Third, it was unclear whether air power more likely aided U-boats in sinking merchant ships or helped convoys to destroy U-boats. Comparative advantage would hinge both on the ability to make more and better long-range planes and the strategic choices of when and how to use such air power.⁴

Fourth, either the German or British admiralty would benefit more from the cooperation of its allies. Although Italy dispatched a few submarines to the Atlantic, there was zero chance that the Italian and Japanese surface fleets would play any prominent role in the Atlantic. And while Germany occasionally sent a U-boat to the Indian Ocean or South Pacific, German submarines of the so-called Monsoon Group were of little help to Japan. In contrast, the Americans and British were full partners at sea in the European theater and rival partners in the Pacific.⁵

Fifth, the ongoing and constantly changing pulse of the war on land would better aid either the German or the British naval effort. Either British or German war obligations beyond the Atlantic would likely siphon off critical naval resources to a greater comparative degree. Most important, changes in strategic geography, prompted by the entrance of the United States and the Soviet Union into the war, would likely alter operations in the Atlantic.

THE SEESAW BATTLE of the Atlantic underwent several phases. All of them were predicated on sudden changes in the five defining moments above. The first months of the submarine war went well enough for the Allies, despite assorted disasters elsewhere on land and in the air. Britain had started the conflict with far more antisubmarine vessels (over 180 destroyers) than the Third Reich had U-boats. The weaker naval power was tasked with going on the offensive not just against the world’s largest navy but also against the enormous merchant marines of North America and the British Empire at large.

Oddly, given all the lessons of U-boat lethality in World War I and talk of Nazi rearmament, Germany began the war with a comparatively insignificant fleet of submarines, many of which were smaller, obsolete Type II coastal boats. The Type IIs lacked the range, speed, size, armament, and communications of the newer Type VII series, which themselves were never really fit for effective service across the vast Atlantic. In addition, well into 1941 the Germans were plagued by faulty magnetic torpedoes, a large percentage of which failed to explode on contact, nullifying the best efforts of U-boat captains and thereby nearly ruining morale.⁶

From their experience in World War I, the British almost immediately began escorting convoys from North America. The Germans had not yet perfected the strategies of, or had the resources for, massed wolf packs deployed deep into the Atlantic, safe from air attack, that laid in wait for slow-moving convoys. For such a small U-boat fleet, the chances that individual submarines would find ships far out in the Atlantic were slim. Nonetheless, Britain immediately saw the need to increase its already-large destroyer fleet by any means necessary. By September 1940 it had pressed the United States for the stopgap measure of an additional fifty World War I mothballed destroyers as part of swaps for bases in Newfoundland and the Caribbean. The deal is often ridiculed today as one-sided and ungenerous on the part of the United States. True, many of the destroyers of the Caldwell and Wickes classes may have been less than modern and in terrible shape. But the majority of them would see plenty of service against U-boats and survive the war. Nineteen of the ships were quite adequate Clemson-class destroyers, which the United States itself used throughout the conflict. Meanwhile, Germany was losing surface ships as Britain was now adding them. Hitler’s two-month-long assault on Denmark and Norway (April 9–June 10, 1940) ended up costing the Kriegsmarine three heavy and light cruisers and ten destroyers, while siphoning off U-boats from the Battle of the Atlantic at precisely the time Britain increased its antisubmarine fleet.⁷

Britain also held the early technological edge, due to much longer experience with early radar and sonar sets (or ASDIC, “Anti-Submarine Detection Investigation Committee”). Together such systems could offer newfound advantages in locating subs on and beneath the surface. British grand strategies for dealing with U-boats—convoys, sonar detection, depth charges, and air surveillance and attack—had primarily been tested since the last year of World War I and had been institutionalized in the fleet. Winston Churchill, as First Lord of the Admiralty, had provided his full support for addressing the U-boat peril. In contrast, German naval strategy still remained confused. Admirals Doenitz and Raeder still vied for Hitler’s attention to focus on either surface ships or U-boats.

