Operation Paravane

'Paravane' was a British air attack which inflicted heavy damage on the German battleship Tirpitz at anchor in the Kaafjord spur of the Altafjord in the far north of German-occupied Norway (15 September 1944).

The attack was made by 21 RAF heavy bombers operating from an airfield in the north of the USSR. The battleship was struck by one bomb, and further damaged by several near misses, and the damage this inflicted rendered Tirpitz unfit for combat, and the the ship could not be fully repaired as it was no longer possible for the Germans to sail her to a major port.

The attack followed a series of largely unsuccessful raids flown against Tirpitz by Royal Navy aircraft carriers between April and August 1944 with the object of sinking or disabling the battleship at her anchorage, so that she no longer posed either a real threat or indeed a 'threat in being' to Allied convoys making the passage to and from the USSR. The first of these raids was successful, but the other attacks failed as a result of shortcomings with the Fleet Air Arm’s strike aircraft and the formidable nature of the German defences. As a result, the task of attacking the battleship was transferred to Air Chief Marshal Sir Arthur Harris’s RAF Bomber Command. Avro Lancaster four-engined heavy bombers of two squadrons flew to their staging airfield in the USSR on the night of 11/12 September, and attacked on 15 September using heavy bombs and air-dropped mines. All of the British aircraft returned to base, though one of the Lancasters later crashed during its flight back to the UK.

From a time early in 1942, Tirpitz had posed a significant threat to the Allied convoys transporting supplies through the Norwegian Sea to the USSR. Based in fjords on the northern sector of the Norwegian coast, the battleship was capable of overwhelming the close escort forces of Arctic convoys or breaking out into the North Atlantic. However, as a result of the overall superiority of the Allied navies, Tirpitz rarely put to sea and made a mere three brief combat sorties into the Norwegian Sea during her career. The Allies needed to keep a powerful force of warships with the British Home Fleet to counter the threat she posed and capital ships accompanied most convoys part of the way to the USSR.

RAF heavy bombers made of abortive raids on Tirpitz shortly after the battleship arrived in Norway from Germany in January 1942. Tirpitz was initially based in the Fættenfjord near Trondheim, which lay within range of British bombers flying from Scotland. The first raid on 30 January involved nine Handley Page Halifax and seven Short Stirling four-engined bombers, but the presence of cloud over the target area meant that only one of the bombers sighted Tirpitz and none inflicted damage. One Halifax crashed into the sea on its way back to Scotland and its crew were rescued. The next raid on the Fættenfjord was flown on 30 March by 33 Halifax bombers. The operation was again frustrated by heavy clouds over the target area. Four of the Halifax bombers were shot down and two others crashed while returning to base. Another attack was mounted by 30 Halifax and 11 Lancaster bombers on the night of 27/28 April. Aircraft of the first wave located and attacked Tirpitz but inflicted no damage lost five of their own number. The final raid in this series took place during the following night and involved 21 Halifax and 12 Lancaster bombers. The attackers found Tirpitz shrouded in a protective smokescreen, and the battleship again escaped damage; two of the British aircraft were destroyed.

Plans for more heavy bomber attacks on Tirpitz were developed throughout 1942, but none took place. One of the options considered was to stage the bombers through a base in the northern USSR, but this was judged impractical as little was known about the suitability of Soviet airfields for heavy bombers. Two squadrons of RAF Coastal Command Handley Page Hampden torpedo bombers operated from Vaenga in northern Russia during mid-September 1942 to counter Tirpitz or any other German warships which attempted to attack Allied convoys, but these aircraft made no contact with the German warship.

Further plans for air attacks on Tirpitz were developed during 1943, but none of these was flown. During 1942 and 1943 British designer and inventor Dr Barnes Wallis tried to develop a version of his 'bouncing bomb', used in the 'Chastise' raid of 16/17 May 1943 on German dams, for use against Tirpitz. No. 618 Squadron was formed in April 1943 and equipped with de Havilland Mosquito twin-engined bombers for this attack, but trials of the 'Highball' bouncing bombs during the year were unsuccessful and the plan was abandoned in September. Tirpitz was transferred to a new base in the Kaafjord in the far north of Norway late in May 1943. This anchorage was well protected, the defences including equipment capable of the rapid generation of an artificial smokescreen as well as many Flak guns located in shore batteries and on warships. During June 1943, consideration was given to attacking the battleship with Boeing B-17 Flying Fortress four-engined heavy bombers of the US Army Air Forces: these aircraft would have flown from the UK to the Kaafjord, flown on to the USSR and made another attack on Tirpitz on their return flights. Such a mission was judged to be impractical by the RAF as it was expected that German fighter aircraft would attack the bombers and the Kaafjord would be covered by a smokescreen by the time the US bombers arrived over the target area. The only attack made on Tirpitz in the Kaafjord by land-based aircraft before September 1944 was a small raid conducted by 15 Soviet bombers on the night of 10/11 February 1944, but this inflicted no damage on the battleship.

