The Battle of the Denmark Strait was a naval engagement in the Second World War, which took place on 24 May 1941 between ships of the Royal Navy and the Kriegsmarine. The British battleship HMS Prince of Wales and the battlecruiser HMS Hood fought the German battleship Bismarck and the heavy cruiser Prinz Eugen, which were attempting to break out into the North Atlantic to attack Allied merchant shipping (Operation Rheinübung) through the Denmark Strait between Greenland and Iceland.
Less than 10 minutes after the British opened fire, a shell from Bismarck struck Hood near her aft ammunition magazines. Soon afterwards, Hood exploded and sank within three minutes, with the loss of all but three of her crew. Prince of Wales continued to exchange fire with Bismarck but suffered serious malfunctions in her main armament. The British battleship had only been completed in late March 1941, and used new quadruple gun turrets that were unreliable. Prince of Wales soon broke off the engagement.
The battle was a tactical victory for the Germans, but its effect was short-lived. The damage done to Bismarck's forward fuel tanks forced the abandonment of the breakout and an attempt to escape to dry dock facilities in occupied France, producing an operational victory for the British. Spurred by the loss of Hood, a large British force pursued Bismarck, resulting in her loss three days later.
Background
German plans
In April 1941, the German Kriegsmarine intended to send the recently completed fast battleship Bismarck into the Atlantic Ocean to raid the convoys carrying supplies from North America to Britain. The operation was intended to complement the U-boat attacks on British supply lines during the Battle of the Atlantic. The two fast battleships Scharnhorst and Gneisenau had just completed a similar operation, code-named Berlin, between January and March that year. The number of major warships available to the Germans was limited; Bismarck's sister ship Tirpitz was not yet operational, Scharnhorst was in need of a boiler overhaul after Operation Berlin, and Gneisenau had been damaged by air attacks in early April while in Brest, France. Work on the heavy cruisers Admiral Hipper and Admiral Scheer, both under refit in Germany after their own raiding operations, was delayed by British air attacks that struck supply depots in Kiel. Admiral Günther Lütjens, the fleet commander who was to command German forces during the planned Operation Rheinübung, sought to delay until repairs to Scharnhorst were completed or Tirpitz could join Bismarck, but the Oberkommando der Marine (Naval High Command) instructed Lütjens to begin the operation as soon as possible to keep pressure on Britain's supply lines. As a result, the only vessel available to support Bismarck was the heavy cruiser Prinz Eugen.
British plans
The British Royal Navy learned of Bismarck's sortie after the Swedish cruiser Gotland spotted the vessels passing through the western Baltic Sea on 20 May; Gotland's report was passed to the British naval attache in Stockholm, who forwarded it to the Admiralty. British reconnaissance aircraft later confirmed the German ship's presence in Norway. Now aware that major German warships were at sea with the intention of breaking for the Atlantic, the Royal Navy began to dispatch vessels to patrol the likely routes, including the heavy cruisers HMS Norfolk and Suffolk to cover the Denmark Strait between Greenland and Iceland. Another group, consisting of the battleship Prince of Wales, the battlecruiser Hood, and a screen of six destroyers, Electra, Achates, Antelope, Anthony, Echo and Icarus, under the command of Vice-Admiral Lancelot Holland in Hood, cruised to the south of Iceland to intercept the Germans once they were detected. Norfolk and Suffolk spotted Bismarck and Prinz Eugen on the evening of 23 May; Suffolk was fitted with radar that allowed them to shadow the Germans through the night whilst remaining outside of German gun range.
Prince of Wales was a newly commissioned King George V-class battleship, similar to Bismarck in size and power. Prince of Wales had not yet been properly "shaken down", and her crew was inexperienced. She still had mechanical problems, especially with her main armament. The ship had sailed with shipyard workers still aboard working on her.
For 20 years after her commissioning in 1920, Hood was the largest and heaviest warship in the world. Combining eight large BL 15-inch Mk I naval guns with a top speed greater than any battleship on the sea, Hood was the pride of Great Britain's navy, and embodied the world dominance of British naval power. Despite this, Hood had a serious shortcoming compared to the super-dreadnought battleships she served alongside: as a battlecruiser, much of her bulk was dedicated to extra engine power instead of comprehensive armour coverage. This came from her design as an Admiral-class battlecruiser to meet the threat of the German Mackensen-class battlecruisers during World War I.
While her 12 inches (300 mm) of belt armour was considered sufficient against most capital ships she was likely to encounter, her 3 inches (76 mm) of deck armour left her vulnerable to plunging fire at long range. At the time of her commissioning in World War I, naval gunnery was severely inaccurate at the ranges necessary to produce plunging fire, and Hood's greater speed and maneuverability were seen as an acceptable trade-off. This approach was proved to be flawed after the loss of HMS Indefatigable at the Battle of Jutland and combined with the accuracy of naval gunfire increasing in the inter-war period, Hood was eventually scheduled to receive an upgrade in 1939 that would have doubled her deck armour to 6 inches (150 mm), but the outbreak of World War II meant the upgrade never took place. She thus sortied to war at a marked disadvantage against the new capital ships of the Axis powers.
Aware of Hood's inadequate protective armour, distant to the southeast of where the battle took place, Holland's superior (Admiral Sir John Tovey) considered ordering him to have Prince of Wales sail ahead of Hood. With the ships in this position, Tovey concluded the better-protected Prince of Wales could draw the German battleships' large-shell gunfire. Ultimately, Tovey did not give the order, later saying "I did not feel such interference with such a senior officer justified."
