SHIPS-IN-CLASS (2): IJN Zuiho; IJN Shoho
OPERATORS: Imperial Japan
PROPULSION: 4 x Boilers feeding 2 x Geared steam turbines developing 52,000 horsepower and driving 2 x Shafts astern.
Detailing the development and operational history of the IJN Shoho Converted Light Carrier.
Entry last updated on 1/25/2018.
Authored by Staff Writer. Content ©www.MilitaryFactory.com.
The Imperial Japanese Navy (IJN) light carrier Shoho was one of two warships constructed to the Zuiho-class standard (the other being lead ship herself, Zuiho, detailed elsewhere on this site). The pair was formed from the existing hulls of seaplane tenders themselves designed to fulfill an IJN requirement of the mid-1930s. In 1940, work began on Zuiho, which was built from Takasaki, and Shoho, built upon the framework of incomplete Tsurugizaki.
The original diesel propulsion scheme was given up in favor of a geared steam turbine pairing and these were fed by four boiler units. All told, the scheme produced 52,000 horsepower and was used to drive 2 x shafts under the stern. The new warship could make headway at 28 knots and reach out to 7,800 nautical miles.
Aboard was a crew of 785 and armament included 8 x 127mm Type 89 Anti-Aircraft (AA) guns in four twin-gunned installations and 8 x 25mm Type 96 AA guns in a similar arrangement. The vessel was set up to support up to thirty warplanes. Over the hull of the ship (which lacked a traditional island superstructure) was set a flattop, straight-through flight deck serviced by a pair of elevators (for access to the hangar) and two catapults for launching the aircraft.
Dimensions included an overall length of 674.1 feet, a beam of 59.7 feet and a draught of 21.6 feet. Displacement was 11,262 long tons.
As the submarine tender Tsurugizaki, she operated from 1939 into 1940 with the Combined Fleet during what became the early part of the war - a period of focus for the Japanese expansion in the Pacific. Her turn at conversion arrived in December of 1940 when the process began and she was brought back online in 1942 as a light carrier built around speed and storage space (little armor protection was had on the vessel in order to keep her light). Her first taste of action was in April of 1942 as part of the invasion force at Port Moresby during Operation Mo - the Japanese attempt to claim Australian New Guinea.
This set the stage for the Battle of Coral Sea which spanned May 4th until May 8th, 1942. The Japanese invasion was eventually repelled in what was marked as a Japanese tactical victory but an Allied strategic one. On May 6th, 1942, as part of the battle, IJN Shoho was making her way to the scene when she came to the attention of a flight of Boeing B-17 Flying Fortress heavy bombers south of Bougainville. They attacked but caused minimal damage to the carrier.
However, misinformation led the Japanese Navy's attention away from American Task Force 17. On May 7th, TF 17, having sighted Shoho, responded with an air attack initially launched by the carrier USS Lexington. The first round revealed little but USS Yorktown's contribution in a second wave managed a pair of direct hits from 1,000 aerial bombs to the deck of Shoho. With restricted movement and a reduction in speed, Shoho could do little more than serve as a tempting target for further strikes. A combination of bombs and torpedoes wracked the light carrier which caused massive flames to erupt.
With the attack now over, the abandon ship signal was given. Shoho then rolled over to her side and began to sink. Of the 834 that were about her decks during the battle, just 255 or so were rescued from their fate. In what became the first carrier-versus-carrier battle in naval history, the Japanese Navy was on the losing side as the American Navy claimed the victory. 1942 also proved very critical for the IJN going forward as the Battle of Midway (June 4th - 7th) claimed a further four of its aircraft carriers - losses that would never - and could never - be replaced.