JS Chiyoda at Kobe on 25 July 2015
History
Japan
Name	Chiyoda (ちよだ)
Builder	Mitsui, Tamado
Laid down	January 19, 1983
Launched	December 7, 1983
Commissioned	March 27, 1985
Decommissioned	March 20, 2018
Class overview
Preceded by	Fushimi class
Succeeded by	Chihaya class (1998)
General characteristics [1]
Displacement	3,650 long tons (3,710 t) standard 4,450 long tons (4,520 t) full load
Length	113 m (370.7 ft)
Beam	17.6 m (57.7 ft)
Draft	4.6 m (15.1 ft)
Propulsion	2× Mitsui 8L42M diesels 7,860 kW (10,540 hp) 2 shafts
Speed	17 kn (20 mph; 31 km/h)
Complement	120
Aviation facilities	Helicopter deck
Notes	Carried one DSRV

JS Chiyoda (AS 405) was a submarine rescue ship of the Japan Maritime Self-Defense Force.^[2]

She was replaced by a newer ship of the same name, with a slightly different designation: JS Chiyoda (ASR 404). The new ship is similar, but improved, at: 128 m (420 ft) long, with a standard displacement of 5,600 tonnes (6,173 tons), and was commissioned on 20 March 2018.^[3]

History

Chiyoda was built by Mitsui Engineering & Shipbuilding in Tamano.^[4] She was laid down on January 19, 1983, and launched later that year on December 7, 1983. The Chiyoda was a multipurpose submarine rescue and saturation-diving capable ship belonging to the Japan Maritime Self-Defense Force (JMSDF). Built in 1985, it served as the mother ship for the sole deep submergence rescue vessel (DSRV) in JMSDF.^[4][5]

The design of the JS Chiyoda served as the basis for the next vessel which was the first ASR ship. However, the submarine support functions present in the JS Chiyoda (AS 405) were no longer built into the follow-on ASR ships.