One Hundred Years of U.S. Navy Air Power

by Smith, Douglas V.

  As conceived in January 1940, the Essex had a long enough flight deck to operate all four squadrons in a single operation. Compared to Yorktown, she had a quarter more aviation gasoline. The new carrier had new lightweight efficient high-temperature high-pressure machinery, which dramatically reduced the size of the uptakes in her island structure. Power increased from 120,000 to 150,000 SHP, more than making up for the effect of considerably increased displacement (26,500 rather than 20,000 tons; ultimately 27,200 tons). The machinery was rearranged so that it could not be knocked out by a single hit. Shrinking the island made it possible to place defensive twin 5-inch guns on the flight deck forward and aft of it (the Yorktowns had a few flight-deck machine guns). The new design retained four of the eight deck-edge 5-inch guns of the earlier class, those on the island side being eliminated.

  Compared to previous carriers, the Essex class showed two great innovations. One was reliable powerful hydraulic catapults (H4 type), which by 1945 were often used to launch heavily loaded aircraft. Since rolling takeoffs were no longer necessary, a carrier could place aircraft much closer to her bow: she could operate many more aircraft. Toward the end of the war, because the Japanese used kamikazes against the U.S. fleet, carriers were provided with more fighters, and the ability to use the flight deck more fully became far more important. Catapults also made it possible to launch aircraft under worse sea conditions, because they provided positive control as the airplane ran down the deck. An unusual feature of early Essex-class carriers was a cross-deck catapult on the hangar deck. It was intended to launch reconnaissance aircraft even when the carrier’s bow was packed with a strike that had recently landed (and had not yet been re-spotted aft). Hangar deck catapults were little used, and they were removed so that more light anti-aircraft guns could be fitted at hangar deck level. The other major change was the deck-edge elevator described above.

  Much of the extra tonnage of the new carrier went into more armor. Compared to a Yorktown, Essex added armor on her hangar deck—which limited the effect of any explosions there (it could resist a 1,000-pound bomb). It was still impossible to provide flight-deck armor. The flight deck was flimsy, but that meant that it could quickly be repaired at sea or in a forward area—and U.S. naval strategy envisaged staging the fleet through the Western Pacific, where it might not have any sort of prepared base. Armor would be fine if it kept bombs out, but any that did penetrate would do damage that could be repaired only in a shipyard. The ships proved remarkably tough, none being sunk. By way of comparison, Yorktown (CV-5) and Hornet (CV-8) were sunk as well as the huge Lexington and the small Wasp. Much of the superiority of the new carriers could be traced to much improved damage control measures, such as changed aviation gasoline practices (Lexington was fatally damaged by a gasoline vapor explosion). Too, by the time the Essex class was in service the United States had sufficient superiority to be able to tow badly damaged ships out of the battle area rather than scuttling them (as with Yorktown at Midway) to avoid their seizure by the Japanese. Even so, the survival of ships such as USS Franklin and USS Bunker Hill was remarkable, a great tribute both to their crews and to their construction. The wartime record of the Essex class was later used to show that carriers could survive multiple cruise missile hits, a Japanese kamikaze being quite equivalent to the later anti-ship missiles.

  Late in September 1939 OpNav sketched a “two-ocean navy” including thirty-six battleships (of which the U.S. Navy already had twenty-two built and building) and eighteen carriers (of which eight had been either built, laid down, or ordered, including Essex). The thinking of the time shows in the proposed initial annual building program: two battleships and one carrier, plus lesser ships (it seemed necessary to expand building capacity before a larger program could be ordered). A March 1938 General Board memorandum written to help lay out a ten-year program argued that “in view of the arising questioned value of aircraft carriers relative to increasing improvement in characteristics of land planes, it is believed that if more carriers are desired they should be built as soon as possible, consequently they are listed for the next two building programs.” Congress was more positive: for 1940–1941 it authorized an additional 30,000 tons of carriers, boosting the total to 215,000 tons. The new tonnage was applied to USS Essex (CV-9) of the FY41 program. Because carriers were assigned a twenty-year lifetime (by treaty), replacements could not begin until 1945 (the Lexingtons would become overage in 1947).