In addition, from September 1939 to June 1940, the French fleet had joined the British in patrolling the European Atlantic coasts. The German navy, however, was still confined to its original North and Baltic Sea ports. For much of the winter there, harbors froze over, and the distance from the Atlantic routes vastly limited U-boat ranges. By early 1940 the brief U-boat offensive had largely failed. For most of 1939 Doenitz was scarcely able to ensure that more than ten U-boats were actually out in the Atlantic on patrol at any given time. He needed new bases, far more late-model U-boats, and a different way of using them if he were to avoid the verdict of the past war.⁸

In the second year of the war, the pulse of the tonnage battle radically changed. The numbers of Allied ships sunk by U-boats in the North Atlantic soared. From an average of about twenty-eight merchant ships destroyed per month in the last four months of 1939, the tally grew to a monthly rate of about forty ships throughout 1940. This was largely due to improved German U-boat production. Only 1.5 ships had been built per month in 1939. But output reached over four per month in 1940 and up to an incredible 16.5 in 1941.

Just as important, newer Type VIIC U-boats slowly entered service. They would eventually become the mainstay of the new U-boat fleet: 568 of them were to be commissioned during the war. The Type VIICs were faster, had longer ranges, and were stocked with more torpedoes than all earlier German models. Nevertheless, their efficacy by global standards was often exaggerated. In comparison to American Gato-class subs of 1941–1942 (which were rapidly replaced and improved upon by the Balao and Tench classes), the nimble and easily maneuverable VIIC was outclassed in a variety of categories: far fewer torpedoes, far smaller, far less range, far more uncomfortable, and slower. The superiority of American submarines and the relative inferiority of German U-boats is rarely noted, given their vastly different theaters of operation.

Doenitz also soon perfected the strategy of wolf pack attacks, in which several U-boats lay in ambush for plodding convoys. Since the mid-1930s the Germans also had broken some British naval codes and often had advance warning of the timing and routes of many convoys. Doenitz carefully charted his zones of attack so that they were well out of range of first-generation British air patrols. Now with months of aggregate experience, dozens of U-boat commanders had vastly improved and refined their operational tactics. The odds were slowly beginning to favor the Germans.⁹

Events on land also helped the Kriegsmarine. The fall of the Western European democracies in June 1940 completely redefined the U-boat war. New bombproof sub pens on the French coast at the warm-water harbors of Bordeaux, Brest, La Rochelle, Lorient, and Saint-Nazaire gave refuge to the Atlantic-bound U-boats some five hundred miles closer to the battle zone than their former North Sea bases. U-boats used that savings in distance to range farther out into the Atlantic. Lufthansa’s premier prewar airliner, the pathbreaking four-engine Focke-Wulf Fw 200 Condor, with wartime adaptations, could stay aloft for fourteen hours with occasional ranges over two thousand miles. Once based on the French coast, small fleets of radar-equipped Condors scoured the mid-Atlantic, providing valuable intelligence to U-boat commanders. By war’s end, the planes, equipped with bomb racks and crude bomb-sights, had also accounted for the sinking of over 350,000 tons of Allied shipping. Yet, inexplicably, fewer than three hundred Condors were to be built—about a tenth of the number of the somewhat smaller two-engine American Consolidated Catalina PBY flying boats—too few to change the tempo of the Atlantic war.¹⁰

The perfect storm of 1940 only grew worse for the British. What was left of the French fleet after July 1940 now was rendered largely irrelevant. A month later, an opportunistic Mussolini would send twenty-six of his own submarines to Bordeaux to aid German U-boats in the Atlantic. The British suddenly found themselves at war in Norwegian waters and in the Mediterranean, at a time when they were forced to send more supply convoys to their distant Pacific colonies in increasing fear of Japan. Meanwhile, fear of German invasion for most of 1940 argued for the Royal Navy to remain closer to home. These added responsibilities conspired to disperse and weaken British antisubmarine strength throughout the North Atlantic. The net result was increasing German confidence that the U-boats might succeed where the Luftwaffe had not in forcing their sole remaining enemy, Great Britain, to accept a negotiated armistice.¹¹

Yet by spring 1941, against all odds and mostly alone, the British slowly began to check German submarine advances. For the third time in two years, the momentum of the seesaw Battle of the Atlantic once again began to reverse. Despite more experienced captains, improved torpedoes, and more submarines, Germany was again on the defensive, as U-boats were rendered little more effective than in 1939. The geostrategic responsibilities of the two adversaries had once again flipped. Germany was now forced to deploy ever more of its manpower from the Arctic Circle to the Sahara, without yet fully exploiting Europe’s aggregate industrial potential. For the first six months of 1941 the Wehrmacht focused on planning Operation Barbarossa, as critical resources were directed to the army and Luftwaffe in an anticipated land and air war well over a thousand miles distant from the North Atlantic.

