War at Sea during Word War II
U-boat terror in the Atlantic and the Arctic convoys
author Paul Boșcu, May 2019
The Allies eventually won the Battle of the Atlantic, but at a needlessly high cost. The armed forces’ lack of interest in anti-submarine warfare before the outbreak of the war was inexcusable, especially in light of their experiences in World War I. When Hitler invaded Russia Britain’s Prime Minister and America’s President supported URSS by establishing Arctic convoys of military equipment.
The British Army’s part in the struggle against Nazism was vastly smaller than that of the Russians, as would also be the US Army’s contribution. Britain’s principal strategic importance became that of a giant aircraft carrier and naval base, from which the bomber offensive and the return to the Continent were launched. It fell to the Royal Navy to conduct the critical struggles of 1940-43 to keep the British people fed, to hold open the sea lanes to the Empire and overseas battlefields, and convoy munitions to Russia.

Naval might could not bring about the defeat of Germany, nor even protect Britain’s eastern empire from the Japanese. It was a fundamental problem for the two Western Allies that they were sea powers seeking to defeat a great land power, which required a predominantly Russian solution. But if German efforts to interdict shipments to Britain were successful, Churchill’s people would starve. A minimum of twenty-three million tons of supplies a year – half the pre-war import total – had to be transported across the Atlantic in the face of surface raiders and U-boats.

The navy had suffered as severely as Britain’s other services from inter-war retrenchment. The construction of big ships required years, and even a small convoy escort took months to build. Britain built and repaired ships more slowly, if much more cheaply, than the United States, and could never match American capacity. For the Royal Navy, shortage of escorts was a pervasive reality of the early war years.

In the first war years, Germany’s surface raiders imposed as many difficulties as U-boats: the need to divert convoys from their danger zones increased the strain on British merchant shipping resources. German sorties between 1939 and 1943 precipitated dramas which seized the attention of the world: the pocket battleship Graf Spee sank nine merchantmen before being scuttled after its encounter with three British cruisers off the River Plate in December 1939. The 56,000-ton Bismarck destroyed the battlecruiser Hood before being somewhat clumsily dispatched by converging British squadrons in May 1941. The British public was outraged when the Scharnhorst and Gneisenau made a dash to Wilhelmshaven from Brest through the Channel Narrows in February 1942, suffering only mine damage amid fumbling efforts by the navy and RAF to intercept them. The presence of Tirpitz in the fjords of northern Norway menaced British Arctic convoys and strongly influenced Home Fleet deployments until 1944.

Hitler never understood the sea. In the early war period, he dispersed industrial effort and steel allocations among a range of weapons systems. He did not recognize a strategic opportunity to wage a major campaign against British Atlantic commerce until the fall of France in June 1940. U-boat construction was prioritized only in 1942-43, when Allied naval strength was growing fast and the tide of the war had already turned. Germany never gained the capability to sever Britain’s Atlantic lifeline, though amid grievous shipping losses it was hard to recognize this at the time.

Major scientific and technical developments during the war helped in the struggle against the U-boat. The Royal Navy used Asdic, the echo-sounding device for tracking U-boats, and 180 ships were fitted with it. It was not foolproof, however, so ships constantly zig-zagged hoping to escape submarines.

The Germans might have improved their chances of winning the war if they had never prosecuted the Battle of the Atlantic but had expended all their resources on the air and ground campaigns. The Third Reich lacked the resources to fight a world war on so many fronts, and war demands hard choices. But Hitler’s method of decision-making, coupled with the inability of the German military to think at the strategic level, made it impossible for leaders of the Third Reich to make the choices that might have brought them victory.

It was not so much the successes and failures of the U-boats themselves as the indirect effects of the U-boat offensive that helped turn the war against Germany. Without the terrible losses inflicted by the U-boats in the summer and fall of 1940, the United States might never have embarked on its massive program to construct merchant shipping. The German successes off the east coast of the United States in early 1942 added even greater impetus to Roosevelt’s support for the program.

Cryptanalysis alone cannot account for the failure of the German naval effort. At the start of the war Dönitz tapped a relatively small staff to control the U-boat battle against British commerce. As the campaign against British commerce expanded and became ever more complex, the German staff at U-boat Headquarters remained at the same small staffing levels; if anything, it contracted, as Dönitz attempted to close off what the Germans regarded as human leaks in their security systems. A number of important consequences flowed from this decision. Most obvious was the general exhaustion of all the officers involved in running the U-boat campaign. But more disabling was the inability of U-boat Headquarters to step back and take a longer look at the war, both to assess its intelligence situation and to implement technological improvements.

The Allies eventually won the Battle of the Atlantic, but at a needlessly high cost. The armed forces’ lack of interest in anti-submarine warfare before the outbreak of the war was inexcusable, especially in light of their experiences in World War I. When the threat emerged again early in World War II, anti-submarine forces received the attention they deserved, but by then it took the most desperate measures, including putting the entire British nation on a near starvation diet, to overcome the challenge.

As was so often the case with their strategic assessments, the Germans had underestimated their opponents. The efforts of Bletchley Park played a crucial role in deflecting the U-boat offensive, particularly in the last half of 1941, when the British were most vulnerable. In spite of great circumstantial evidence that the British had broken into their codes, the Germans refused to believe the evidence because of their confidence in the superiority of their technology. As a result of this arrogance, the British were able to tip the playing field against the U-boats for virtually the entire last half of the war.

As was so typical of the German approach to war, Dönitz fully seconded Raeder’s efforts to get Hitler to declare war on the United States in the second half of 1941. Yet, when that declaration of war came, instead of concentrating his submarines for a deadly strike against the east coast of the United States, the Gulf of Mexico, and the Caribbean, Dönitz committed his boats in small numbers. The damage they wrought was considerable, but in the end it merely forced the United States to devote sufficient naval forces and resources to the problem without delivering irreparable damage to the Allied cause.

The effort to thwart the U-boats was one of the high points of war for the British. When its leaders recognized the threat, the Royal Navy developed the tactics, the technology, and the leadership to handle the grim business of anti-submarine warfare. The integration of technology into effective tactical systems was crucial to mastering the U-boats in 1943; similarly, the integration of intelligence into the conduct of anti-submarine and convoy operations substantially boosted the chance of victory. The mental flexibility of those responsible for the anti-submarine campaign allowed the British to get maximum utility out of civilian scientists, reserve intelligence officers, and operations research analysts.

A decisive moment in the course of the Second World War was the Allied cracking of the German Enigma codes, producing a stream of decrypts known by their British special security classification, Ultra. This allowed the Allies, for much of the war, to read many of the communications sent and received by the Germans, amounting in total to several million items of intelligence. From the correspondence of the Führer himself right down to that of the harbor-master of Olbia in Sardinia, messages were routinely decoded by the Allies. Its importance can be gauged from the jokey acronym ‘BBR’ that the Americans gave to Ultra, which stood for Burn Before Reading.

Far from being a school, Bletchley was a department of SIS, operating from a Victorian mansion that housed 150 workers in 1939, before expanding into huts in the grounds to fit 3,500 people by 1942 and no fewer than 10,000 by the end of the war. Huts 6 and 3 deciphered, translated, annotated and passed on Wehrmacht and Luftwaffe signals, while Huts 4 and 8 (run by Turing and subsequently the chess champion Hugh Alexander) did much the same thing for the Kriegsmarine, sending reports to the Naval Intelligence Division of the Admiralty. Hut 4 also analyzed sudden increases and decreases of signals traffic volume, which could suggest possible enemy intentions.

It was not until the beginning of April 1941 that the German naval Enigma codes were broken – except for a very brief period in April 1940 – although there had been no shortage of plans to try to obtain German codebooks to help the process along. The most hare-brained of these was the scheme of the intelligence officer and future Bond author Ian Fleming: to crash a captured aircraft into the English Channel, and then ambush the rescue boat. It turned out to be the capture off Norway of the German trawler Krebs that yielded up the vital settings list that Bletchley needed to operate Turing’s Banburismus procedure for decryption.

Five weeks before Hitler unleashed Blitzkrieg on the West, same-day decoding of the German Army codes first became possible, but on 1 May the British at Bletchley and Poles in France were ‘blinded’ for three weeks when the Germans altered their indicating systems. Overall, however, Wehrmacht and Luftwaffe signals were decoded between three and six hours after they were sent, and naval signals during the battle of the Atlantic could be read as swiftly as one hour after transmission.

