The repair of damage caused by the X-Craft attack was complete by the beginning of March, 1944; Tirpitz then began a series of trials to test the efficacy of these repairs. These were to have culminated in prolonged sea trials in early April.
The first movements in Altenfjord were observed by our reconnaissance aircraft and C.-in-C. Home Fleet was therefore asked to lay on a bombing attack using Fleet Air Arm Aircraft. This attack took place on 3 April. Forty Barracudas were escorted by 81 Corsair, Hellcat and Wildcat fighters. Enemy reconnaissance was avoided by sending the Carrier force about a day behind a large Russia bound convoy. Complete surprise was achieved, the striking force reached the ship just as she was about to get underway for the open sea trials. Weather conditions were good.
The first strike began its attack at 0530 just as the second anchor was being weighed. Before a smoke-screen could be developed and before the flak batteries had been fully manned, the accompanying fighters were strafing the upperworks with machine-gun fire. Diving attacks by Barracudas carrying 1,600 lb. armour-piercing, 500 lb. semi-armour-piercing, and medium capacity bombs followed. A few 600 lb. anti-submarine bombs were also used. In all, nine hits (with one profitable near miss) were scored by this strike on the German ship. The second strike attacked at 0630 but found Tirpitz obscured by smoke, this time five hits and three near misses were obtained.
Unfortunately, owing to the low height from which the bombs were released (the Germans gave figures between 300 and 1300 ft.) none succeeded in penetrating the armour deck – in fact only two reached it. Two other bombs ricochetted off the 2-in. thick upper deck, and one lodged half-way through this deck. As all the vital parts of a large capital ship lie below armour, only superficial damage to living spaces and other unessential compartments was caused by the direct hits. This damage, however, was fairly extensive and several large fires resulted. Heavy casualties were caused both by the bombs and by the fighters. The greatest nuisance value was achieved by a bomb, probably 1600 lb. A.P., which struck the water a few ft. from the ship’s side, penetrated the side plating beneath the armour belt and detonated near the main longitudinal protective bulkhead. This bomb flooded bulge compartments nearby and extensive work by divers was required to effect a repair.
In about a month Tirpitz was again operationally fit, no significant damage to armament or main machinery having been sustained in the attack. About two more months were required to complete the less important repairs.
Fleet Air Arm Attacks
Although Tirpitz showed no signs of leaving the Kaa Fjord it was suspected that the attack on 3 April had not inflicted any vital damage as it was realised that the bombs might not have been dropped from a height sufficient to enable them to penetrate the thick deck armour. Intelligence reports and reconnaissance photographs also indicated that the battleship was ready for further action. Attacks on the above dates were therefore made by bomber forces flown from Carriers of the Home Fleet in an attempt to prolong Tirpitz’s stay in the Kaa Fjord.
The first of these attacks developed during the early hours of 17 July, the Arctic summer being then at its height. Warning of the attack had been received about half-an-hour before the planes arrived and all necessary preparations, including the smoke-screen, had been made in Tirpitz. The aircraft dropped 1600 lb. armour piercing and 500 lb. bombs; no hits were scored.
Two attacks made at noon and in the evening of 22 August were also anticipated; again Tirpitz was enveloped in a smoke-screen, and no hits were registered. 500 lb. semi-armour-piercing bombs were used in these strikes. The attack on 24 August was made during the afternoon, 80 aircraft being employed. The defences were once more in fully effective operation when the planes reached the Tirpitz, but this time, despite the difficulty of aiming through smoke, two of the 23 large armour-piercing bombs and 10 smaller semi-armour-piercing bombs which were dropped, scored hits. One of these detonated on the armour roof of ‘B’ turret which was only slightly damaged but the other – a 1600 lb. armour-piercing bomb – hit the port side of the upper deck abreast the forward conning tower, and penetrated through the armour deck to the lower platform (inner bottom) where it came to rest but – because of a fuse failure – did not detonate. Had this bomb been effective the main fire control rooms, switchboard rooms, etc., would have been put out of action. The resultant flooding would probably have extended to the forward auxiliary boiler room. In their official report on this attack the Germans stated:
“The attack on 24 August, 1944, was undoubtedly the heaviest and most determined so far experienced. The English showed great skill and dexterity in flying. For the first time they dived with heavy bombs. During the dive-bombing, fighter planes attacked the land batteries which, in comparison with earlier attacks, suffered heavy losses. The fact that the armour-piercing bomb of more than 1,540 lbs. did not explode must be considered an exceptional stroke of luck, as the effects of that explosion would have been immeasurable. Even incomplete smoke screening upsets the correctness of the enemy’s aim, and it has been decided from now on to use smoke in wind strengths up to 9 m. per second irrespective of possible gaps.”
The last of this series of attacks made on 29 August by 26 Barracudas, seven Hellcats, 10 Fireflies and 17 Corsairs from Indefatigable and Formidable, was carried out in exactly similar conditions. No hits were obtained.
