The Japanese Maritime Self Defense Force retired its 33-year old submarine rescue ship JS Chiyoda on 20 March 2018 and replaced her with an identically named rescue ship commissioned the same day. The older ship, numbered AS-405 and pictured here transporting a deep submersible rescue vehicle, was launched in December 1983 and commissioned in March 1985. Displacing 4,450 tons fully loaded, AS 405 served as flagship for the 2nd Submarine Flotilla, a role now being carried out by the new Chiyoda, ASR-404. Both rescue ships were built by Mitsui Engineering and Shipbuilding in Tamano, Japan. With a 420-foot hull that displaces more than 6,000 tons, the newer Chiyoda is 51 feet longer and more than 1,550 tons heavier than her older namesake. While both units are powered by twin diesels, the younger rescue ship boasts more powerful engines providing a higher top speed. The newer Chiyoda also incorporates more advanced submarine rescue capabilities.