At the beginning of World War II, the Royal Navy was the strongest navy in the world,[1] with the largest number of warships built and with naval bases across the globe.[2] It had over 15 battleships and battlecruisers, 7 aircraft carriers, 66 cruisers, 164 destroyers and 66 submarines.[2] With a massive merchant navy, about a third of the world total, it also dominated shipping. The Royal Navy fought in every theatre from the Atlantic, Mediterranean, freezing Northern routes to Russia and the Pacific ocean.
Over the course of the war the United States Navy grew tremendously as the United States was faced with a two-front war on the seas.[3] By the end of World War II the U.S. Navy was by far the largest and most powerful navy in the world with 7,601 ships, including 28 aircraft carriers, 23 battleships, 71 escort carriers, 72 cruisers, over 232 submarines, 377 destroyers, and thousands of amphibious, supply and auxiliary ships.[4]
The United States Navy grew rapidly during World War II from 1941–45, and played a central role in the Pacific theatre in the war against Japan. It also played a major supporting role, alongside the Royal Navy, in the European war against Germany.
The Imperial Japanese Navy (IJN) sought naval superiority in the Pacific by sinking the main American battle fleet at Pearl Harbor, which was built around its battleships. The December 1941 surprise attack on Pearl Harbor did knock out the battle fleet, but it did not touch the aircraft carriers, which became the mainstay of the rebuilt fleet.
Naval doctrine had to be changed overnight. The United States Navy (like the IJN) had followed Alfred Thayer Mahan's emphasis on concentrated groups of battleships as the main offensive naval weapons.[18] The loss of the battleships at Pearl Harbor forced Admiral Ernest J. King, the head of the Navy, to place primary emphasis on the small number of aircraft carriers.[19]
By war's end in 1945, the United States Navy had added thousands of new ships, including 18 aircraft carriers and 8 battleships, and had over 70% of the world's total numbers and total tonnage of naval vessels of 1,000 tons or greater.
The American war plan was Rainbow 5 and was completed on 14 May 1941. It assumed that the United States was allied with Britain and France and provided for offensive operations by American forces in Europe, Africa, or both. The assumptions and plans for Rainbow 5 were discussed extensively in the Plan Dog memo, which concluded ultimately that the United States would adhere to a Europe first strategy, making the war against Germany a higher priority than the war against Japan. However President Roosevelt did not approve the plan—he wanted to play it by ear.[24] The Navy wanted to make Japan the top target, and in 1941–1943 the U.S. in effect was mostly fighting a naval war against Japan, in addition to its support for Army landings in North Africa, Sicily and Italy in 1942–1943.[25]
U.S. strategy in 1941 was to deter Japan from further advances toward British, Dutch, French and American territories to the South. When the Allies cut off sales of oil to Japan, it lost 90% of its fuel supply for airplanes and warships. It had stocks that would last a year or two. It had to compromise or fight to recapture British and Dutch wells to the South. in November 1941, U.S. Army Chief of Staff
George Marshall
explained the American air war strategy to the press—it was top secret and not for publication:
We are preparing for an offensive war against Japan, whereas the Japs believe we are preparing only to defend the Philippines. ...We have 35 Flying Fortresses already there—the largest concentration anywhere in the world. Twenty more will be added next month, and 60 more in January....If war with the Japanese does come, we'll fight mercilessly. Flying fortresses will be dispatched immediately to set the paper cities of Japan on fire. There won't be any hesitation about bombing civilians—it will be all-out.[26]
Marshall was talking about long-range B-17 bombers based in the Philippines, which were within range of Tokyo. After Japan captured the Philippines in early 1942, American strategy refocused on a naval war focusing on the capture of islands close enough for the intensive bombing campaign Marshall spoke about. In 1944, the Navy captured Saipan and the Mariana Islands, which were within range of the new B-29 bombers.
After its Pearl Harbor victory in early December the Imperial Japanese Navy (IJN) seemed unstoppable because it outnumbered and outgunned the disorganized Allies—US, Britain, Netherlands, Australia, China. London and Washington both believed in Mahanian doctrine, which stressed the need for a unified fleet. However, in contrast to the cooperation achieved by the armies, the Allied navies failed to combine or even coordinate their activities until mid-1942. Tokyo also believed in Mahan, who said command of the seas—achieved by great fleet battles—was the key to sea power. Therefore, the IJN kept its main strike force together under Admiral Yamamoto and won a series of stunning victories over the Americans and British in the 90 days after Pearl Harbor.
Outgunned at sea, with its big guns lying at the bottom of Pearl Harbor, the American strategy for victory required a slow retreat or holding action against the IJN until the much greater industrial potential of the US could be mobilized to launch a fleet capable of projecting Allied power to the enemy heartland.
