O SPREY New Vanguard PUBLISHING US Navy Aircraft Carriers 1942–45 WWII-built ships Mark Stille Illustrated by Tony Bryan • CONTENTS ORIGINS 3 • US avy mid to late war carrier doctrine DEVELOPMENT 4 • Mid to late war air groups and aircraft • Weapons Commander (retired) MARK • Radar STILLE served as a career Naval Intelligence Officer, CHRONOLOGY 10 spending over five years of his naval career assigned to THE ESSEX CLASS 14 various US Navy carriers. He continues to work in this field • Origin in a civilian capacity. He holds • Design and construction an MA from the Naval War • Propulsion College and has had several wargames published. He lives • Armament in Virginia, USA. • Aircraft-handling facilitie • Wartime modifications • Operational hi torie • As essment THE INDEPENDENCE CLASS 36 • Origins • De ign and con truction • Armament • Aircraft-handling facilities • Wartime modification • Operational historie • Asses ment TONY BRYAN is a freelance BIBLIOGRAPHY 43 illustrator of many years' experience. He initially COLOR PLATE COMMENTARY 44 qualified in Engineering and worked for a number of years in Military Research INDEX 48 and Development, and has a keen interest in military hardware - armor, small arms, aircraft and ships. Tony has produced many illustrations for partworks, magazines and books, including a number of titles in the New Vanguard series. New Vanguard • 130 US Navy Aircraft Carriers 1942–45 WWII-built ships Mark Stille Illustrated by Tony Bryan • NVG 130 mono pp correx.qxd:NVG 130 mono pp correx.qxd 12/3/12 09:16 Page 2 FirstpublishedinGreatBritainin2007byOspreyPublishing, MidlandHouse,WestWay,Botley,OxfordOX20PH,UK 443ParkAvenueSouth,NewYork,NY10016,USA E-mail:[email protected] ©2007OspreyPublishingLtd. Allrightsreserved.Apartfromanyfairdealingforthepurposeofprivatestudy, research,criticismorreview,aspermittedundertheCopyright,Designsand PatentsAct,1988,nopartofthispublicationmaybereproduced,storedina retrievalsystem,ortransmittedinanyformorbyanymeans,electronic, electrical,chemical,mechanical,optical,photocopying,recordingorotherwise, withoutthepriorwrittenpermissionofthecopyrightowner.Inquiriesshouldbe addressedtothePublishers. 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US NAVY AIRCRAFT CARRIERS 1942–45 WWII-BUILT SHIPS ORIGINS T he US Navy’s seven prewar carriers had halted the Japanese advance in the Pacific by the middle of 1942 (see New Vanguard 114, US Navy Aircraft Carriers 1922–45 Prewar Classes). This book focuses on the Essex class fleet and Independence class light carriers that entered US Navy service during the war. These ships would be essential elements in the US Navy’s campaign to defeat the Japanese Empire. For the Essexclass, of the 24 built, 14 saw action during the war. The ships completed after the war and the extensive postwar service and modernization of the Essex class are not covered. Of the light carriers, all nine Independenceclass ships saw action. Two other light carriers of the Saipanclass did not see service during the war and are not discussed. US Navy mid to late war carrier doctrine The arrival of a growing number of Essex and Independence class carriers forced the US Navy to revise its carrier doctrine. Experience from 1942 clearly showed the benefits of operating several carriers together. The early war practice of operating only one or two carriers in a task group was abandoned. Now the arrival of new ships permitted up to four separate carrier task groups to be formed under the Commander, Fast Carrier Force Pacific. Each would operate up to five carriers (usually four) – a mix of fleet and light carriers. These would be typically escorted by a division of battleships, four cruisers (including some dedicated antiaircraft cruisers), and a dozen or so destroyers. To provide the best protection against air attack, the carriers would be placed in the middle of a 4-mile (6.4km) radius circle of escorts. Task groups usually steamed in formation with 12 miles (19.3km) between their centers, leaving A study in sea power: Task Group 38.3 enters Ulithi Atoll on December 12, 1944, following operations off the Philippines. The lead carrier is Langley; she is followed by Ticonderoga, three battleships, and four light cruisers. Ulithi Atoll was seized in September 1944 and was used as the fast carriers’ primary support anchorage for the remainder of the war. 3 8 miles (12.9km) from screen to screen. This cruising disposition was based on the effective range of the formation’s heavy antiaircraft guns. In addition to presenting any attacker with a continuous wall of antiaircraft fire, it provided enough room for maneuver. It also provided overlapping radar coverage, serving to fill in blind spots. By 1943, the US Navy had transformed naval warfare in the Pacific. Not only did the numbers of carriers in service dramatically increase, but so did the effectiveness of each ship and its air group. A new generation of aircraft manned by well-trained pilots, improvements in air search and fire control radars, the effectiveness of the Combat Information Center concept that fuzed information on a real-time basis, and the growing number and effectiveness of shipboard antiaircraft guns combined to make US fast carrier task forces essentially immune to conventional air attack. This defensive capability