The is a class of

destroyer In naval terminology, a destroyer is a fast, manoeuvrable, long-endurance warship intended to escort larger vessels in a fleet, convoy or battle group and defend them against powerful short range attackers. They were originally developed ...

, serving with the

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 (IJ ...

(JMSDF). It was the first class of first generation of general-purpose destroyers of the JMSDF.

Background

Destroyers of the JMSDF had been divided into two series, anti-aircraft gunfire-oriented destroyers (DDA) and ASW-oriented destroyers (DDK). However, in the 1970s, a drastic review of the fleet became necessary due to the enhancement of the

Soviet The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...

submarine A submarine (or sub) is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term is also sometimes used historically or colloquially to refer to remotely op ...

fleet and the reinforcement of the

anti-ship missile An anti-ship missile (AShM) is a guided missile that is designed for use against ships and large boats. Most anti-ship missiles are of the sea skimming variety, and many use a combination of inertial guidance and active radar homing. A goo ...

s. After consideration by

Operations research Operations research ( en-GB, operational research) (U.S. Air Force Specialty Code: Operations Analysis), often shortened to the initialism OR, is a discipline that deals with the development and application of analytical methods to improve decis ...

, the concept of eight ships / eight helicopters was adopted as a new fleet organization. In this concept, each flotillas would be composed of one helicopter destroyer (DDH), five general-purpose destroyers (DD), and two

guided-missile destroyer A guided-missile destroyer (DDG) is a destroyer whose primary armament is guided missiles so they can provide anti-aircraft warfare screening for the fleet. The NATO standard designation for these vessels is DDG, while destroyers who have a prim ...

s (DDG). are a new type of destroyers for this concept, combining the

anti-aircraft Anti-aircraft warfare, counter-air or air defence forces is the battlespace response to aerial warfare, defined by NATO as "all measures designed to nullify or reduce the effectiveness of hostile air action".AAP-6 It includes surface based ...

capability of the DDA and the

anti-submarine An anti-submarine weapon (ASW) is any one of a number of devices that are intended to act against a submarine and its crew, to destroy (sink) the vessel or reduce its capability as a weapon of war. In its simplest sense, an anti-submarine weapo ...

capability of the DDK, while also capable of operating missiles and

helicopters A helicopter is a type of rotorcraft in which lift and thrust are supplied by horizontally spinning rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward and laterally. These attribu ...

. This was the first class to be built based on this concept.

Design

The hull structure was based on the shelter deck style adopted in the , and a long forecastle style was adopted which truncated the rear end. The shape under the water line resembles . In order to reduce noise, Prairie-Masker was installed after the 3rd ship and was retrofitted to the 1st and 2nd ships at a later date. From DD-129 onward, steel replaced aluminium for key elements of the superstructure including the

bridge A bridge is a structure built to span a physical obstacle (such as a body of water, valley, road, or rail) without blocking the way underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually someth ...

to improve resistance and durability. However, due to this design change, ballast had to be installed, the classes displacement increased and the maneuvering performance deteriorated. It was the first class to use

combined gas or gas Combined gas or gas (COGOG) is a propulsion system for ships using gas turbine engines. A high efficiency, low output turbine is used for cruising speeds with a high output turbine being used for high-speed operations. A clutch allows either turb ...

(COGOG) propulsion system in the JMSDF. The all-gas-turbine propulsion system is composed of two Kawasaki-

Rolls-Royce Tyne The Rolls-Royce RB.109 Tyne is a twin-shaft turboprop engine developed in the mid to late 1950s by Rolls-Royce Limited to a requirement for the Vickers Vanguard airliner. It was first test flown during 1956 in the nose of a modified Avro Linc ...

RM1C

gas turbine A gas turbine, also called a combustion turbine, is a type of continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part (known as the gas generator or core) and are, in the directio ...

s for cruising and two Kawasaki-

Rolls-Royce Olympus The Rolls-Royce Olympus (originally the Bristol B.E.10 Olympus) was the world's second two- spool axial-flow turbojet aircraft engine design, first run in May 1950 and preceded only by the Pratt & Whitney J57, first-run in January 1950. It is ...

TM3B gas turbines for high-speed operation. This combination and mounting method of these engines are similar to the

Type 21 frigate The Type 21 frigate, or ''Amazon''-class frigate, was a British Royal Navy general-purpose escort that was designed in the late 1960s, built in the 1970s and served throughout the 1980s into the 1990s. Development In the mid-1960s, the Royal Na ...

s of the British

Royal Navy The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by English and Scottish kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years' War against Fr ...

, so it was not possible to adopt an alternating

engine room On a ship, the engine room (ER) is the compartment where the machinery for marine propulsion is located. To increase a vessel's safety and chances of surviving damage, the machinery necessary for the ship's operation may be segregated into var ...

arrangement like a conventional JMSDF destroyer, the lack of redundancy was pointed out.