Although the Abwehr set up regular investigations into the security of Enigma, and the commander of the U-boat branch of the German Navy, Karl Dönitz, had himself questioned whether it could have been broken, the Germans only continued to refine the existing machine settings rather than institute a brand-new communications system. Geheimschreiber, for example, was a non-Morse cipher that had up to ten rotary wheels, against the Enigma’s maximum of five. Its product was codenamed Fish at Bletchley and was far harder to crack, but it was not universally employed.

Although the Allies could not be seen to rely on it too much, for fear that the Germans would realize it had been compromised, information gleaned from Ultra was used to great advantage at many key moments of the war – for example, it enabled the sinkings of the Bismarck and Scharnhorst, disclosed Rommel’s weaknesses and shortages prior to El Alamein, simplified Montgomery’s advance into Tunisia in March 1943, made the planning for the invasions of Sicily and southern France much easier, exposed the whereabouts of German divisions before D-Day and revealed Hitler’s orders for a counterattack at Falaise in August 1944. Yet it was undoubtedly in the battle of the Atlantic that Ultra was put to greatest use.

In February 1940, however, the German submarine U-33 was attacked off the west coast of Scotland and two of the extra rotor wheels used by the naval Enigma were captured. Five weeks later, a brilliant, eccentric, accident-prone, Cambridge mathematics don called Alan Turing installed something known as a bombe machine, an electro-mechanical device which made hundreds of computations every minute, at the Government Code and Cypher School at Bletchley Park in Buckinghamshire, 40 miles north-west of London. Other heroes of Bletchley were to include the mathematicians Stewart Milner-Barry and Alfred Dilwyn (‘Dilly’) Knox. In modern computing parlance, while the Poles provided the Enigma hardware, the assorted civilian geniuses stationed at Bletchley provided the software that produced Ultra.

Far from being a school, Bletchley was a department of SIS, operating from a Victorian mansion that housed 150 workers in 1939, before expanding into huts in the grounds to fit 3,500 people by 1942 and no fewer than 10,000 by the end of the war. Huts 6 and 3 deciphered, translated, annotated and passed on Wehrmacht and Luftwaffe signals, while Huts 4 and 8 (run by Turing and subsequently the chess champion Hugh Alexander) did much the same thing for the Kriegsmarine, sending reports to the Naval Intelligence Division of the Admiralty. Hut 4 also analyzed sudden increases and decreases of signals traffic volume, which could suggest possible enemy intentions.

It was not until the beginning of April 1941 that the German naval Enigma codes were broken – except for a very brief period in April 1940 – although there had been no shortage of plans to try to obtain German codebooks to help the process along. The most hare-brained of these was the scheme of the intelligence officer and future Bond author Ian Fleming: to crash a captured aircraft into the English Channel, and then ambush the rescue boat. It turned out to be the capture off Norway of the German trawler Krebs that yielded up the vital settings list that Bletchley needed to operate Turing’s Banburismus procedure for decryption.

Five weeks before Hitler unleashed Blitzkrieg on the West, same-day decoding of the German Army codes first became possible, but on 1 May the British at Bletchley and Poles in France were ‘blinded’ for three weeks when the Germans altered their indicating systems. Overall, however, Wehrmacht and Luftwaffe signals were decoded between three and six hours after they were sent, and naval signals during the battle of the Atlantic could be read as swiftly as one hour after transmission.

Although the Abwehr set up regular investigations into the security of Enigma, and the commander of the U-boat branch of the German Navy, Karl Dönitz, had himself questioned whether it could have been broken, the Germans only continued to refine the existing machine settings rather than institute a brand-new communications system. Geheimschreiber, for example, was a non-Morse cipher that had up to ten rotary wheels, against the Enigma’s maximum of five. Its product was codenamed Fish at Bletchley and was far harder to crack, but it was not universally employed.

Although the Allies could not be seen to rely on it too much, for fear that the Germans would realize it had been compromised, information gleaned from Ultra was used to great advantage at many key moments of the war – for example, it enabled the sinkings of the Bismarck and Scharnhorst, disclosed Rommel’s weaknesses and shortages prior to El Alamein, simplified Montgomery’s advance into Tunisia in March 1943, made the planning for the invasions of Sicily and southern France much easier, exposed the whereabouts of German divisions before D-Day and revealed Hitler’s orders for a counterattack at Falaise in August 1944. Yet it was undoubtedly in the battle of the Atlantic that Ultra was put to greatest use.

Part of the explanation for the heavy losses on the Atlantic and Arctic convoys was that the British convoy code had been cracked by German intelligence, something that was not discovered until after the war. In February 1942 the German Beobachtungsdienst (radio monitoring service) managed to crack about 75 percent of Naval Cipher No. 3. The Germans were reading Royal Navy codes, although only 10 percent of the intercepts could be used operationally because of the time taken to decipher them. If they had achieved real-time decryption, as Turing was to do, it could have been potentially as decisive an advantage to the Germans as the cracking of the Enigma code was for the Allies.

Instead of recognizing the danger, the Admiralty put the U-boats’ remarkable success in intercepting convoys down to the advanced hydrophone equipment they used, which it was thought could detect propeller noise for over 80 miles. When marvelling at the Germans’ continuing trust in Enigma, therefore, one must also consider the British faith in the Royal Navy’s own compromised codes. Naval Cipher No. 3 was not replaced with No. 5, which the Germans never cracked, until June 1943.

Most British battleships were old, slow and could not be adapted for bulky modern fire-control equipment. The Dutch navy’s triaxially stabilized Hazemeyer system represented the most advanced AA gunnery technology in the world, to which the Royal Navy gained access in 1940. It was fragile and unreliable, however, and a British version entered general service only in 1945; anti-aircraft fire-control remained ineffective meanwhile. Throughout the conflict, the Royal Navy displayed the highest standards of courage, commitment and seamanship. But until 1943, it struggled against odds to fulfil too many responsibilities with too few ships, all vulnerable to air attack.

Britain had more carriers than the US Navy until 1943, but there were never enough to go round, or rather to meet global demand, and they were too small to carry powerful air groups. Fleet Air Arm pilots displayed notable courage, but their performance was indifferent in both air combat and anti-shipping operations. The RAF, doctrinally committed to a strategic bomber offensive, resisted the diversion of resources to support operations at sea.

The long-term problems confronting the Royal Navy were considerable. It possessed too few escorts, air support was minimal, and the escorts had yet to face the wolfpacks. Moreover, because it had woefully underestimated the U-boat menace, the navy had not developed tactics and operational concepts adequate to protect large convoys. As for the Royal Air Force, it offered little help. Not until late 1942 did the RAF Coastal Command begin to receive the resources it needed to play its part in the battle.

When the war broke out, both the British and German Admiralties assumed that the great German surface ships would be crucial in deciding whether Britain survived or starved. It was thought that if these capital ships could dominate the Ocean Gap, the New World would be incapable, to adopt Churchill’s phrase in his ‘fight on the beaches’ speech, of stepping ‘forth to the rescue and liberation of the Old’. If, on the other hand, the Allies could sink these huge vessels, the danger was thought to be far less great. On the outbreak of war Graf Spee and Deutschland were already stationed to attack the trade routes, and Scharnhorst and Gneisenau put to sea in November 1939. Yet both Admiralties were wrong in assuming that the big battleships would be decisive. In fact, it very soon became clear that the U-boats posed the primary threat.

The forced scuttling of Graf Spee outside Montevideo harbour in December 1939, the victim of a brave naval action at the Battle of the River Plate but also a brilliant British deception operation, dented the myth of invincibility that had begun to surround the big German raiders. Similarly, although it was successful, the German invasion of Norway in April 1940 cost the German Navy dear – almost half its entire destroyer force.

The fall of France in June allowed the Kriegsmarine to establish itself right along France’s Atlantic seaboard, with major bases at Lorient, Brest, La Rochelle and Saint-Nazaire. October 1940 saw Admiral Scheer break into the Atlantic Ocean, followed two months later by the heavy cruiser Admiral Hipper. The British Admiralty seemed incapable of preventing German raiders from sailing through the Denmark Straits between Greenland and Iceland. ‘For the first time in our history,’ Vice-Admiral Günther Lütjens told the crews of Scharnhorst and Gneisenau in January 1941, as they passed through the Faroes–Iceland gap, ‘German battleships have today succeeded in breaking through the British blockade. We shall now go forward to success.’ He was right in the short term: in two months the two ships together sank 116,000 tons of Allied shipping.

