If there is any single point upon which most historians agree, it is the role Naval aviation played in winning World War Two. And if any single class of ship can be said to have played the most important part in that war, that warship has to be the Essex-class fleet carriers which gave Naval aviation the mobility, stamina and punch needed to wrest control of the Pacific from the far-flung legions and fleet of the Imperial Japanese Army and Navy.
Up to the time of Japan's dramatic sneak attack on Pearl Harbor, the strategy and tactics of carrier-borne air armadas was largely a theoretical debate conducted by Naval planners, politicians and a few far-sighted air power visionaries. Though the US Navy possessed seven aircraft carriers which were fast being outmoded by the size and requirements of the aircraft they were to operate, the battleship was still regarded as the citadel of seapower; the aircraft carrier in the pre-radar era being principally the floating airfield from which to launch and recover scout and assault aircraft of unproven effectiveness. Indeed, in the opening actions of WWII, there was little cause for carrier advocates to celebrate when some of the first major warship losses to the British were the sinkings of the carriers Courageous (1939), Glorious (1940) and Ark Royal (1941) at the hands of an enemy which did not possess a single aircraft carrier or battleship!
Pearl Harbor was not only cause for national trauma, but the genesis for a complete turnaround in Naval thinking. Overnight, the aircraft carrier, not the battleship, became the capital ship of the fleet, and what little American seapower remained in the Pacific suddenly focused on the vital importance of the Navy's floating airfield.
The inadequacy of our prewar carriers and the obsolescence of their aircraft were tragically demonstrated in the early sea battles of 1942 when the veteran Lexington, Yorktown, Wasp and Hornet were lost in uneven contests against superior Japanese airpower. Though the Battles of the Coral Sea and Midway were hailed as American victories, their outcome did little more than stem the tide of Japanese conquest eastward across the Pacific at tremendous cost in men and ships to the US Navy. Had Americans at home known late in 1942 that for several weeks Enterprise was the only carrier in the Pacific, their jubilation over the Doolittle raid on Tokyo, launched in April from the Hornet, would have blanched considerably.
It would be the better part of a full-year's wait before the new Naval theology became a reality with the first major Naval airborne attacks against land targets launched from the new .Essex-class fleet carriers Lexington and Yorktown in the fall of 1943. Aided by the new light carriers of the Independence class, which had been hastily converted from the cruiser hulls, US Navy airpower seemed to have emerged overnight in a miraculous rebirth that for the first time in the Pacific War saw our Navy taking the offensive in a manner Nav-Air visionaries had promised years earlier. Their effectiveness hailed in print and in deed, the new Essex-class carriers were majestic capital war ships that quickly captured both the Navy and the public's fancy. Their appearance at such a critical period in the Pacific War was little short of a true miracle and was a tribute not to divine providence but the production skills of American industry and the dogged tenacity of carrier advocates who pressed home the need for modern carriers years before Pearl Harbor.
As war in Europe seemed ever more a reality and Japan's expansionist goals became more self-evident in the late 1930s, more attention was gradually paid to the Navy's carriers. Even with the commissioning of the new Ybrktown-class in 1936, the inadequacy of these 19,900-ton goliaths became all-too-soon apparent for it was clear that the size, weight and performance of new Naval aircraft then on the drawing boards mandated the need for still larger, more efficient and better armored carriers. Lessons learned in the construction and operation of the early carriers were outlined in the requirement for these new sophisticated warships in design studies commenced in 1937 through the encouragement of the pro-Navy Roosevelt administration. By May 1938, new Naval construction tonnage had been increased 20-percent providing for the building of the Hornet and a 20,000-ton allocation for a new carrier which was to become the CV-9, later Essex-class.
Clearly, the major design prerequisites were a serious problem for Naval architects, for the Navy wanted a lot of ship packed into a 20,000-ton hull. Foremost in a long list of requirements was:
A: Larger flight deck to handle an additional squadron of aircraft for a total of five squadrons each of 18 aircraft;
B: Larger hull in order to stow the 240,000-gal of avgas as opposed to the Yorktown's 178,000-gal capacity. Naval aircraft burned an average of 37-gph in 1939 as opposed to 24-gph in 1936;
C: More and better stowage of aircraft munitions;
D: Increased armor belt to 4-in on the waterline, 3-in on major bulkheads, 1.5-in on the main deck and, for the first time, 3-in armor on the hangar deck, the result being an additional 100-tons;
E: Increased propulsion from the Yorktown's 120,000-shp to 150,000-shp to maintain the required 30-kt speed;
F: Increased hangar deck for the storage of replacement aircraft parts, engines and components amounting to 25-percent of the air wing aircraft composition;
G. Increased defensive firepower for the ship itself.
Luckily, as the beat of war drums lapsed most treaty restrictions, BuShips were allowed to enlarge on the initial concept. By 1940, the CV-9 project had progressed through six transformations that ended with a 28-percent increase in displacement over the first proposal.
