. A series of subsequent aircraft carrier attacks were unsuccessful, including Operation Mascot on 17 July and Operation Goodwood which was conducted between 22 and 29 August 1944.

As it was believed that further aircraft carrier raids would be fruitless due to shortcomings with the Royal Navy’s aircraft and their armament, responsibility for sinking Tirpitz was transferred to the RAF’s Bomber Command. On 15 September 1944, the elite Nos. 9 and 617 Squadrons attacked the battleship at Kaafjord during what was designated Operation Paravane. This operation employed Avro Lancaster heavy bombers armed with Tallboy heavy bombs and “Johnnie Walker” mines. The Tallboy bomb weighed 12,000 pounds and had been developed to destroy heavily armoured targets. When dropped from a high altitude, the bomb could penetrate a battleship’s deck armour before exploding within the vessel. Tirpitz was struck by a single Tallboy during the attack, which caused extensive damage to her bow and rendered her unfit for combat.

As Tirpitz could not be repaired and Soviet forces were advancing towards Kaafjord, Grand Admiral Karl Dönitz, the commander of the Kriegsmarine, ordered that she be transferred to near the northern Norwegian town of Tromsø and used as an immobile battery to defend the area from attack. Dönitz hoped that this would also convince the Allies that Tirpitz continued to pose a threat. An anchorage was selected just off the coast of the island of Håkøya where it was believed the water was shallow enough to prevent the battleship from sinking if she was attacked again. Tirpitz arrived there on 16 October. The depth of water at the mooring was found to be greater than anticipated, leaving the battleship vulnerable to capsizing. Due to the space needed by Tirpitz’s torpedo nets, it was not possible to move her closer to shore.

British reconnaissance aircraft located Tirpitz at Tromsø on 18 October. As the Allied intelligence services had not been able to confirm that the battleship had been crippled, it was considered necessary to conduct further air raids against her. Nos. 9 and 617 Squadrons attacked Tirpitz on 29 October in what was designated Operation Obviate. As the Tromsø area was within range of RAF bases in northern Scotland if the Lancasters were modified, this attack was somewhat simpler to conduct than Operation Paravane. To extend their range, the Lancasters were fitted with extra fuel tanks and more powerful engines, and their forward and mid-upper gun turrets and pilot’s armour plate were removed. The reduction in armament left the Lancasters very vulnerable to German fighter aircraft, and they would have to fly without escort as no British fighters had the range needed to reach Tromsø.

During Operation Obviate, the bombers flew north over the Norwegian Sea, and met up over Torneträsk lake in Northern Sweden. This violated Sweden’s neutrality, but allowed the bombers to approach Tromsø from the south-east, which it was believed the Germans would not expect. Despite clear weather for most of the flight, Tirpitz was covered by cloud shortly before the Lancasters reached the point where they were to release their Tallboy bombs. This made it impossible to accurately target the battleship, and while 33 aircraft bombed no hits were achieved. Tirpitz was slightly damaged by a near miss. One of the Lancasters made a forced landing in Sweden after being damaged by anti-aircraft gunfire, and the remainder returned to base.

British

Bomber Command remained determined to sink Tirpitz as soon as possible, and preparations for another attack began shortly after Operation Obviate. A report issued by the Royal Navy’s Naval Intelligence Division on 3 November judged that it remained necessary to attack Tirpitz in northern Norway as the battleship could potentially be repaired and made fully operational if she was left unmolested and able to reach a major base. As it would be difficult to target the battleship during the period of perpetual darkness in the northern winter, further attacks needed to be made within the 23 days before this commenced. No. 5 Group RAF directed on 3 November that the next attack on Tirpitz was to take place on 5 November, and would re-use the plans developed for Operation Obviate. The raid was designated Operation Catechism.

Two de Havilland Mosquito meteorological aircraft were stationed at RAF Sumburgh from 4 November, from where they conducted daily sorties to monitor weather conditions in the Tromsø area. On the same day, twenty No. 9 Squadron and nineteen No. 617 Squadron Lancasters were dispatched to airfields in northern Scotland in preparation for the operation. A gale warning was issued that night, however, and the raid was cancelled as a result on the morning of 5 November. Both squadrons returned to their home bases during the day. The two squadrons deployed again to Scotland on 7 November, but soon returned to their home bases when the attack was cancelled.

On 10 November the Lancaster crews were briefed for another attack on Tirpitz. Both squadrons moved to northern Scotland on 11 November in response to meteorological reports which indicated that there would be clear weather over Tromsø for up to two days. The aircraft were split between RAF Kinloss, RAF Lossiemouth and RAF Milltown.

German

Tirpitz’s defences were improved after Operation Obviate. Additional anti-aircraft guns were emplaced in the Tromsø area and torpedo nets were laid around the battleship. These augmented the protection offered by the anti-aircraft ships Nymphe and Thetis and several anti-aircraft batteries on the shore. Dredging operations to reduce the water level below the battleship’s hull began on 1 November. By 12 November these were half complete. The smoke generators which had previously protected Tirpitz at Kaafjord were still being installed at the time of Operation Catechism and were not yet operational. In their place, seven fishing boats fitted with smoke generators were stationed near the battleship; these were not capable of generating a smokescreen which could completely cover Tirpitz.

