One Hundred Years of U.S. Navy Air Power (36 page)

As a hint of U.S. naval thinking, in July 1920 the now-familiar system of ship type symbols was introduced. Carriers were placed in the cruiser (i.e., combatant) category, rather than in an auxiliary category, with the symbol CV (C for cruiser, V for fixed-wing—Z was for airships, and much later the symbol H was introduced for helicopters). At the same time symbols were created for fighters (VF) and for torpedo bombers (VT), but not for bombers as such; dive-bombing had not yet been formally introduced, so torpedoes were the principal way in which U.S. naval aircraft could directly attack enemy warships. Symbols were, however, introduced for scouting (VS) and for observation (VO), the latter meaning spotting for heavy gunfire. At this time the Navy's Bureau of Ordnance was much intrigued by the possibility that spotting aircraft could extend battleship gunfire range even beyond the visual horizon, offering the U.S. fleet a battle-winning advantage. Carriers might or might not launch the spotters, but their fighters would make it possible for them to work unmolested. It was assumed that torpedo attack, bombing (level, not dive, which did not yet exist), and scouting functions could all be combined in one type of airplane. Only torpedoes, which had to be launched at close range, could be expected to hit and damage maneuvering ships, but a 1924 report suggested that gas, which had been used to great effect during World War I, might be a useful air weapon,
because a cloud of gas did not have to be delivered very precisely. There was a real fear that, once gassed, a ship could not be decontaminated (the Royal Navy of this period seems to have had similar fears). It turned out that gas was the one weapon of this period whose further use was ruled out by deterrence.

By 1920 public support for the expensive naval program was evaporating: if World War I had indeed been fought “to end wars” why should the U.S. Navy be preparing for another? U.S. strategists understood differently: it was unlikely that a war would break out in the near future, but it seemed entirely possible that at some point the United States and Japan would fight over Pacific dominance. Like other navies, the U.S. Navy needed to develop carrier aviation. With no prospect of a carrier in the FY21 program, C&R proposed converting one of the ten
Omaha
-class light cruisers then under construction. The General Board rejected the idea on the grounds that the Navy badly needed light cruisers (it had no modern ones) and that the proposed carrier would be mediocre. It much preferred a new design.
⁷

In November 1920, the General Board, responsible for advising the Secretary of the Navy, called not only for two ships in the FY22 program, but for more in subsequent ones, up to a total of six or seven. Congress had already authorized a massive building program in 1916: ten battleships, six huge battle cruisers, ten light cruisers, and many lesser ships, most of them suspended during the war as destroyer construction became the highest priority (to defeat the German U-boats). For a time after the war it seemed that the 1916 program would be completed and further ships laid down to give the United States its desired position as premier sea power. In that context it was perfectly reasonable to assume that Congress would approve the important new carrier.

Looking toward the 1922 program, in the winter of 1920 the General Board drew up characteristics while C&R's preliminary designers developed a pair of alternatives, one displacing 25,000 tons (about thirty knots) and the other 35,000 tons (about thirty-five knots). The larger ship offered a larger flight deck (800 × 100 feet), greater speed, a steadier platform (due to the greater displacement), and ample stowage space, at the cost of greater expense and building time. The board chose the larger design as the basis for characteristics it submitted in February 1921, for a 35,000-ton, 32.75-knot carrier.
⁸
A model based on the design showed a flush-deck (island-less) carrier, her twin 6-inch guns arranged along the side of the flight deck, with smoke pipes extending to the ship's sides. This was much the pattern the Royal Navy had just followed in its prototype carrier, HMS
Argus
(a converted merchant ship), and what it was pursuing in rebuilding HMS
Furious
as a satisfactory carrier. The U.S. Navy had plans of
Argus
but not of the rebuilt
Furious
. In July 1921, the General Board ruled on several vital design questions, based on studies conducted by C&R. It rejected flush-deck designs because wind tunnel tests had just shown that in a flush-decker, gases were drawn in against the ship's side and across the flight deck, even
with a slight crosswind. Moreover, no one had ever tried to dispose of the vast volume of gas associated with high power (for the desired high speed) without using a conventional funnel. The same experiments suggested that a closed stern would be much safer than an open one for the ship—the hangar would therefore be buried in the hull, as in HMS
Hermes
. The flight deck would not be armored, because even 2 inches would add enormous topweight (about 1,800 tons, and another 1,450 for each additional inch), and it would provide little real protection. In contrast to a C&R sketch design, the fore and aft hangar spaces would not be separated, “as the greatest facility of stowage and transportation of planes seems the chief point to be considered.” On the basis of wind tunnel tests the General Board rejected earlier arrangements in which defensive guns were mounted along the ship's side. Instead she should have six twin 6-inch mounts and twelve 5-inch anti-aircraft guns, all on the open deck. These decisions shaped the design adopted for the two U.S. battle cruiser conversions,
Lexington
and
Saratoga
, and to some extent subsequent designs.
⁹