The Royal Navy attacked Tirpitz in the Kaafjord between September 1943 and August 1944. On 23 September 1943, the crews of two British midget submarines penetrated the defences around the battleship in 'Source' and placed explosive charges in the water beneath her. This attack caused extensive damage to Tirpitz, putting her out of service for six months. Further midget submarine attacks were not considered feasible, and an air raid designated 'Tungsten' was undertaken by Royal Navy aircraft carriers on 3 April 1944 as repairs to the battleship neared completion. Tirpitz did not suffer heavy damage in this operation, but was out of action for several more months while repairs were effected. The Home Fleet sortied to attack the Kaafjord on a further four occasions between April and July: all but the last of these operations were frustrated by bad weather, and the 'Mascot' raid on 17 July did not inflict any damage on Tirpitz. Four more carrier attacks targeting Tirpitz were undertaken between 22 and 29 August as 'Goodwood' (ii), but again resulted in the infliction of only minor damage on the battleship.

Senior Royal Navy officers attributed the failure of the raids between April and August 1944 to the shortcomings of the Fleet Air Arm’s main attack aeroplane, the Fairey Barracuda. Although 'Tungsten' had succeeded because the Germans were taken by surprise, during subsequent raids the slow speed of the Barracuda gave the Kaafjord’s defenders the time they needed to cover the area with artificial smoke before the British aircraft arrived over the target area. Moreover, the Barracuda was unable to carry any bomb large enough to cause significant damage to Tirpitz when hits were achieved. As a result, before and after 'Goodwood' (ii), further consideration was given to using the smaller but considerably faster Mosquito to attack the battleship: under initial plans developed in mid-August these aircraft would have been launched from aircraft carriers and attacked Tirpitz with 2,000- or 4,000-lb (907- or 1814-kg) armour-piercing bombs before flying farther to the east to reach a base in northern Russia. These proposals came to nothing as the Supreme Allied Commander of the Allied Expeditionary Force, General Dwight D. Eisenhower, was unwilling to release any Mosquitos in July as this might weaken the 'Overlord' effort, and in August the Mosquito was also judged to be too slow to reach the Kaafjord from aircraft carriers before it was covered by smoke.

In August RAF Bomber Command, which controlled the force’s heavy bombers, began developing plans to strike Tirpitz in the Kaafjord. During a meeting on 28 August between Harris and the Air Marshal Douglas Evill, the vice-chief of the Air Staff, Air Marshal Sir Douglas Evill, to discuss the feasibility of dispatching Mosquito bombers against the Kaafjord, Harris stated that he had ready a plan to attack the battleship with Lancaster bombers. Under this plan, 24 Lancaster machines were to depart a base in the far north of Scotland, bomb Tirpitz, and return to an airfield in the Shetland islands group. If the return trip was judged impossible, the bombers would instead land at Murmansk in northern Russia before returning to the UK. RAF Bomber Command’s staff had contacted Soviet officials about the latter element of the plan, and concluded that it would be feasible. Owing to the complex nature of the mission, RAF Bomber Command’s two special duties units, Nos 9 and 617 Squadrons, would conduct the attack. This proposal was viewed favourably, and was approved by Eisenhower’s headquarters on 5 September.

