Bismarck-class battleship

The Bismarck-class battleships were 251 m (823 ft 6 in) long overall and 241.60 m (792 ft 8 in) long at the waterline. The ships had a beam of 36 m (118 ft 1 in), and a designed draft of 9.30 m (30 ft 6 in); the draft at standard displacement was 8.63 m (28 ft 4 in), and 9.90 m (32 ft 6 in) at a full load. The ships had a designed displacement of 45,950 metric tons (45,220 long tons); Bismarck's standard displacement was 41,700 t (41,000 long tons), and when fully laden, the ship displaced 50,300 t (49,500 long tons). Tirpitz was heavier, displacing 42,900 t (42,200 long tons) and 52,600 t (51,800 long tons), respectively. The ships had a double bottom for 83 percent of the length of the hull, and twenty-two watertight compartments. The ships were 90 percent welded construction.[1] The stern was weakly constructed; this had significant consequences on Bismarck's only combat mission.[21] The building cost of Bismarck was 196 million Reichsmarks, while Tirpitz was slightly cheaper at 191.6 million Reichsmarks. Both ships had seven searchlights.[22]

The ships were very stable, primarily because of their wide beam. The ships suffered from only slight pitching and rolling, even in the heavy seas of the North Atlantic. Bismarck and Tirpitz were responsive to commands from the helm; they were capable of maneuvering with rudder deflections as small as 5°. With the rudder completely over, the ships heeled only 3°, but lost up to 65% of their speed. The ships handled poorly at low speeds or when traveling astern. As a result, tugs were necessary in confined areas to avoid collisions or grounding. The ships had a standard crew of 103 officers and 1,962 enlisted sailors, although the crew of Tirpitz expanded to 108 officers and 2,500 men by 1943.[22] The ships carried smaller boats, including three picket boats, four barges, one launch, two pinnaces, two cutters, two yawls, and two dinghies.[3]

Although both ships were from the same class, there were substantial differences between Bismarck and Tirpitz. The funnel cap on Bismarck was silver-grey, however the cap on Tirpitz was always black. The two cranes on Bismarck were sited 3.5 m (11 ft) further outboard and 3 m (9.8 ft) further aft, and Tirpitz mounted her two cranes on the superstructure deck. The 10.5 cm (4.1 in) flak guns (starboard II and port II) were mounted 5 m (16 ft) further inboard on Bismarck. When Bismarck was launched she had a straight stem, and Tirpitz had the Atlantic bow. Both ships had a degaussing coil fitted prior to commissioning. Bismarck had a single aircraft hangar on each side of the funnel and a double hangar at the base of the mainmast.[6] Tirpitz had two double hangars on each side of the mainmast base.[23] Four minesweeping paravanes were carried, two on either side of the aft superstructure deck. These were used in conjunction with the bow protection gear.[24]

Bismarck in drydock, showing the three-shaft arrangement

The Bismarck-class ships both had three sets of geared turbine engines; Bismarck was equipped with Blohm & Voss turbines, while Tirpitz used Brown, Boveri, and Co. engines. Each set of turbines drove a 3-bladed screw that was 4.70 m (15 ft 5 in) in diameter. The three-shaft arrangement was chosen over a four-shaft system, as was typically used on foreign capital ships, since it would save weight. At a full load, the high and medium-pressure turbines ran at 2,825 rpm, while the low-pressure turbines ran at 2,390 rpm. The ships' turbines were powered by twelve Wagner ultra high-pressure, oil-burning water-tube boilers. Bismarck and Tirpitz were originally intended to use electric-transmission turbines that would have produced 46,000 shp (34,000 kW) apiece. These engines would have provided for a higher top speed, but at the cost of greater weight. The geared turbines were significantly lighter, and as a result had a slight performance advantage. The geared turbines also had a significantly more robust construction, and so they were adopted instead.[2][25]

