The ''Yaeyama'' class is the largest class of

Japan Maritime Self-Defense Force , abbreviated , also simply known as the Japanese Navy, is the maritime warfare branch of the Japan Self-Defense Forces, tasked with the naval defense of Japan. The JMSDF was formed following the dissolution of the Imperial Japanese Navy (IJN) ...

minesweepers A minesweeper is a small warship designed to remove or detonate naval mines. Using various mechanisms intended to counter the threat posed by naval mines, minesweepers keep waterways clear for safe shipping. History The earliest known usage of ...

, designed for open-sea

mine Mine, mines, miners or mining may refer to: Extraction or digging * Miner, a person engaged in mining or digging *Mining, extraction of mineral resources from the ground through a mine Grammar *Mine, a first-person English possessive pronoun ...

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 and is one of the largest-sized wooden hull ships designed today. ''Jane's Fighting Ships'' notes their similarity to the U.S. ''Avenger''-class minesweepers.

Design

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. In order to cope with an increase in

shear stress Shear stress, often denoted by (Greek: tau), is the component of stress coplanar with a material cross section. It arises from the shear force, the component of force vector parallel to the material cross section. '' Normal stress'', on ...

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 The Douglas fir (''Pseudotsuga menziesii'') is an evergreen conifer species in the pine family, Pinaceae. It is native to western North America and is also known as Douglas-fir, Douglas spruce, Oregon pine, and Columbian pine. There are thre ...

- keel skeg, bottom stringer, chine material, frame, the outer plate-deck * Keyaki - Kiel friction material *

Oleaceae Oleaceae, also known as the olive family, is a taxonomic family of flowering shrubs, trees, and a few lianas in the order Lamiales, It presently comprises 28 genera, one of which is recently extinct.Peter S. Green. 2004. "Oleaceae". pages ...

- 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

Comparable ships

* Avenger class minesweepers

References

* ''Minesweeper Division 51'' (see above) *
Mine warfare force JMSDF (Japanese, Official)
' * ''Jane's Fighting Ships 2005–2006''

External links

{{Combatant ship classes of the Japan Maritime Self-Defense Force Minesweepers of the Japan Maritime Self-Defense Force Mine warfare vessel classes