World War 2 Developments in Naval Warfare
Naval developments in World War II may be divided into four categories: (1) carrier operations, (2) amphibious operations, (3) mobile logistics, and (4) antisubmarine warfare. But the development that overshadowed all others was the task force system. A system whereby both carrier and amphibious operations were conducted in the Pacific. Also of major importance was the development of the mobile logistics that enabled the task force system to be employed. In addition, the developments that resulted from the campaign against German submarines may have been particularly significant because of their relation to future naval warfare.
Task Force System
During World War II the expression “task force” used in connection with fast carrier operations in the Pacific caught the imagination of the American people and became part of their language, though with a variety of meanings. In the working language of the United States Navy, however, “task force” is one of a group of terms employed in connection with a system of organization which it has evolved for managing its combat ships in order to make the most effective use of sea and air in modern, fast-moving warfare, while at the same time providing for te maintenance, support, and constant replenishment needed by these ships. In naval warfare it is the manned ship that fights, not the man himself. A combat ship functions only at sea, but it must return to port at various intervals to prepare and replenish itself again for sea duty. It is therefore possible to separate in time the tactical employment from the logistics of a ship, its operation from its administration, and this separation is carried over into naval organizational structure in a manner not possible in land warfare.
The task force method of conducting naval warfare is a byproduct of what might be called the task-type organization of naval operating forces. In this method of organization a combat ship’s captain actually works for two commanders. He is under the operational control of a task commander, who is responsible for completing some task within the Navy’s mission; and is under the administrative control of a type commander, who is responsible for the ship’s upkeep, supply, discipline, and (within certain limits) training. Broadly speaking, a task commander is concerned with functions of purpose, and he serves as operational commander of a composite force of ships suited to a particular purpose. A type commander is concerned with the functions of support, and he maintains the readiness of his ships, which are usually of one type, such. as carriers, cruisers, or destroyers. He is an administrative commander and does his job primarily with such of his ships as are in port.
The task force organization of combat ships was best represented during World War II by the carrier task forces, which also included battleships, cruisers, and destroyers. Amphibious task forces were composed of amphibious ships of all types, as well as battleships for gunfire support, small carriers for air support, and destroyer types for antisubmarine protection. Replenishment task forces consisted primarily of tankers, ammunition ships, and salvage tugs, with a cruiser flagship and small carriers and destroyer types for protection. These task forces could be divided into task groups and task units, while the administrative commands retained the older designations of squadron and division. The task concept was expanded to the fleet level in 1944. The two task fleets in the Central Pacific were the Fifth and Third fleets: the Fifth Fleet conducted the operations against the Marianas, Iwo Jima, and Olcinawa, while the Third Fleet assisted Gen. (later General of the Army) Douglas MacArthur in the recapture of the Philippines. The units that composed these fleets came from the pool of Central Pacific ships, which were assigned or withdrawn as operations required and the condition of the individual ships warranted. When ships were withdrawn from operational status, they reverted to the control of their type commander, whose headquarters were usually located with that of the commander of the Pacific Fleet. Ships newly commissioned or reverting to operational status after extensive repairs were assigned temporarily by the type commander to training commands, which specialized in preparing ships for combat. Such training was usually conducted outside of operational areas, although Japanese forces on bypassed Pacific islands provided targets for aircraft training.
The task force system was most widely exemplified in carrier operations. The destruction of the battleships at Pearl Harbor in December 1941 made the capital ship of the United States Navy the carrier, with its main battery of manned striking aircraft carrying torpedoes and bombs and a defensive system consisting primarily of fighter planes. Only the Japanese and United States navies developed carrier operations to a high degree. The technique of operating aircraft from carrier decks and the tactics of various aircraft types, especially the dive bomber, had been developed before the war and were similar in both navies. Usually the Americans initiated these developments, while the Japanese copied and perfected them.