Prelude
Both plans go awry
The Kriegsmarine had hoped that the Bismarck force would enter onto trans-Atlantic commerce raiding, from the Norwegian Sea via the Denmark Strait, undetected and unopposed. The Germans based this hope upon a transit from German territorial waters on the North Sea; and, through the territorial waters of German-occupied Norway into the Norwegian Sea, undetected by aerial searches; neutral ship encounters; and traditional "coast-watching" observations performed by formal and informal efforts of maritime intelligence gathering, in the neutral and occupied countries surrounding the North Sea.
In the event, the ground-level coast-watching observations from both neutral and occupied territories identified the principal combatant units sortied for the Exercise Rhine operation from the moment they left German territorial waters. The combatants (Bismarck and Prinz Eugen) were identified by in-country coast-watchers located in Denmark; who were able to identify the ships and communicate with their clandestine contacts, the dates and times of the German surface units, moving in their designated coast-watch areas of responsibility.
The HSwMS Gotland spotted the transit of Bismarck and Prinz Eugen in the normal shipping lanes in the North Sea, and reported the movement to the Swedish authorities. Swedish territory as well hosted individual ground-level coast watchers who were able to follow and report on movements in Swedish coastal waters. These observations were passed directly to Royal Navy intelligence by routine maritime diplomatic channels maintained by the British naval attaché in Stockholm. Thus, when Bismarck and her escort moved into the unoccupied fjords of German-occupied Norway, for final coastal refuelling and topping off of ships' stores and supplies, the RAF (weather permitting) was able to keep a final watch on the location and timing of the German raider force.
Holland's battle plan was to have Hood and Prince of Wales engage Bismarck while Suffolk and Norfolk engaged Prinz Eugen (which, Holland assumed, still steamed behind Bismarck and not ahead of her). He signalled this to Captain John C. Leach of Prince of Wales but did not radio Rear-Admiral Wake-Walker, who as Commander of the 1st Cruiser Squadron directed Suffolk and Norfolk, for fear of disclosing his location. Instead, he observed radio silence. Holland hoped to meet the enemy at approximately 02:00. Sunset in this latitude was at 01:51 (ship's clocks were four hours ahead of local time). Bismarck and Prinz Eugen would be silhouetted against the sun's afterglow while Hood and Prince of Wales could approach rapidly, unseen in the darkness, to a range close enough not to endanger Hood with plunging fire from Bismarck. The Germans would not expect an attack from this quarter, giving the British the advantage of surprise.
The plan's success depended on Suffolk's continually unbroken contact with the German ships. However, Suffolk lost contact from 00:28. For 90 minutes, Holland neither sighted the German ships nor received any further news from Norfolk or Suffolk. Reluctantly, Holland ordered Hood and Prince of Wales to turn south-southwest but he detached his destroyers which continued searching to the north. However, the loss of contact should be understood as temporary and tactical only; and not strategic in terms of the tactical outcome. Suffolk lost contact with its reconnaissance target (the enemy fleet) in what was essentially a closed, confined rectangular space; aligned generally northeast (the entrance to the Denmark Strait) to southwest (the exit of the Strait into the Atlantic). The enemy units were firmly constrained by the Greenland ice pack to the north, and the extensive Royal Navy minefield to the south along the coast of Iceland, then under British occupation. Given the prior warning of the German sortie, there was ample time for the Royal Navy to place armed reconnaissance at both ends of this narrow alignment. Suffolk and Norfolk were at the eastern entrance to the Strait (where contact was made immediately upon Bismarck's entry). Holland was waiting at the western end as the Bismarck force exited the Strait.
Strategically, it was an unquestioned fact (including the approximate timing) that Bismarck's and Prinz Eugen's entrance into the Atlantic (the fundamental objective of Rhine Exercise), was known from the moment the fleet left German territorial waters. And that was a long enough time span before the fleet's final fitting out for transit to the Denmark Strait, that Lütjens could not have helped but to realize, that his force would not under any circumstance enter the Atlantic undetected nor would it enter unopposed. And by the time it was opposed, it would occur with forces that would likely ensure his fleet's ultimate destruction. And such destruction would take place before any supply convoy units (the whole purpose of the operation) were threatened by Operation Rhine Exercise.
Before contact was re-established, the two squadrons missed each other narrowly. Had the German ships not altered course to the west at 01:41 to follow the line of the Greenland icepack, the British would have intercepted them much earlier than they did. The British destroyers were just 10 mi (8.7 nmi; 16 km) to the southeast when the Germans made this course change. If the visibility had not been reduced to 3–5 mi (2.6–4.3 nmi; 4.8–8.0 km), the German vessels would probably have been spotted (since generally on a calm, clear day ship lookouts can observe large objects and ships about 12 miles (19 km) distant on the horizon. And if the ship's lookouts are in a crow's nest, the observable distance is even farther).
Just before 03:00, Suffolk regained contact with Bismarck. Hood and Prince of Wales were 35 mi (30 nmi; 56 km) away, slightly ahead of the Germans. Holland signalled to steer toward the Germans and increased speed to 28 kn (32 mph; 52 km/h). Suffolk's loss of contact had placed the British at a disadvantage. Instead of the swiftly closing head-on approach Holland had envisioned, he would have to converge at a wider angle, much more slowly. This would leave Hood vulnerable to Bismarck's plunging shells for a much longer period. The situation worsened further when, at 03:20, Suffolk reported that the Germans had made a further course alteration to the west, placing the German and British squadrons almost abeam of each other.