Japanese submarine Yu 21
Imperial Japanese Army Yu 1-class submarine
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Yu 21 was an Imperial Japanese Army transport submarine of the Yu 1 subclass of the Yu I type. Constructed for use during the latter stages of World War II, she served in the waters of the Japanese archipelago.
- Surrendered August 1945
- Scuttled or scrapped
| History | |
|---|---|
 Japan | |
| Name | Yu 21 |
| Builder | Hitachi Kasado Works, Kudamatsu, Japan |
| Fate |
|
| General characteristics Yu I type | |
| Type | Transport submarine |
| Displacement |
|
| Length | 41.40 m (135 ft 10 in) overall |
| Beam | 3.90 m (12 ft 10 in) |
| Draft | 3.00 m (9 ft 10 in) |
| Propulsion |
|
| Speed |
|
| Range |
|
| Test depth | 100 m (328 ft) |
| Capacity | 24 tons freight or 40 troops |
| Complement | 23 |
| Armament |
|
Construction
In the final two years of World War II, the Imperial Japanese Army constructed transport submarines — officially the Type 3 submergence transport vehicle and known to the Japanese Army as the Maru Yu — with which to supply its isolated island garrisons in the Pacific Ocean. Only submarines of the Yu I type were completed and saw service. The Yu I type was produced in four subclasses, each produced by a different manufacturer and differing primarily in the design of their conning towers and details of their gun armament. None carried torpedoes or had torpedo tubes. Yu 21 was a unit of the Yu 1 subclass.[1]
The Hitachi Kasado Works (Hitachi Kasado Seisakujo) at Kudamatsu, Japan, constructed Yu 21.[1][2] Records of the details of the construction of Yu 21 have not been discovered, but the earlier Yu I-type submarines were laid down and launched during the latter half of 1943 and entered service at the end of 1943 or early in 1944.[2][3]
Service history
Yu 21 spent her operational career in Japanese home waters.[4] Surviving records of the activities of Imperial Japanese Army submarines are fragmentary,[3][5] and no records have been discovered describing her specific activities in support of any particular operation.[2][4]
World War II ended with the cessation of hostilities on 15 August 1945. Yu 21 surrendered to the Allies later in August 1945.[2] She subsequently either was scuttled or scrapped.[4]