The Atlantic was the dominant naval battlefield, forever the cruel sea. While Germany’s capital ships commanded headlines and their sorties inflicted some injuries, Axis submarine and air forces represented a much graver long-term threat, and the men of both arms displayed courage and skill. U-boats achieved striking early successes, such as sinking the old battleship Royal Oak in Scapa Flow, and wreaking havoc upon vulnerable merchantmen. Merchant ships were obliged to waste weeks waiting for convoys to assemble. Once ocean-bound, they travelled painfully slowly, and were offloaded on arrival by a lethargic and sometimes obstructive British dock labor force.

Many ships that carried commodities in peacetime had to be diverted to move troops and munitions across huge distances by circuitous routes, to avoid Axis air and submarine concentrations. For instance, almost all Egypt-bound cargoes travelled via the Cape of Good Hope. The voyage to Suez lengthened from 3,000 miles to 13,000, while a Bombay-bound ship made a passage of 11,000 miles against the pre-war 6,000.

As with men in every circumstance of conflict, merchant seamen’s performance was uneven: drawn from many nations and lacking the armed forces’ discipline, they were often careless of convoy routines, courses and signal procedures. Crews sometimes panicked and abandoned ships that might have been saved.

In his memoirs Churchill wrote: ‘The only thing that ever really frightened me during the war was the U-boat peril… I was even more anxious about this battle than I had been about the glorious air fight called the Battle of Britain.’ It is a moot point whether, in the event of the U-boats closing down her imports completely, Britain’s armaments industry would have ground to a halt before or after mass starvation struck every urbanized area. Yet that was unlikely to happen, for Hitler saw only too late the potential war-winning capacity of the U-boat, despite its almost bringing Britain to her knees in 1917.

The fall of France in June 1940 altered the geographic framework of the Battle of the Atlantic. From French bases, U-boats had easy access to the terminus of Britain’s sea lines of communications, while the Luftwaffe could conduct its reconnaissance missions and air attacks on shipping with greater ease.

In May 1941 the Germans took the initiative, unleashing the battleship Bismarck and the new heavy cruiser Prinz Eugen into the Atlantic shipping lanes, in the hope of asphyxiating Britain and forcing her to sue for peace. These two warships left port at Gotenhafen (present-day Gdynia) in Operation Rheinübung (Rhine Exercise), a break for the Atlantic. The British fleet pursued the two German monsters and, after a bloody engagement, Bismark, the pride of the German Navy, was sunk. The British also lost an important ship, the HMS Hood. Bismarck had been launched in Hamburg by the Iron Chancellor’s granddaughter, Dorothea von Löwenfeld, in February 1939, and Göring, Goebbels, Hess, Ribbentrop, Himmler, Bormann, Keitel and of course Raeder were all present; the Führer gave a speech. The ship was one-sixth of a mile long, recalled the British writer Ludovic Kennedy, who was a junior reserve lieutenant when he took part in the operation to try to sink her, ‘120 feet wide, designed to carry eight 15″ guns and six aircraft, with 13″ armour made of specially hardened Wotan steel on her turrets and sides. Listed as 35,000 tons to comply with the London Treaty, she would in fact be 42,000 tons standard displacement and over 50,000 tons fully laden. There had never been a warship like her: she symbolized not only a resurgent Navy but the whole resurgent German nation… Warships combine uniquely grace and power, and Bismarck, massive and elegant, with the high flare of her bows and majestic sweep of her lines, the symmetry of her turrets, the rakish cowling of her funnel, her ease and arrogance in the water, was then the most graceful, most powerful warship yet built. No German saw her without pride, no neutral or enemy without admiration.’ Furthermore she had twelve boilers, her four gun turrets each weighed 1,000 tons – they were nicknamed Anton, Bruno, Caesar and Dora – she could sail at 29 knots and her crew numbered 2,065. Prinz Eugen, meanwhile, displaced 14,000 tons, had eight 8-inch guns and a speed of 32 knots.

Built on Clydeside in 1916, the Hood was 38 feet longer even than the Bismarck. Like Bismarck she had eight 15-inch guns in four massive turrets. With her maximum speed of 32 knots – she was the fastest ship of her size afloat – a ton of oil only got her half a mile. She had everything except upper deck armor, because she had been built just before the battle of Jutland, when three British battle cruisers had been lost from shells falling vertically through their decks. Despite this, she had not been reconditioned after the Great War ended.

Captain John Leach of the Prince of Wales continued firing at Bismarck, hitting her twice but only on the seventh salvo, yet once he was himself hit, he was forced to escape under smoke cover. In an engagement lasting only twenty minutes, the Germans had sunk the maritime pride of the British Empire. Thereafter, their luck changed. One of the shells that the Prince of Wales landed on Bismarck had ruptured her fuel tanks, and she started leaking oil. Since she had sailed under-oiled and had not been resupplied when she might have been, this meant that her skipper had to try to reach her supply ships and, he hoped, lead his antagonists into a wolf-pack. Meanwhile, Prinz Eugen broke off westwards, covered by an attack by Bismarck on Norfolk and Suffolk.

Because several Polish laborers had been killed by oil fumes while cleaning her tanks, Bismarck sailed 200 tons of fuel short, something which her captain, Ernst Lindemann, would bitterly regret later. Bismarck and Prinz Eugen skirted as far as possible away from the major British naval base of Scapa Flow and sailed through the Denmark Straits, where on the afternoon of Friday, 23 May they were shadowed with radar by the Royal Navy heavy cruisers HMS Norfolk and HMS Suffolk, until HMS Prince of Wales and HMS Hood were able to intercept them at dawn the next day.

Nine Fairey Swordfish torpedo-bombers from the aircraft carrier HMS Victorious braved Bismarck’s sixty-eight anti-aircraft guns and scored a hit with their torpedoes. With the battleship still leaking oil steadily, it changed course for Brest. Then Enigma made its vital contribution, when a senior Luftwaffe officer in Athens using the Lufwaffe Enigma code enquired of his son serving in Bismarck where he was headed, and received the reply ‘Brest.’ She almost escaped anyway after her bearings were incorrectly plotted, but she was spotted by a US Navy patrol pilot called Leonard Smith in a Consolidated Catalina flying-boat, part of RAF Coastal Command (and seven months before America entered the war).

When the Hood and Prince of Wales exchanged fire, at a range of 13 miles, with Bismarck and Prinz Eugen, Norfolk and Suffolk were not close enough to provide support. Without the Norfolk and Suffolk to harry Bismarck from the rear, there was nothing to draw her fire from Hood, which was also taking fire from Prinz Eugen. Also, because the two German ships had swapped places since the last visual report, Hood was firing at the wrong target – Prinz Eugen rather than Bismarck – as the two looked alike at that distance. The Germans also had the weather gauge working in their favor, so that the British range-finders on the forward turrets were drenched with spray and other, less accurate instruments in the control tower had to be used instead. Furthermore, only the front turrets could be engaged as the British ships sailed towards the Germans, whereas their antagonists were able to deploy every high-caliber weapon they had.

Only a thorough re-armoring of Hood’s upper deck in the inter-war years could have saved her. For a shell from Bismarck, in naval officer’s Ludovic Kennedy’s phrase, ‘came plunging down like a rocket, hit the old ship fair and square between center and stern, sliced its way through steel and wood, pierced the deck that should have been strengthened but never was, penetrated the ship’s vitals deep below the waterline, exploded, touched off the 4″ magazine which in turn touched off the after 15″ magazine. Before the eyes of the horrified British and incredulous Germans a huge column of flame leapt up from Hood’s center.’ No one who witnessed that flame ever forgot it, as Hood exploded and then sank, with only three survivors out of a crew of over 1,400.

Force H, based in Gibraltar, and including the battlecruiser HMS Renown and the aircraft carrier HMS Ark Royal, attacked the Bismarck. Planes from Ark Royal landed two hits with contact-detonating torpedoes, one of them entering the starboard steering compartment, exploding, and thrusting the starboard rudder against the central propeller. This jammed Bismarck’s steering and wrecked her chances of getting to Brest. The following day the battleships King George V and Rodney attacked the German ship once again, with Norfolk taking part too, and the cruiser Dorsetshire finished Bismarck off with torpedoes. At 10.36 she sank, killing all but 110 of her crew. It seems that she was also scuttled, evidence of which was discovered when she was found on the seabed, 300 miles off south-west Ireland, in 1989.

The sinking of the Bismarck – although of course it cost the Hood – saw the last of the German surface-fleet raiders threatening the Atlantic sea-lanes, and in that sense marked a major turning point in the battle. Bismarck’s and Prinz Eugen’s supply ships were immediately targeted, using the German Home Waters key of the naval Enigma code called Dolphin, and hardly any made it back to port. That meant that the Germans had henceforth to rely on underwater tankers and supply carriers, which had much smaller capacities and slower speeds.

