Sejong the Great-class destroyer

The Sejong the Great-class destroyers (Sejongdaewang-Geup Guchukam or Hangul: 세종대왕급 구축함, Hanja: 世宗大王級驅逐艦), also known as KD-III, are three guided missile destroyers of the Republic of Korea Navy (ROKN). The second ship was commissioned in August 2010 and the third in August 2012. As at 2013, the ROKN has deployed three ships with an option for three more; in December 2013 the option to acquire the second three was taken up.[3]

ROKS Sejong the Great (DDG 991) broadside view
ROKS Sejong the Great (DDG-991)
Class overview
Operators:  Republic of Korea Navy
Preceded by: Chungmugong Yi Sun-sin class
Cost: $923 million (per ship)[1]
Planned: 6
Building: 3
Completed: 3
Cancelled: 0
Active: 3
General characteristics
Type: Destroyer
  • 8,500 tons standard displacement
  • 11,000 tons full load
Length: 166 m (544 ft 7 in)
Beam: 21.4 m (70 ft 3 in)
Draft: 6.25 m (20 ft 6 in)
Speed: exceeds 30 knots (56 km/h; 35 mph)
Range: 5,500 nautical miles (10,200 km; 6,300 mi)
Complement: 300-400 crew members
Sensors and
processing systems:
  • AN/SPY-1D(V) multi-function radar
  • AN/SPG-62 fire control radar
  • DSQS-21BZ hull mounted sonar
  • MTeQ towed array sonar system
  • Sagem Infrared Search & Track (IRST) system
Electronic warfare
& decoys:
LIG Nex1 SLQ-200K Sonata electronic warfare suite[2]
Aircraft carried: Hangar for two Super Lynx or SH-60 Seahawk, one more on landing pad


The ship features the Aegis Combat System (Baseline 7 Phase 1) combined with AN/SPY-1D multi-function radar antennae.

The Sejong the Great class is the third phase of the South Korean navy's Korean Destroyer eXperimental (KDX) program, a substantial shipbuilding program, which is geared toward enhancing ROKN's ability to successfully defend the maritime areas around South Korea from various modes of threats as well as becoming a blue-water navy.

At 8,500 tons standard displacement and 11,000 tons full load, the KDX-III Sejong the Great destroyers are by far the largest destroyers in the South Korean Navy,[4] and built slightly bulkier and heavier than Arleigh Burke-class destroyers or Atago-class destroyers to accommodate 32 more missiles. KD-III are currently the largest ships to carry the Aegis combat system.[5]


Sejong the Great-class destroyers' main gun is the 127 mm/L62 Mk. 45 Mod 4 naval gun, an improved version of the same gun used on other warships from several foreign nations. Point-defense armaments include one 30 mm Goalkeeper CIWS and a RIM-116 Rolling Airframe Missile Block 1 21-round launcher, the first Aegis platform to carry RAM.[6] Anti-aircraft armament consists of SM-2 Block IIIA and IIIB[7][8] in 80-cell VLS. Anti-submarine warfare armaments consists of both K-ASROC Hong Sahng-uh (Red Shark) anti-submarine rockets and 32 K745 LW Cheong Sahng-uh (Blue Shark) torpedoes. Anti-ship capability is provided by 16 SSM-700K Hae Sung (Sea Star) long-range anti-ship missile, each with performance similar to the U.S. Harpoon. Land-attack capability is provided by the recently developed Hyunmoo-3C (Guardian of the Northern Sky) cruise missile, which is similar to the U.S. Tomahawk.

Missile batteries

  • VLS: 128 cell
    • Mk 41 VLS 48 cell (Fwd)
    • Mk 41 VLS 32 cell (Aft)
    • K-VLS 48 cell (Aft)
  • Anti-ship missile launchers: 16


The Sejong the Great-class destroyers' are often compared to the Arleigh Burke and Atago classes because they utilize the AN/SPY-1 multi-function radar, have similar propulsion and capabilities. One notable difference between the Sejong the Great-class ships and Arleigh Burkes is the number of VLS cells. Destroyers of the Sejong the Great-class have a capacity of 128 missiles, as opposed to 96 on the Arleigh Burke class and the Japanese Atago-class destroyers. The Sejong the Great class is thus one of the most heavily armed ships in the world,[9] with even greater missile capacity than the Chinese People's Liberation Army Navy Type 055 destroyer[10] (112 VLS cells), or the U.S. Navy Ticonderoga-class guided missile cruiser (122 VLS cells), and considering only surface ships is surpassed only by the Kirov-class battlecruiser with 352 missiles (entire missile load).[11] The four American Ohio-class submarines converted to guided-missile configuration carry 154 cruise missiles each. Another similarity to Arleigh Burke Flight IIA and Atago-class destroyers is the presence of full facilities for two helicopters, a feature missing from earlier Arleigh Burke and Kongō-class destroyers.