In contrast, by spring 1941 Great Britain no longer had any Western European exposure. In the months before the Japanese attack on Singapore, its responsibilities had shrunk largely to a one-front war in North Africa, the failed defense of Greece, and a still-anemic air campaign over the continent. As was true during even the worst months of the Blitz, when a supposedly beleaguered Britain outproduced Germany’s aircraft industry, the British and Canadians built more merchant ships, destroyers, and corvettes than the Third Reich could produce U-boats per month, even at the Kriegsmarine’s new accelerated rate.

With the sinking of the German flagship Bismarck in May 1941, the prior twenty-month effort of the Third Reich’s surface fleet to harass the Royal Navy and weaken the British merchant marine for all practical purposes came to an end. Many of Admiral Raeder’s once-promising new cruisers and battleships were at the bottom of the Atlantic, damaged, hiding, or bottled up by British ships in French, German, or Norwegian ports. The responsibility of containing what was left of the German surface navy was largely outsourced to British fighter and bomber forces, freeing up yet more Royal Navy ships to focus on U-boats.¹²

Equally important, improved British radar sets were not yet matched by German countermeasures. Their effectiveness was further enhanced after May 1941 when the British Navy salvaged from two U-boats—one captured, one sunk—cryptographic tables and elements of the Enigma cipher machine itself. For the last six months of 1941, British code breakers were able to read German naval communications routed through the Enigma cipher, an effort enhanced by Admiral Doenitz’s micromanagement of his fleet that required a vast corpus of daily coded radio transmissions. The British admiralty could either route North American convoys well around wolf pack rendezvous points, or intercept and destroy lone U-boats heading to and from their engagement areas. Again, the key to British cryptological superiority in the U-boat war was not just technological or predicated on chance capture of German codes and coding machines, but rather on a much more sophisticated and comprehensive approach to deciphering and disseminating such knowledge to the armed forces in a rapid and pragmatic fashion.¹³

Germany was not quite done yet. By early 1942 the Axis and Allies had opened yet a fourth—and the most lethal—chapter to the Battle of the Atlantic, once again hinging on vastly changed strategies, geography, technology, and productive capacity. In February 1942 German naval intelligence introduced a so-called fourth wheel and greater complexity to the Enigma cipher machines that all but ended the ability of the Allies to listen in on U-boat communications for several months. At about the same time, the German naval surveillance service (B-Dienst) also made greater inroads in cracking the so-called British and Allied Merchant Ships code (BAMS). For a critical few months of 1942, most communications about planned Allied convoy operations and routes were known in advance to the Kriegsmarine, suggesting that U-boat commanders now knew far more about the plans of their intended targets than their British targets knew about them.

The entry of the United States into the war in December 1941 should have offered immediate and unequivocal advantages for the British. The prewar US fleet was still the second largest in the world and now could operate freely against U-boats. Unfortunately, for the first six months of the American war the very opposite proved true. Germany enjoyed newfound advantages precisely because America’s mostly unprotected merchant fleet at last became fair game. For a variety of reasons, Admiral Ernest King, Chief of Naval Operations, did not immediately deploy American warships to escort Britain-bound convoys. In the initial months of outrage over Pearl Harbor, King resisted diverting too many US ships from the war against Japan. And in truth, for all his anti-British posturing, King did not yet have many American destroyers and long-range bombers on hand to focus on the U-boats. The result was that U-boats could feast on American merchant ships as they first set out from their East Coast ports. Slow-moving transports were often easily silhouetted against brightly lit cities that were not subject to blackouts. Month after month, cargoes of food, gas, and war materiel were blown up, often with most of their crews, in sight of the American coast.¹⁴

In the first eight months of the new U-boat war against America, the Germans in Operation Paukenschlag (“Drumbeat”) sank over six hundred ships, totaling over three million tons of shipping, at a loss of little more than twenty U-boats. Such lopsided totals should have broken the back of any incoming belligerent without sizable reserves of merchant ships.