Hitler learned the lesson of the vulnerability of great surface raiders to air attack. He told Martin Bormann that although he had once ‘planned to construct the most powerful squadron of battleships in the world’ – which he was going to name after the great sixteenth-century poet-adventurers Ulrich von Hutten and Götz von Berlichingen – now ‘I am very pleased that I abandoned the idea.’ The reason was that ‘it is now the infantry of the sea which assumes the prime importance,’ and submarines, corvettes and destroyers ‘are the classes that carry on the fight’. To illustrate the point, the Führer said that although the Japanese had the greatest battleships in the world, ‘it is very difficult to use them in action. For them, the greatest danger comes from the air. Remember the Bismarck!’

Although there were other major battles to be fought against vessels such as the battlecruiser Scharnhorst (sunk off the Northern Cape of Norway), Bismarck’s sister ship the Tirpitz (sunk by Lancaster bombers with 12,000-pound Tallboy bombs), the battlecruiser Gneisenau (scuttled at Gotenhafen) and the Prinz Eugen (which ended her days as a nuclear-test target in the Pacific after the war), none of these ships posed the same level of danger during the battle of the Atlantic.

Until 1943, the Royal Navy was desperately short of escorts and effective technology to hunt U-boats. The British sank twelve German submarines in 1940, and just three in the six months between September that year and March 1941; intelligence and skilful convoy routing did more to frustrate Admiral Karl Dönitz than did anti-submarine escorts. The Royal Navy was slow to realize the vulnerability of merchantmen off the African coast, where in 1941-42 just two long-range Type IX U-boats achieved some spectacular destruction, partly because they maintained wireless silence and partly because few defensive resources were available.

In the course of the entire war, while 6.1 percent of Allied shipping losses were inflicted by surface raiders and 6.5 percent by mines, 13.4 percent were caused by air attack and 70 percent by U-boats. The British suffered their first severe blow in the autumn of 1940, when the slow eastbound Atlantic convoy SC7 lost twenty-one out of thirty ships, and twelve out of forty-nine in the fast HX79. Thereafter, the tempo of the undersea war rose steadily.

Changes of Kriegsmarine ciphers caused periodic ‘blackouts’ of Allied signal interception, with severe consequences for convoys unable to avoid submarine lines. But the Allies progressively raised their game: antisubmarine warfare techniques improved and escort numbers grew; naval radar sets profited from the introduction of cavity magnetron technology; escort groups gained from TBS – Talk Between Ships – voice communication, and even more from experience.

Though by 1941 few U-boats were sunk by naval escorts, which were slowly being equipped with improved radar and Asdic underwater detection systems, the Germans failed to force a crisis upon Churchill’s besieged island. By late summer of that year, the British were reading German U-boat signal traffic with reasonable regularity. Some of Dönitz’s submarines were transferred to the Mediterranean, or to northern Norway to screen the flank of Germany’s assault on the Soviet Union. By Christmas 1941, Hitler had already lost his best chance of starving Britain; once the United States entered the war, the consequent enormous accession of shipping and construction capability transformed the struggle.

Churchill became deeply alarmed. His post-war assertion that the U-boats caused him greater anxiety than any other threat to Britain’s survival has powerfully influenced the historiography of the war. It is scarcely surprising that the Prime Minister was so troubled, when almost every week until May 1943 he received loss statistics that represented a shockingly steady, debilitating depletion of British transport capabilities.

To hunt and sink U-boats, close collaboration between two or three warships was vital: a single ship could seldom drop depth-charges with sufficient accuracy to achieve a ‘kill’. It became difficult for the Germans to operate close to the US or British coasts, within range of air patrols. U-boats could travel fast only on the surface; submerged craft struggled to intercept a convoy. Overhead aircraft forced them to dive, a more effective countermeasure than bomber attacks on the concrete-encased U-boat ‘pens’ of Brest and Lorient, which cost the RAF much wasted effort.

Dönitz had been a highly decorated U-boat commander in World War I until captured by the British in 1918. After a successful career in surface vessels that lasted into the mid-1930s, he took over the effort to rebuild the U-boat force. Dönitz believed that submarines offered the best avenue to defeat the British. Dönitz’s operational aim for his offensive was simple: to sink the maximum number of Allied ships possible, without regard to their cargo, their destination, or even whether they had any cargo on board at all.

He was also a micromanager, and his obsessive control of U-boats at sea and the concomitant reliance on massive numbers of Enigma messages to and from the U-boats played a major role in the ability of the British to break into the highest levels of German radio traffic. Dönitz also displayed little interest in technology until it was too late; as a result, his boats would confront vastly more sophisticated opponents in the climactic battles of 1943 with the technological capabilities they had possessed at the war’s outset.

A major problem with British strategy at the start of the war was that too much attention was paid to taking the offensive against the U-boat threat, and not enough to protecting convoys, which the Great War had proved was the best way of keeping the sea-lanes open. It was not until May 1941 that convoys were escorted all the way across the Atlantic, and even then they were often woefully under-protected. The Americans took even longer to institute a proper convoy system. After Enigma had been cracked in April 1941, between July and December 1941 Allied convoys were re-routed so expertly that not one was intercepted in the North Atlantic. Although there were still significant losses, these were heavily reduced.

‘Instead of employing the maximum number of vessels in the escort role,’ Vice-Admiral Sir Peter Gretton believed, the Royal Navy ‘wasted a great deal of energy in hunting for submarines in the open ocean’. When the captain of the unarmored, converted passenger liner HMS Jervis Bay, Edward Fogarty Fegen, bravely but suicidally attacked the pocket battleship Admiral Scheer in November 1940, thereby allowing convoy HX-84 to scatter in a smokescreen at dusk, she had been the only escort vessel accompanying thirty-seven merchantmen.

Although Liberator bombers from Britain had the range to search the Eastern Atlantic for enemy submarines on the surface, and then attack them before they could dive to safety, Bomber Command would release only six squadrons to Coastal Command, which was not enough to make a serious difference. Air cover was generally scanty, and completely non-existent in the mid-Atlantic ‘Ocean Gap’, the area several hundred miles wide which planes could not reach from Iceland, Britain or Canada. The Gap was closed in 1943 by the introduction of Very Long Range Liberators.

RAF Coastal Command entered the war badly under-equipped, under-staffed and undertrained, considering that its main role was to search for surface ships rather than submarines. There was also an absurd rivalry between the Admiralty and the Air Ministry that stymied efficiency in the opening stages.

The submarine force commanded by Dönitz was far weaker than it could have been. Germany’s pre-war industrial planning envisaged a fleet which achieved full war-fighting capability only in 1944. Naval construction was skewed by a focus on big ships: a hundred U-boats could have been built with the steel lavished on the Bismarck. Until June 1940, Dönitz did not anticipate waging a major campaign in the Atlantic, because he was denied means to do so; the small, short-range Type VII boats that dominated his armory were designed to operate from German bases. Even when the strategic picture radically changed with Hitler’s seizure of Norway and of France’s Atlantic ports, the Kriegsmarine continued to build Type VIIs.

Productivity in German shipyards, hampered by shortages of steel and skilled labor, and later by bombing, fell below British levels. U-boats remained technically primitive. Innovation – for instance, the 1944-45 Schnorkel underwater air-replenishment system – was not matched by reliability: the revolutionary Type XXI sailed on its first war patrol in April 1945.

Germany never built anything like enough submarines to make them a war-winning weapon. Dönitz calculated that he needed to sink 600,000 tons of British shipping a month to achieve a decisive victory, for which he required three hundred U-boats in commission to sustain a third of that number in operational areas. Yet only thirteen U-boats were on station in August 1940, falling to eight in January 1941, rising to twenty-one the following month. This small force inflicted impressive destruction: two million tons of British shipping were sunk between June 1940 and March 1941. But in the same period just seventy-two new U-boats were delivered, far short of the number Dönitz needed.

Once Hitler finally recognized their potential, a huge increase in U-boat production took place, but it was too late to win the all-important battle of the Atlantic. With only one-third of submarines operational at any one time, the others needing crew training and boat refitting, a massive building effort should have been instituted by Hitler by 1937 at the very latest, but he missed the opportunity.

As the war developed, while the Allied navies grew apace in skill and professionalism, the quality and determination of U-boat crews declined. One by one Dönitz’s aces were killed or captured, and the men who replaced them were of lesser caliber. German torpedo technology was almost as flawed as that of the 1942-43 US Navy. Direction of the U-boat campaign was hampered by changing strategies and impulsive interventions by Hitler. German naval intelligence and grasp of Allied strategy, tactics and technology were chronically weak.