Air Vice Marshal the Hon. Ralph Cochrane’s No. 5 Group was assigned responsibility for planning the attack on Tirpitz late in August. The group’s staff officers judged that it was essential for the raid to take the Kaafjord’s defenders by surprise so that the battleship could not be covered in smoke by the time the bombers arrived. As the seaward approaches to the fjord were covered by a comprehensive radar network, the planners decided that the attack force should approach the region overland from the south-east and at a high speed to limit the defenders' warning time to eight minutes or less. As a result of the difficulty of damaging the heavily armoured battleship, the main weapon selected for this operation was the 12,000-lb (5443-kg) Tallboy bomb, the largest such weapon then in service with the RAF and capable of penetrating well-protected targets, but some of the bombers were to be armed with 400-lb (181-kg) 'Johnnie Walker' (commonly called 'JW') self-propelled mines, which were designed to be dropped from aircraft and move through the water by rapidly diving and surfacing until they struck their target. The Tallboy had been successfully used by No. 617 Squadron against tunnels and other facilities, but the mines had not been used in combat, and Harris and several other senior RAF officers were sceptical of their effectiveness.

As test flights undertaken by No. 617 Squadron proved that it was not possible to make a return trip to the Kaafjord from Scotland, and an evaluation of the main airstrip in Shetland determined that it was unsuitable for Lancaster operations, No. 5 Group’s staff officers judged that it would be necessary for the aircraft to refuel in the USSR. Detailed investigation of the airstrips near Murmansk found that they were at best only marginally suitable for heavy bombers and possessed almost no accommodation or aircraft servicing facilities. Moreover, the airstrips were vulnerable to attack from fighters operating from nearby German bases. Instead, it was decided that the attack force should fly over northern Sweden and Finland after raiding the Kaafjord and refuel at Yagodnik airstrip, which was on an island near Arkhangyel’sk. This plan was accepted by the Air Ministry on 6 September. Soviet naval aviation offered to attack German fighter bases at the same time as the British bombers arrived over the target area, but No. 5 Group rejected this proposal and requested that Soviet aircraft not fly near Kaafjord and thereby avoid alerting the Germans. Also early in September, five aircraft from No. 192 Squadron, which specialised in monitoring German radars, conducted sorties to locate German radar stations in northern Norway and identify any gaps in their coverage.

The operation order setting out how the raid was to be conducted was issued by No. 5 Group on 7 September. It stated that the Kaafjord was believed to be protected by 16 heavy and 16 light Flak guns, as well as by Tirpitz's guns, and that it took the defenders some 10 minutes to cover the battleship with a smoke screen. The attack force was to be organised into two groups. Force A, comprising 12 Lancaster bombers from No. 9 Squadron and an equal number from No. 617 Squadron, and each armed with a single Tallboy, was to continue to Yagodnik after bombing. Force B was to comprise six Lancasters from each of the squadrons, each carrying a single 'JW' mine, and return directly to either Scotland or the Shetland islands group. A Lancaster of the RAF Film Unit, which was attached to the RAAF’s No. 463 Squadron, would accompany Force B and also return to the UK after the bombers completed their attack. It was intended that the attack would be conducted in daylight, and that the Lancaster bombers would assemble into formations near the Kaafjord before attacking. If the fjord was covered by cloud or smoke, Force A was ordered to not drop its valuable bombs and continue onto Yagodnik. Force B was directed to drop the 'JW' mines regardless of cloud or smoke cover as long as an aiming point could be identified. The entire attack group was to maintain strict radio silence. Two Consolidated Liberator transport aircraft of No. 511 Squadron were assigned to carry maintenance personnel and supplies from the UK to Yagodnik, and a Mosquito outfitted for the photo-reconnaissance task from No. 540 Squadron would scout ahead of the attack force. The aircrews were briefed on this plan on either 8 or 9 September. Group Captain C. C. McMullen, the commander of No. 9 Squadron’s home base of RAF Bardney, was appointed the overall leader of the detachment, and No. 617 Squadron’s commanding officer, Wing Commander 'Willy' Tait, was selected to lead the strike force.

To provide pre-attack weather reports and post-attack damage assessments from the Kaafjord, agents on the ground were needed, but the last radio group in the area had been extracted in May 1944. The first attempt at re-establishing a presence near Tirpitz occurred in August 1944, when a Norwegian of the Secret Intelligence Service agent was despatched to the nearby village of Alta. The agent infiltrated from neutral Sweden together with a radio transmitter codenamed 'Sinding', but managed to begin transmissions to the UK only on 22 September, too late for the preparation stage for the operation. In a second attempt at establishing an agent group in the area, the Norwegian SIS agents Knut Moe and Anton Arild were dropped by parachute into the wilderness between the Kaafjord and Alta on 8 September by a US Liberator diverted from 'Carpetbagger' operations. During the drop the agents became separated from most of their equipment, with the exception of the radio transmitter. Without weapons and equipment, the agents were forced to relocate to the village of Bossekop, where Moe’s mother lived. The radio transmitter operated by the SIS team, codenamed 'Aslaug' was operational by 13 September, sending weather reports to the UK every other hour. As well as reporting on the weather, Moe and Arild transmitted assessments of the damage Tirpitz had suffered in the air attacks before 'Paravane'. Local contacts helped the agents in spying on Tirpitz before and after the 15 September attack. By the time of the attack, Moe and Arild had established an observation post overlooking Tirpitz's anchorage in the Kaafjord.