Doenitz was able to deploy scarcely more than a dozen submarines off the American East Coast, a fact that makes the U-boat achievement even more astonishing. By marginally custom-fitting Type VIIs for extended ranges, and deploying a handful of the larger, new Type IX U-boats, the Battle of the Atlantic now sought to expand permanently into American waters. Over two hundred of the Type IX U-boats would eventually be built. If they were less agile and submerged far more slowly than earlier models, they also had a greater range of operation, as well as six torpedo tubes (rather than the five of most Type VII models) and more powerful engines.¹⁵

As autumn 1942 approached, Doenitz believed that at last he was harvesting Allied ships faster than they were being built—the most important calculus of the Battle of the Atlantic—while Britain’s factories and armies were running out of vital resources. He assumed likewise that the Japanese fleet—unbeaten in a string of victories from December 1941 to May 1942—was drawing off American surface ships to the Pacific. The need to supply the Soviet Union likewise meant that additional American merchant ships were diverted from the North Atlantic route. The result was that as the Allies spread their strength, a refocused German U-boat fleet found advantage against North American convoys. Yet the blinkered Doenitz did not grasp that his startling success after the entry of the United States into the war was a temporary aberration that was due less to German prowess than to American inexperience and poor choices. Once Admiral King released convoy escorts, and new, long-range B-24 Liberators began air escorts (though never in enough numbers), the U-boats would find 1943 as terrible a year as much of 1942 had proved uplifting.¹⁶

The greatest obstacle to the success of the U-boats was the unprecedented US production of destroyers, corvettes, and more merchant ships. By the last three months of 1942, less money was spent on building battleships, carriers, and cruisers, as well as armored vehicles, due to the urgent need to win the war against U-boats. American strategists saw that if their supply ships could not reach Great Britain and keep the sea-lanes open for troop transport, then the size of the American expeditionary army targeted to land on the shores of Mediterranean and Western Europe would not much matter.¹⁷

The brief German resurgence had also been based on a transitory intelligence advantage. But in October 1942, the British once again cracked the modified German naval code after the salvaging of Enigma key sheets and settings from another wrecked U-boat, and by December were once again reading Admiral Doenitz’s communications. The British also appointed a new antisubmarine commander, Admiral Sir Max Kennedy Horton, who continued the key innovations of his predecessor, Admiral Percy Noble. The two together had fashioned novel tactics, among them more independent killer antisubmarine ships that were able to range more widely to focus on convoys under attack by U-boats, as well as providing support vessels to help save crews.

The hunters then soon permanently became the hunted. As was true of General James Doolittle’s command decision of February 1944 to release American fighters from their direct bomber-escort duties so that they might range freely in search of German airfields and distant Luftwaffe fighters, so too British surface ships increasingly proactively took the war to the U-boats. Whether in the air or on the seas, the rationale was similar: individual pilots and captains, when freed from direct proximity to bombers and merchant ships, could find all sorts of multidimensional ways to hunt down their adversaries where and when they were most vulnerable. The best defense proved to be an audacious offense freed from preset doctrine.¹⁸

While Germans worked on long-term technological breakthroughs like snorkels and hydrogen-powered propulsion, the Allies implemented more incremental and practical advances: multiple-firing depth-charge throwers, powerful new airborne searchlights, small escort carriers that could bring their own air cover along with the convoy, and, always, improved radar and sonar. By mid-1943 these changes had at last all but doomed the entire U-boat effort.