In 1921, too, the U.S. Navy created a Bureau of Aeronautics (BuAer), which was unique among the bureaus of the Navy in combining administration (e.g., of pilots) and technical functions. The Act that created the bureau decreed that officers commanding aviation units (except for carriers and seaplane tenders) had to be aviators. Because there were not nearly enough senior pilots, BuAer created a course that could train senior officers (typically captains) as aviation observers. Senior officers were encouraged to seek aviation training, even at advanced ages; they included Captain Ernest J. King, who commanded the U.S. Navy during World War II as Chief of Naval Operations, as well as Captain William F. Halsey. The many senior officers who therefore sought aviation training apparently educated non-aviators such as Admiral Chester Nimitz and Admiral Raymond Spruance. For that matter, officers who had already seen a great deal of the rest of the Navy presumably were better at integrating the new naval air arm into it.

By July 1921 the U.S. government was planning an international naval disarmament conference in Washington, which it held in November 1921. Apparently an influential senator (William Borah, R-ID) had demanded that the government seek an international agreement to end new naval construction before asking for money to complete the 1916 ships, and the Harding administration called the conference to forestall him. Many in Congress saw the conference as an opportunity to discard the expensive 1916 program. It seemed at the time that a capital shipbuilding competition was beginning among Britain, Japan, and the United States; it was widely imagined that the pre-1914 competition between Germany and Britain had helped cause the ruinous war recently ended (this idea now seems much less convincing). The main outcome of the conference was that the United States achieved naval parity, at least in capital ships, with Great Britain—in the past by far the dominant naval power. Japan was forced to accept a limit of 60 percent of U.S. or British tonnage,
creating the famous 5:5:3 ratio. The Washington Naval Treaty that emerged from the conference dominated warship design—including carrier design—during the interwar period. In July 1921 one senator linked naval disarmament with a proposal to convert two of the incomplete battle cruisers into carriers.
¹⁰
They were the closest the Navy could hope to come to the General Board's preferred 35,000-tonner.

Although they were new, the Washington Treaty treated carriers as capital ships, subject to the same 5:5:3 ratio as battleships. With preliminary designs for the converted battle cruisers in hand, the U.S. delegation secured a clause that allowed any of the three main signatories to convert two existing or incomplete capital ships into carriers, displacing up to 33,000 tons (battleships could displace up to 35,000).
¹¹
New carriers could displace up to 27,000 tons, a figure based on a contemporary U.S. design study. The U.S. position was to seek enough tonnage for the two battle cruisers plus
Langley
. The British, who were already using carriers, believed that a fleet needed a substantial number. This position in turn reflected the British belief that no single carrier could operate very many aircraft (see below). The effect of this British concern was to set a much higher total, 135,000 tons, than might have been expected for what many still imagined was an entirely experimental type of ship (the battleship total was set at 525,000 tons). Clauses in the treaty allowed replacement of existing ships after a set lifetime, but the British were allowed an escape clause: their World War I ships were classed as experimental and hence could be replaced much earlier. However post-1918 Royal Navy could never convince the British government to do so.