The 'Paravane' attack force was placed on alert on 8 September. Good weather was vital, and the crews waited at their home bases for the next two days as forecasts proved unfavourable. Meanwhile, the Air Ministry, No. 5 Group and British military liaison officers in the USSR continued to work with the relevant Soviet headquarters to finalise the arrangements for Force A’s flight from Norway to Yagodnik.

Later forecasts suggested that weather conditions in the Kaafjord area were changing rapidly, and during the morning of 11 September Harris judged that it would not be feasible to launch the bombers from Scotland with confidence that the Kaafjord would be free of cloud by the time they arrived. Accordingly, he decided to change the plans for the operation, with all of the bombers now flying to Yagodnik first and then mounting the attack from that airfield. Harris instructed the attack force to depart that afternoon, before advising the Air Ministry or Soviets of the change in plans.

Both bomber squadrons began to take off at 17.00. No. 9 Squadron despatched 18 Lancaster aircraft from Bardney and No. 617 Squadron sent 20 Lancaster aircraft from Woodhall Spa: of the bombers, 26 were armed with Tallboy bombs and 12 with 'JW' mines. The Lancaster of the Film Unit also departed from Bardney carrying three RAF cameramen as well as an Associated Press journalist and a BBC radio reporter. The Liberator aircraft departed Bardney just before the bombers, carrying McMullen, maintenance personnel and spare parts. The Mosquito of No. 540 Squadron left Bardney on the following day.

Despite the fact that they had not been notified of the new plan until after all of the Lancaster bombers were airborne, the Soviet military quickly agreed to the changed arrangements.

The passage of the Lancaster bombers to Yagodnik initially proceeded well. After departing their bases, the 39 aircraft flew north to the Shetland islands group before turning to the east. During the early stages of the flight one of No. 9 Squadron’s aircraft was forced to dump its Tallboy into the North Sea after it became decoupled from its mounting and the bomber returned to base. The remaining aircraft passed over neutral Sweden where the aircrew, most of whom had only conducted night flying over countries observing black-outs, were pleased to see illuminated towns. After overflying the Gulf of Bothnia, the Lancaster aircraft continued over Finland toward the USSR. Several aircraft were engaged by Swedish, Finnish and Soviet Flak defences, but only one suffered any damage.

Despite pre-departure forecasts of good weather, however, the force encountered thick cloud after entering Finnish airspace, and this lasted for the rest of the outward flight. The conditions made navigation difficult, and forced the pilots to fly at a low altitude so that ground features could be used to determine their location. Only 26 of the Lancaster bombers were able to locate Yagodnik and land there during the morning of 12 September, the other 13 touching down at other airfields or crash landing in open spaces. Five or six of the last were written off, and two of the seven which eventually reached Yagodnik were too badly damaged to be used in the operation. Despite the number of crashes, none of the airmen on board these aircraft suffered injury. McMullen recorded that it was 'extraordinary that so few crashes occurred' given the adverse circumstances, and that the majority of the aircraft despatched could have been destroyed.

After concentration at Yagodnik, the British force was readied to attack the Kaafjord. The Soviet personnel at the airfield provided considerable assistance, but for lack of adequate equipment the process of refuelling the aircraft could not be completed until 13 September. The ground crews also repaired some of the damaged bombers, in some cases with parts salvaged from the aircraft which had been written off. The British officers and senior non-commissioned officers were accommodated in a boat, and all other personnel slept in overcrowded underground huts. Both the boat and the huts were infested with bed bugs, and almost all of the airmen were bitten before the accommodation was fumigated by the detachment’s medical officer.