Equipment

The core of the combat system is the OYQ-5 Tactical Data Processing System (TDPS), composed of one

AN/UYK-20 The AN/UYK-20 "Data Processing Set" was a ruggedized small computer manufactured by Univac and used by the United States Navy for small and medium-sized shipboard and shore systems built in the 1970s. It featured non-volatile magnetic core memory ...

computer and five OJ-194B

workstation A workstation is a special computer designed for technical or scientific applications. Intended primarily to be used by a single user, they are commonly connected to a local area network and run multi-user operating systems. The term ''workst ...

s and capable of receiving data automatically from other ships via Link-14 (

STANAG In NATO, a standardization agreement (STANAG, redundantly: STANAG agreement) defines processes, procedures, terms, and conditions for common military or technical procedures or equipment between the member countries of the alliance. Each NATO st ...

5514). This is the first destroyer class in the JMSDF equipped with the Sea Sparrow Improved basic point defense missile system. The IBPDMS of this class uses

FCS-2 Type 81 Fire Control System (FCS-2) is a Japanese shipboard gun and missile fire-control system. This series of systems has been installed on destroyers of the Japan Maritime Self-Defense Force built between FY1977 and FY2001 to control medium-cal ...

fire-control system A fire-control system (FCS) is a number of components working together, usually a gun data computer, a director, and radar, which is designed to assist a ranged weapon system to target, track, and hit a target. It performs the same task as a ...

s of Japanese make and one octuple launcher at the afterdeck. And in the JMSDF,

OTO Melara 76 mm The OTO Melara 76 mm gun is a naval gun built and designed by the Italian defence company OTO Melara. It is based on the OTO Melara 76/62C and evolved toward 76/62 SR and 76/62 Strales. The system is compact enough to be installed on rel ...

compact gun and

Boeing Harpoon The Harpoon is an all-weather, over-the-horizon, anti-ship missile manufactured by McDonnell Douglas (now Boeing Defense, Space & Security). The AGM-84E Standoff Land Attack Missile (SLAM) and later AGM-84H/K SLAM-ER (Standoff Land Attack ...

surface-to-surface missile A surface-to-surface missile (SSM) or ground-to-ground missile (GGM) is a missile designed to be launched from the ground or the sea and strike targets on land or at sea. They may be fired from hand-held or vehicle mounted devices, from fixed ins ...

are adopted from the ship of FY1977 including this class. Also, ships built in FY1979 and beyond carried

Phalanx CIWS The Phalanx CIWS (often spoken as "sea-wiz") is a gun-based close-in weapon system to defend military watercraft automatically against incoming threats such as aircraft, missiles, and small boats. It was designed and manufactured by the Gen ...

and were retrofitted to previous ships. This class introduced the capability of

shipboard helicopter operations Shipboard helicopter operations is the use of techniques which allows operation of rotary wing aircraft from naval vessels. In the case of military vessels the operations also include tactics and associated weapons and troops. Landing a helicopt ...

. While the JMSDF already had the "helicopter destroyer", the ''Hatsuyuki'' class were the first air-capable general purpose destroyer class. Although it has a small aviation deck, through a beartrap system, the class can operate the Mitsubishi HSS-2B anti-submarine helicopter safely in a wider range of weather conditions. Later, HSS-2B was replaced by

Mitsubishi SH-60J The Mitsubishi H-60 series is twin-turboshaft engine helicopter based on the Sikorsky S-70 helicopter family for use by the Japan Self-Defense Forces (JSDF). The SH-60J/K/L are anti-submarine patrol versions for the Japan Maritime Self-Defense F ...

, but there was no room to install a large data link device for SH-60J, so a simplified type was installed. They were initially planned to carry out passive operation with

sonobuoy A sonobuoy (a portmanteau of sonar and buoy) is a relatively small buoy – typically diameter and long – expendable sonar system that is dropped/ejected from aircraft or ships conducting anti-submarine warfare or underwater acoustic resea ...

s laid by helicopters and

towed array sonar A towed array sonar is a system of hydrophones towed behind a submarine or a surface ship on a cable. Trailing the hydrophones behind the vessel, on a cable that can be kilometers long, keeps the array's sensors away from the ship's own noise sou ...

(TASS) as sensors, but because the development of TASS was delayed, they was retrofitted later on only four ships. OQS-4 hull sonar was the Japanese equivalent of American AN/SQS-56, and OQR-1 TASS was of AN/SQR-19.

Sub-class

Four ships of this class have been re-purposed as training vessels: JS ''Shimayuki'' (1999), JS ''Shirayuki'' (2011), JS ''Setoyuki'' (2012) and JS ''Yamayuki'' (2016). These ships have been converted for training, yet they still have their weapons systems intact. They are referenced after the lead ship as the: ''Shimayuki''-class.

Ships in the class

References

Books

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External links

JMSDF DD Hatsuyuki Class
{{Combatant ship classes of the Japan Maritime Self-Defense Force Destroyer classes Auxiliary training ship classes