Hitler was fascinated by the great surface ships such as the battleships Bismarck and Tirpitz, the pocket battleships Deutschland, Admiral Graf Spee and Admiral Scheer, the battle cruisers Scharnhorst and Gneisenau and the heavy cruiser Prinz Eugen, but he understood very little of naval strategy and the influence of sea-power. He certainly failed to spot the potential of a massive U-boat campaign, and largely ignored his admirals’ pleas for more ships and submarines during 1940, preferring to concentrate resources on the Wehrmacht and Luftwaffe. It was to be one of his greatest blunders of the war.

As the Russians made their way along the Baltic coast, the Germans had to relocate their U-boat fleet to Norway. Although their number peaked at the huge figure of 463 in March 1945, it was far too late for them to be able to make a difference. In total, throughout the war Germany deployed 1,162 U-boats, of which 785 were destroyed (over 500 by British ships and planes). Altogether they sank 145 Allied warships and 2,828 Allied and neutral merchantmen.

The U-boat crewmen were immensely brave, and at 75 percent suffered among the highest death rates of any branch of service in the Reich, in what they themselves dubbed iron coffins. As the war progressed, the U-boat sailors’ life expectancy decreased. Furthermore, heavy Allied bombing of U-boat construction and marshalling yards meant that the newest-pattern U-boat – once hailed as a super-weapon – did not slide down the slipway until May 1945, just as Dönitz was negotiating peace terms with the Allies.

After April 1941 Dönitz pioneered Rudeltaktik (herd tactics), by which the first U-boat to spot a convoy shadowed it while sending out signals to headquarters and other U-boats in the area, prior to a concerted night-time, surface, close-range torpedo attack by them all, acting as a wolf-pack.

U-boats were often faster than their prey, averaging 17 knots on the surface, where they often sailed at night (they managed only 3 knots when submerged). Long after the war, Dönitz enumerated the advantages of the U-boat, which were more maneuverable than their Great War predecessors and: ‘had only a small silhouette consisting only of the conning tower and that is why the submarine could only be seen with difficulty during a night attack. Gradual development in communications meant the submarines were no longer obliged to fight alone, but they could attack together. This enabled us to develop the “wolf-pack” tactics that became very useful against the convoys.’

British sailor and author Nicholas Monsarrat described how the U-boats took the upper hand in 1941: ‘The enemy was planning as well as multiplying. At last, the U-boats were co-ordinating their attack: they now hunted in packs, six or seven in a group, quartering a huge area of the convoy route and summoning their full strength as soon as a contact was obtained. They had the use of French, Norwegian and Baltic ports, fully equipped for shelter and maintenance: they had long-range aircraft to spot and identify for them, they had numbers, they had training, they had better weapons, they had the spur of success.’

In 1942, by far the most alarming year of the U-boat war, 609 ships were sunk in the North Atlantic, a total of some six million tons. So prodigious was American shipbuilding capacity, however, that in the same period the Allies launched 7.1 million tons of ships, increasing their available pool of thirty million tons. Yet, as is the way of mankind, the Allies perceived most of the difficulties on their own side. While posterity knows that in 1942 the U-boats inflicted the utmost damage of which they were capable, and that thereafter the tide of the convoy war turned steadily against them, at the time Churchill and Roosevelt saw only a steeply rising graph of losses which, if it had continued, would have crippled the war effort.

In 1942 British imports fell by five million tons, imposing severe strains on food and oil supplies – the latter were reduced by about 15 percent, requiring the government to dip into its admittedly large strategic stockpiles. This was attributable less to Dönitz than to the diversion of two hundred ships from the Atlantic shuttle to open an Arctic supply line to Russia. Whatever the causes, however, Britain’s shrunken deliveries alarmed a nation with its back to the wall in many theaters and three dimensions.

Even when the US supplied Britain with a few B-24 Liberators – suitable for very-long-range conversion and thus ideal for Atlantic convoy support – initially the RAF chose to use most of them elsewhere. Sir Arthur Harris, Commander-in-Chief of Bomber Command between 1942-45, fiercely resisted the diversion of heavy aircraft to the convoy war: ‘It was a continual fight against the navy to stop them as usual pinching everything,’ said Harris, who disliked British sailors almost as much as he abhorred the Germans. ‘Half my energies were given to saving Bomber Command from the other services. The navy and army were always trying to belittle the work of the air force.’

An average of just over one convoy a week made the North Atlantic passage each way. Many crossed without suffering attack, because the Germans did not locate them. Ultra intercepts of U-boat position reports, together with ‘Huff-Duff’ – High Frequency Direction Finding by warships – often made it possible to divert convoys away from enemy concentrations.

If the German offensive was mismanaged, especially in 1941-42, Allied merchant seamen suffered grievously from its consequences. Crews were drawn from many nationalities; although some young British men chose the merchant service in preference to conscription into the armed forces, it would be hard to argue that this represented a soft option: some seamen were obliged to abandon ship two or three times. Michael Page described one such experience, in Atlantic darkness: ‘One minute we had been on watch on deck or in the engine-room, or sleeping snugly in our bunks; the next we were engaged in a frenzied scramble through the dense, shrieking blackness which assailed us with squalls of freezing spray, and slipped and fell on the wet iron decks which canted faster and faster into the hungry sea with every passing second … “What’s happening? What’s happening?” someone kept demanding in a high-pitched wailing cry, full of agonized bewilderment … We struggled with stiff reluctant ropes and the bulky gear of the boat in a kind of automatic frenzy … The boat was lowered somehow, and we scrambled down towards it. Some of us got there, some did not – misjudging the distance as they jumped. “Cast off!” bawled someone when the boat seemed crowded; a cry echoed by several others, but answered at once by yells and screams above us – “No, no wait! Wait a second!” A darker body hurtled through the darkness and hit the waves with a tremendous splash, reappearing to splash towards the boat and grab at her gunwale … A wave broke fully into the boat, drenching and swamping us completely; we gasped and spluttered with the icy shock … Someone immediately slipped the painter … Whether everyone who could be was in the boat, God knows; we were swirled away in an instant.’

In May and June 1942, a million tons of shipping were sunk in United States eastern coastal waters, often by submarines firing torpedoes at vessels silhouetted against the blaze of shore lights. In the year as a whole, six million tons went to the bottom. America’s merchant fleet paid dearly for the US Navy’s refusal to join the established Canadian convoy network, and to heed British experience. The Germans began to concentrate ‘wolf packs’ of up to a dozen U-boats, to swamp convoy escort groups.

The U-boats enjoyed a surge of success in the months following Pearl Harbor, chiefly because the US Navy was slow to introduce effective convoy and escort procedures. In those days, before attrition diluted the quality of the Kriegsmarine’s personnel, the Freikorps Dönitz, as they proudly called themselves, was an elite. U-boat captain Erich Topp wrote: ‘Living and working in a submarine, one has to develop and intensify the ability to cooperate with other members of the crew, because you could need each other simply to survive… When you are leaving harbor, closing the hatch, diving, you and your crew are bidding farewell to a colorful world, to the sun and stars, wind and waves, the smell of the sea. All are living under constant tension, produced by living in a steel tube – a very small, cramped and confined space with congested compartments, monotony and an unhealthy lifestyle, caused by bad air, lack of normal rhythms of day and night and physical exercise.’ Topp took immense pains to nurture morale. Once, a few hours after leaving port, he found his navigator looking morose. The man revealed that he had inadvertently left behind a myrtle wreath, the German symbol of marriage which was also his operational talisman. He was convinced that U-552 was thus doomed. Topp reversed course and returned to Bergen to let the navigator fetch his wreath before sailing again, a happy man.

In March 1943 there was another breakdown of U-boat radio traffic decryption. In consequence, for two months half of all Atlantic convoys suffered attack, and one in five of their merchantmen were sunk. Yet this proved the final crisis of the campaign. That spring, at last the Western Allies committed resources which overwhelmed the U-boats. Escort groups equipped with 10cm radar, VLR aircraft with improved depth-charges, small carriers and renewed penetration of Dönitz’s ciphers combined to transform the struggle. Dönitz found himself losing a U-boat a day, 20 percent of his submarine strength gone in a month. He was obliged to drastically curtail operations.

Admiral Sir Max Horton, who became Commander-in-Chief of Western Approaches in November 1942, was a former World War I submariner of the highest gifts, who made a critical contribution to victory, directing the Atlantic campaign from his headquarters in Liverpool.