As a capital ship, the carrier caused a revolution in naval tactics. As long as the gun remained the major weapon, the standard combat formation was the battleline, with light forces disposed on the engaged van and rear. When carriers first operated with the fleet, they took station on the unengaged side. As the manned airplane with its longer range replaced the big gun, the battle formation was changed to a circular one, with the carriers in the center, and other forces disposed around them to give them protection. United States formations were generally tight, with all the ships making tactical movements together in a task group that included four carriers. The Japanese operated in looser formations, and carriers with their attached ships conducted flight operations independently.
The primary striking carrier weapons in the United States Navy were the TBF Grumman Avenger, which could be used as a torpedo plane or as a level bomber, and the SDB Douglas Dauntless, a scout and dive bomber. The fighter that finally triumphed over the Japanese Zero was the Grumman F6F Hellcat. Japanese. aircraft were also given identification names by the Allied forces. The famous Mitsubishi Zero fighters, for example, were called Zekes, while the long-range, two-engine Mitsubishi bombers were known as Bettys.
All American ships were equipped with aircraft and surface radar by the end of 1942, but radar did not come into general use in the Japanese Navy until late in 1943. The Japanese fought such major actions as the battles of the Coral Sea and Midway without it. United States fighter aircraft in these and subsequent engagements were directed against oncoming raids by fighter directors using radar, thereby enabling the fighters to meet enemy aircraft from 50 to 70 miles out. The extensive use of radar resulted in the establishment in United States ships of a combat information center ( CIC), where all information received was analyzed and plotted and then relayed to the flag or commanding officer for his action. In some cases the officer in tactical command took his station in the CIC. It was surface radar that finally enabled the Americans to overcome the superiority of the Japanese in night actions.
Antiaircraft fire from United States ships early in the war was not effective, and enemy planes that were able to elude the United States fighter planes had good chances of making a successful attack. The variable-time (VT) or proximity fuze in antiaircraft ammunition, which was adopted in the Pacific in January 1943, changed this situation. An influence fuze, the VT was actually a small radar set that triggered the firing mechanism within 70 feet of the target in its destructive zone. At first it was restricted to naval actions, since it was feared that its use against land targets would result in its discovery by the enemy. In 1944, VT fuzes were employed successfully against V-1 flying bombs, as well as by ground forces in the Battle of the Bulge, the importance of which was considered to justify the possibility of discovery. Exploding a short distance above the ground, this fuze made the foxhole valueless as a safeguard for the foot soldier.
All ground operations in World War II began with amphibious assaults. The first, made in August 1942 at Guadalcanal, was a defensive operation designed to seize the island in order to halt the Japanese thrust into the Solomons. It was followed. in November by landings in North Africa. Amphibious operations in Europe included the assault on Sicily in July 1943, the cross-Channel invasion of Normandy in June 1944, and the movement into southern France in August. These were all primarily operations intended to seize beachheads from which large forces would subsequently break out for land campaigns. In the Pacific, however, one amphibious operation necessarily followed another. Amphibious operations in the Southwest Pacific were made at frequent intervals in relatively short shore-to-shore movements, while in the Central Pacific they involved large lifts over long distances. The assaulting forces in Europe were Army troops, whereas in the Central and Southwest Pacific both Marine and Army forces were employed. A greater amount of improvisation was necessary in the Southwest Pacific than in the Central Pacific, since naval elements were smaller and the theater generally received lower priorities for amphibious equipment.
Because of sound doctrine and proper landing equipment, all United States amphibious operations in World War II were successful. The doctrine had been developed by the United States Marine Corps in the two decades before the war, under the shadow of the British failure at Gallipoli in World War I. It was set forth in a Manual for Landing Operations, which attempted to define (1) command relationships; (2) naval gunfire support; (3) air support; (4) ship-toshore movement; (5) the securing of the beachhead; and (6) logistics. The basic doctrine outlined in this manual withstood the long trial by fire in war without fundamental changes.