Both ships were rated for a top speed of 30 knots (56 km/h; 35 mph); Bismarck just exceeded this speed on sea trials, reaching 30.01 knots (55.58 km/h; 34.53 mph), while Tirpitz made 30.8 knots (57.0 km/h; 35.4 mph) on trials. This difference was largely the result of a significant increase in horsepower for Tirpitz, which reached 163,023 PS (160,793 shp; 119,903 kW), compared to 148,116 for Bismarck. The two ships had different fuel stores; Bismarck was designed to carry 3,200 tons of fuel oil, but could store up to 6,400 tons of fuel in a normal configuration; with extra fuel bunkers, the fuel carried could be increased up to 7,400 tons. Tirpitz was designed to carry 3,000 tons of fuel, and with additional bunkers, was able to store up to 7,780 tons. At 19 knots, Bismarck could steam for 8,525 nautical miles (15,788 km), and Tirpitz had a maximum range of 8,870 nautical miles (16,430 km) at that speed.[1]

Robert Ballard, the discoverer of Bismarck, noted that the adoption of the three-shaft arrangement caused serious problems for Bismarck. The center shaft weakened the keel, especially where it emerged from the hull. In addition to retaining greater hull strength, a four-shaft arrangement would have allowed a greater ability to steer the ship using only propeller revolutions than the three-screw system according to Ballard.[26] During Bismarck's Atlantic operation in May 1941, the ship's rudder was disabled by a torpedo hit, and her course could not be corrected by altering screw revolutions;[27] this problem had already been revealed during sea trials, but it could not be corrected.[28]

Electric power was provided by a variety of generators, including two electric plants of four 500 kW diesel generators, two electric plants each with five 690 kW turbo-generators, one at 460 kW generator connected to a 400 kVA AC generator and one 550 kVA AC diesel generator. The generators were manufactured by Garbe, Lahmeyer & Co.[29] The electrical plant provided a total 7,910 kW at 220 volts.[3]

Bismarck's and Tirpitz's main battery consisted of eight 38 cm (15 in) SK C/34 guns in four twin turrets, Anton and Bruno in a superfiring pair forward of the superstructure and Caesar and Dora aft.[30] The turrets allowed elevation to 30°, which gave the guns a maximum range of 36,520 m (39,940 yd). The guns fired 800 kg (1,800 lb) projectiles at a muzzle velocity of 820 meters per second (2,690 ft/s).[31] The main battery was supplied with between 940–960 shells total, for approximately 115–120 shells per gun.[3] As with other German large-caliber naval rifles, these guns were designed by Krupp and featured sliding wedge breech blocks, which required brass cartridge cases for the propellant charges. Under optimal conditions, the rate of fire was one shot every 18 seconds, or three per minute.[32] The gun turrets were electrically trained and the guns were hydraulically elevated. Gun elevation was controlled remotely. The turrets required each gun to return to 2.5° elevation for loading.[33] Tirpitz was eventually provided with time-fuzed shells to combat the repeated Allied bombing attacks.[34]

The Bismarcks' use of four twin turrets (the 4 × 2 configuration) was a design practice that hearkened back to the First World War. Almost all other post-1921 capital ships had triple or even quadruple turrets, which allowed for additional heavy caliber guns, while reducing the number of turrets.[lower-alpha 4] Fewer turrets reduced the length of the battleship's armored citadel (particularly magazine length and the armor needed to protect it) and shortened the vessel itself. Although triple turrets were considered for the Bismarcks, there were concerns that the extra barrel would lower the overall rate of fire in each turret, along with fears that a single well-aimed hit could disable a larger proportion of the ship's firepower. It was also felt that four twin turrets allowed for a better field of fire and a more effective sequence of salvos.[35]

One of Bismarck's 15 cm gun turrets

The ships' secondary battery consisted of twelve 15 cm (5.9 in) SK C/28 guns mounted in six twin turrets.[36] The 15 cm gun turrets were based on the single-gun turrets used aboard the Scharnhorst class. They could elevate to 40° and depress to −10°; they had a rate of fire of around six shots per minute.[34] The 15 cm guns fired a 45.3 kg (100 lb) shell at a muzzle velocity of 875 m/s (2,871 ft/s). At maximum elevation, the guns could hit targets out to 23,000 m (25,000 yd).[31] As with the main battery guns, Tirpitz's 15 cm guns were later supplied with time-fused shells.[34]

The decision to mount low-angle 15 cm guns has been criticized by naval historians, including Antony Preston, who stated that they "imposed a severe weight penalty", while American and British battleships were being armed with dual-purpose guns.[37] Naval historians William Garzke and Robert Dulin note that "the use of dual-purpose armament would have possibly increased the number of anti-aircraft guns, but might have weakened the defence against destroyer attack, which German naval experts deemed more important."[38]