There was a steep fall in merchant ship sinkings, so that by the last quarter of 1943 only 6 percent of British imports were lost to enemy action. The wartime Atlantic passage was seldom less than a gruelling experience, but for the rest of the war British and American forces dominated the ocean, challenged by a shrinking U-boat force, with German crews whose inexperience and waning morale were often manifest.

Britain’s merchant fleet was devastated to a degree which contributed to the nation’s post-war economic woes: almost all the fourteen million tons of new Allied shipping launched in 1943 were American. But the immediate reality was that Germany had lost its war against Atlantic commerce.

As the battle of the Atlantic progressed, there were a number of factors that secured victory for the Allies, including the vast expansion of the Canadian Escort Force based in Halifax, Nova Scotia; side-firing as well as back-firing depth-charges; the new high-frequency, direction-finding (HF/DF) apparatus; Anti-Surface-Vessel radar, which the Germans greatly overestimated and often blamed for intelligence coups that actually derived from Ultra; Very Long Range bombers that reported U-boat positions, bombed them and closed off the Ocean Gap; powerful Leigh floodlights for spotting conning towers and periscopes; airborne centimetric radar; and the alteration of the Royal Navy codes in June 1943 which plunged the German decrypters in the dark.

As so often, it was the Commonwealth that played a vital, if largely unsung, part in winning the battle. The Royal Canadian Navy grew fifty-fold in the course of the conflict, and its anti-submarine arm, the Canadian Escort Force, contributed almost as much to victory as the Royal Navy. Protecting the HX (Halifax-to-Britain) and SC (Sydney-or Cape-Breton-to-Britain) eastbound convoys in one direction, and the westbound ONF (fast outbound-from-Britain) and the ONS (slow outbound-from-Britain) convoys in the other, they were invaluable.

Dönitz was forced to withdraw all his U-boats from the North Atlantic, and report to Hitler in Berlin. ‘There can be no let-up in submarine warfare,’ Hitler told him at a conference also attended by Karl-Jesko von Puttkamer, the Führer’s naval adjutant. ‘The Atlantic is my first line of defense in the West, and even if I have to fight a defensive battle there, that is preferable to waiting to defend myself on the coast of Europe.’ No longer did Germany see the Atlantic as a potential means of strangling Britain; now it was somewhere to hold off the coming invasion of north-west Europe. Yet Dönitz was powerless to obey his Führer and in June 1943 Allied ships were allowed to sail across the Atlantic without convoy protection for the first time in four years.

When Hitler invaded Russia, the British and American Chiefs of Staff alike opposed the dispatch of military aid, on the grounds that their own nations’ resources were too straitened to spare arms for others. The Royal Navy saw a further strategic objection: any material shipped to the Soviets must be transported through their Arctic ports, Murmansk and Archangel, the latter accessible only in the ice-free summer months. This would require convoys travelling at a speed of eight or nine knots to endure at least a week-long passage under threat or attack from German U-boats, surface warships and aircraft based in nearby northern Norway. Britain’s prime minister and America’s president overruled these objections, asserting – surely rightly – that support for the Soviet war effort was an absolute priority.

Hitler at first took little heed of the significance of the Arctic link to Russia, despite the fact that his obsession with a possible British landing in Norway caused him to fortify its coastline. Churchill remained a strong advocate of such an assault until as late as 1944, although he was thwarted by the implacable opposition of his service chiefs. What mattered in 1942, however, was the strong German naval and air presence in the far north, which threatened Arctic convoys.

The First Sea Lord, Admiral Sir Dudley Pound, deplored the diversion of resources from the Battle of the Atlantic to open a hazardous new front merely to aid the repugnant Soviets, who seemed likely to succumb soon to the Germans. Pound was especially uneasy about the prospect of outgunned elements of the Home Fleet meeting one of Hitler’s capital ships, most likely the Tirpitz: the navy was scarred by memories of its difficulties and losses before the Bismarck succumbed.

Churchill remained implacable: he insisted that the navy must brave the passage, whatever its perils, carrying to Russia such weapons and supplies as Britain and America could spare. He was undeterred by the prospect of battle. In 1941-42 one of his foremost objectives was to exploit opportunities to engage German forces; he thus demanded the establishment of a continuous cycle of Arctic convoys. The few merchantmen which Britain sent to Russia in late 1941 arrived unscathed, carrying small quantities of tanks, aircraft and rubber. The Germans barely noticed their passage.

The first regular convoys, which all had the codename PQ followed by a consecutive number, started out from Iceland to Murmansk and Archangel via Bear Island. PQ-1 set out packed with military supplies and large quantities of the vital raw materials that Stalin had asked for personally, including rubber, copper and aluminium. Soon afterwards, Churchill announced that Britain’s entire tank production for the month of September 1941 was going to be dispatched to Russia. The tanks were badly needed, for the Nazis launched Operation Typhoon on Moscow.

In 1942, however, as the British began to transport substantial shipments eastwards, Hitler’s forces intervened with mounting vigor. The experiences of the ‘PQ’ convoys, as they were designated, and of the return ‘QP’ series, became one of the war’s naval epics. On the Murmansk passage, almost every ship suffered weather damage, to which even the greatest ships were vulnerable. As the convoy battles of 1942 became progressively harder and more costly, merchant service officers voiced dismay about their treatment by the navy. Above all, they protested about the fact that they were expected to sail day after day through the most perilous waters in the world, knowing nothing of what was happening save what they could see from their ice-encrusted upper decks.

Even before the Germans entered the story, Arctic weather was a terrible foe. Ships often found themselves ploughing through mountainous seas, forty feet from trough to wave crest, while laden with a topweight of hundreds of tons of ice. More than a few men were lost overboard, and a monstrous wave once stripped the armored roof from the cruiser Sheffield’s forward turret.

British dockers, especially in Glasgow, gained a deplorable reputation for carelessness in cargo stowage which contrasted with painstaking American practice. Not only did much materiel arrive damaged at Murmansk, but the ships’ very survival was threatened by loads breaking loose. Crews were obliged to labor relentlessly, hacking dangerous weights of ice from upperworks and guns, testing weapons on which lubricants froze. Men moved sluggishly in heavy layers of clothing which never sufficed to exclude the cold.

Because of the Tirpitz threat, each convoy required the protection of almost as many warships as there were merchantmen. Destroyers provided close protection against U-boats. Merchantmen were fitted with AA guns, and the assembled ships could mount a formidable barrage against attacking Heinkels. Cruisers offered cover against German destroyers as far east as Bear Island, to the north of Norway. Over the horizon lurked big ships of the Home Fleet, hoping to intervene if German capital units sortied.

On the Allied side, while some merchant navy personnel showed remarkable spirit, others too readily fled damaged vessels. Panic-stricken British and American sailors on several occasions lowered lifeboats so clumsily that their occupants were tipped into the sea. As for the Germans, convoy crews were surprised by the irresolution of some Luftwaffe pilots, who failed to press attacks through heavy barrages. The German navy, meanwhile, was hamstrung by Berlin’s insistence on making all decisions about when and whether to deploy capital ships. Again and again, disgusted Kriegsmarine officers were ordered to break off action and scuttle for the safety of Norwegian fjords.

Churchill angrily rejected the Royal Navy’s urgings to suspend convoy operations during the perpetual daylight of Arctic summer. ‘The Russians are in heavy action and will expect us to run the risk and pay the price entailed by our contribution,’ he wrote. ‘The operation is justified if half gets through. Failure on our part to make the attempt would weaken our influence with both our major allies.’

In the winter of 1942 another reckless Admiralty decision was made: to run some single merchantmen to Russia unescorted, manned by volunteer crews lured by cash bonuses of £100 an officer, £50 a man. Five out of thirteen such ships arrived. Even when ships reached Russia, they found little to cheer them. ‘The arrival in Kola Inlet was eerie,’ wrote one sailor. ‘It was December and pretty dark. There were great swirls of fog, black water and white snow-covered ice. The bare rocks on either side of the inlet were menacing and silence was broken only by constant sounding of mournful fog-horns of various pitches … I felt that if Hell were to be cold, this would be a foretaste of it.’ At Murmansk they remained subject to almost daily Luftwaffe attack.

One of the most serious setbacks of the naval war occurred in July 1942, when Convoy PQ-17 was spotted by German submarines and aircraft. It was hard to miss, comprising thirty-five merchant ships, protected by six destroyers and fifteen other armed vessels. Four merchantmen were sunk by Heinkel torpedo-bombers, and, fearing that four powerful German warships – including the Tirpitz – were on their way, Admiral Sir Dudley Pound, the First Sea Lord, ordered the convoy to scatter, overriding the C-in-C Home Fleet Admiral Sir John Tovey. It was a virtual death sentence. The scattered convoy was picked off from the air and by submarines.

