IJN Hosho

IJN Hosho Story

The seaplane carrier was part of the Imperial Japanese Navy program after World War I, which resulted in two such ships, the IJN Shokaku and IJN Hosho, dedicated to the role. The former was cancelled, and the latter eventually developed from its original seaplane form into the IJN's purpose-built aircraft carrier in 1921, as Japanese observers in Britain liked what they saw on HMS Hermes.

The hull of a marine tanker (keel laid in 1919) was used in her construction, but she would be a purpose-built vessel - the second of its kind in the world after HMS Hermes - although IJN Hosho beat Hermes Line became the world's first aircraft carrier in service.

The shift in priorities from seaplane carrier to aircraft carrier forced a revision of the propulsion scheme from a steam-based triple expansion engine to a pair of geared military marine steam turbines to meet the 25 knot speed requirement. Powered by 8 Kampon B-type boiler units up to 30,000 hp with two shafts under the stern.

A flush, flat upper flight deck with forced exhaust along the starboard side from bow to stern. These funnels are further articulated to fold down if the aircraft were to operate on deck. The hangar lift allows the fighter to move from below deck to the flight deck.

A navigation bridge superstructure was added for command and control, although the structure was eventually removed in 1923. Of the 32 originally planned, 21 could be carried, but in actual use, the warship decided to use 15. Crew number 512.

Final dimensions include 552 ft overall length, 59 ft beam and 20.2 ft draft. Displacement is 7,600 tons under standard load. Range peaks at 8,700 nautical miles.

For point defense, the ship is armed with 4 x 140mm/50 caliber Year 3 Anti-Aircraft Guns (AA) and 2 x 80mm/40 caliber Year 3 AA guns.

The IJN Hosho was launched on November 13, 1921, and entered service on December 27 of the same year. In her early career, she provided training and testbeds for a new generation of Japanese naval pilots and war planners.

By 1924, all peripheral structures preventing efficient deck operations had been removed.

The warship's career saw the "Shanghai Incident" against China in 1932 and later the actual Sino-Japanese War (1937-1945). These two campaigns provided the IJN with a wealth of knowledge and experience, and aided its future offensive in the Pacific during World War II (1939-1945), although the ship's 15-strong air force limited its ability to Tactical and Strategic Value Semester.

From 1939, IJN Hosho was retained and used for additional training programs.

That all changed when America went to war with Japan. The ship was part of the assault force on Pearl Harbor, Hawaii (December 7, 1941), and appeared during the Battle of Midway (June 4-7, 1942), but did not have a direct front-line role. The attack on the island was devastating for the Japanese navy, with four carriers killed in action.

Due to the lack of carriers, the service assigned other ships to stem the tide, but Hosho was again sent to a reserve role from 1942 to train more pilots and support personnel.

Surprisingly for an IJN warship, the USS Hosho managed to survive the entire war, suffering damage from a 1944 run aground and a U.S. aerial bombardment. It was allowed to be used as a means of transport for Japanese military personnel shortly after the war.

Tens of thousands of men were brought back to mainland Japan by Hosho (she was further modified for the role in December 1945). In early 1946-47 she was stripped of use and her hull was scrapped. Her name was officially removed from the Naval Register on August 31, 1946.

Hosho played an important role in the design of several important wartime aircraft carriers in Japan - namely Akagi, Kaga and Ryujo.

Specification

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Performance

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Wing