As built, Bismarck and Tirpitz were equipped with an anti-aircraft battery of sixteen 10.5 cm (4.1 in) C/33 65-caliber guns in eight twin mounts, sixteen 3.7 cm (1.5 in) C/30 guns in eight dual mounts, and twelve 2 cm (0.79 in) C/30 guns in individual mounts.[36] The 10.5 cm guns were the same weapons as used aboard the Scharnhorst class, and were mounted on the first superstructure deck. After Bismarck was sunk in 1941, two amidships guns on Tirpitz were moved forward so as to provide them with better fields of fire. The sixteen guns were guided by four fire-control directors, two just aft of the conning tower, a third positioned aft of the main mast, and the fourth directly behind turret Caesar. Tirpitz's directors were covered by protective domes, though Bismarck's were not.[39]

The ships' 3.7 cm 83-caliber guns were twin mounted and placed in the superstructure. The mounts were hand-operated and automatically stabilized for roll and pitch.[40] These guns were supplied with a total of 32,000 rounds of ammunition.[41] Bismarck and Tirpitz were initially armed with twelve 2 cm guns in single mounts, though these were augmented over time.[3] Both ships initially carried twenty-four thousand 2 cm rounds.[41] Bismarck received a pair of quadruple gun mountings, for a total of twenty 2 cm guns. Over the course of her career, Tirpitz's 2 cm battery was increased to 78 guns in single and quadruple mountings.[40] By 1944 she carried over ninety thousand 2 cm rounds.[41]

Bismarck had none, while Tirpitz was fitted with two banks of 53.3 cm (21 in) quadruple torpedo tube mounts between the end of 1941 and early 1942. Tirpitz carried 24 torpedoes.[41]

The armor plate was mainly Krupp cemented steel. This had two classifications, Ww for Wotan (soft) and Wh for Wotan hard.[42] The Bismarck-class ships had an armored belt that ranged in thickness from 220 to 320 mm (8.7 to 12.6 in); the thickest section of armor covered the central portion, where the gun turrets, ammunition magazines, and machinery spaces were located. This portion of the belt was capped on either end by 220 mm thick transverse bulkheads. The ships had an upper deck that was 50 mm (2 in) thick, and an armored deck that was between 100 to 120 mm (3.9 to 4.7 in) thick amidships, and tapered down to 60 mm (2.4 in) at the bow and 80 mm (3.1 in) at the stern.[1] The deck was mounted low in the hull, however, which reduced the volume of internal space protected by the armored citadel. This contrasted with contemporary British and American designs that featured a single thick armored deck mounted high in the ship.[21]

The forward conning tower had a 200 mm (7.9 in) thick roof and 350 mm (13.8 in) thick sides, while the range finder had an armored roof 100 mm (4 in) thick and 200 mm (8 in) thick sides. The aft conning tower had much lighter armor: the roof was 50 mm thick and the sides were 150 mm (5.9 in), while the aft range finder had a 50 mm thick roof and 100 mm sides. The main battery turrets were reasonably well-protected: the turret forward roofs were 180 mm (7.1 in) and roof rears were 130 mm (5.1 in) thick, the sides were 220 mm thick, and the faces were 360 mm (14 in) thick with 220 mm (8.7 in) thick shields.[1] These armor thicknesses were less than those of contemporary British (King George V) and French (Richelieu) designs. Conversely, the secondary battery was better-protected than most rivals.[43] The 15 cm gun turrets had 35 mm (1.4 in) thick roofs, 40 mm (1.6 in) sides, and 100 mm fronts. The 10.5 cm guns had 20 mm (0.79 in) shields.[1] The roof armour was 40mm (1.6 in).[42]

Regarding underwater protection, the armor was resistant to a 250kg TNT explosive charge. Armour depth was 5.5 meters (216.5 in), with the longitudinal bulkhead thickness being 53mm (2.1 in). Overall bottom protection had a depth of 1.7 meters (66.9 in). The citadel could resist a hit from a 38cm shell of a weight of 1,016kg fired from ranges between 10,793 meters and 21,031 meters for the machinery, and from 23,319 meters for the magazine.[44]

