Naval Expansion Act of 1938
The initial CV-9 was ordered in the Naval Expansion Act of 1938.
Specifications for an improved Yorktown class aircraft carrier was issued in June 1939. The Navy wanted to be able to deploy larger and heavier aircraft and add additional protection.
7,000 tons was added to the class to provide additional armament and aviation fuel.
Two Ocean Navy Act of June 1940
Three more Essex class carriers (CV-10, CV-11, CV-12) were ordered in the Two Ocean Navy Act of June 1940.
Fall of France
With the Fall of France seven carriers (CV-13, CV-14, CV-15, CV-16, CV-17, CV-18, CV-19) were ordered in August 1940.
After the attack on Pearl Harbor two more Essex class carriers (CV-20, CV-21) were ordered.
In August 1942 ten more Essex class carriers (CV-31, CV-32, CV-33, CV-34, CV-35, CV-36, CV-37, CV-38, CV-39, CV-40) were ordered.
In June 1943 three Essex class carriers (CV-45, CV-46, CV-47) were ordered.
The hangar had a second armored deck that was to detonate bombs before they penetrated further into the ship. The hangar deck was open which allowed for the aircraft to be warmed up before being brought up to the flight deck.
Initially there was a single catapult on the flight deck. There were three elevators on the Essex class. One of the elevators was located on the edge of the flight deck and could be folded up to allow for transit through the Panama Canal.
On either side of the Island were two sets of twin 5" L/38 guns.
The hull had a torpedo bulge to help protect it against torpedo explosions.
One type of Essex class ship had a hull of only 872' / 265.8 m in length.
The other type of Essex was the long hull type with a hull of 888' / 270.6 m in length. This extra length was from the clipper type bow.