  In November 1939 Congress passed a 25 percent increase in underage tonnage in each category. That seemed sufficient to build four more 24,000-ton Essex-class carriers (CV 10–13). Because designed tonnage had risen to 26,500 tons by May 1940, the number fell to three, leaving a four-ship class (CV 9–12). These ships would bring the total U.S. carrier force to eleven. At this point CV-9 was expected to complete in January 1944, CV-10 in June 1944, CV-11 in July 1944, and CV-12 in February 1945. Once war began, the shipyards did infinitely better, so that CV-9 (Essex) was completed in December 1942. The others quickly followed, in April, August, and November 1943.

  France collapsed in June 1940. This was far worse than the “two-ocean navy” case considered in 1938–1939, because the United States had relied on Britain and France for a degree of protection against aggression by Germany. In the worst case the Royal Navy might fall into Axis hands. The United States could not possibly, it seemed, quickly build a fleet sufficient for offensive action in both oceans, but the General Board recommended starting at once on a fleet sufficient to maintain a defense in one ocean while mounting an offensive in the other. The recommended fleet gives an idea of the value then being placed on carriers: thirty-two battleships and fifteen carriers. Of these, however, the existing fifteen U.S. battleships were slow and obsolescent, whereas all seven existing carriers were fast, modern ships. To meet the desired force level the General Board asked for another four carriers (CV 13–16), which would more than double the existing carrier force. The “Two-Ocean Navy” Act Congress passed envisaged a 70 percent increase in tonnage, equivalent to seven rather than four more carriers (the Navy did not need 70 percent more battleships, so much of the newly available battleship tonnage went into cruisers and destroyers—but not into carriers). Thus by December 1940 ten new carriers (CV 10–19) were under contract beyond Essex.

  A July 1941 General Board study showed that in addition it would be possible to complete another seven carriers by December 1946 if the twelve on order were all completed as planned by December 1945, giving a potential total of eighteen carriers in December 1945. The board proposed adding four carriers in FY43, both to replace ships reaching retirement age and to make up for possible war losses. However, in September 1941 an OpNav conference decided tentatively to extend the existing program by, among other ships, six carriers (CV 20–25). A somewhat more optimistic BuShips thought it could lay down the carriers between March 1944 and May 1945 and complete them between August 1946 and November 1947. The first two ships (CV 20–21) were ordered in December 1941. They were part of an initial war program (forty-three ships) approved by the Secretary of the Navy between 15 and 24 December 1941.

  CNO Admiral Harold R. Stark had already proposed to President Franklin Roosevelt that new ships be laid down as soon as slips were vacated; that way 900,000 tons of combatant ships could be built. Unlike previous authorizations, this one should allow the tonnage to be used however the Navy decided, to reflect war experience. The president himself urgently wanted new carriers. Against considerable opposition, he pushed through the conversion of nine light cruisers to light carriers (the Independence-class CVLs). On 14 March 1942 CNO Admiral King proposed extending the building program to produce Essex or better carriers at the rate of at least eight per year beginning in 1943, light carriers to make up deficiencies (in the eight per year), and at least two escort carriers (see below) each month. By March 1942 the projected 1943–1944 program included ten Essexes plus four of a new type of heavy carrier (which became the Midway class). For several months the program sh
ifted back and forth, but in the end it retained these numbers. The Independence class became CVL 22–30, the ten fleet carriers became CV 31–40, and the four big Midways were listed as CVB 41–44. Remarkably, nearly all Public Domain of these ships were completed before the end of World War II, although one Essex (CV-35 Reprisal) and one Midway (the unnamed CVB-44) were cancelled. A further program included three more Essex-class carriers (CV 45–47, of which one, CV-46 Iwo Jima, was cancelled at the end of the war). Two more light carriers (CVL 48–49) were built as such from the keel up, based on a heavy cruiser design. Plans to order six more Essex class (CV 50–55) and two more Midways (CVB 56–57) were abandoned in March 1945.