After Bismarck joined the fleet, plans were drawn up for a sortie into the North Atlantic, which was codenamed Operation Rheinübung (Rhine Exercise). The operation initially called for a force composed of Bismarck, Tirpitz, and the two Scharnhorst-class battleships. Tirpitz was not yet ready for service by May 1941, and Scharnhorst was being overhauled. The force was reduced to Bismarck, Gneisenau, and the heavy cruiser Prinz Eugen. Gneisenau was damaged by a British bombing raid on Brest, so it was decided that only Bismarck and Prinz Eugen would conduct the operation. Admiral Günther Lütjens was placed in command of the pair of ships.[48]

Early on the morning of 19 May, Bismarck left Gotenhafen, bound for the North Atlantic.[49] While on the trip through the Danish Belt, Bismarck and Prinz Eugen encountered the Swedish cruiser HSwMS Gotland in Kattegat; the sighting was passed through the Swedish Navy to the British naval attaché in Stockholm.[50] The British Royal Air Force conducted aerial reconnaissance of the Norwegian fjord in which Bismarck and Prinz Eugen had stopped, to confirm the sighting. While in Norway, Lütjens failed to replenish the approximately 1,000 long tons (1,016 t) of fuel Bismarck had spent on the first leg of the voyage.[51]

By 23 May, Bismarck and Prinz Eugen had reached the Denmark Strait. That evening, the British cruisers Suffolk and Norfolk briefly engaged Bismarck before dropping back to shadow the German ships.[52] At 06:00 the following morning, observers aboard Bismarck spotted the masts of the battlecruiser Hood and the new battleship Prince of Wales.[53] The British ships steamed directly towards Bismarck and Prinz Eugen, before attempting a turn to bring the two forces on a roughly parallel course. During the turn, at least one of Bismarck's 38 cm shells penetrated one of the aft ammunition magazines aboard Hood, which caused a catastrophic explosion and destroyed the ship.[54] There were only three survivors from Hood's crew of 1,421. The German ships then concentrated their fire on Prince of Wales, which was forced to withdraw. Bismarck did not emerge unscathed; a direct hit on her bow from Prince of Wales caused Bismarck to take in some 2,000 long tons (2,032 t) of water. The ship was also leaking oil, which made it easier for the British to track her.[55]

Bismarck after the battle with Hood and Prince of Wales

After retreating, Prince of Wales joined Norfolk and Suffolk; the ships briefly engaged Bismarck at around 18:00. Neither side scored a hit.[56] By this time, 19 warships were involved in the chase.[57] This included six battleships and battlecruisers and two aircraft carriers, along with a number of cruisers and destroyers.[58] After the second engagement with Prince of Wales, Lütjens detached Prinz Eugen to continue the operation while Bismarck sailed for port.[59] Shortly before midnight on 24 May, a group of Fairey Swordfish torpedo bombers from 825 Naval Air Squadron on Victorious attacked Bismarck. One torpedo struck the ship amidships, though without doing any serious damage. The shock from the explosion, coupled with Bismarck's maneuvering at high speed, damaged the temporary repairs that had stopped the flooding from the earlier battle damage. Her speed was reduced to 16 knots (30 km/h; 18 mph) to slow the flooding while repair teams fixed the reopened wounds.[60]

Early on 25 May, Bismarck doubled back past her pursuers in a wide circle. The maneuver successfully shook off the British ships, which turned west in an attempt to find the ship. Despite the maneuver, Lütjens was unaware that he had evaded the British, and so sent a series of radio transmissions, which were intercepted by the British and used to gain a rough fix on his position.[58] Due to the damage his ship had sustained, Lütjens decided to head for occupied France rather than continue his mission. On the morning of 26 May, a Coastal Command PBY Catalina flying boat spotted Bismarck 690 nmi (1,280 km; 790 mi) to the north-west of Brest; she was steaming at a speed that would put her under the protective umbrella of German aircraft and U-boats within 24 hours. The only British forces close enough to slow her down were the aircraft carrier Ark Royal and her escort, the battlecruiser Renown.[61] At approximately 20:30, a flight of fifteen Ark Royal's 820 Naval Air Squadrons Swordfish torpedo bombers launched an attack on Bismarck. Three torpedoes were believed to have struck the ship; the first two torpedoes failed to do serious damage to the ship, but the third hit jammed Bismarck's rudders hard to starboard. The damage could not be repaired, and the battleship began turning in a large circle, back towards her pursuers.[58]