Only thirteen ships reached Archangel; of the 156,500 tons loaded on board the convoy in Iceland back on 27 June, 99,300 tons were sunk, with the loss of no fewer than 430 of the 594 tanks and 210 of the 297 planes on board. It was astonishing that not more than 153 sailors were drowned.

The turn of the year 1942 proved the critical landmark of the campaign. Weather and the enemy – especially U-boats armed with acoustic homing torpedoes – ensured that service on Arctic convoys never became less than a miserable and alarming experience, but losses fell dramatically. In 1943 the Royal Navy was at last able to deploy escort carriers and powerful anti submarine and anti-aircraft defenses. The Germans, hard-pressed in Russia and the Mediterranean, were obliged to divert much of their air and U-boat strength away from Norway. The US began to move massive supplies by other routes.

Hitler refused to sanction major warship attacks on convoys until an ill-judged sortie was attempted by Scharnhorst in December 1943, which resulted in its sinking off the North Cape by a British fleet led by the battleship Duke of York.

Half of all wartime American shipments reached Russia through its Pacific ports, a quarter through Persia, and only a quarter via Archangel and Murmansk. The human cost of the PQs was astonishingly small by the standards of other battlefields: though eighteen warships and eighty-seven merchantmen were lost, only 1,944 naval personnel and 829 merchant seamen died serving on Arctic convoys between 1941 and 1945. The Germans lost a battleship, three destroyers, thirty-two U-boats and unnumbered aircraft.

The Royal Navy accounted the Russian convoys among its most formidable wartime challenges. The Fleet Air Arm never distinguished itself in the north, partly for lack of good aircraft. Some of the navy’s most senior officers failed to display imagination to match the courage and seamanship of their subordinates. They refused to acknowledge, as Churchill and Roosevelt always acknowledged, that at any cost aid must be seen to be sent to Russia.

Between 1940 and 1943, the Mediterranean witnessed some of the bloodiest fighting of the Royal Navy’s war. British submarines, based on Malta when conditions there allowed, attacked Axis supply lines to North Africa with some success. Battle squadrons sought to assert themselves in the face of the Italian navy, U-boats and the Luftwaffe. In 1942, the hazards were increased by German deployment of U-boat reinforcements. But Churchill conducted the war effort on the basis that Britain must be seen to challenge the enemy at every opportunity, especially when the army accomplished so little for so long. Malta, within easy range of Axis Sicilian air bases, suffered almost three years of intermittent bombardment.

Admiral Sir Andrew Cunningham inflicted severe damage on the Italian fleet in his November 1940 carrier air strike against Taranto, and in the surface action off Cape Matapan in March 1941. But every capital ship sortie into open waters within range of the enemy was a perilous venture, which took a harrowing toll. The carrier Illustrious was badly damaged by German bombing in January 1941. In November that year, the battleship Barham blew up, with the loss of most of its crew, after being torpedoed by a German submarine.

In March and April 1942 Malta received twice the bomb tonnage dropped on London during the entire Blitz; its people almost starved, and its resident submarine flotilla had to be withdrawn. Under almost continuous bombardment from nearby Sicily, at times Malta became unserviceable as an offensive base for submarines and surface ships, but it remained a vital earnest of Britain’s will to fight. Hitler blundered by failing to seize Malta in 1941, and huge efforts and sacrifices were made to sustain it thereafter.

The battleships Queen Elizabeth and Valiant rested for seven months on the floor of Alexandria harbor after falling victim to an attack by courageous Italian human-torpedo crews in December 1941. The Royal Navy, having lost five capital ships in a month, was for a time obliged to cede the central Mediterranean to the Axis. There was a steady drain of British cruiser and destroyer losses to mines, bombs and torpedoes. For some months in 1941, the navy suffered severely while holding open a sea link to besieged Tobruk, which was deemed symbolically if not militarily important.

Prime Minister Winston Churchill’s decision to make a major British military effort in North Africa obliged the navy to conduct operations in the Mediterranean with negligible air cover, and in the face of strong Axis air forces operating from fields in Italy, Sicily, Libya, Rhodes, Greece and Crete. Malta, the only offshore outpost in the central Mediterranean from which Axis supply routes to North Africa could be interdicted, faced three years of siege. Between June 1940 and early 1943, the Mediterranean was largely unusable as an Allied supply route, but Churchillian war-making emphasized assertion of the navy’s presence and engagements of opportunity, especially against the Italian fleet. Some of the fiercest naval fighting of the war, and heavy British losses, took place in those limpid waters.

The requirement to sustain Malta became a priority for the Royal Navy, and every supply ship had to be fought through in the face of air, U-boat and surface attack. Each convoy demanded a supporting fleet operation: there must be battleships in case Italian heavy units sortied, carriers to provide air cover, and cruiser and destroyer escorts. Each venture precipitated an epic battle. The most famous, or notorious, took place in August 1942, when Malta’s shortages of oil, aircraft and food attained desperate proportions: Operation Pedestal was launched to bring relief. Despite heavy losses, the British navy managed to bring in enough supplies for the island to continue resisting.

Vice-Admiral Edward Syfret took command of the battlefleet that sailed from the Clyde, escorting fourteen merchantmen. Several of these were chartered American ships, notably the tanker Ohio, provided with British crews. All had been fitted with anti-aircraft armament manned by soldiers, and on the passage to Gibraltar the convoy intensively exercised both gunnery and maneuver.

The ships that set forth on 10 August to make the Malta passage formed a mighty array: the battleships Nelson and Rodney; fleet carriers Victorious, Indomitable and Eagle; the old carrier Furious, ferrying Spitfires to reinforce the island as soon as the range narrowed sufficiently to fly them off; six cruisers; twenty-four destroyers and a flotilla of smaller craft. A host of German and Italian eyes, watching Gibraltar from Spain and North Africa, saw the fleet sail. Axis commanders were undeceived by a feint convoy which sailed simultaneously from Alexandria, trailing its coat in the eastern Mediterranean.

Amid a still, azure sea, Furious began flying off its Spitfires, which set course for Malta, 550 miles distant, where most arrived safely. But now the first disaster struck. In the western Mediterranean, Asdic was confused by freak underwater conditions created by the confluence of warm seas with colder Atlantic currents: ships were thus acutely vulnerable to submarine attack. Even as the fighters were being launched, a salvo of torpedoes fired by U-73 struck Eagle, which sank in eight minutes with the loss of 260 of her crew of 1,160 men. ‘She presented a terrible sight as she heeled over, turned bottom up and sank with horrible speed,’ wrote an awestruck witness. ‘Men and aircraft could be seen falling off her flight deck as she capsized … It makes one tremble. If anyone took a good film of it, it should be shown throughout the country … I remember thinking of the trapped men.’ That evening Furious, its flight deck now empty, turned for home and safety. One of her escorts, the destroyer Wolverine, spotted an Italian submarine and raced in to ram; the Axis boat sank, but Wolverine suffered severe damage.

The first enemy air attack was launched against Pedestal, by thirty-six Heinkel 111s and Ju88s flying from Sicily. These achieved no hits, and four German aircraft fell to the intense AA barrage. Next day at noon, a much more serious strike took place, by seventy bombers and torpedo-carriers with fighter escort. The ensuing battle lasted two hours. The freighter Deucalion was damaged and later sunk off the Tunisian coast by a torpedo-bomber, despite gallant efforts to save the ship by her master, Captain Ramsay Brown. During the afternoon, the convoy survived a submarine ambush unscathed. The destroyer Ithuriel rammed and sank another Italian boat, at the cost of crippling herself.

The Luftwaffe and Italian air force came again. A hundred bombers and torpedo-carriers launched attacks from every direction and altitude, designed to swamp the defense. The destroyer Foresight was sunk, and the carrier Indomitable badly damaged by three armor-piercing bombs. Still short of the Sicilian Narrows, Syfret withdrew his capital ships westwards, leaving a close escort headed by six cruisers, commanded by Rear-Admiral Harold Burrough, to fight the convoy through to Malta.