By the morning of 14 September, 26 Lancaster aircraft from the attack force and the film unit were ready: 20 of the bombers were armed with Tallboys and the other five with 'JW' mines. The Mosquito took off and headed to the Kaafjord at 02.10, but the planned departure of the bombers at 08.00 am cancelled after the Mosquito had returned to Yagodnik at 06.45 and reported that conditions over the target area were unsuitable. For the rest of the day the Soviets provided hospitality including a formal lunch, a football tournament and a film during the evening. Work on repairing the damaged Lancaster machines also continued on 14 September, and an additional Tallboy-armed aeroplane was ready by the next morning.

The plan for the raid was further modified while Nos 9 and 617 Squadrons were waiting at Yagodnik. The Lancaster bombers were to take off together, and fly at low altitude until they reached the Finno-Soviet frontier to avoid detection by German radar stations located around Kirkenes. The Force A aircraft were then to climb to around 20,000 ft (6095 m) and the six Force B bombers to 16,000 ft (4875 m). Three Lancaster aircraft from No. 9 Squadron were to proceed ahead of the main body to determine wind conditions over the Kaafjord. When the main body reached a position some 60 miles (100 km) from the fjord, at which point the British expected that the Germans would have detected the bombers, the Lancaster aircraft were to move into attack formation and start their bombing run. It was decided that all of the aircraft should attack simultaneously, with Force A flying in four groups of five aircraft which would approach the Kaafjord from the south and drop Tallboys from altitudes between 14,000 and 18,000 ft (4265 and 5485 m). Force B was to fly in two lines abreast, pass over the fjord from south-east to north-west, and release the 'JW' mines from at altitudes between 10,000 and 12,000 feet (3095 and 5330 m).

No. 540 Squadron’s Mosquito reconnoitred the Kaafjord again during the morning of 15 September, and at 07.00 local time reported that conditions were suitable for an attack. The 27 bombers and the Film Unit Lancaster began to take off shortly after this. The aircraft flew in a loose formation and the journey to northern Norway went as planned, though six Lancasters were forced to abort and return to Yagodnik. Despite passing near several German bases, the British force was undetected and no German fighters were airborne over the Kaafjord at the time of the attack.

The Kaafjord’s defenders detected the Lancaster aircraft some 10 minutes before they arrived, and the protective smokescreen was beginning to form when the attack started at 10.55. Only the first group of Lancaster bombers, led by Tait, was able to aim their bombs at Tirpitz before the battleship was obscured by smoke. It is believed that the bomb dropped from Tait’s aircraft struck the battleship, and the other bombs dropped by this group landed in the water close alongside. All the other Force A aircraft aimed their Tallboys at the anti-aircraft gunfire rising from the ship, and dropped 17 of the weapons. Several Lancaster bombers made more than one pass over the target area as their bomb-aimers sought to locate Tirpitz or as technical problems prevented their Tallboys from being dropped on the initial pass.

Force B began its attack after the Tallboy-armed Lancaster bombers had completed their attack so that the shock waves from bomb explosions did not prematurely set off the 'JW' mines. As none of the Force B aircrew were able to spot Tirpitz through the smokescreen, they dropped the mines on the battleship’s estimated position. These weapons did cause no damage. The smokescreen over the Kaafjord prevented the Allied aircrew from being able to assess the results of their bombing, though several large spouts of water and explosions were observed. Tait was also pleased to see a column of black smoke rising through the smokescreen. Some of the bombs and mines landed up to 1 mile (1.6 km) from the battleship, however. Tirpitz's Flak guns and a further 98 guns located in nearby shore batteries and warships fired on the bombers throughout the attack, but only four Lancasters sustained damage.

All of the Lancaster aircraft had completed their attacks by 11.07, and the 21 bombers began the return journey to Yagodnik. The Force A aircraft which had not been able to bomb brought their Tallboys back. This flight proved uneventful, and all 27 Lancasters landed at Yagodnik in the evening. The Film Unit aeroplane flew straight from the Kaafjord to the UK, and arrived at its home station after a 15.5-hour flight: this was the longest operational Lancaster mission of World War II.

The Mosquito flew a reconnaissance sortie over the Kaafjord on the afternoon of 15 September, arriving at about 13.30. Its crew found that the fjord was covered with cloud and smoke. They could briefly see Tirpitz, and reported that no damage was evident to the battleship, which remained afloat. The Mosquito undertook more reconnaissance sorties on 16 September, but the fjord was completely obscured on all occasions. McMullen considered launching a second attack, but decided against doing so as only two Tallboys and one load of JW mines were available.

