Japanese Aircraft Carrier Akagi - Design - Flight Deck Arrangements

Flight Deck Arrangements

Akagi and Kaga were completed with three superimposed flight decks, the only carriers ever to be designed so. The British carriers converted from "large light cruisers", HMS Glorious, HMS Courageous, and HMS Furious, each had two flight decks, but there is no evidence that the Japanese copied the British model. It is more likely that it was a case of convergent evolution as a means to launch as many aircraft as quickly as possible. Akagi's main flight deck was 190.2 meters (624 ft 0 in) long, her middle flight deck (beginning right in front of the bridge) was only 15 meters (49 ft 3 in) long and her lower flight deck was 55.02 meters (180 ft 6 in) long. The utility of her middle flight deck was questionable as it was so short that only some lightly loaded aircraft could use it, even in an era when the aircraft were much lighter and smaller than during World War II. The upper flight deck sloped slightly from amidships toward the bow and toward the stern to assist landings and takeoffs for the underpowered aircraft of that time.

As completed, the ship had two main hangar decks and a third auxiliary hangar, giving a total capacity of 60 aircraft. The third and lowest hangar deck was only used for storing disassembled aircraft. The two main hangars opened onto the middle and lower flight decks to allow aircraft to take off directly from the hangars while landing operations were in progress on the main flight deck above. The upper and middle hangar areas totaled about 80,375 square feet (7,467.1 m2), the lower hangar about 8,515 square feet (791.1 m2). No catapults were fitted. Her forward aircraft lift was offset to starboard and 11.8 by 13 meters (38 ft 9 in × 42 ft 8 in) in size. Her aft lift was on the centerline and 12.8 by 8.4 meters (41 ft 10 in × 27 ft 7 in). The aft elevator serviced the upper flight deck and all three hangar decks. Her arresting gear was an unsatisfactory British longitudinal system used on the carrier Furious that relied on friction between the arrester hook and the cables. The Japanese were well aware of this system's flaws, as it was already in use on their first carrier, Hōshō, but had no alternatives available when Akagi was completed. It was replaced during the ship's refit in 1931 with a Japanese-designed transverse cable system with six wires and that was replaced in turn before Akagi began her modernization in 1935 by the Kure Model 4 type (Kure shiki 4 gata). There was no island superstructure when the carrier was completed; the carrier was commanded from a space below the forward end of the upper flight deck. The ship carried approximately 150,000 US gallons (570,000 l) of aviation fuel for her embarked aircraft.

As originally completed, Akagi carried an air group of 28 Mitsubishi B1M3 torpedo bombers, 16 Nakajima A1N fighters and 16 Mitsubishi 2MR reconnaissance aircraft.