Tsugaru-class patrol vessel

Tsugaru-class patrol vessel

Settsu (PLH-07)
Class overview
Name	Tsugaru class
Operators	Japan Coast Guard
Preceded by	Sōya
Built	1978–2001
In commission	1979–present
Completed	9
Active	9
General characteristics of the Ryukyu class
Type	PLH (Patrol vessel Large with Helicopter)
Displacement	4,037 tonnes full load
Length	105.4 m (345 ft 10 in)
Beam	14.6 m (47 ft 11 in)
Draught	8.0 m (26 ft 3 in)
Propulsion	2 × shafts 2 × diesel engines
Speed	23 knots (43 km/h; 26 mph)
Range	6,000 nmi (11,000 km; 6,900 mi)
Complement	69
Armament	1 × L/90 35 mm gun 1 × JM61-RFS 20 mm gun
Aviation facilities	1 × ASR helicopter

The Tsugaru-class patrol vessel (つがる型巡視船, Tsugaru-gata-junnshi-senn) is a class of PLH type patrol vessels of the Japan Coast Guard (JCG; former Maritime Safety Agency, MSA).^[1][2]

Backgrounds

In late 1970s, it was clear that the new international rules on exclusive economic zone would need a considerable increase in the size of the Maritime Safety Agency fleets. In order to cover a wide ocean with a small number of vessels, JMSA began considering the shipping operation of air-sea rescue helicopters.^[1]

At first, Sōya was built as a prototype in the plan of FY1977. Then, from the supplementary budget for the same year, construction of this class was started.^[1]

Design

This class is roughly based on its prototype, Sōya, it is the same as having a long forecastle, but her icebreaking capability was omitted. In order to operate helicopter with these small ships, antiroll tanks and fixed fin stabilizers were set up. Since this class were built for a long time, the design are slightly different.^[1] In particular, the overall improvement was added to the design of the last two vessels, so the United States Naval Institute dealt them as a separate group, Ryukyu class.^[2]

Like Sōya, these ships are not only a helicopter platform but also a command ship, so an operations room, OIC section, is installed adjacent to the bridge. The ability of Command and control is improved sequentially. Currently, Heli-TV system are installed to enable transmission of TV signals directly from a helicopter to OIC section. There are also SATCOM system to relay these TV signals to headquarters onshore.^[3]

In the earliest ships, one L/60 Bofors 40 mm gun and one L/70 Oerlikon 20 mm cannon were set up. But both of them became obsolete, so later, 40 mm guns were replaced by L/90 Oerlikon 35 mm guns, and 20 mm cannons were replaced by JM61-M 20 mm rotary cannons. And in the Ryukyu class, the 20 mm rotary cannons are upgraded to JM61-RFS, remotely operated version with an optical director.^[4]

In the early days, Bell 212 air-sea rescue helicopters were deployed as the shipboard helicopters. Then, with the aging of the Bell 212, they were superseded by the Sikorsky S-76C/D by 2016.^[5]

In service

These ships are operated as command ships of each Regional Coast Guard Headquarters flotilla or task force, and conducting many search and rescue operations.^[6]

In the Incident of Suspicious Boats off the Coast of Noto Peninsula, Chikuzen acted as a forward operating base of the Special Security Team (SST). She also fired warning shots by her JM61-M.^[7]

With their high-endurance and aviation patrol capability, these ships also attend to overseas dispatch including counter-piracy operations in the Strait of Malacca.^[6]

18 January 2023 Echigo ran aground on, or struck a reef off Kashiwazaki, Niigata Prefecture, Honshu, in the Sea of Japan. later anchored.^[8]

Ships in the class

Pennant number	Ship name	Builder	Commission	Decommission	Homeport
PLH-02	Tsugaru	IHI Corporation	17 April 1979		Hakodate
PLH-03	Ōsumi	Tamano Shipyard, Mitsui Engineering & Shipbuilding	18 October 1979		Kagoshima
PLH-04	Uruma (former Uraga, Hayato)	Maizuru Shipyard, Hitachi Zosen Corporation	5 March 1980		Naha
PLH-05	Zaō	Nagasaki Shipyard, Mitsubishi Heavy Industries	19 March 1983		Sendai
PLH-06	Okinawa (former Chikuzen)	Kawasaki Shipbuilding Corporation	28 September 1983		Naha
PLH-07	Settsu	Uraga Shipyard, Sumitomo Heavy Industries	27 September 1984		Kobe
PLH-08	Echigo	Tamano Shipyard, Mitsui Engineering & Shipbuilding	28 February 1990		Niigata
PLH-09	Ryukyu	Nagasaki Shipyard, Mitsubishi Heavy Industries	31 March 2000		Naha
PLH-10	Daisen	Tsurumi Shipyard, JFE Engineering	1 October 2001		Maizuru

References

1. Asanaga, Youichirou; Ōtsuka, Yukitaka (1995). Japan Maritime Safety Agency - their vessels and aviation. Seizando-shoten publishing co., ltd. pp. 120–126. ISBN 4-425-77041-2.
2. Wertheim, Eric (2013). The Naval Institute Guide to Combat Fleets of the World, 16th Edition. Naval Institute Press. pp. 383–384. ISBN 978-1591149545.
3. Okada, Hiroshi (December 2001). "Mechanism of JCG's helicopter patrol vessels". Ships of the World (590). Kaijin-sha: 146–151.
4. Nakanomyo, Masami (October 2015). "History of shipboard guns on JCG's patrol vessels". Ships of the World (825). Kaijin-sha: 168–173.
5. Nanba, Yoko (July 2016). "From 212 to 76C/D: Model change of JCG onboard helicopter". Ships of the World (840). Kaijin-sha: 146–151.
6. Henmi, Masakazu (December 2001). "PLH BUILDING PROGRAM AND ITS BACKGROUND". Ships of the World (590). Kaijin-sha: 141–145.
7. Hirose, Hajime (1999). "Research on new order formation with neighboring countries" (in Japanese). Retrieved 9 November 2017.
8. "Japanese patrol ship aground, Japan sea". Fleetmon. Retrieved 18 January 2023.

External links

• Media related to Tsugaru class patrol vessels at Wikimedia Commons