Yaeyama-class minesweeper

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JMSDF MSO 301 Yaeyama.JPG
JDS Yaeyama (MSO-301)
Class overview
Operators:  Japan Maritime Self-Defense Force
Succeeded by: Awaji-class minesweeper
Planned: 6
Completed: 3
Cancelled: 3
Retired: 3
General characteristics
  • 1,000 tons standard (Official)
  • 1,250 tons full load (estimated)
Length: 67 m (220 ft)
Beam: 11.8 m (38.7 ft)
Draft:   3.1 m (10.2 ft)
Depth:   5.2 m (17 ft)
  • Diesel, two Mitsubishi 6NMU-TA1 diesels 2,400 hp (1.76 MW), two shafts
  • one 350 hp (257 kW) hydrojet bow thruster
Speed: 14 knots (26 km/h)
Complement: 60

The Yaeyama class is the largest class of Japan Maritime Self-Defense Force minesweepers, designed for open-sea mine clearance operations. Three ships were built in the class, a further three ships were planned but were cancelled. The ships use wooden hulls to reduce their magnetic signature. Yaeyama class is one of the largest-sized wooden hull ships designed today (except old and replica ships).

Jane's Fighting Ships notes their similarity to the U.S. Avenger-class minesweepers.

All three vessels are named after World War II Japanese ships: Yaeyama after a minelayer, and Tsushima and Hachijo after kaibōkan. Of their World War II namesakes, only Hachijo survived the war.


The forecastle was stretched to more than 3/4 of the total length to suppress the increase of retention and member dimensions of the longitudinal strength.[1]

In order to cope with an increase in shear stress accompanying the enlargement of the ship and thickness increase, the outer plate structure has a three layer double arrow blade structure in which the inner layer plates are inclined at right angles to each other and a vertical laminate of the outer layer is stretched to this It is said. In the case of adopting the same double arrow blade structure as the conventional minesweeping boat, it was thought that the inner layer board thickness became 47 mm, but it is suppressed to 20 mm by this.

The use of various tree species, seen in the list below, is the same as the Uwajima-class minesweepers.

  • Douglas fir - keel skeg, bottom stringer, chine material, frame, the outer plate-deck
  • Keyaki - Kiel friction material
  • Oleaceae - plywood

The main engine is equipped with Mitsubishi Heavy Industries 4-cycle non-magnetic diesel engines of the same design as in the Uwajimas but with a larger output (1,200 hp / 1,000 Rpm) mounted via a double anti-vibration device. It is the first minesweeper in the Japanese navy to feature a bow thruster, GPS equipped with a precision navigation equipment and automatic Sokan apparatus in order to improve the ship's ability to hold position.

Ships in the class[edit]

Pennant no. Name Laid down Launched Shipyard Commissioned Decommissioned Home port Unit
MSO-301 Yaeyama 30 August 1990 29 August 1991 Hitachi, Kanagawa 16 March 1993 28 June 2016  Yokosuka Minesweeper Division 51
MSO-302 Tsushima 20 July 1990 20 September 1991 Nikko, Tsurumi 23 March 1993 1 July 2016 Yokosuka Minesweeper Division 51
MSO-303 Hachijyo 17 May 1991 15 December 1992 Nikko, Tsurumi 24 March 1994 6 June 2017 Yokosuka Minesweeper Division 51

Comparable ships[edit]


  1. ^ "船体 (現代の掃海艦艇を解剖する)". 世界の艦船. 海人社 (427): 76–79. October 1990.

External links[edit]

JDS Tsushima (MSO-302)