The result was a ship of 27,500-tons displacement, with a length-to-beam ratio of 8.8:1, in which every single ton had its planned purpose. It was heavier than the Yorktowns but lighter than the Lexingtons of the same length. It followed the lead of all its predecessors - with the exception of Lexington - in that the hangar, built over the main deck, was not part of the load-bearing structure, and the outer skin only connected the hull, the island and the superstructure on the starboard side near the island. The flight deck (886-ft 1-in by 89-ft 10-in) was wood planked as before, and had only very light armor plating, as had the main deck. In the interests of faster takeoff operations, propeller-driven aircraft had to be able to warm up in the hangar, and this necessitated adequate hangar ventilation; the hangar openings protected against the weather by roll doors. The dimensions of the hangar were 580-ft by 70-ft 10-in by 18-ft. The gallery deck, "suspended" beneath the flight deck, although not running the entire length, contained standby rooms and living quarters for the aircraft crews, who could therefore reach their machines as quickly as possible. In this design there were two central elevators and a deck edge elevator; the latter could be folded down vertically, thus enabling the ships to navigate the Panama Canal. The side elevator was, incidentally, a replacement for a third central elevator, which was included in a preliminary design in 1940. The central elevator shafts extended down to one deck below the hangar/main deck. The arrester wires, initially nine at the stern and six at the bows, could stop aircraft with a landing weight of 5.4-tons. The arrester systems were later reinforced.
The passive defense improvements largely consisted of the division of the hull into a much greater number of watertight compartments than had been the case in the older carriers; the success of this system can be measured by the fact that no Essex-class carrier had to be written off as a total loss, despite some of the units suffering severe damage. Inspite of the increased heavy AA armament (twelve barrels), there were only two Mk 37 directors, which meant that only part of the gun armament could be radar controlled at any one time. As on all US Navy ships, a considerable number of 40mm and 20mm AA guns were installed during the course of the war, but the number of weapons varied from ship to ship and from one refit to the next.
The construction of a total of 32 ships of the class was authorized, starting in 1940; 24 of them were completed, of which seven came too late to take part in WWII. The construction of Oriskany (CV-34) was suspended after launching, and the ship was eventually completed in 1951. The carriers of this class joined the fleet just when they were most needed. They, together with the two veterans Enterprise and Saratoga, the nine smaller carriers of the Independence-class and the main body of the escort aircraft carriers, destroyed the aerial superiority of the Japanese.
In numbers of ships, the Essex-class was the largest class of fleet carriers ever constructed and as such could also claim to be the largest group of capital ships constructed during the steam age. The FY40 (Financial Year 1940) program provided for eleven, of which five - Essex (CV-9), Yorktown (CV-10), Intrepid (CV-11), Lexington (CV-16) and Bunker Hill (CV-17) - were begun prior to the outbreak of war. The remaining six, together with two more provided under FY41, and an additional 13 provided under the wartime FY42 (ten units) and FY43 (three units) were laid down during the war. Another six ships were included in FY44 but these were subsequently canceled and were never laid down.
The size of this class, and indeed the great size of the entire US war construction effort, reflected not only the enormous industrial capacity of the United States, but also its ability to mastermind cooperative effort and the simplification of production requirements and methods.
Early in the war it was decided to concentrate on the construction of existing warship designs, hence the Essex-class represented the entire war production of fleet carriers. Another class, the Midways, was begun in 1943 but none saw service during the war. Cruisers were largely represented by the 6-in gun Cleveland-class (of which no less than 52 were ordered) and the 8-in Baltimore-class, destroyers by the Fletcher- and Gearing-classes and so on. By concentrating on such standardized designs, building yards could streamline production, resulting in remarkably short construction times. Intrepid was built in 20-months, while one Essex, the Franklin (CV-13), was completed in just under 14-months.
This system was applied to material and equipment as well as ship design, and a high degree of standardization was adopted for such things as steel sections and plates, ship fittings, machinery and armaments. Production of AA weapons was almost entirely concentrated on the 5-in/38, the 40mm Bofors and the 20mm Oerlikon for air defense.