An hour after the Swordfish attack, Lütjens transmitted the following signal to Naval Group Command West: "Ship unable to maneuver. We will fight to the last shell. Long live the Führer."[62] At 08:47 the following morning, the battleship Rodney opened fire, followed directly by King George V.[63] Bismarck replied three minutes later, though at 09:02 a 16-inch shell from Rodney destroyed the forward turrets.[64] Half an hour later, Bismarck's rear turrets were silenced as well.[65] At around 10:15, both British battleships had ceased fire, their target a burning wreck. The British were running dangerously low on fuel, but Bismarck, although aflame and foundering, had not yet sunk. The cruiser Dorsetshire fired several torpedoes into the crippled ship, which then took on a severe list to port. At approximately the same time as Dorsetshire's attack, engine room crew detonated scuttling charges in the engine rooms.[66] There is still significant debate as to the direct cause of Bismarck's sinking. Only 110 men were rescued by the British before reports of U-boats forced them from the scene.[67] A further five men were rescued by German vessels.[68]

Tirpitz and several destroyers off the Norwegian coast

Tirpitz's first action following her commissioning into the Kriegsmarine on 25 February 1941 was to act as a deterrent to a possible Soviet attempt to break out their Baltic Fleet following the German invasion of the Soviet Union. The ship was joined by the heavy cruiser Admiral Scheer and the light cruisers Leipzig, Nürnberg, and Köln. The force patrolled off Åland for a few days before returning to Kiel.[69] On 14 January 1942, Tirpitz left German waters for Norway, escorted by the destroyers Z4 Richard Beitzen, Z5 Paul Jacobi, Z8 Bruno Heinemann and Z29,[70] arriving at Trondheim on the 17th.[71] The Germans used the ship as a fleet in being to tie down British naval forces to protect the convoy route to the Soviet Union and to deter an invasion of Norway.[72]

On 6 March, Tirpitz, escorted by the destroyers Z25, Z14 Friedrich Ihn, Z5 Paul Jacobi and Z7 Hermann Schoemann,[70] launched a raid on the British convoys to the Soviet Union.[69] The Germans attempted to intercept convoys PQ-12 and QP-8,[71] but the inclement weather prevented them from finding the convoys.[69] A Soviet freighter that was sailing independently of the convoys was sunk by the destroyers. The British submarines Trident and Seawolf reported Tirpitz. A Home Fleet squadron consisting of the battleships King George V and Duke of York, the aircraft carrier Victorious, the heavy cruiser Berwick and destroyers failed to find the Germans.[70] Victorious launched a strike of twelve Fairey Albacore torpedo bombers, however the aircraft were repulsed without having scored any hits on the German ships. Tirpitz and the destroyers were back in port by 12 March.[71] The close call prompted Hitler to mandate that Tirpitz was not to attack another convoy unless its escorting aircraft carrier had been sunk or disabled.[73]

The RAF launched a series of unsuccessful bombing raids against Tirpitz while she was moored in the Faettenfjord. The first on 30/31 January by seven Short Stirling of No 15 Squadron and nine Handley Page Halifax bombers of No 76 Squadron. Next came a raid by 36 Halifax bombers, took place on 30/31 March. On 27/28 April, Tirpitz was attacked by 26 Halifax bombers of No 4 Group and 10 Avro Lancasters of No 5 Group. This was followed on 28/29 April by 23 Halifaxes of No 76 Squadron and 11 Lancasters.[70] A combination of heavy German anti-aircraft fire and poor weather caused all three missions to fail.[69] Over the rest of the year and into late 1942, Tirpitz underwent a refit in the Faettenfjord, which lacked dockyard facilities of any type. As a result, the work was done incrementally; a large caisson was built to allow the rudders to be replaced.[74] Naval historians William Garzke and Robert Dulin stated that "the repairs to this ship were one of the most difficult naval engineering feats of World War II."[75]