The reason for this success was without doubt the provision of adequate craft for the landing of assault units and for logistic support over the beaches until proper port facilities could be built. The landing craft were of two basic types: (1) ships and boats that had the ability to beach without swamping, and also to withdraw; and (2) amphibians. Hulls of the first type were designed so that the craft grounded on only a small area forward. In withdrawing, the slipstream from the protected propeller washed away sand in the grounded area, thus releasing the craft from the beach. A ramp forward facilitated the rapid discharge of passengers and cargo. The smaller types, which were carried aboard transports, were designed by Andrew J. Higgins, a New Orleans boatbuilder. These were the LCVP (landing craft, vehicle and personnel) and the LCM (landing craft, medium), which were capable of transporting a tank. A larger type, designed to proceed under its own power to the designated area, was of British design; it included the LST (landing ship, tank) and the LCI (landing craft, infantry). The LCI subsequently evolved into a close-support gunboat type, while the LST with its ample tank deck became one of the most useful crafts in the war, employed in a range of logistic services far beyond those originally intended. LST’s were employed as hospital ships, barrack ships, tenders for small landing craft, floating machine shops, and issue ships. When they were forced to beach out from the shoreline because of shallow gradients, they could carry pontoon causeways with them. Intermediate types between shipboard craft and the LST were the LSM (landing ship, medium), a small LST, and the LCT (landing craft, tank), which was essentially a powered barge.
The second basic type of landing vehicle, the amphibian, could be propelled both in water and on land. The caterpillar type, invented by Donald Roebling, was able to cross the shoals and beaches of the Pacific. Two models were employed: the personnel carrier, LVT (landing vehicle, tracked), with a ramp in the rear, which allowed troops to debark quickly under some cover; and the LVT (A), or armored amphibian, which was actually an amphibious tank. The Army developed a vehicle of its own, code named the DUKW, an amphibious truck with a propeller drive in the water and a wheeled drive on land.
Special types of large amphibious ships also were built, mainly for the transport and support of landing craft, such as the LSD (landing ship, dock) and the LSV (landing ship, vehicle), an amphibian carrier. The assault transport or cargo ship carried as many as 9 LCM’s and 26 LCVP’s.
An important element in an amphibious operation was the shore party, which included the labor for quick unloading under difficult conditions. In the Central Pacific, where troop space in large overwater movements was limited, such labor was performed by a small number of specialized service troops augmented by reserves, although the latter were often called into combat when the unloading phase was at its most critical stage. In the Southwest Pacific the engineer special brigade was employed; it had regiments consisting of a boat battalion and a shore battalion, ably officered and with needed service troops attached.
The major carrier and amphibious operations in the Pacific could not have been carried out without a highly developed system of mobile logistics. By means of this system ships of the Pacific Fleet were able not only to remain indefinitely in forward areas adjacent to enemy territory, but also to cruise at sea for long periods in readiness for combat. Such mobile logistics enabled combat ships to receive fuel and other needs from service ships either while under way or at anchorages near operating areas. Advanced base facilities were maintained afloat at all times, and techniques were developed for transferring fuel, ammunition, stores, and personnel at sea, thus freeing combat ships from the necessity of returning to port at frequent intervals.
The maintenance of logistics afloat had two advantages in addition to keeping combat ships at sea: (1) Service craft could move forward relatively easily either under their own power or by towing. (2) Better storage and handling facilities and more accurate inventory control were available than in primitive shore areas. The disadvantage was the great demand for ships.
The primary requirement of a floating base is a large anchorage affording good holding ground and capable of being protected from submarine attack. Adjacent land is required only for fighter strips, recreation areas, and those naval facilities that can perform their functions better on shore. The atolls and islands of the Central Pacific provided such areas, and in the advance across the ocean United States naval forces used the anchorages at Majuro, Eniwetok, and Ulithi. Earlier in the war floating bases were established in conjunction with shore facilities at Noumea in New Caledonia, Espiritu Santo in the New Hebrides, and Manus in the Admiralty Islands. Afloat bases were later located at Samar in the Philippines and the Kerama-retto near Okinawa.