The building of Essex-class carriers covered a good five-years and, as might be expected, external and internal alterations were made, some of them while the ships were still on the stocks; experience during the war dictated some of these changes. There were also minor differences in the amount of oil and aviation fuel carried. The more obvious, external alteration was the ships' division into ten "short hull" and 13 "long hull" types. One group had a stem with very little rake which was overhung by the flight deck; the bows were so narrow that only one 40mm quadruple could be fitted. The other group had a stem of greater rake, which led to an increase in the ships' overall length and also permitted the fitting of two 40mm quadruples side by side. The new bow shape did have a detrimental effect on ship handling in high waves and heavy seas; the forecastle had to take heavy punishment in these conditions.
A further variation concerned the starboard side of twelve units (CV-10, -11, -12, -13, -14, -15, -16, -17, -18, -19, -31 and -37), where from 1944 three 40mm AA mounts were fitted below the island on detachable sponsoons that could be removed to transit the Panama Canal, and two more toward the stern, below right deck level.
One of the design requirements built into the Essex-class was "expandability" - a factor that was to pay off handsomely not only in the war but later as these ships became the initial test-beds for jet aircraft. Taking aboard the hulking size of the Curtiss SB2C Helldiver posed no problem either on the hangar or flight deck as these brutish dive-bombers joined the fleet in 1944. Of course every ship has only so much "stretch" built into it and as the size of wartime complements grew due to the increased number of aircraft crews, gunners and plane handlers, conditions became extremely crowded to say the least. By 1945 typical figures for an Essex were 50-percent over the number anticipated by BuShips with 382 officers, including 175 aviation and 3060 enlisted men with 2790 handling the ship and deck operations while the rest served the Air Group or flag.
In contrast to modern carriers, the .Essex-class ships were equipped to handle aircraft landing over the bows - exactly as with the Yorktowns while the carrier was running astern at up to 20-kts. The ship's stern was suitably shaped for this type of operation, and the rudder was also strengthened. The arrester system consisted of numerous thick steel wire ropes, between nine and 16 of them at the aft end. The practice of landing over the bow did not, however, prove successful and was discontinued during the wars as was the launching of aircraft from the hangar deck catapults installed at 90-degrees to the ship's longitudinal axis; the small number of hangar catapults installed on CV-9 to -13 were replaced by a second flight deck catapult. This was 86-ft 7-in long and, with its thrust of 7.3-tons, could accelerate an aircraft to a speed of 90 mph. The later catapults (thrust 6.5-tons) could accelerate machines up to 100-mph; they were more than twice as powerful as the catapults on Yorktown (CV-5). Hangar stowage provided for 120 aircraft; with another 80 on the flight deck the total transport capacity was 200 aircraft.
By today's standards, the cost of building an Essex was a bargain at 70 to 78 million dollars each and even that number was intensified by the labor costs of keeping workers on a round-the-clock three-shift basis. The result was extremely short building times considering the complexity of the vessel.
The war resulted in many developments not envisaged when the ships were designed - the most obvious being the proliferation of radar and AA weapons which in turn required larger crews resulting in both substantially increased topweight and overcrowding. Consequently the Essex-class, and practically all other US warship types, were by 1945 suffering from a substantial reduction in their level of stability and hence survivability in the event of damage.
Prewar US design emphasized offensive over defensive qualities as had those of the Royal Navy prior to the First World War. However, whereas this had proved a less than successful policy in Britain's Naval war against Germany, it resulted in a close to ideal group of ships for the war against the Japanese. In aircraft carrier development this manifested itself in the provision of ships in which a large air group and its efficient operation took priority over passive defense. The logic behind this was that the aircraft were the carrier's principal means of both offense and defense and if operated efficiently few if any enemy aircraft would reach the ship itself and even then they would have to penetrate the ship's AA barrage before they could inflict any damage. Thus the hull was provided with sufficient armor and watertight subdivision to ensure survivability under all but the severest of circumstances, but the remainder of the ship - that is everything above the main deck, which included her hangar and flight deck - was completely unprotected apart from the splinter plating applied to the bridge and gun positions.
The alternative was that employed by the Royal Navy in the Illustrious-class in which the flight deck and hangar were armored but, on a given displacement, this degree of protection could be achieved only by a considerable sacrifice in the air group - US prewar doctrine required carriers with hangar accommodation for 72 aircraft, whereas the Illustrious-dass carried 36. It had its effect on carrier operation as well, for while US carriers with their open hangars could start and warm up aircraft engines while they were still in the hangar, and thus speed up the rate of launch, this was not possible with a closed hangar.