The Battle of Midway, together with the Guadalcanal campaign, marked the turning point in the Pacific.[27][28][29] Between June 4–7, 1942, the United States Navy decisively defeated a Japanese naval force that had sought to lure the U.S. carrier fleet into a trap at Midway Atoll. The Japanese fleet lost four aircraft carriers and a heavy cruiser compared to the U.S. Navy's one American carrier and a destroyer. After Midway, and the exhausting attrition of the Solomon Islands campaign, Japan's shipbuilding and pilot training programs were unable to keep pace in replacing their losses while the U.S. steadily increased its output in both areas. Military historian John Keegan called the Battle of Midway "the most stunning and decisive blow in the history of naval warfare."[30]
Guadalcanal
Main article:
Battle of Guadalcanal
Guadalcanal, fought from August 1942 to February 1943, was the first major Allied offensive of the war in the Pacific Theater. This campaign saw American air, naval and ground forces (later augmented by Australians and New Zealanders) in a six months campaign slowly overwhelm determined Japanese resistance. Guadalcanal was the key to control the Solomon Islands, which both sides saw as strategically essential. Both sides won some battles but both sides were overextended in terms of supply lines.
In preparation of the recapture of the Philippines, the Navy started the Gilbert and Marshall Islands campaign to retake the Gilbert and Marshall Islands from the Japanese in summer 1943. Enormous effort went into recruiting and training sailors and Marines, and building warships, warplanes and support ships in preparation for a thrust across the Pacific, and to support Army operations in the Southwest Pacific, as well as in Europe and North Africa.[32]
In the
Bougainville Campaign
the United States retook the Solomon Islands to the west of Guadalcanal.
1944
The Navy continued its long movement west across the Pacific, seizing one island base after another. Not every Japanese stronghold had to be captured; some, like the big bases at Truk, Rabaul and Formosa were neutralized by air attack and then simply leapfrogged. The ultimate goal was to get close to Japan itself, then launch massive strategic air attacks and finally an invasion. The US Navy did not seek out the Japanese fleet for a decisive battle, as Mahanian doctrine would suggest; the enemy had to attack to stop the inexorable advance.
The climax of the carrier war came at the Battle of the Philippine Sea.[33] Taking control of islands that could support airfields within B-29 range of Tokyo was the objective. 535 ships began landing 128,000 Army and Marine invaders on June 15, 1944, in the Mariana and Palau Islands. The Japanese launched an ill-coordinated attack on the larger American fleet; its planes operated at extreme ranges and could not keep together, allowing them to be easily shot down in what Americans jokingly called the "Great Marianas Turkey Shoot."[34]
Japan had now lost most of its offensive capabilities, and the U.S. had air bases on Guam, Saipan and Tinian for B-29 bombers targeted at Japan's home islands.
The final act of 1944 was the Battle of Leyte Gulf, the last naval battle in history in which the battle line of one navy "crossed the T" of the battle line of its enemy, enabling the crossing line to fire the full broadsides of its main batteries as against only the forward guns of only the enemy's lead ship. The Japanese plan was to lure the main body of the U.S. fleet away from the action at Leyte Gulf by decoying it with a dummy fleet far to the north, and then to close in on the U.S. Army and Marines landing at Leyte with a pincer movement of two squadrons of battleships, and annihilate them. The movements of these Japanese fleet components were terribly uncoordinated, resulting in piecemeal slaughter of Japanese fleet units in the Sibuyan Sea and the Surigao Strait (where "the T was crossed"), but, although the ruse to lure the main body of the U.S. fleet away had worked to perfection, the Japanese were unaware of this, with the result that an overwhelmingly superior remaining force of Japanese battleships and cruisers that massively outnumbered and outgunned the few U.S. fleet units left behind at Leyte, thinking it was sailing into the jaws of the more powerful U.S. main body, turned tail and ran away without exploiting its hard-won advantage. After which Japan had now lost all its offensive naval capability.
Technology and industrial power proved decisive. Japan failed to exploit its early successes before the immense potential power of the Allies could be brought to bear. In 1941 the Japanese
Zero fighter had a longer range and better performance than rival American warplanes, and the pilots had more experience in the air.[36] But Japan never improved the Zero and by 1944 the Allied navies were far ahead of Japan in both quantity and quality, and ahead of Germany in quantity and in putting advanced technology to practical use. High tech innovations arrived with dizzying rapidity. Entirely new weapons systems were invented—like the landing ships, such as the 3,000-ton LST ("Landing Ship, Tank
") that carried 25 tanks thousands of miles and landed them right on the assault beaches - invented by the British and delivered by industrial capacity of the US. Furthermore, older weapons systems were constantly upgraded and improved. Obsolescent airplanes, for example, received more powerful engines and more sensitive radar sets. One impediment to progress was that admirals who had grown up with great battleships and fast cruisers had a hard time adjusting their war-fighting doctrines to incorporate the capability and flexibility of the rapidly evolving new weapons systems.