From its beginning the United States Navy had a tradition of operating with afloat logistics, since historically it was a navy without proper bases even in its own country. Nevertheless, the immensity of the logistic problem in a crossPacific war had not been realized in prewar planning. Various reasons may be advanced for this failure, the most logical being the discontinuance of the study of logistics at the Naval War College and the fact that fleet problems could not be made broad enough for the impact of logistics to be felt. As a result, major problems had to be solved just before or during the war. A logistic structure had to be improvised, and the reason that it was clone so quickly and so well was that abundance could cover mistakes.
The first conception for providing logistics for the fleet was the establishment of advanced base units on shore. Such units were specially organized in the United States with equipment packaged for erection in forward areas. Designated as Lions (major bases), Cubs (minor bases), and Acorns (aviation bases), they included construction battalions, boat pools, harbor defense units, repair facilities, and other functional components. These had to be set up in advanced areas and could not readily be moved forward as the war advanced. Cubs were established at Espiritu Santo and Gaudalcanal, and a Lion was set up at Manus. As the war moved closer and more. rapidly toward Japan, this conception was largely abandoned.
With the capture of the Marshall Islands in February 1944, the practice of afloat logistics came into its own. Most of the service ships at Pearl Harbor were transferred to Majuro to form Service Squadron 10. This force-was a medley of floating equipment, including repair ships, floating dry docks, tenders, provision ships, ammunition ships, hospital ships, station tankers, lighters, tugs, floating cranes, distilling ships, survey ships, cold storage ships, and floating barracks. The largest piece of floating equipment used during the war was the ABSD ( advanced base sectional dock), capable of lifting 90,000 tons and docking any ship in the Pacific. Any of its sections (a maximum of 10) could be towed forward separately and be docked by the others.
The second element in mobile logistics during the war was afloat replenishment, which enabled ships to remain at sea longer than steam vessels had ever done before. The continuing requirement was fuel oil, of which a combat ship always required sufficient for battle. The practice in the Pacific therefore was to fuel at sea every three to five days. The technique of such fueling, which had been developed in the United States Navy before World War I, did not change essentially thereafter. Two ships would steam alongside each other, one at a slightly greater speed so as barely to tow the other, and both under rudder control. Fuel would be delivered through flexible hoses that were kept suspended and out of the water between the two ships by booms and running gear. The British Navy, having operated through two world wars largely in the North Sea and with bases elsewhere in the world, had not developed an efficient technique of fueling at sea, and the Royal Navy carrier force that joined the Pacific Fleet in 1945 had to fuel by the slow method of towing in tandem with a floating hose between the two ships. The major replenishment need after fuel was ammunition, for magazine space in combat ships was limited. In the later stages of the war provisions and special stores, replacement aircraft, and even personnel also were transferred at sea.
The replenishment force operated as Service Squadron 6 during the Iwo Jima and Okinawa. campaigns. While its composition varied with conditions, it was generally composed of a light cruiser flagship, about 16 tankers, 4 ammunition ships, 4 fleet tugs or salvage ships for towing crippled ships from the battle area, 2 aircraft transports, provision ships as required, and protective escort carriers and destroyer types.
The realization of the importance of mobile logistics was illustrated in the Okinawa campaign by the seizure before the assault landing date of the Kerama-retto, an island group west of Okinawa that had a good anchorage. Mobile logistics was not nearly as essential for ground forces and land-based forces in the Pacific as for naval forces, but it was found that, where sufficient shipping was available, it was preferable to retain supplies afloat until they were needed ashore. The transfer forward of army bases from the New Guinea coast after the recapture of the Philippines necessitated the withdrawal of a large number of LST’s from combat operations.
To move men and materials across two oceans required a complete reorganization of the American merchant marine and a tremendous shipbuilding program. In February 1942, the War Shipping Administration (WSA) was established to provide shipping needs for the war economy and the armed services. Two standard types of cargo ships were built rapidly and in quantity by the American shipbuilding industry: the 10knot Liberty ship and, later, the 15-knot Victory ship. These ships were then outfitted and manned by shipping companies but were operated by the WSA.