Thus a large air group meant accepting the risk of a carrier being put out of action by damage to her flight deck or hangar. This proved a greater risk than imagined prewar, at which time it was assumed that any bomb hole in the comparatively light flight deck could easily be repaired aboard ship. This was in fact the case with some of the less severe instances of damage but it did not take account of the inherent vulnerability of the hangar contents - aircraft, their gasoline, and munitions - and, in many cases, US carriers suffered severely from fires and secondary explosions caused by a bomb or kamikaze hit. In this respect, the kamikaze proved to be the most dangerous weapon used against the Essex-class, although it was a form of attack that could not, of course, have been envisaged at the design stage. Being virtually a piloted bomb, it stood a high chance of success but, fortunately, aircraft have poor penetrating power and thus were normally stopped by the flight deck - although their bombs, and occasionally their engines, penetrated to the hangar. However, the alternative to the Essex design, the following Midway-class, which had a 3.5-in armored flight deck and many other improvements including a larger air complement, displaced 47,000-tons, nearly twice the tonnage of the previous class.
The Essexes were part of the last generation of US warships to be designed without major provision for radar. That meant cramped antennas topside, with all their problems of mutual interference and smoke damage, radar rooms (and radar personnel) in a ship whose design was already tight, and a CIC. On the other hand, radar was the solution to the problem of a carrier fighter defense - only it could provide sufficient warning and information to bring airborne or deck-launched fighters into position to intercept an incoming raid. Radar operation in turn required the integration of information from all available sources in a CIC, generally adjacent to (but not included in) a fighter direction office Those sources would include both the ship's own radars and her lookouts, sometimes her ECM warning receivers, and information from other ships of the fleet. The CIC concept predated the Essex-class, and ships were completed with relatively cramped CICs in their island structures. Ultimately, however, these functions were moved to larger spaces in the gallery deck, which offered considerable spaces but, unfortunately, no protection from bomb or kamikaze attack.
The Essex-class radar arrangements were both complex and individualistic, the latter so much so that ships can often be identified in photographs by their radars. At first, the single massive tripod carried an SK for long-range air search, an SG for surface search, and the usual aircraft homing antennas. However, the failure of the Yorktown's airsearch radar during the Battle of the Coral Sea led to a demand for a second air-search set as insurance against a similar failure in the future. In an Essex-class carrier, that meant the provision of a second (often lattice) mast sponsoned outboard from the single compact funnel, carrying a smaller air-search set, generally an SC-2. Often a second SG was provided abaft the funnel, to make up for the blind spots represented by the major radars. There were, in addition, the usual 5in fire-control sets. This was hardly enough, as it was soon discovered that efficient fighter controls needed accurate height information. Requirements for a height finder were formulated in the spring of 1942, and the prototype SM (CXBL) was installed aboard the carrier Lexington in March 1943; production sets were installed aboard the Bunker Hill in September and the Enterprise in October 1943.
The other major external change to the Essex-class during WWII was the explosive growth of their antiaircraft battery, sometimes at the expense of aviation assets. Throughout the fleet, the quadruple 1.1-in machine cannon and the .50-cal machine gun were ordered replaced by, respectively, the 40mm Bofors and the 20mm Oerlikon in August 1941. These weapons were not yet available, but production would begin the following year; a twin Bofors weighed about as much as the quadruple 1.1s. Large ships as the carriers could accommodate quadruple Bofors in place of the 1.1s. As of August 1941, an additional pair of twin Bofors was planned, one in the bows and one offset to port aft under the overhang of the flight deck. At this time, a total of 44 20mm guns were planned, including six located outboard of the island at the first level above the flight deck. The rest were to be on walkways 4.5-ft below flightdeck level, on platforms that could be removed for passage through the Panama Canal. The very large number of 20mm guns, compared to the light .50-cal battery originally contemplated, reflects the prestige this weapon had already developed in British service, a prestige it would not lose until its failure against kamikaze attack in 1944-1945.
By the time the first ships had been completed, the bow and stern mounts had been made quadruples, so that there were eight in all; they carried a total of 46 single 20mm Oerlikons.
By late 1943, combat experience had shown the need for an even greater battery of medium- and close-range A/A weaponry to augment the twelve 5-in guns used against distant attackers. The number of 40mm Bofors kept increasing until they totaled 68 in all plus 55 20mm Oerlikons.