Convoy ONS 5 that crossed the Atlantic in April and May 1943 is often viewed as emblematic of the final Allied victory in the Atlantic. The ensemble steamed across the Atlantic with one accompanying warship for every three merchant vessels. Despite being attacked by wolf packs of nearly forty U-boats for over a week, at least thirty of forty-two Allied merchant ships got through. Six of the attacking U-boats, however, were lost, and more were damaged. In later weeks, Atlantic convoys suffered minimal losses, or at least far fewer than did the U-boat packs that attacked them. The Battle of the Atlantic had all but ended by autumn 1943. In May alone, the Germans had lost a quarter of all their deployed U-boat fleet (43 in one month), while sinking only fifty-eight ships, a mere fraction of the Allied monthly new production. Meanwhile, American shipyards were turning out hundreds of Liberty and larger Victory merchant ships, totaling well over thirty-two hundred by the end of the war.¹⁹

Although U-boats remained an irritant throughout the war, they posed no serious threat in the conflict’s final twenty-four months. Admiral Doenitz confessed that by early 1943, “radar, and particularly radar location by aircraft, had to all practical purposes robbed the U-boats of their power to fight on the surface.… I accordingly withdrew the boats from the North Atlantic.… We had lost the Battle of the Atlantic.” Despite monthly increases in Allied convoys, the transatlantic route for the vast majority of merchant ships in 1944 and 1945 from North America to Britain was nearly risk free.

Although he had destroyed an enormous amount of Allied shipping at sea, Doenitz never curtailed Allied convoys nor, of course, could he extinguish factory production at the source—the most economical method of destroying the means to conduct a war. Consequently, the Allied merchant fleet was larger after the Battle of the Atlantic than before. The best that could be said for the German U-boat campaign was that it was the only theater of the war where Germany may have won in the narrow terms of a relative cost-to-benefit analysis of men and materiel, even as it lost the Battle of the Atlantic.²⁰

NAVAL SUPREMACY IN the eastern Mediterranean determined critical entrance to and exit from the Suez Canal, the proclivities of a neutral but always opportunistic Turkey, and the fate of key British supply bases in Egypt. Yet after the bold German capture of Crete in April 1941, the eastern Mediterranean remained largely static: Germans and Italians went on to occupy the Dodecanese Islands that remained Axis controlled until the end of the war, and from there used their air power to control much of the Aegean. Yet Germany and Italy were never able to exploit that propitious beginning to alter the course of the Mediterranean theater, much less permanently alter transit via Suez from the Atlantic to the Pacific. The Axis failure, again, was attributable to the vast superiority of the Royal Navy, which, protected by RAF squadrons, continued to operate freely out of Alexandria and Cyprus. Neither base was ever systematically bombed by the Germans or Italians. And after the December 1941 attack by Italian frogmen on two British battleships in Alexandria and the German failure at El Alamein, British bases in the eastern Mediterranean were all but secure for the rest of the war. Far from using Crete and the Dodecanese Islands as starting points for further conquests that might result in strategic advantage, Germany’s earlier eastern Mediterranean acquisitions died on the vine, becoming irrelevant by the end of 1943.

Fantasists in Japan and Germany had earlier dropped their illusions of ever meeting at Suez. Yet Churchill’s grand plans in autumn 1943 of retaking the Greek Aegean and Dodecanese Islands also proved a failure on all counts. The Germans enjoyed air superiority from Aegean island air bases. America was not interested in the Dodecanese campaign. And it was hard to see how replacing Germans with British in the Aegean would much aid the Allied cause that was soon to be determined in Western and Eastern Europe. In sum, the Mediterranean east of Greece, despite occasional bitter fighting, to the end of the war became a backwater without much change after summer 1941. It was a veritable Mediterranean Norway—another occupation that had idled needed German troops since 1940—that cost the Third Reich capital and manpower without offering much strategic recompense.²¹

The central and western Mediterranean were quite a different story. Unlike British-held Egypt, North Africa from eastern Libya to the Atlantic was soon the scene of constant battle, especially as southern France and Italy became the focus of Allied amphibious landings. Malta and Sicily—closer to Germany’s borders and the ultimate nexus of the war—were as violently fought over in 1942 and 1943 as Cyprus and Crete remained quiet. Despite initial British victories in a series of encounters with the Italian surface navy, from 1940 to mid-1942 the Axis still enjoyed the advantage. The French fleet was either sunk or retired by June 1940. The United States had little presence in the Mediterranean until late 1942. British airfields at Gibraltar, Malta, and Alexandria were offset by Axis fighter bases in Crete, Libya, and Sicily. There were still more Italian surface ships and German U-boats in the Mediterranean than there were British vessels. Against such odds, somehow Britain maintained a Mediterranean passage to its beleaguered troops in Malta and Egypt.²²