In so far as future warfare was concerned, the most important naval developments of World War II may have occurred in the North Atlantic, where the struggle for survival of Great Britain was won before the United States offensive in the Pacific began. The victory over the German submarine was mainly the result of British efforts, the United States contribution consisting primarily of mass production processes.
Karl Doenitz (Donitz), the German admiral in command of submarines, was one of the toughest naval antagonists that the Allies met during the war. He believed that Germany could win only by sinking an average of 750,000 tons of Allied shipping monthly, and his strategy was to keep his submarines moving to areas where sinkings were easiest to obtain. Against convoys he preferred to use heavy concentrations of Uboats known as wolf packs in continuous attacks, directing them individually from his headquarters ashore. The weakness in this method of control was the amount of two-way radio traffic required: Allied high frequency direction finders were able to locate German submarines with considerable accuracy. Wider convoy routing and better antisubmarine precautions in distant areas forced Doenitz to return to the shipping lanes of the North Atlantic, and it was there that the battle was finally settled in the summer of 1943.
The German submarines were defeated by the Royal Navy’s battle-scarred escorts and by aircraft of the Royal Air Force (RAF) Coastal Command under the operational control of the Admiralty. British scientists also made contributions to this victory, two of them major: microwave radar and operational research on antisubmarine warfare methods. The British success can be attributed to radar; sonar (asdic in British terminology), high frequency direction finding; the escort carrier; antisubmarine support groups of destroyers, which reinforced the escorts of convoys under attack; and the extension of landbased airpower across the Atlantic by the employment of B-24 Liberators. The principal United States contribution was the escort carrier, used to cover the areas in the mid-Atlantic that landbased aircraft did not reach. Escort groups, consisting of a small carrier and about 4 destroyer types, began operating in June 1943. They were especially successful in locating submarine refueling rendezvous. Hunter-killer groups of this type are still retained in the operating forces of the United States Navy.
The technological advance that proved most fruitful for the British in the antisubmarine campaign was microwave radar. German submarines while on the surface were able to detect enemy use of long-wave radar and could submerge in time to avoid attack. They failed, however, to discover that microwave radar was being employed against them until 1944, with the result that surface vessels were able to approach close enough to a submarine before it submerged to get it on the sonar. Coastal Command aircraft were eventually fitted with this type of radar. Used in conjunction with the Leigh light, a powerful searchlight controlled by the radar set, it was able to surprise surfaced submarines, which could be attacked before they submerged.
Late in the war antisubmarine ordnance was radically improved by the introduction of a projectile to augment the depth charge. The mount, called a hedgehog, threw 24 missiles over the bow of the attacking ship. Since the missiles exploded only after one of them had struck the submarine, there was no explosion in an unsuccessful attack to disturb the sonar search and give the submarine time to escape.
Because sailing in convoys delayed shipping, vessels capable of making 15 knots and over sailed singly, with the expectation that faster turnarounds would compensate for submarine losses. Pressure was brought on the Admiralty to sail 13-knot ships singly as well, but this change proved a mistake, and the 13-knot convoys were reestablished in May 1941.
Improved convoy efficiency was finally attained through operational research. By analytical studies of attacks, British scientists discovered that the number of sinkings bore no relation to the size of the convoy and depended only on the number of attacking U-boats, on whether the convoy had air escort, and, when it did not, on the number of surface escorts. Convoys were therefore increased in size from 32 to 54 ships, providing both better protection and faster delivery of cargoes. Air escort during daylight was found to decrease losses by an additional 64 percent, making sinkings negligible.
Late in the war the Germans developed the snorkel, by which a submarine could both cruise and charge batteries underwater with only the extension of this breather pipe exposed. It was perfected too late to affect the German submarine effort and require antisubmarine methods to counter it. But the problem of countermeasures remained with the postwar nuclear-powered submarine, a true submersible able to remain underwater constantly and cruise at great depths with high speed.