The proximity fuze reduced by a factor of 5 to 10 the amount of anti-aircraft shells needed to shoot down a plane. Proximity fuzes were also very effective against troops on the ground.
Radar proved to be an essential technology against ships and aircraft, for detection of the presence of the enemy as well as for fire control.
Ships
The ships of the American and Japanese forces were closely matched at the beginning of the war. By 1943 the American qualitative edge was winning battles; by 1944 the American quantitative advantage made the Japanese position hopeless. The German navy, distrusting its Japanese ally, ignored Hitler's orders to cooperate and failed to share its expertise in radar and radio. Thus the Imperial Navy was further handicapped in the technological race with the Allies (who did cooperate with each other). The United States economic base was ten times larger than Japan's, and its technological capabilities also significantly greater, and it mobilized engineering skills much more effectively than Japan, so that technological advances came faster and were applied more effectively to weapons. Above all, American admirals adjusted their doctrines of naval warfare to exploit the advantages. The quality and performance of the warships of Japan were initially comparable to those of the US.
The Americans were supremely, and perhaps overly, confident in 1941. Pacific commander Admiral Chester W. Nimitz boasted he could beat a bigger fleet because of "...our superior personnel in resourcefulness and initiative, and the undoubted superiority of much of our equipment." As Willmott notes, it was a dangerous and ill-founded assumption.[37] Nimitz would later make good on his boast by defeating a larger Japanese force in the Battle of Midway and turning the tide in the Pacific War.[38]
Battleships
The American battleships before Pearl Harbor could fire salvos of nine 2,100-pound armor-piercing shells every minute to a range of 35,000 yards (19 miles). No ship except another battleship had the thick armor that could withstand that kind of firepower. When intelligence reported that Japan had secretly built even more powerful battleships, Washington responded with four Iowa-class battleships. The "big-gun" admirals on both sides dreamed of a great shootout at twenty-mile (32 km) range, in which carrier planes would be used only for spotting the mighty guns. Their doctrine was utterly out of date. A plane like the Grumman TBF Avenger could drop a 2,000-pound bomb on a battleship at a range of hundreds of miles. An aircraft carrier cost less, required about the same number of personnel, was just as fast, and could easily sink a battleship. During the war the battleships found new missions: they were platforms holding all together dozens of anti-aircraft guns and eight or nine 14-inch or 16-inch long-range guns used to blast land targets before amphibious landings. Their smaller 5-inch guns, and the 4,800 3-inch to 8-inch guns on cruisers and destroyers also proved effective at bombarding landing zones. After a short bombardment of Tarawa island in November 1943, Marines discovered that the Japanese defenders were surviving in underground shelters. It then became routine doctrine to thoroughly work over beaches with thousands of high-explosive and armor-piercing shells. The bombardment would destroy some fixed emplacements and kill some troops. More important, it severed communication lines, stunned and demoralized the defenders, and gave the landing parties fresh confidence. After the landing, naval gunfire directed by ground observers would target any enemy pillboxes that were still operational. The sinking of the battleships at Pearl Harbor proved a blessing in deep disguise, for after they were resurrected and assigned their new mission they performed well. (Absent Pearl Harbor, big-gun admirals like
Raymond Spruance might have followed prewar doctrine and sought a surface battle in which the Japanese would have been very hard to defeat.)[39]
Naval aviation
In World War I the US Navy explored aviation, both land-based and carrier based. However, the Navy nearly abolished aviation in 1919 when Admiral William S. Benson, the reactionary Chief of Naval Operations, could not "conceive of any use the fleet will ever have for aviation", and he secretly tried to abolish the Navy's Aviation Division.[40] Assistant Secretary of the Navy Franklin D. Roosevelt reversed the decision because he believed aviation might someday be "the principal factor" at sea with missions to bomb enemy warships, scout enemy fleets, map minefields, and escort convoys. Grudgingly allowing it a minor mission, the Navy slowly built up its aviation. In 1929 it had one carrier (USS Langley), 500 pilots and 900 planes; by 1937 it had 5 carriers (the Lexington, Saratoga, Ranger, Yorktown and Enterprise), 2000 pilots and 1000 much better planes. With Roosevelt now in the White House, the tempo soon quickened. One of the main relief agencies, the PWA, made building warships a priority. In 1941 the U.S. Navy with 8 carriers, 4,500 pilots and 3,400 planes had more air power than the Japanese Navy.[41]