forced the Japanese to rely on night attacks and eventually on kamikaze, or suicide, aircraft. Together with these technological advances, there was a corresponding operational leap. A sophisticated mobile logistics capability was developed which allowed the US Navy to forward deploy to fleet anchorages and operate the Fast Carrier Force at sea for months at a time using underway replenishment. This maintained a high operational tempo, keeping the Japanese off-balance, and provided the capability not just to raid, as the Imperial Japanese Navy’s carrier task force had done early in the war, but to project power on a sustained basis. It was a war-winning formula. DEVELOPMENT Mid to late war air groups and aircraft In 1942, carrier air groups were assigned numbers with the first being Air Group 9. In June 1944, the designation of air groups was changed to reflect the type of carrier they were assigned to. An Essex class carrier’s air group was designated CVG and an Independence class carrier’s group was designated CVLG. The ability of the US Navy to sustain operations at sea was one of the unheralded reasons for the American victory in the Pacific. Here Hornetis shown refueling from an oiler in August 1944. As an example of the US Navy’s logistical capabilities, between October 6, 1944 and January 26, 1945, the Fast Carrier Force was at sea for 13 of 16 weeks. To maintain this effort required a dedicated force 4 of 34 fleet oilers. COMPOSITION OF ESSEX CLASS AIR GROUPS Fighters Dive bombers Torpedo bombers 1943 36 36 18 July 1944 54 (4 night) 24 18 December 1944 73 (4 night) 15 15 Essex in May 1943 during work-ups. This view shows her early air group that included Essex class carriers, as commissioned, had an air group with a large SBD Dauntless dive bombers fighter squadron of 36 fighters, plus 18 aircraft scout, dive bomber, and (the aircraft on the aft portion torpedo squadrons. One additional dive bomber for liaison duties was of the flight deck without folding included for a total air group of 91 aircraft. There were also nine reserve wings), TBF Avenger torpedo bombers, and F6F Hellcat aircraft, three of each type. fighters. Early Essexclass By 1944, the need for a dedicated scout bomber squadron was gone, so air groups were notable the two squadrons equipped with dive bombers were combined into a for their large proportion single 24-aircraft squadron. The fighter squadron grew and included of strike aircraft at the expense special radar-equipped night fighter and photo-reconnaissance fighter of fighters. Essexappears in her early configuration with variants. As the kamikaze threat became paramount, the number of fighter five radio masts, a single stern aircraft was again increased in December 1944. Now a single 73-aircraft 40mm quadruple mount, and fighter squadron was embarked and the number of strike aircraft reduced no starboard outboard sponsons. to 30, organized into two 15-aircraft dive bomber and torpedo squadrons. Interestingly, she would remain With 73 aircraft and 110 pilots, the fighter squadron had become basically unaltered throughout the war. too unwieldy. In January 1945 it was split into two squadrons, one with 5 36 fighters, the other with 36 fighter-bombers. In practice, the two Hellcat fighters preparing to squadrons were interchangeable. In 1945, two air groups discarded their take off from Ticonderoga. The dive bomber squadron and operated 93 fighters and 15 torpedo aircraft. two leading aircraft are F6F-5N variants; the pod on the wing Most Essex class carriers took a number of different air groups into contains a radar for night action. With a large pool of aviators available, the US Navy could rotate operations. tired veteran air groups. In addition to casualties, the air groups had to contend with fatigue brought on by incessant combat. In January 1944, it was decided that complete air groups would be rotated after six to nine months of combat. This was later shortened in April to six months as the pace of the war intensified. It became necessary to rotate some air groups after only four months. This contributed to the requirement to bring US Marine Corps fighter squadrons aboard the fleet carriers in late 1944. Eventually, two air groups were planned for each carrier. The arrival of the new carriers coincided with the arrival of new aircraft. Most prominent among these was the Grumman F6F Hellcat. The first mass-produced variant, the F6F-3, entered service in 1943 and was faster and better armored and had more firepower than its Japanese counterparts. The Hellcat was the mainstay fighter of the US Navy from 1943 to 1945, with over 12,000 built. The improved F6F-5 began to enter service in April 1944. Late in the war, some CVGs received the Vought F4U Corsair. Introduced in 1943, the Corsair would remain land-based until late 1944, when the kamikaze crisis and a fighter shortage brought it aboard fleet carriers on a permanent basis. With its speed and ruggedness, it proved to be the best carrier fighter of the war. Into the mid-war period, the dive bomber role continued to be filled by the Douglas SBD Dauntless. The upgraded Dauntless SBD-5 was not finally replaced until July 1944. Its replacement was the Curtiss SB2C Helldiver. This aircraft experienced a long gestation period before being wholly