The is a class of 1,000 ton-class PL type
patrol vessels
A patrol boat (also referred to as a patrol craft, patrol ship, or patrol vessel) is a relatively small naval ship, naval vessel generally designed for Coastal defence and fortification, coastal defence, Border control, border security, or law ...
of the
Japan Coast Guard
The is the coast guard responsible for the protection of the Geography of Japan#Composition, topography and geography, coastline of Japan under the oversight of the Ministry of Land, Infrastructure, Transport and Tourism. It consists of about ...
(JCG).
Backgrounds
In the 2000s, the JCG was building 1000-ton class PLs with a high speed planing hull, such as and es. Although these ships were excellent in security missions, they were also unsuitable for rescue missions because of their poor low-speed stability and cruising capacity.
Since the mass retirement of the was planned in the 2010s, general-purpose ships as replacements were needed. For this purpose, construction of the was started under the FY2009 supplement budget, but they were too expensive to build in large quantities.
Because their high cost, construction of this class was started under the FY2010 supplement budget as more reasonable but still versatile vessels.
Design
Due to the demand for multi-mission capabilities, displacement hull made of steel was adopted as same as the ''Kunigami'' class. The superstructure is made of
aluminium alloy
An aluminium alloy ( UK/IUPAC) or aluminum alloy ( NA; see spelling differences) is an alloy in which aluminium (Al) is the predominant metal. The typical alloying elements are copper, magnesium, manganese, silicon, tin, nickel and zinc. There ...
. She is designed to assume the towing of a distress ship with a bollard pull of 45 tons, two
funnels
A funnel is a tube or pipe that is wide at the top and narrow at the bottom, used for guiding liquid or powder into a small opening.
Funnels are usually made of stainless steel, aluminium, glass, or plastic. The material used in its constructi ...
separated on the left and right ensure backward visibility.
Because the aviation capability was not required, the
helipad
A helipad is the landing area of a heliport, in use by helicopters, powered lift, and vertical lift aircraft to land on surface.
While helicopters and powered lift aircraft are able to operate on a variety of relatively flat surfaces, a fa ...
on the stern deck was omitted. Also no fin
stabilizer
Stabilizer, stabiliser, stabilisation or stabilization may refer to:
Chemistry and food processing
* Stabilizer (chemistry), a substance added to prevent unwanted change in state of another substance
** Polymer stabilizers are stabilizers used ...
was equipped,
but
antiroll tanks Antiroll tanks are tanks fitted onto ships in order to improve the ship's response to roll motion. Fitted with baffles intended to slow the rate of water transfer from the port side of the tank to the starboard side and the reverse, the tanks are ...
were retained since low-speed stability was required.
Based on the lesson learned from the operation of
humanitarian response to the 2011 Tōhoku earthquake and tsunami, the last four ships strengthened the capacity of the fresh water generator, and additionally equipped with a water supply unit, a fuel supply unit, and a loading
crane.
As a main weapon, a
Bushmaster II 30 mm
3 (three) is a number, numeral and digit. It is the natural number following 2 and preceding 4, and is the smallest odd prime number and the only prime preceding a square number. It has religious and cultural significance in many societies ...
chain gun
A chain gun is a type of autocannon or machine gun that uses an external source of power to cycle the weapon's action via a continuous loop of chain, similar to that used on a motorcycle or bicycle, instead of diverting excess energy from the ...
system with an optical director is installed.
In service
The level of stability of this class was good, the automation was also proceeding, and it was a popular boat for the crew. However, this class was considered not to be so suitable for the security missions on the
Senkaku Islands
The Senkaku Islands, known as the Diaoyu Islands in China and the Tiaoyutai Islands in Taiwan, are a group of uninhabited islands in the East China Sea, administered by Japan. They were historically known in the Western world as the Pinnacle ...
, and the ''Kunigami'' class began construction again in FY2012. This additional construction reduced costs, therefore construction of ''Kunigami'' class is continuing from FY 2013 onwards.
Ships in the class
See also
*
List of Japan Coast Guard vessels and aircraft
List of Japan Coast Guard vessels and aircraft.
Fleet
PLH (Patrol Vessel Large With Helicopter)
* 2 Helicopter class
** :w:jp:しゅんこう型巡視船, ''Shunkō'' class ''(ja)''
**
**
* 1 Helicopter class
** ''Reimei'' class (Modified '' ...
References
{{Reflist
Patrol vessels of the Japan Coast Guard
Patrol ship classes