Essex Class Aircraft Carrier - Overview

Overview

The preceding Yorktown-class aircraft carriers and the designers' list of trade offs and limitations forced by arms control treaty obligations formed the formative basis from which the Essex class was developed — a design formulation sparked into being when the Japanese and Italians repudiated the limitations proposed in the 1936 revision of the Washington Naval Treaty of 1925 (as updated in October 1930 in the London Naval Treaty) — in effect providing a free pass for all five signatories to resume the interrupted naval arms race of the 1920s in early 1937.

At the time of the repudiations, both Italy and Japan had colonial ambitions intending or already conducting military conquests and their fascist governments, like the Nazis in Germany, were firmly controlled by military regimes. With the demise of the treaty limitations, and the growing tensions inculcated by the Nazi menace in Europe suggesting war was looming, naval planners were free to apply both the lessons they'd learned operating carriers for fifteen years and those of operating the Yorktown class carriers to the newer design.

Designed to carry a larger air group, and unencumbered by the latest in a succession of pre-war naval treaty limits, Essex was over sixty feet longer, nearly ten feet wider in beam, and more than a third heavier. A longer, wider flight deck and a deck-edge elevator (which had proven successful in the one-of-a-kind USS Wasp (CV-7)) facilitated more efficient aviation operations, enhancing the ship's offensive and defensive air power.

Machinery arrangement and armor protection was greatly improved from previous designs. These features, plus the provision of more anti-aircraft guns, gave the ships much enhanced survivability. In fact, during the war, none of the Essex-class carriers were lost and two, USS Franklin (CV-13) and USS Bunker Hill (CV-17), came home under their own power even after receiving extremely heavy damage and were successfully repaired. Some ships in the class would serve until well after the end of the Vietnam conflict as the class was retired by newer build classes.

While debates raged, and continue to this day, regarding the effect of strength deck location (flight deck level on British ships vs. hangar deck level on American ships), British designers' comments tended to disparage the use of hangar deck armor, but some historians, such as D.K. Brown in Nelson to Vanguard, see the American arrangement to have been superior. Subsequently, the larger size of the first supercarriers necessitated a deeper hull and shifted the center of gravity and center of stability lower, enabling moving the strength deck to the flight deck thus freeing US Naval design architects to move the armor higher and remain within compliance of US Navy stability specifications without imperiling sea worthiness. In the late 1930s, locating the strength deck at hangar deck level in the proposed Essex-class ships reduced the weight located high in the ship, resulting in smaller supporting structures and more aircraft capacity for the desired displacement. One of the design studies prepared for the Essex project, "Design 9G", included an armored flight deck, and displaced 27,200 tons or about 1,200 tons more than "Design 9F", which formed the basis of the actual Essex design; 9G became the ancestor of the 45,000-ton Midway class.