In January 1943, Tirpitz emerged from the lengthy overhaul, after which she was transferred to Altafjord. Here, she participated in extensive training operations with Scharnhorst and the heavy cruiser Lützow, which lasted until the middle of the year.[76] On 6 September, Tirpitz, Scharnhorst, and the destroyers Z27, Z29, Z30, Z31, Z33, Z15 Erich Steinbrinck, Z20 Karl Galster, Z10 Hans Lody and Z6 Theodor Riedel bombarded the island of Spitzbergen, which served as a British refueling station.[77] The two battleships destroyed their targets and returned safely to Altenfjord; this was the first time Tirpitz fired her main guns in anger.[78] On 22/23 September, six British midget submarines attacked Tirpitz while at anchor. Only two of the submarines, X6 and X7 successfully planted explosive charges against the battleship's hull. The first charge exploded at 0812, the second shortly afterwards. Very extensive damage was sustained; nearly all electric lighting failed, partial flooding of electric switchboard room 2, flooding of the double bottom and fuel bunkers on the port side. Structural damage in the engine plant of the housing and components of the port turbine and condenser; the tail shafts were out of alignment, the thrust bearing was damaged, the propellers were immobilized, and the port rudder assembly was flooded. The main gun turrets had been jolted off their roller tracks, only one rangefinder was still active, one 15cm turret was jammed, three of four fire control centers were damaged, the aircraft catapult was inoperable and two Arado 196 floatplanes were seriously damaged. Casualties were light however, one dead and 40 wounded.[77] Tirpitz had been successfully neutralized.[76] Over the next six months, a workforce of some 1,000 men effected the needed repairs, which were finished by March 1944.[79]

Tirpitz under attack by Barracuda bombers on 3 April

The British resumed the series of air attacks almost immediately after repairs were completed. On 3 April, the Royal Navy launched Operation Tungsten, during which 40 fighters and 40 Barracuda bombers from six carriers attacked the ship. They scored 15 direct hits and two near misses, which caused heavy damage, killed 122 men, and wounded 316 more. The Royal Navy attempted to repeat the attack three weeks later on the 24th, but had to call the operation off due to inclement weather. Operation Brawn, another carrier-launched attack, followed on 15 May, but again weather interfered. Another carrier strike was attempted on 28 May, but it too was cancelled due to poor weather conditions. Operation Mascot, which was to be conducted by the carriers Victorious, Furious, and Indefatigable on 17 July, was frustrated by the heavy smokescreen over the battleship.[80]

The Royal Navy launched the Operation Goodwood series in late August. Goodwood I took place on 22 August, with 38 bombers and 43 fighters from five carriers. The attackers failed to score any hits. Goodwood III followed two days later, with 48 bombers and 29 fighters from Formidable, Furious, and Indefatigable. The bombers made two hits on the ship, which did only minor damage. The last Royal Navy operation, Goodwood IV, followed on 29 August. Thirty-four bombers and 25 fighters, launched from Formidable and Indefatigable, attacked the ship, though fog prevented them from scoring any hits.[80]

The task of sinking Tirpitz now fell to the RAF, which performed three airstrikes armed with new 5,400 kg (11,900 lb) Tallboy bombs.[80] The first attack, Operation Paravane, came on 15 September, when a force of 27 Lancasters dropped a single Tallboy each; the bombers succeeded in hitting Tirpitz directly in the bow with one of the bombs. The bomb completely penetrated the ship and exploded directly under her keel. This caused 1,500 long tons (1,524 t) of water to flood the ship; Tirpitz had again been disabled.[81] A month later, on 15 October, Tirpitz was moved to Håkøya Island off Tromsø to be used as a floating artillery battery. Two weeks later, on 29 October, the British launched Operation Obviate, which consisted of 32 Lancaster bombers. Only a near miss was achieved, though it caused Tirpitz to take in more water. The last attack, Operation Catechism, took place on 12 November. Thirty-two Lancasters attacked the ship and scored a pair of direct hits and a near miss. The bombs detonated one of Tirpitz's ammunition magazines and caused the ship to capsize. Casualties were high: 1,204 men were killed in the attack. Another 806 men managed to escape the sinking ship, and a further 82 were rescued from the capsized hulk.[71] The wreck was gradually broken up for scrap between 1948 and 1957.[82]