The battleship’s crew continued regular training exercises, and remained concerned about further air attacks. On 4 November Tirpitz’s commanding officer Captain Wolf Junge departed. He was replaced by the executive officer, Captain Robert Weber. Weber believed that within three weeks the days would be short enough to prevent further air attacks. On 12 November around 1,700 men were on board Tirpitz.

A force of 38 fighters was transferred to Bardufoss after Operation Obviate to bolster the Tromsø region’s air defences. These aircraft formed part of Jagdgeschwader 5, and were under the temporary command of Major Heinrich Ehrler. The unit had been evacuated from Kirkenes in the far northeastern region of Norway as Soviet forces advanced towards the town, and was disorganised at the time of Operation Catechism. Most of the pilots at Bardufoss were inexperienced and ill-trained, and the unit had not been properly briefed on Tirpitz’s presence in the area. Ehrler arrived at Bardufoss on 9 November en-route to Alta, and decided to remain there until the morning of 12 November to oversee an emergency training programme for the fighter pilots.

The decision to launch Operation Catechism was made in the early hours of 12 November. A weather forecast issued on the afternoon of 11 November predicted that clouds might be encountered over northern Norway. One of the Mosquito meteorological aircraft flew over the area that evening, and its crew reported encountering patches of cloud when they returned to Scotland shortly after midnight on the night of 11/12 November. Nevertheless, the commander of No. 5 Group, Air Commodore Ralph Cochrane, decided to attempt another attack in the hope that the bombers would encounter clear weather over Tromsø. The plan for this operation remained the same as that used in Operation Obviate, with the attack force to use identical routes.

A total of 32 Lancasters were dispatched. No. 617 Squadron contributed eighteen, and No. 9 Squadron thirteen. As with Operations Paravane and Obviate, they were joined by a Lancaster fitted out as a film aircraft from No. 463 Squadron RAAF. The role of this aircraft was to collect material for use in propaganda films. Seven No. 9 Squadron Lancasters, including that of its commanding officer Wing Commander James Bazin, were unable to participate, as they could not be cleared in time of the snow and ice which had formed on them overnight. The No. 617 Squadron aircraft took off between 2:59 and 3:25 am BST, and the No. 9 Squadron aircraft between 3:00 and 3:35 am BST. The aircraft flown by No. 9 Squadron’s deputy commander, Squadron Leader Bill Williams, was among those able to take off and he assumed command of the unit.

The Lancasters flew individually over the Norwegian Sea. As had also been the case during Operation Obviate, they crossed the Norwegian coast between the towns of Mosjøen and Namos where a gap in the German radar coverage had been located. Several of the bombers flew too far to the north, and came within range of German radar stations. The attack force rendezvoused over Torneträsk Lake. After making two orbits, No. 617 Squadron’s commanding officer, Wing Commander Tait fired a flare gun from his aircraft to signal the force to proceed to Tromsø. Two No. 9 Squadron Lancasters failed to reach Torneträsk Lake in time, and returned to base without attacking.

Approach

The attack force proceeded north-west towards Tromsø, and climbed to 14,000 feet to clear the mountains along the border of Sweden and Norway. They were guided by radio homing signals transmitted by a Norwegian Milorg agent stationed near the border between the two countries. By the time they reached the Tromsø area, both of the squadrons had formed up into loose formations. No. 617 Squadron led the attack, followed by No. 9 Squadron. The Lancasters were grouped into “gaggles” of four to six aircraft which flew at altitudes of between 14,000 feet and 15,000 feet. The No. 463 Squadron film aircraft approached Tromsø at 6,000 feet, and dropped to 2,000 feet to evade anti-aircraft fire at the start of the attack.

The German forces in the Tromsø area failed to adequately respond to multiple warnings of the approaching British bombers. Between 7:39 am and 8:50 am local time several reports of Lancasters in the area were received from observation posts. As the first aircraft to be spotted were flying east, it was thought that they might be headed to the Soviet Union. Tirpitz was not notified of the reports until 8:15 am local time, and few reports were passed on to the JG 5 detachment at Bardufoss. Tirpitz’s air raid siren was sounded at 8:51 am, and Weber informed her crew seven minutes later that an attack was possible.

At around 9:15 am local time Tirpitz contacted Bardufoss to request that fighters be dispatched to provide air cover. This was too late for any of the fighters to reach Tromsø before the bombers arrived. The local Luftwaffe command ordered the fighters to be scrambled at 9:18 am. Due to various delays, the aircraft did not begin taking off from Bardufoss until approximately 9:32 am. Ehrler took off first, but the others were delayed from doing so for several minutes while an aircraft landed on the runway. Ehrler proceeded to the Tromsø area by himself, but was unable to locate the British bombers before they attacked. It is not clear where the other fighters were dispatched to, as one post-attack report states they were sent to the border with Sweden, another that they proceeded to Kaafjord and two pilots claimed to have reached Tromsø after Tirpitz was destroyed.

