With such a long run of aircraft carriers of the same design, it is natural that there were many differences among members of the class. Most of the modifications to the Essexes stemmed from a need for increased anti-aircraft defence. There were also changes made to improve aircraft operation, as well as peculiarities of various yards in which the ships were built.
The most noticeable distinction among the ships of the Essex class was the shape of the cutwater and overall length, altered to improve anti-aircraft capabilities. The quadruple 40mm Bofors gun was an excellent weapon and as the war progressed more mounts were desired. A large, wide sponson was added to the stern that could accommodate two quadruple mounts, but to similarly double the number at the bow required a more radical redesign of the forecastle. The cutwater was swept further forward and flaired outwards to carry a wide two-quad sponson. The new bow shape and the addition of the stern sponson added 16 feet 5 inches to the design, resulting in a subdivision of the class into two variants, the original short-hull design and the revised long-hull version. With the single exception of Essex, all the short-hull ships received the two-mount stern sponson during wartime refits, but of course the bow shape remained unchanged.
As part of the plan to increase the effectiveness of AA defence for the long-hull ships, it was proposed to shorten the deck by eleven feet at the bow and seven feet at the stern in order to improve the fields of fire of the bow and stern guns. Additionally, it was proposed to use a forward port sponson in lieu of the existing hangar deck catapult outrigger as a position for an additional Mk 37 AA director. This would require cutting a notch in the deck to allow better coverage for the radar, reducing the width of the flight deck at that point by six feet. Aviation personnel were adamantly opposed to both the shortened deck and the reduced width. In the end they had their way, as most of the long-hull members of the Essex class were not given shorter decks, and none received a port side Mk 37 director. However, the first long-hull ships, Ticonderoga and Hancock, had the shorter deck and notch for the port side director at first. By 1945 Ticonderoga had the notch filled in and longer deck installed but Hancock may have finished the war with the shorter deck; the notch was subsequently removed on Hancock as well. Randolph may have had the shorter deck with no notch upon completion, but the long deck had been restored by the time she reached the Pacific.