As aircraft grew larger, counterbalancing certain critical areas became necessary, as did the strengthening of portions of the flight deck itself. By comparison, the widely-used Grumman F6F Hellcat at 13,800-lbs gross weight outweighed its F4F predecessor by 40-percent. The Grumman TBF Avenger was a hulking 16,700-lbs and the already mentioned Curtiss Helldiver flew at 16,29-lbs.
These heavier aircraft had to be accommodated in larger numbers than had originally been expected. The Essex was commissioned with a "double" fighter squadron of 36 aircraft, plus single scout (dive-bomber), bomber (dive-bomber), and torpedo-bomber squadrons, each of 18 aircraft; she also had an extra dive-bomber for liaison, making a total of 91 operational aircraft, plus nine more (three of each type) in reserve. As radar developed, the need for specialized scouts was reduced, so that by 1944 the "scoutbomber" and dive-bomber squadrons had typically been amalgamated, for a total of 24 such aircraft. The slack was taken up by the fighters, which included specialized night interceptors and photoreconnaissance aircraft. For example, in October 1944, the new carrier Shangri-La accommodated a total of 49 day fighters (F4U-4s), four night-fighting Hellcats, and two photo-reconnaissance Hellcats. By that time, however, fighter-bombers were beginning to displace the pure dive-bombers. By the summer of 1945, the typical Essex air group included one large fighter squadron of 36 or 37 aircraft, a fighter-bomber squadron of similar size, and reduced dive- and torpedo-bombers of 15 aircraft each, for a total of 103 aircraft; the fighter squadron included specialist aircraft.
The heavier aircraft landed faster and required new arresting gear Mk V, a late-war modification that alone was credited with adding about 125tons, all of it high in the ship.
Bomb loads also increased, and by the spring of 1945, in common with most other US warships of wartime construction, the Essexes were weight critical; in January, BuShips warned that "the margins of stability possessed by the earlier vessels of the CV-9 class have completely disappeared on CV-21, CV-31-40, 45-47 and that the Bureau will require complete weight and moment compensation for any changes or alterations requested or directed on these vessels in the future. It is believed that the ships which have been in service for some time compare unfavorably with new ships because of a general accumulation of weight of all kinds."
The yard's inventory revealed that there was on board in topside locations an average of 800 rounds of 40mm ammunition per gun barrel, and 4076 rounds of 20mm ammunition per gun. The total weight was 247-tons, about 50-percent of the weight of the ship's complement of aircraft. "The Franklin has adequate stability in the intact condition [but] the ability of the ship to survive damage has been seriously impaired because of loss of freeboard and stability... The ship with one torpedo hit would take about the same list as the Essex, as originally built, with two torpedo hits..." In July, after the Franklin and the Bunker Hill had very nearly been lost in action, the Bureau imposed severe restrictions of ready-service light ammo to 500 rounds per 40mm barrel and 1420 per 20mm gun.
In invasion after invasion and attack after attack, the .Essex-class carriers proved themselves in battle. The carrier task force concept was honed to a fine art that, with minor variations, is still used today. As battle after battle made history in the Pacific sea war, the awesome effect of Naval airpower altered the face of Naval warfare forever. By late 1944, Pacific carriers were able to launch 1000 plane raids against Japanese targets. The great Marianas "Turkey Shoot" alone had virtually broken the back of Japan's air might, spelling largely the end to conventional airborne attack, and helped to foster the desperate use of the kamikaze suicide squadron.
The Essex-class carriers were far from being perfect ships, but in the regimen of the Pacific War they were virtually custom-tailored to the task of putting men, planes and ordnance on an enemy target. Had they not been so handsomely designed and efficiently utilized, the course of the Pacific War would at best have drawn out to a more grueling, protracted conflict requiring the conquest of still more land bases from which to launch air attacks at the Japanese home islands. They could give and take tremendous punishment and the proof of their mobility and expansibility is the truism that in highly modified forms they remained the numerical backbone of carrier aviation for well over 35-years.
Just after the end of WWII, 19 carriers of this class were taken out of service, "mothballed" and placed in the reserve fleet. Only the four newest ships, CV-21, 32, 45 and 47, remained on active service, and their aircraft fought out the first aerial battles of the Korean War from 1950 onward: most of their sister-ships were subsequently reactivated one after another and completely modernized.
© 2007 Challenge Publications Inc. Provided by ProQuest LLC. All Rights Reserved.
Source: Sea Classics