Weather conditions over Tromsø continued to be clear when the attack force arrived in the area. Tait spotted Tirpitz from 20 miles away, and later recalled that she was “lying squat and black among her torpedo nets like a spider in her web, silhouetted against the glittering blue and green waters of the fjord”.

Tirpitz fired the first shots of the battle at 9:38 am BST when she opened fire on the bombers with her 380-millimetre calibre main guns from a range of 13.5 miles. Other anti-aircraft guns also fired on the Lancasters as they approached, but did not disrupt them. No smokescreen was present as they flew north-west towards their bombing positions.

The attack commenced at 9:41 am BST. Tait’s aircraft was the first to drop its Tallboy, which hit Tirpitz. No. 617 Squadron completed its attack at 9:44 am BST with all aircraft bombing. No. 9 Squadron aircraft began dropping their Tallboys at 9:45 am BST. By this time the battleship was on fire and covered in smoke. The last bomb was released at 9:49 am BST.

Tirpitz was rapidly destroyed. She was struck by two Tallboys which penetrated her armoured deck. One hit to the port of “Bruno” turret in the forward section of the ship but did not explode. The other, which was dropped by Tait’s aircraft, struck the port side amidships near the tracks for the aircraft catapult and exploded over the port boiler room. This explosion caused severe damage which resulted in extensive flooding, fires throughout the ship and a list of 15 to 20 degrees to port. Several other bombs detonated in the water near Tirpitz, which caused further damage to her hull and additional flooding. These explosions also created large craters below the ship, and blew away much of the gravel which had been dumped beneath her. Almost all the hits and near misses were on the port side of Tirpitz, which destabilised her and led the list to rapidly increase. Many sailors manning Tirpitz’s anti-aircraft guns were killed or wounded by the bombs, resulting in a significant reduction in the volume of fire directed at the Lancasters.

After the first bomb struck his ship Weber ordered the crew to evacuate the armoured citadel and attempt to counter the flooding. Despite the list, Weber expected that Tirpitz would not sink as the water beneath her hull was too shallow. Counter-flooding proved impossible, as the controls for the necessary systems had been abandoned and the volume of water which was entering the ship was well beyond their ability to fight had they been operational. Weber ordered that the lower decks be evacuated at 9:45 am, by which time the list had reached between 30 and 40 degrees. At 9:50 am the magazine for “Caesar” turret exploded, causing extensive damage. Tirpitz’s list rapidly increased, and she was soon lying on her side. Weber then gave the order to abandon ship. The battleship continued to heel over, and capsized at 9:52 am. Almost 1,000 of her crew had either been killed by this time, or were trapped inside the hull.

The crews of several Lancasters observed Tirpitz capsize. The No. 463 Squadron film aircraft made a final pass over the battleship at an altitude of just 50 feet to capture footage of the event. Just after 11:00 am BST a photo-reconnaissance Mosquito overflew the Tromsø region, and photographed the wreck. The Secret Intelligence Service agent Egil Lindberg also sent radio reports from Tromsø confirming that Tirpitz had been destroyed.

Tirpitz following Operation Catechism

The German forces in the Tromsø area endeavoured to rescue the surviving members of Tirpitz’s crew. Within two hours, 596 had swum to shore or been rescued from the water. Others were trapped in air pockets within the wreck. These sailors were doomed unless they were able to move to the former bottom of the ship and be rescued before their air supply ran out. Shortly after Tirpitz capsized, parties of sailors climbed onto the hull and painted marks on locations were they heard signs of life. Acetylene torches were needed to cut into the thick hull, and none were initially available. Local Norwegian civilians who owned torches hid them, and only one could be found. A total of 87 sailors were rescued from within the hull in the 24 hours after the attack. Cutting continued for two further days, and was finally abandoned when it was assessed that the oxygen supply inside the wreck would have been exhausted; no survivors were recovered during this period. Estimates of the total number of sailors killed vary, with the most common figures lying between 940 and 1,204. Weber and all of his senior officers were among the dead.

Many Norwegian civilians in Tromsø were pleased that Tirpitz had been destroyed, not least as it meant the end of an order requiring that they billet members of her crew. Several civilians who showed pleasure at the event in public were arrested by the Gestapo. However, other Norwegians were saddened by the way in which the battleship’s crew had died.

Work began on stripping Tirpitz’s wreck soon after rescue efforts ended, and continued until the late 1950s. Prior to the end of the war German personnel removed the ships’ brass propellers so they could be melted down, as well as some other components. The wreck was sold to a Norwegian scrap dealing company in 1948, and was broken up in situ. Salvage work concluded in 1957, by which time most of the battleship had been removed. The bodies of German sailors recovered from the wreck by scrappers were initially buried alongside unwanted parts of Tirpitz, but this ceased following complaints by a local church minister. The hundreds of other bodies which were recovered were buried in cemeteries.

Ben Davidson

Hello, I have been studying all aspects of history for about 25 years. I have a BA History from the University of Bedfordshire. My historical areas of interest are anything really, but I specialise in 19th - 20th century Britain, America and Ireland. I am also strongly aligned with most military history, really enjoying WW2 and the US Civil War. Chuck in the king or queen and Bob's your uncle.

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