Attack by Bomber Command Lancasters
A great improvement in technique was made on 15 September, 1944, when Tirpitz was attacked with the newly-developed Tallboy bombs. These massive bombs contained 5100 lbs. of desensitized torpex in a comparatively thin streamlined case and were fitted with fuses having a slight time delay of 0.07 sec. Although it was anticipated that they might be damaged in passing through the heavy deck armour, it was hoped that the very large charge would compensate for any loss of efficiency and that even near misses would have considerable destructive value.
The operation was carried out by about 30 Lancasters which had previously flown from Scotland to North Russia, where they were based for the attack. The aircraft approached the target at high altitude from the South-East, descending to about 12,000 ft. for their attacks which they made in groups of about six, in close formation. The battleship was found moored at her berth; she had been given warning by shore radar installations so that shortly after the attack commenced an extensive and effective smoke-screen covered the greater part of the fjord, leaving only the boom surrounding Tirpitz and small portions of the ship visible. The main armament, directed by the shore radar installations, was used for putting up a barrage in way of the attacking aircraft.
Out of the 21 heavy bombs dropped, only one fell sufficiently close to Tirpitz to damage her. This bomb hit the upper deck on the extreme starboard side some 50 ft. abaft the bow, passed out through the flare of the forecastle into the water and detonated below keel level close to the ship. The explosion wrecked a large portion of the fore end, particularly that part below the waterline, and as a result of this damage the first 120 ft. of the ship became flooded to the waterline. Although this single hit did not seriously affect either machinery or armament, the damage to the fore end of Tirpitz could not be repaired without docking her, and she was henceforth unfit to undertake a voyage in the open sea and in consequence ceased to be an effective fighting unit.
The following resume, extracted from the translation of a captured German document shows the German reaction to this attack:–
“It was estimated that repairs, if they could be carried out without interruption, would take at least nine months.”
“It was eventually decided at a conference on 23 September, 1944, at which the C.-in-C. and Naval War Staff were present, that it was no longer possible to make the Tirpitz ready for sea and action again. It was therefore considered that, in order to preserve the remaining fighting efficiency of the ship, she should be used as a reinforcement to the defences in the Polar Area. For this purpose Tirpitz was to be moved as soon as possible to the area west of Lyngenfjord, moored in shallow water and brought into the operation as a floating battery. A suitable berth had to be selected which would be reasonably secure and would offer favourable operational possibilities for the ship’s armament. Adequate anti-aircraft, smoke-cover and net protection were to be provided. Makeshift repairs were to be made and the Tirpitz moved with the assistance of powerful tugs.”
“The operation of moving the Tirpitz was carried out on 15 October, 1944. A berth was selected near Tromsø, Haakoy net enclosure, by F.O.I.C., Polar Coast in co-operation with Flag Officer, First Battle Group. The ship was protected against underwater attacks and aerial torpedoes by means of a double net barrage. Shore anti-aircraft guns and smoke-screen units were moved from Kaa Fjord to Tromsø. As the ship was only partially seaworthy, the crew, particularly the engine room complement, was decreased. It was found that there were varying depths of water at the selected berth; in particular there was a hollow below the midship section. Too many difficulties would have arisen if the ship were to be moved again, so it was decided to fill in the hollow till the water was 2 m. deep below the keel. Work was commenced by dredgers on 1 November, and by 12 November about 14,000 cm. had been filled in at both sides below the midship section.”
Second Bomber Command Tallboy Attack
On 29 October, 1944, the lame Tirpitz now moored at Tromsø off Haakoy Island was again attacked by Bomber Command. A force of 32 Lancasters flying this time from British bases and carrying one Tallboy each, began bombing her at 0850. The target was seen obliquely as the aircraft approached, but low clouds obscured her from view during the bombing runs and made accurate bomb-aiming impossible. Once again, prior warning of the approaching raid was received and the ship was in a high state of readiness when the attack commenced. No direct hits were scored but the end was brought one stage nearer by a near miss off the port quarter, which damaged the port shaft and rudder and flooded about 100 ft. of the aft end of the ship on the port side.
Final Bomber Command Attack
The struggle between the British armed forces and Tirpitz came to an end on 12 November, 1944, when Bomber Command aircraft executed what was undoubtedly one of the most effective British air operations of the late war. 29 Lancasters, again carrying one 12,000 lb. M.C. bomb each, attacked the ship as she lay in her anchorage at Tromsø. Bombing commenced at 0941 and finished eight minutes later in clear weather and excellent visibility. Tirpitz had received ample warning by radio of the approach of the bombers and was again prepared when the attack developed. Intense anti-aircraft fire was augmented from nearby flak ships and shore batteries, but there was no effective smoke-screen. The bombing runs were made at heights varying between 12,500 ft. and 16,500 ft. Tirpitz received severe structural damage from, at least, two direct hits and one near miss, and as a result of this damage she capsized to port about ten minutes after the first bomb was dropped. Part of the starboard side of her hull is still to be seen above the surface – a reminder of the inability of a capital ship without adequate fighter cover to resist a determined and concentrated attack with modern airborne weapons.