  Naval History and Heritage Command

  The USS Midway in a gale off Sicily, February 1949. Photograph taken from the Essex-class carrier Philippine Sea.

  The Essexes won the great Pacific battles that broke the Imperial Japanese Navy. They became the core of the postwar U.S. carrier force. Of the twenty-four Essex-class carriers completed, one (CV-34 Oriskany) was suspended at the end of the war and redesigned to operate the new jets.

  As a measure of U.S. naval thinking on the eve of war, in September 1941 the Naval War College produced “A Study of the Relative Merits of a Balanced Navy and a Carrier Navy and the Conclusions Reached.”28 The two-ocean fleet then being built (including 60,000-ton Montana-class battleships) was compared to a carrier fleet of equivalent cost built around 60,000-ton carriers (rather than battleships) and 27,000-ton carriers instead of cruisers. It was assumed that bases ashore were more efficient than carriers in operating aircraft, and were also more difficult to knock out. There was no question of building an all-surface ship fleet; the study was intended mainly to show that a fleet without any battleships or cruisers (as some air enthusiasts presumably wanted) would be ineffective in important ways. Heavy guns, for example, were all-weather weapons, whereas aircraft were not. The new U.S. program envisaged half as many carriers as battleships, and more carriers (eleven) had recently been ordered than battleships (nine). War experience certainly suggested that a combination of carriers and heavy gun ships was needed. Only at the end of the war could massed carriers effectively sink battleships, as in the cases of the Japanese superbattleships Yamato and Musashi.

  WORLD WAR II

  U.S. carriers underwent three essential wartime modifications. One was multiple radars: surface and air search and height-finding. A related change, begun before the war, was provision of an aircraft homing beacon. That greatly increased effective striking range, and it permitted a carrier to maneuver much more freely while aircraft were in flight beyond the horizon. The navigation beacon also provided a reference point for scouting aircraft and hence for strikes against the targets they found. A second major change was the Combat Information Center (CIC) which correlated the ship’s own data with those from other fleet units and from aircraft. Successful fighter control for self-defense was a consequence of the combination of CIC and radar. The CIC operated manually, and could track only a limited number of targets. In 1945 Japanese kamikaze tactics succeeded because attackers split up far more than had conventional attackers, and CICs were flooded with data. CIC also controlled the ship’s own defensive guns, and again the kamikazes tended to saturate the ship’s ability to handle targets. The combination of radar/CIC success in 1944 and CIC saturation in 1945 led the U.S. Navy to intensive postwar work, ultimately on automating its CICs in the 1960s. The third major change was of course the proliferation of light anti-aircraft weapons, by 1945 often locally controlled to overcome kamikaze saturation.

  Carrier operation changed, too. The prewar idea that carriers should be solitary was dropped as large numbers of new fleet carriers entered service beginning in December 1942. It turned out that up to four large carriers (usually three large and one small) could operate together as a carrier task group, such groups working together to form the fast carrier task force (Task Force 38 or 58 depending on whether the fleet commander was Admiral Halsey or Admiral Spruance).

  The kamikaze threat again changed the way carriers operated. Fighters multiplied, so that in 1945 an Essex might operate as many as seventy-three of them, her bomber complement cut to fifteen dive-bombers (no scouts) and fifteen torpedo bombers. At this time a more conventional combination was thirty-six fighters, thirty-six dive- and scout bombers, and eighteen torpedo bombers.

  By this time the U.S. Navy also operated specialized night fighters. From 1943 on, the Japanese exploited the lack of U.S. night fighters to attack with single medium bombers, which sometimes succeeded in torpedoing U.S. carriers. Initially radar was so heavy that aircraft operated in pairs, a torpedo bomber carrying the radar and directing a single-seat fighter. Then a lightweight night fighter radar was developed, and carriers were assigned specifically to operate all night fighter air groups. In 1945, for example, USS Enterprise was classed as a night carrier, equipped with thirty-seven night-fighter Hellcats and eighteen radar-equipped Avenger torpedo bombers.