Within an hour of Syfret parting company, the Italian submarine Axum achieved a brilliant triple success: in a single attack, it sank Burrough’s flagship Nigeria and the anti-aircraft cruiser Cairo, also hitting the tanker Ohio. These losses wiped out the convoy’s Fighter Direction capability, since the two cruisers carried the only radio sets capable of voice communication with Malta-based planes. Then, as the light began to fade, with British ships losing formation and huddling into a scrum, the Luftwaffe came again. Ju88s sank the merchant ships Empire Hope and Clan Ferguson and crippled Brisbane Star. Soon afterwards, a submarine torpedo damaged the cruiser Kenya. German and Italian motor torpedo boats launched a series of attacks which persisted for hours. The cruiser Manchester was fatally damaged, four more merchantmen sunk and a fifth hit.

At daybreak the Luftwaffe returned, sinking another merchantman. Ohio suffered further damage, but limped onward until renewed attacks later in the morning stopped her engines. Two more merchantmen were crippled, and had to be left behind with a destroyer escort. At 16.00, in accordance with orders, Burrough’s three surviving cruisers turned back for Gibraltar. Three merchantmen – Port Chalmers, Melbourne Star and Rochester Castle, the last with its deck almost awash – struggled to cover the final miles into Malta shepherded by small craft from the island. As cheering crowds lined the old fortifications, they steamed into Grand Harbour. The Germans set about demolishing the stragglers, sinking the damaged Dorset and hitting Ohio yet again.

The Pedestal convoy delivered 32,000 tons of stores, 12,000 tons of coal and two months’ supply of oil; five merchantmen survived out of fourteen. The navy’s aggressive posturing dissuaded the Italian fleet from joining the battle. The three-day drama of Pedestal was almost matched by the experiences and sufferings of other Malta convoys and their escorts. By the winter of 1942, the worst of Britain’s Mediterranean struggles were over. Ultra decrypts enabled Allied warships and aircraft to wreak increasing havoc on Erwin Rommel’s supply line. In November 1942, Bernard Montgomery was victorious at El Alamein and the Americans landed in North Africa. The siege of Malta was relieved soon afterwards.

Mussolini’s battleships were immobilized anyway by lack of fuel, and RAF aircraft dropped flares over five cruisers which put to sea, convincing them that they faced unacceptable risk if they persevered. Lieutenant Alastair Mars, commanding the submarine Unbroken, extracted some revenge for British warship losses by torpedoing the Bolzano and Muzio Attendolo. But after the Pedestal battle was over, Commander George Blundell of the battleship Nelson looked back in deep gloom: ‘Most of us felt depressed by the party. Operation “M” for Murder we call it. “The navy thrives on impossibilities,” said the BBC. Yes, but how long can it go on doing so?’

Not all those who sailed distinguished themselves: there were cases of merchant ship crews abandoning their ships unnecessarily, of seamen scuttling for lifeboats while their vessels were still steaming. A disgusted Captain Brown of Deucalion, some of whose men quit their posts prematurely, said later, ‘I could never have imagined that any Britishers could have shown up in such poor colours.’ But the overall story is one of a fine endeavor.

Holding the island since 1940 had cost the Royal Navy one battleship, two carriers, four cruisers, one minelayer, twenty destroyers and minesweepers and forty submarines. The RAF lost 547 aircraft in the air and another 160 destroyed on the ground. Ashore, Malta’s defense forfeited the lives of 1,600 civilians, seven hundred soldiers and nine hundred RAF personnel. Afloat, 2,200 warship crewmen, 1,700 submariners and two hundred merchant seamen perished.

After the siege of Malta was lifted in 1943 and 1944, Allied dominance of the Mediterranean remained contested and imposed continuing losses, but strategic advantage tilted relentlessly away from the Axis. The Royal Navy’s critical responsibilities in the last two years of the war became those of escorting Allied armies to new battlefields, and organizing and protecting a succession of massive amphibious landings.

Although the threat from Germany’s submarines and aircraft persisted to the end – British warships suffered severely in the ill-fated autumn 1943 Dodecanese campaign – the Royal Navy had won the decisive battles of the European war at sea; not in actions between fleets, but by sustaining Britain’s global rights of passage in the face of air power and U-boats.

The Soviet Union's navy was involved in important operations primarily in the Black Sea, but there is very little evidence of Stalin's recognition then of the extent to which Allied strategy was dominated by the problem of shipping. The role of the Soviet navy was primarily one of supporting land operations. In the north, the units of the fleet there assisted in the defense of Murmansk and played a small role in receiving the convoys from the West. The Russians had few merchant ships in the Pacific; the United States, therefore, began transferring ships to the Soviet flag so that they could cross the Pacific to the Soviet Union without escort, as the Japanese allowed Soviet ships to travel designated routes unmolested.

In the pre-war years Stalin had begun to push for the building of a Soviet blue-water navy, and he had utilized the period of alignment with Germany to obtain items useful in such a buildup in exchange for Soviet support of the German war against Allied shipping. However, these measures represented a small beginning of naval planning, not a real comprehension of the role of sea power in global war.

It was precisely because the Soviet Union did not have either the shipping to carry the goods or the warships for escorts that the bulk of the cargo ships and escorts was provided by the British and Americans. Russian ships were regularly included in the convoys, and Soviet warships played a role as escorts and in clearing mines laid by the Germans. To reinforce their northern fleet, the Western Powers transferred numerous smaller warships to the Russians, and in 1944, as a compensatory arrangement in connection with the surrender of the Italian navy, turned over a battleship, a cruiser, and a destroyer. All the Russian ships as well as the units of the Red Air Force stationed in the far north played a part in protecting the convoy route.

In the very years that the Red Army was tearing the guts out of the German army, a huge volume of supplies was flowing unhindered to the Soviet Union under the noses of their Japanese ally. As the volume of shipments increased, the level and frequency of German protests to the Japanese increased as well. The latter, however, regardless of their feelings on the subject, believed very strongly that they could not interfere with the shipments or refuse to recognize the transfer of American ships to the Soviet merchant fleet without endangering their own relations with the Soviet Union.

On the few occasions when the Japanese detained Soviet vessels, the repercussions were immediate. The government of the Soviet Union insisted on the release of the ships and let it be understood that any other action by Japan would constitute a violation of the Soviet-Japanese Neutrality Treaty of 1941. As an angry Vyacheslav Molotov explained to the Japanese ambassador in 1943: ‘We are fighting a war and have to have stuff. We have lost some fine industrial and agricultural land and we must have food, machinery, and raw materials, and we are not going to stand for you Japanese standing in our way of getting them.’ Ambassador Sato Naotake consistently and insistently urged his government to accede to the Soviet demands and to refrain from ship seizures in the first place. Japan in his view simply could not afford to antagonize the Soviet Union and was in no position to argue about the legal status of the reflagged American ships. Tokyo gave in reluctantly but comprehensively.

In the Baltic, the Russian navy units based at Kronstadt were of importance in two ways. The possibility of Soviet ships coming out of the Gulf of Finland into the Baltic and interfering with Germany's supply routes to Finland, her trade with Sweden, or her training of submarine crews always agitated the German navy. The Russians also used this route to supply a section of the front that had been cut off from the rest of the Red Army.

The failure of the initial German offensive in 1941 cost the Germans heavily in a way that has not always been recognized: the Baltic did not become a safe German lake as Berlin had confidently expected.

At the northern end of the front, the Germans had cut off Leningrad, but they had not been able to clear the whole southern shore of the Gulf of Finland. The Red Army held on to a portion of the south shore: a segment which the Germans called the Oranienbaum Kessel and the Soviets referred to as the Coastal Operations Group. It could obviously survive only by receiving at least minimal reinforcements and supplies from the main defense of Leningrad, and this required the protection of the Soviet navy.

If the function of the Red Baltic Fleet was primarily one of army support, the same was true for most of the operations of the Soviet Black Sea Fleet. Its successful evacuation of the Odessa garrison was only one of many operations carried out by what was probably the most effective and efficient portion of Soviet naval forces in World War II. The Black Sea Fleet's role in the Soviet winter counter-offensive in the Crimea has also been mentioned. There the fleet not only reinforced the garrison but brought in other units, evacuated machinery, and generally organized under Black Sea Fleet Commander Admiral F.S. Oktyabskiy a very efficient defense.

The Soviet leaders had no reason to regret the portion of their resources allocated to the navy; though small and often forgotten by historians, its role was significant at precisely that portion of the Eastern Front where the Germans would make their greatest effort and suffer their greatest defeat at the hands of the Red Army in 1942. The naval struggle in the Black Sea was both in kind and in distance far removed from the endless battles in the Atlantic, the Allied blockade of Japan in the Pacific, and the efforts to maintain a blockade of Germany against her resourceful attempts to breach the ring around her; but these were all inter-related portions of a struggle for control of the oceans which cover much of the globe and which claimed so many lives that slid beneath the seas.