Major Naval Battles in the Mediterranean

The reason was again superior British operational skill. In a series of showdowns with the British Mediterranean navy, the larger Italian fleet—lacking good radar, secure fuel supplies, and familiarity with night fighting—was often port-bound or limited to brief breakouts. Like the Imperial Japanese Navy’s initial parity with the American Pacific fleet, numbers proved deceiving. Whereas Britain could transfer warships from the Atlantic and Pacific, and build more ships, Italy’s resources were ossified, and its shipbuilding industry was static. Britain risked battleships and cruisers, and most survived; Italy hoarded and lost them.

In the first major battle at the Italian base at Taranto (November 11–12, 1940), carrier-based British aircraft, under their audacious admiral, Andrew Cunningham, torpedoed the Italian fleet in its home port, seriously damaging three battleships (two disabled, one sunk). The battle was the first in history in which carrier-based planes without help from surface ships had sunk battleships, and its effect on Mussolini was dramatic. The Italian fleet was soon transferred northward from its opportune, but now exposed, Mediterranean perch. Although the fleet often ventured out to challenge Malta-bound convoys, and two of the damaged battleships were back in service in less than a year, the Regia Marina would never take on the British fleet with any degree of confidence.

Ironies followed from the landmark battle. The Japanese supposedly studied the attack closely in planning for Pearl Harbor, especially the innovative ability of British planes to use their torpedoes in a shallow-water port. Perhaps this close emulation was also why they, like the British, did not later follow up initially successful strikes with further attacks that could have destroyed the American fleet and its facilities entirely. Meanwhile, even the British had apparently learned little from their own revolutionary success. A little over a year later, the battleship Prince of Wales and the old, but still powerful battle cruiser Repulse would be sent to Singapore without fighter escort and would easily be blown apart by Japanese land-based planes in even more dramatic fashion than the manner in which British carrier pilots had earlier trounced Italian battleships.²³

Admiral Cunningham struck again at Cape Matapan (March 27–29, 1941) off the Greek Peloponnese a little over four months later. His Commonwealth fleet sank three Italian cruisers and two destroyers—all without radar capability—without suffering serious losses. Again, better British seamanship, audacity, radar, and intelligence explained the lopsided result. The only way for the Axis powers to destroy the British Mediterranean fleet was through air power and U-boats, and not through the numerical superiority of their Italian cruisers and battleships. For example, in fights off Crete in May 1941, the Luftwaffe sank two British light cruisers and six destroyers with minimal losses. In the constant struggle to isolate Malta and disrupt British supplies to North Africa, Axis air power, along with U-boats and mines, seemed close to winning the battle of the Mediterranean by the end of 1942, sinking two British carriers, a battleship, over ten cruisers, and more than forty destroyers, along with forty submarines.²⁴

To aid the U-boats, the Italian fleet was supposed to whittle down British destroyers that could be used for antisubmarine operations. Yet once again, the Italian navy would not take risks. The British, even with far greater resources deployed elsewhere, did. The British Mediterranean fleet grew larger than the Italian throughout 1942 and 1943, even as it lost more ships. Until the late arrival of the Americans in November 8, 1942, the British had envisioned three aims in winning the Mediterranean naval war: ensuring that reliable supply routes to their troops in North Africa could soon be maintained, diminishing Axis sea power enough to ensure amphibious landings in North Africa and southern Europe, and reestablishing a much safer route from Britain through the Suez Canal to the Indian and Pacific Oceans. In achieving these agendas, Admiral Cunningham proved to be not just a better sea lord than his German and Italian counterparts, but perhaps the premier admiral of the entire European theater.