  ARMORED FLIGHT DECKS

  Prewar the British developed a different kind of fleet carrier, with consequences for the U.S. Navy. Believing that carrier fighters could not possibly provide sufficient protection, the British had two choices: they could follow the U.S. practice of trying to kill the enemy’s carriers preemptively, or they could design carriers that could ride out air attacks without losing their capabilities. In 1935 the British found themselves facing Italian air strength in the Mediterranean. The Italians used land bases, and there was little possibility that any pre-emptive strike could eliminate the air threat. In 1936, then, the British designed the revolutionary Illustrious-class carrier with an armored hangar (including part of the flight-deck overhead). As U.S. designers had told many U.S. officers, there was a considerable price. In this case it was a smaller flight deck and a small hangar, sufficient for only thirty-six aircraft (the previous British carrier accommodated seventy-two). In U.S. terms, the shorter flight deck dramatically reduced the ship’s overall aircraft capacity. Later in the war the Royal Navy adopted the U.S. practice of deck parking aircraft, installing a U.S.-style barrier. The short flight deck seems to have caused problems, the British suffering an undue number of accidents when landing aircraft bounced over the barrier to hit the parked aircraft forward. Ironically, the Illustrious design proceeded at just about the same time that the British began to develop their own radar, which made effective fighter control possible and thus made the armored hangar, with its limitations, much less important.

  The General Board periodically considered armored-deck carriers. In January 1940 it asked C&R for sketch designs. BuAer’s strong preference for open-sided hangars (both to warm up aircraft and for athwartship catapults) greatly complicated any such design, because the flight deck had to be a superstructure. C&R’s study envisaged moving an inch of armor from the fourth deck (the protective deck in the Yorktowns, and the lower protective deck in an Essex) to the flight deck, and adding another inch and a half. The price was at least 2,200 tons, about 7.5 feet more beam, and a knot of speed. The 2.5-inch deck could resist ordinary 1,000-pound bombs (not armor-piercing ones), but they could still enter the hangar if they fell at an angle (as they usually did) and came under the flight deck; after all, the hangar could not be protected at all. To move quickly, moreover, the elevators were made of light alloys; they could not retain both their speed and be protected like the flight deck. Much of the added weight came from the massive supports required by the heavy flight-deck structure to withstand the racking stresses of rolling and beam winds. Too, the topweight would make the carrier heel more steeply on high-speed turns, with unfortunate effects. The idea died—for the moment.

  Initially the British kept the armored flight deck secret, but by the spring of 1940 senior U.S. officers were discussing comments on this type of ship by the British Director of Naval Construction—the same Stanley V. Goodall who had helped C&R in 1917–1918. Initial views were that the Norwegian campaign did not show any need for such
protection, although it did show a need for naval aircraft with sufficient performance to challenge land-based ones. Since the U.S. war plan against Japan envisaged seizing Japanese-held islands, the idea that no landing could succeed without sea-based air superiority was a very important lesson of the Norwegian campaign. No particular agitation for a U.S. armored deck carrier followed Goodall’s remarks, but Captain John S. McCain (a carrier commander), who had pushed for such a ship since 1939, remained its strong advocate through the fall of 1940. One consequence was that in October 1940 the British were asked for details of the armored carriers. Meanwhile BuShips studied future carriers armored much like Essex but with heavier gun batteries (one had 8-inch guns), responding to an August 1940 General Board request. One was armed with the new 5-inch/54 dual-purpose gun, then in the concept stage. By June 1941 it had been developed into a sketch of a 44,500-ton carrier. Its future significance was that it became the basis for a study of a carrier with a protected hangar, which in July 1941 the preliminary designers were about to start. At a June 1941 General Board hearing, the Chief of BuAer suggested building this ship if the decision were taken to replace the planned 65,000-ton Montana-class battleships with aircraft carriers. This CV-A would have been 900 feet long, protected against 8-inch cruiser guns. Given her size, she would have accommodated more aircraft: the usual thirty-six fighters, plus thirty-eight dive-bomber/scouts and thirty-eight torpedo bombers. BuAer saw much larger carriers as the only way to retain existing numbers while adopting larger higher-performance aircraft.