1942 1943 1944 1945 Associated articles Operation Obviate was an unsuccessful British air raid of World War II which targeted the German battleship Tirpitz.

It was conducted by Royal Air Force heavy bombers on 29 October 1944, and sought to destroy the damaged battleship after she moved to a new anchorage near Tromsø in northern Norway.

As Allied intelligence was unaware that the battleship could no longer operate at sea and warships needed elsewhere were being retained in British waters to counter her, it was decided to make another attack.

After a period of planning and preparations, 38 British bombers and a film aircraft departed from bases in northern Scotland during the early hours of 29 October.

The attack took place that morning, but was frustrated by clouds over the Tromsø area which made it difficult for the Allied airmen to accurately target Tirpitz.

From early 1942, the German battleship Tirpitz posed a significant threat to the Allied convoys transporting supplies through the Norwegian Sea to the Soviet Union.

Tirpitz could also potentially attempt to enter the North Atlantic to attack Allied convoys travelling to the United Kingdom, as her sister ship Bismarck had sought to do in May 1941.

[2][3] To counter these threats, 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.

Royal Air Force (RAF) heavy bombers made four unsuccessful raids on the battleship between January and April 1942 while she was stationed at Fættenfjord.

During Operation Source on 22 September 1943, she was severely damaged by explosives placed beneath her hull by Royal Navy personnel who had used midget submarines to penetrate Kaafjord.

This operation employed Avro Lancaster heavy bombers armed with Tallboy bombs and "Johnnie Walker" mines, and was mounted from Yagodnik in the Soviet Union.

[10] A meeting involving Grand Admiral Karl Dönitz, the commander of the German Navy, was held in Berlin on 23 September to discuss Tirpitz.

Dönitz was informed that it would take nine months to repair the ship, and that all the work had to be done at Kaafjord as the battleship would be extremely vulnerable if she tried to sail to a major port.

As Soviet forces were rapidly advancing towards northern Norway at that time, Dönitz judged that it was not feasible to either return the ship to ocean-going service or retain her at Kaafjord.

Instead, he decided to use Tirpitz as a floating artillery battery to defend Tromsø against amphibious landings and bolster a defensive line which was being prepared in the Lyngenfjord area.

[16] The commander of the German Navy's task force in northern Norway, Konteradmiral Rudolf Peters, was directed to position Tirpitz at a location near Tromsø where the water was shallow enough to prevent the battleship from sinking completely if she suffered further damage.

[17] This location lacked the natural defences Tirpitz had enjoyed at her previous Norwegian bases where she had sheltered in fjords which had steep mountains rising from the sea; this had made it difficult for attacking aircraft to spot and target the battleship.

[18] To prepare Tirpitz for the 170-mile (270 km) voyage south-west, a repair ship was sent to Kaafjord and helped the battleship's crew to weld steel plates over the hole in her hull.

While Tirpitz was able to move under her own power, the flotilla included ocean-going tugboats tasked with towing the battleship if her damaged bow broke off.

[23] In response to these reports, the British aircraft carrier HMS Implacable was dispatched from the Home Fleet's main base at Scapa Flow on 16 October tasked with confirming the location of Tirpitz.

All of the aircraft selected for the operation were fitted with powerful Rolls-Royce Merlin 24 engines, which were hurriedly obtained from maintenance units and airfields across the UK.

[31] The operational order stated that the attack was required as "it appears likely that the Germans may attempt to get the battleship back to a base in Germany, where the necessary repairs and refit can be carried out".

[34][35] After the rendezvous was completed and if weather conditions remained suitable, the bombers would proceed to Tromsø and attack Tirpitz if she could be visually spotted or, if obscured, her location confirmed relative to unobstructed landmarks.

[31] Group Captain Colin McMullen was selected to command the ground crew and aircrew ahead of the start of the attack, a role he had also played in Operation Paravane.

If any of the bombers experienced engine problems or lacked sufficient fuel to return to the UK, they were to proceed to the Soviet airfields at Vaenga or Yagodnik.

5 Group also requested that three Royal Navy destroyers be stationed along the return route from Tromsø to rescue the crews of any bombers forced down over the Norwegian Sea.

In the evening of 27 October, the aircrew selected for Operation Obviate were briefed on the plan and told they would proceed to the Scottish airfields the next morning.

A photo reconnaissance Mosquito flew over Tromsø that morning, and confirmed that Tirpitz was still moored off Håkøya and that weather conditions remained favourable for an attack.

Sixteen aircraft from the squadron released Tallboys aimed at Tirpitz's estimated position, several making multiple bomb runs before attacking.

German post-battle reports broadcast by radio which were intercepted and decoded confirmed that damage was limited to the propeller shaft and rudder.