The U.S. delegation was determined to obtain enough tonnage to complete the two battle cruisers. Chief Constructor David W. Taylor knew that preliminary designs for the huge converted battle cruisers would require about 36,000 tons, and it was impossible to demand more for a carrier than for a battleship (when the U.S. delegation tried, the British demanded that the limit be raised to 45,000 tons, which would have allowed them to complete some entirely new ships that would have outclassed all existing ones). On the other hand, the treaty allowed navies to rebuild existing battleships (to reduce incentives to build new ones) to improve their protection against the threats of bombs and underwater weapons, which had not really been taken into account when most existing ships had been built. Navies were allowed 3,000 tons per ship for this purpose. The U.S. interpretation of the treaty treated the two huge ex–battle cruisers as existing ships that could be so modified (several attempts to redesign them without the extra 3,000 tons showed just how necessary that tonnage was). Like the United States, Japan converted two new capital ships, as yet incomplete, into large carriers. Unfortunately for the Royal Navy, in 1921 it had just ordered new ships, but none had yet been laid down, so it had to make do with conversions of two much smaller “large light cruisers,” HMS
Courageous
and HMS
Glorious
, plus further reconstruction of HMS
Furious
.

The treaty provided the U.S. Navy with the two largest carriers in the world, USS
Lexington
and USS
Saratoga
. A distinctive U.S. way of operating carriers (see below) gave the nation the largest Carrier Air Wings in the world, and experience with those air wings showed the U.S. Navy what carriers could do. Second, the generous tonnage allowance encouraged the U.S. Navy to build a substantial carrier force during the interwar period. The designs of this time became the basis for the fleet carriers the U.S. Navy built during World War II.

While U.S. naval aviation developed in the decade after World War I, U.S. naval planners worked out the details of a war against the most likely future enemy, Japan, code-named “Orange.” By 1929 it was clear that an Orange war would involve large numbers of airplanes, far beyond what the treaty-limited carrier force could possibly accommodate. The Orange war plan therefore envisaged converting merchant ships into auxiliary carriers (XCV, the X indicating conversion) as well as into numerous other types of auxiliaries. Conversion plans were drawn up for several large U.S. liners. The relatively anemic U.S. Merchant Marine of the time offered too few suitable ships (even the largest liners were relatively slow), and the conversion plan was eventually dropped because the plans envisaged would have taken far too long to carry out. In 1936 a new U.S. Maritime Commission was created to revive the U.S. merchant fleet, and specifically to build fast merchant ships that might be suited to wartime conversion. Within a few years it had designed a passenger ship (P4-P) specifically suited to carrier conversion (it was never built). The Maritime Commission did develop the C3 freighter, which became the basis for World War II escort carriers, and it created the industrial base that built, among many other things, fifty
Casablanca
-class escort carriers during World War II. Merchant ship conversion was considered by the other two carrier navies, the Royal Navy and the Imperial Japanese Navy. Only the Japanese took it really seriously, subsidizing merchant ships specifically intended for wartime conversion—including some that became World War II carriers.

The
Lexington
design was undoubtedly influenced by the British designs for their first two fleet carriers, HMS
Eagle
and HMS
Hermes
. In both ships the flight deck was integral with the hull, the hangar a cavity scooped out of the hull. The hangar was a closed space without side openings. That in itself limited hangar capacity for a hull of a given size (estimated capacity was seventy-two aircraft).
¹²
Unlike the British ships, the U.S. carrier was given a powerful surface gun battery, eight 8-inch guns in four twin mounts. They were intended to defend her in the event she was caught by cruisers, but they consumed valuable flight-deck space (and the ships' flight decks narrowed forward because they were blended into the hull). These were the most powerful guns allowed on board carriers by the Washington Treaty, and presumably they were considered essential because the treaty encouraged creation of a new kind of 8-inch gun cruiser. The initial sketch showed two turrets forward of the island and two more alongside the flight deck aft, but ultimately the ship had all four turrets on
deck, and her flight deck was widened aft. The new Bureau of Aeronautics resisted the idea of this kind of encroachment from the beginning of the new carrier design. No other navy placed heavy guns on the flight deck; the bureau did succeed in killing the proposed torpedo tubes, on the grounds that the ship's own torpedo bombers should suffice, and also succeeded in moving the 5-inch guns down to cuts in the flight deck rather than, as planned, on the flight deck itself. On the eve of World War II modernization plans included removal of the heavy gun battery, which was to be replaced by twin 5-inch dual-purpose guns (
Lexington
was sunk after her 8-inch guns were removed but before new flight-deck guns could be installed). Because the ships were expected to operate not only wheeled aircraft but the floatplanes otherwise launched by cruiser and battleship catapults, the design included a flywheel-powered catapult (one forward and one aft in the original design, only the bow one as built). This catapult was not intended to launch the ship's wheeled aircraft (the British later adopted much the same approach). Catapults became important only later.