In contrast, it would be hard to come up with a worse Axis maritime strategy in the Mediterranean than what Hitler and Mussolini had crafted. Malta, not Crete, was the strategic linchpin between the continents, and yet it was never seriously assaulted by land. Again, the Dodecanese Islands were a strategic dead end. Seizing Gibraltar should have been the overriding concern of Hitler. Yet he failed in negotiations with Spain’s Francisco Franco—who, after the cataclysm of the Spanish Civil War, wanted to stay out of Hitler’s war or, barring that, wanted much of Vichy France’s North African territory. Hitler’s failure to win over Spain created the anomaly of British Gibraltar controlling the western entry into and exit from the Mediterranean, despite being surrounded on all shores by hostile neutrals or Axis enemies. It was perhaps ironic that had Germany not supplied Franco during the Spanish Civil War, and had the Republicans won, Hitler in autumn 1940 likely could have simply invaded an exhausted Spain shortly after the fall of France and might well have taken Gibraltar.

The Pacific war in 1942 drew off British naval assets to Burma and for the protection of India, but not to the same degree that Operation Barbarossa shorted the Axis Mediterranean, an area that Hitler himself once scoffed that the Germans “had no interests in.” As was true almost everywhere else in the war, the disastrous decision to invade the Soviet Union ensured that the Axis could never marshal the wherewithal to drive the British out of the Mediterranean for good.²⁵

After late 1942, the Italian fleet was almost out of both oil and ships. It could play no real role in salvaging the North African Axis expeditionary forces. German U-boats on occasion would sink Allied ships even in the very last days of the war, but the era of wolf pack attacks crippling Mediterranean commerce were long over. The British and American fleets by mid-1943 could land on Mediterranean shores anytime and anywhere they chose. Of the some sixty U-boats that at one time or another entered the Mediterranean, only one survived the war.²⁶

Mussolini’s pipe dream of an ever-growing (“whoever stops is lost”) North African empire and refashioned Mare Nostrum vanished. So did Erwin Rommel’s brief hope of heading to Suez and perhaps even meeting up with Army Group South—the southern prong of Hitler’s three armies that had invaded the Soviet Union in June 1941—to drive through the Middle East to the Caspian Sea. The key to success in the Mediterranean was never how much area a power controlled—a map of Italian versus British territory in 1942 proved lopsided in favor of the former—but the location of the territory. As long as Gibraltar, Suez, and Malta—the entry, exit, and midway valves of the Mediterranean—remained British, they proved far more important Mediterranean bases than did Rhodes, Crete, and Sicily. Given growing Allied fleet and air power, the only Axis hope in the Mediterranean was a swift German victory over the Soviet Union, the addition of allies such as neutral Turkey and Spain, greater availability of ships and planes, and Japanese naval approaches to the Suez Canal. All were still possible in late 1941, unlikely by autumn 1942, and impossible by early 1943.

Still, the Mediterranean never quite panned out for the Allies, at least as Churchill originally envisioned, as the entry point into Austria and Germany through the “soft underbelly” of Europe. At best, Allied naval superiority in the Mediterranean meant that Sicily, Italy, and southern France were all to be invaded, with the stationing of long-range Allied bombers in Italy for deeper penetration into eastern Germany and its Eastern European partners. In addition, once the Kriegsmarine and the Regia Marina ceased to exist as viable navies, Britain could ensure relatively easy transport of supplies and troops through the Mediterranean to the Pacific.²⁷

THE ANOMALY ABOUT naval war in the European theater was that it largely ended two years before the collapse of Germany and Italy. Despite occasional losses to vestigial U-boats, after late 1943 Allied ships were largely free to go where they wished and do what they wanted—in a way not so true of land operations until late 1944 or early 1945.

The Pacific naval war should have progressed with far more difficulty for the British and the Americans, given the greater resources of the Japanese imperial fleet and the ostensible Allied “Europe first” policy of allotting resources. Instead, the British and American fleets achieved parity in six months, naval superiority in two years, and outright supremacy in less than three. By 1944 Allied naval power was free to turn nearly all its attention to ensuring supply and enhancing ground and air power—the chief objectives of putting a fleet to sea.