accepted for fleet use. Difficult to handle, it possessed no greater range than the Dauntless, carried a similar bomb load, and proved more difficult to maintain. It was, however, faster and more rugged. The torpedo bomber mission was handled by the Grumman TBF Avenger from mid-1942 to the end of the war. This aircraft also performed in a level bomber role. Some 6 7,500 were built under the TBF and the General Motors TBM designation. Weapons The war-built US carriers were well provided for in terms of antiaircraft protection. For long-range air defense, the mainstay weapon was the 5in/38 dual-purpose gun. This weapon had been fitted on the prewar Yorktown class and had proved itself to be an excellent gun possessing good accuracy, a long barrel life, and, most importantly, a high rate of fire. It was the finest weapon of its type in service during the war and remained in service long after. Aside from making a brief appearance on the lead ship, the Independenceclass did not carry the 5in/38 gun. In the middle of the war the effectiveness of the 5in was further increased when the VT (variable timed) fuze, containing a tiny radio transmitter in the Long-range antiaircraft protection for Essexclass nose of the shell, entered service. The fuze sensed the reflected radiation carriers was provided by the off the target and detonated the shell within 30ft (approx 9m) – a lethal redoubtable 5in/38 dual-purpose range. When used with radar fire direction, it was a deadly combination. gun. Two twin mounts were located forward and aft of the island; the forward mounts on SPECIFICATIONS FOR THE 5IN/38 GUN Intrepidare shown here, trained to starboard. This photograph of Bore 5in (127mm) Intrepidwas taken after June Shell weight 55lb (25kg) 1944, as the ship has received Muzzle velocity 2,600ft/sec (792.4m/sec) the modified bridge and the Maximum range 18,200yd (16,642m) SC-2 radar has been moved to Rate of fire 15–20 rounds/min the starboard side of the stack. The Mark 37 Director provided primary fire control for the 5in/38. On Essex class ships two were fitted on the island, one forward and one aft. This director was provided with a twin parabolic trough antenna Mark 4 Radar to further increase its performance. The Mark 37 proved very successful in handling all but the fastest targets. Later, the Mark 4 was replaced by the Mark 12 Radar, which used the same antenna, but which offered a limited blind-fire capability. Introduced with the Mark 12 was the Mark 22 Height-finder Radar. This was a small parabolic antenna attached to one side of the Mark 12. When completed, early Essex class ships received the Mark 4 Radar, with later ships receiving the Mark 12/22. Earlier ships got the Mark 12/22 upgrade during the course of refit or repair. The next layer of air defense was provided by the 40mm Bofors gun. These entered service on Essex class ships in quadruple mounts and on Independence class ships in quadruple and double mounts. These proved very effective in service, but later in the war even these lacked the power to stop onrushing kamikazes. Fire control for the 40mm Bofors was usually provided by the Mark 51 Director. This was a simple and lightweight system and incorporated the Mark 14 Gunsight. It proved very effective out to about 3,000yd (2,743m). Early ships used a mix of the simple Mark 51 and the 7 Shown here is a 40mm quadruple mount on Hornet in February 1945, during the raids on Tokyo. This is the gun mount on the port side of the flight deck, just forward of the aft pair of 5in/38 single guns. Note the expended shells to the right of the photo and the ready rounds lining the gun tub. The 40mm gun was probably the most successful medium-range antiaircraft gun of the war. more complex Mark 49 Director that was coupled with the Mark 19 Radar in an attempt to provide a blind-fire capability. The Mark 49 proved unsuccessful in service and was quickly removed. Beginning in late 1944, some Mark 51s were replaced by the similar Mark 57 with the Mark 29 Radar. The Mark 57 did provide a blind-fire capability. In 1945, the Mark 63 was introduced, which placed its associated radar directly on the 40mm mount. In some cases, both the Mark 51 and Mark 57 Directors could be used to direct 5in guns, thus increasing the number of targets that could be engaged by the ship’s 5in battery. SPECIFICATIONS FOR THE 40MM BOFORS GUN Bore 1.575in (40mm) Shell weight 1.985lb (.9kg) Muzzle velocity 2,890ft/sec (880.8m/sec) Maximum range 11,000yd (10,058m) Rate of fire 160 rounds/min (less in service) The standard short-range antiaircraft weapon aboard US carriers after 1942 was the Swiss-designed 20mm Oerlikon gun. It was originally fitted in a single mount, but a double mount was later introduced to increase the weapon’s firepower. The 20mm gun was air-cooled, required no external power source, and was lightweight, so it was fitted in large numbers. It was a last-ditch weapon that, by war’s end, had fallen out of favor, as its weight of shell was clearly inadequate to stop kamikazes. The 20mm was equipped with a ring sight for aiming, and fire was spotted by the use of tracers. The Mark 14 Gunsight could be mounted on the 20mm to provide target tracking. On both Essex and Independenceclass ships, these guns were usually fitted on platforms along 8 the flight deck.