Tirpitz was rendered unfit for combat by 'Paravane'. The Tallboy bomb that struck the battleship passed through the foredeck and hull, and exploded in the water on the starboard side of her bow. The resultant damage wrecked the bow and left the battleship’s forward compartments flooded with 2,000 tons of water. The explosions of several other Tallboys in the water near Tirpitz also buckled some of her hull plates and bulkheads. At five men killed and 15 wounded, the battleship’s casualties were not heavy. The physical damage was assessed as needing nine months' worth of work to repair. After reporting on the damage, Tirpitz's commanding officer, Kapitän Wolf Junge, recommended to the German navy’s high command that the battleship be removed from service.

The attack force returned to the UK in several groups. Tait led 16 Lancaster aircraft out of Yagodnik during the evening of 16 September: most of these aircraft flew over southern Finland, Sweden and Denmark, but one strayed off course and crashed on a mountain near Nesbyen in Norway, killing all 11 men on board: these were the only Allied casualties of 'Paravane'. Nine other Lancaster aircraft departed on 17 September, followed by five on the following day and the final on 21 September. The remaining Lancaster machines had been judged to be damaged beyond repair, and were handed over to the Soviets. The Mosquito, which had been damaged by anti-aircraft fire during a sortie over the Kaafjord, returned on 26 September after repairs had been effected. The two Liberator transports were the final aircraft to depart, and flew out of Yagodnik carrying McMullen on 27 September.

After the attack, the British intelligence services sought to determine the extent of Tirpitz's damage. Late in September, Norwegian SIS agents in the Kaafjord area reported that the battleship had been struck by a bomb and appeared damaged. Intercepted German radio traffic was decoded on 25 and 29 September, and revealed that Tirpitz had suffered a single hit from a large bomb. Photographs taken by the No. 540 Squadron Mosquito and a Soviet aeroplane on 20 September indicated that the bow of the ship was damaged, although it was not possible to decide how severe this damaged was. Drawing on this evidence, the Royal Navy’s Naval Intelligence Division concluded on 30 September that Tirpitz had 'almost certainly' been struck by a Tallboy and may have been further damaged by near misses, and that the damage to the ship may have been 'considerable' and rendered her unable to put to sea. A report from a Norwegian agent on 30 September was more specific, stating that Tirpitz had suffered a direct hit, which had opened a 56-ft (17-m) gash on her bow. Further agent reports early in October provided little new evidence. By a time late in October, with no major German warships left in the Kaafjord, the agents operating the 'Aslaug' transmitter left the area, sending their last transmission to the UK on 22 October. Moe and Arild made their way on foot across the Finnmarksvidda plateau to Kautokeino and from there through Finland to Karesuando in Sweden, which they reached on 5 December. The agents made their journey without resupplies of food as 'Carpetbagger' had ceased to use Soviet air bases after a Liberator was inadvertently shot down by a Soviet fighter during a follow-up operation to Finnmark shortly after the insertion of Moe and Arild.

A meeting involving Dönitz was held in Berlin on 23 September to discuss the damage to Tirpitz. Dönitz was informed that it would take nine months to repair the ship, and that all the work had to be done in the Kaafjord as the battleship would be extremely vulnerable if she tried to make passage to a major port. As Soviet land forces were also advancing rapidly toward northern Norway, Dönitz judged that it was not feasible either to return the ship to ocean-going service or to retain her in the Kaafjord. Instead, he decided that Tirpitz should be redeployed for use as a floating artillery battery for the defence of Tromsø. The commander of the German naval forces in northern Norway, Konteradmiral Rudolf Peters, was accordingly ordered to anchor Tirpitz at a location near Tromsø where the depth of the water was too shallow to allow the battleship sink completely if she suffered further damage.

As the intelligence available to them was not conclusive, the Allies believed that Tirpitz still posed a possible threat. Accordingly, Nos 9 and 617 Squadrons made two further attacks on the battleship after she moved to Tromsø on 15 October. These were simpler to undertake than 'Paravane' as the port lay within the range of Lancaster bombers flying from airfields in northern Scotland. The first of these raids was 'Obviate' on 29 October and caused only minor damage to the battleship. During the subsequent 'Catechism' attack on 12 November, Tirpitz was struck by several Tallboy bombs and capsized with heavy loss of life among her crew.