Germany's main naval weapon was the U-boat; its main mission was to cut off the flow of supplies and munitions reaching Britain by sea. Submarine attacks on Britain's vital maritime supply routes in the "Battle of the Atlantic" started immediately at the outbreak of war. Although they were hampered initially by the lack of well-placed ports from which to operate, that changed when France fell in 1940 and Germany took control of all the ports in France and the Low Countries. The U-boats had such a high success rate at first that the period to early 1941 was known as the First Happy Time. The Kriegsmarine was responsible for coastal artillery protecting major ports and possible invasion points, and also handled anti-aircraft batteries protecting major ports.[42]
In 1939–1945 German shipyards launched 1,162 U-boats, of which 785 were destroyed during the war (632 at sea) along with the loss of 30,000 crew. The British anti-submarine ships and aircraft accounted for over 500 kills. At the end of the war, 156 U-boats surrendered to the Allies, while the crews scuttled 221 others, chiefly in German ports. In terms of effectiveness, German and other Axis submarines sank 2828 merchant ships totaling 14.7 million tons (11.7 million British); many more were damaged. The use of convoys dramatically reduced the number of sinkings, but convoys made for slow movement and long delays at both ends, and thus reduced the flow of Allied goods. German submarines also sank 175 Allied warships, mostly British, with 52,000 Royal Navy sailors killed.[43]
Surface fleet
Main articles:
Black Sea campaigns (1941–44)
The German fleet was involved in many operations, starting with the
In April 1940, the German navy was heavily involved in the invasion of Norway, where it lost the heavy cruiserBlücher, two light cruisers, and ten destroyers. In return it sank the British aircraft carrier HMS Glorious and some smaller ships.
United Kingdom
Main articles:
History of the Royal Navy § Second World War
At the start of the war, the Royal Navy was the largest navy in the world. In the critical years 1939–43 it was under the command of
(1877–1943).
As a result of the earlier changes the Royal Navy entered the
Second World War
as a heterogeneous force of World War I veterans, inter-war ships limited by close adherence to treaty restrictions and later unrestricted designs. Though smaller and relatively older than it was during World War I, it remained the major naval power up until 1944-45 when it was overtaken by the American navy.
At the start of World War II, Britain's global commitments were reflected in the Navy's deployment. Its first task remained the protection of trade, since Britain was heavily dependent upon imports of food and raw materials, and the global empire was also interdependent. The navy's assets were allocated between various fleets and stations.[44]
Western North Atlantic, Caribbean Sea, Eastern Pacific
Eastern Fleet
Indian Ocean (excluding South Atlantic and Africa Station, Australian waters and waters adjacent to Dutch East Indies)
Eastern Fleet
North-west Pacific and waters around Dutch East Indies
There are sharply divided opinions of Pound's leadership. His greatest achievement was his successful campaign against German
Norwegian Campaign in 1940, his dismissal of Admiral Dudley North in 1940, Japan's sinking of the Repulse and the Prince of Wales by air attack off Malaya in late 1941, and the failure in July 1942 to disperse Convoy PQ 17 under German attack.[46]
During the early phases of
Hood was sunk by the German battleship Bismarck in May 1941. Although the Bismarck was sunk a few days later, public pride in the Royal Navy was severely damaged as a result of the loss of the "mighty Hood".[citation needed
]
The RN carried out a bombardment of Oran in Algeria against the
attack on Taranto torpedo bombers sank three Italian battleships in their naval base at Taranto and in March 1941 it sank three cruisers and two destroyers at Cape Matapan
. The RN carried out an evacuation of troops from Greece to Crete and then from that island. In this the navy lost three cruisers and six destroyers but rescued 30,000 men.
The RN was vital in interdicting Axis supplies to North Africa and in the resupply of its base in Malta. The losses in Operation Pedestal were high but the convoy got through.
The Royal Navy was also vital in guarding the sea lanes that enabled British forces to fight in remote parts of the world such as
Mediterranean and the Far East. Convoys were used from the start of the war and anti-submarine hunting patrols used. From 1942, responsibility for the protection of Atlantic convoys was divided between the various allied navies: the Royal Navy being responsible for much of the North Atlantic and Arctic oceans. Suppression of the U-boat
threat was an essential requirement for the invasion of northern Europe: the necessary armies could not otherwise be transported and resupplied. During this period the Royal Navy acquired many relatively cheap and quickly built escort vessels.
The defence of the ports and harbours and keeping sea-lanes around the coast open was the responsibility of