These destroyers have the capability to track and monitor any missile launched from anywhere from North Korea. This capability was demonstrated by the tracking of a North Korean missile in April 2009.[12]


In August 2016, press reports revealed that South Korea was considering adding the SM-3 interceptor to its Sejong the Great-class ships to enable them to perform ballistic missile defense in response to North Korean efforts to bolster offensive missile capabilities. This comes just months after the U.S. decision to deploy the THAAD missile interceptor system on mainland South Korea. The addition of SM-3s to the ships may require software and computer hardware upgrades.[13] The following month, Aegis manufacturer Lockheed Martin confirmed the next three Sejong the Great vessels will be capable of performing "integrated air and missile defense" (IAMD) to supplement U.S. Army ground-based missile interceptors on the peninsula, likely being outfitted with the SM-3. While the first three destroyers are fitted with Aegis Baseline 7 based on older proprietary computers that can't carry out IAMD operations, the following three will be fitted with the Baseline 9 version of the Aegis Combat System that combines modern computing architecture to allow the AN/SPY-1D(v) radar to perform air warfare and BMD missions at the same time.[14]

Hull names

On April 20, 2007, South Korean Chief of Naval Operations announced that the lead ship of KDX-III class destroyers will be referred as Sejong the Great. Sejong the Great (Hangul: 세종대왕) is the fourth king of the Joseon Dynasty of Korea. He is credited with the creation of the Korean alphabet.

Ships in the class

Name Pennant number Builder Launched Commissioned Decommissioned Status
ROKS Sejong the Great (Korean: 세종대왕함) DDG-991 Hyundai Heavy Industries 25 May 2007 22 December 2008 Active
ROKS Yulgok Yi I (Korean: 율곡 이이함) DDG-992 Daewoo Shipbuilding & Marine Engineering 14 November 2008 31 August 2010 Active
ROKS Seoae Yu Seong-ryong[15](Korean: 서애 류성룡함) DDG-993 Hyundai Heavy Industries 24 March 2011 30 August 2012 Active

On 10 December 2013 the ROKN confirmed ordering three more vessels on the same class.[3]

See also


  1. ^ Pike, John. "KDX-III Destroyer". Archived from the original on 2006-02-16. Retrieved 2006-02-17.
  2. ^ "Archived copy". Archived from the original on 2008-06-25. Retrieved 2008-07-21.CS1 maint: Archived copy as title (link)
  3. ^ a b "ROK (Republic of Korea) Navy to increase KDX-III Aegis destroyers to six by 2027". December 11, 2013. Archived from the original on December 12, 2013. Retrieved December 12, 2013.
  4. ^ "Koreas KDX-III AEGIS Destroyers". Archived from the original on 2009-12-11. Retrieved 2010-03-08.
  5. ^ "Aegis Weapon System Verified During Korean Navy Ship - at DefenceTalk". Archived from the original on 2010-12-05. Retrieved 2010-10-21.
  6. ^ "KDX-III / DDH-III Sejongdaewang". Guide to Military Equipment and Civil Aviation. Archived from the original on 2006-10-07. Retrieved 2009-04-07. These ships will be the world's first combining proven AEGIS and RAM.
  7. ^ "Korea to acquire new missiles for Aegis destroyer". The Korea Herald. 2009-06-28. Retrieved 2009-06-27.
  8. ^ "Republic of Korea - SM-2 Standard Missiles" (PDF). Defense Security Cooperation Agency. 2009-05-26. Archived from the original (PDF) on 2011-05-27. Retrieved 2009-06-27.
  9. ^ Burleson, Mike (2010-05-25). "South Korean Naval Plight Our Own". New Wars. Archived from the original on 2011-10-28. Retrieved 2011-11-10.
  10. ^ China's New Guided Missile Destroyer To Be Its Biggest Yet Archived 2016-12-06 at the Wayback Machine -, 24 October 2016
  11. ^ Kirov class Archived 2016-03-04 at the Wayback Machine -
  12. ^ "Korea Launches 3rd Aegis Destroyer". Archived from the original on 2012-06-14. Retrieved 2012-05-10.
  13. ^ Report: South Korea Wants BMD Capability for Guided Missile Destroyers Archived 2016-08-15 at the Wayback Machine -, 15 August 2016
  14. ^ New South Korean Destroyers to Have Ballistic Missile Defense Capability Archived 2016-09-07 at the Wayback Machine -, 6 September 2016
  15. ^ "NAVSEA on Flight III Arleigh Burkes - USNI News". 7 June 2013. Archived from the original on 14 July 2017. Retrieved 29 May 2017.

External links


The AN/SPY-1 is a United States Navy 3D radar system manufactured by Lockheed Martin. The array is a passive electronically scanned system and is a key component of the Aegis Combat System. The system is computer controlled, using four complementary antennas to provide 360 degree coverage. The system was first installed in 1973 on USS Norton Sound and entered active service in 1983 as the SPY-1A on USS Ticonderoga. The -1A was installed on ships up to CG-58, with the -1B upgrade first installed on USS Princeton in 1986. The upgraded -1B(V) was retrofitted to existing ships from CG-59 up to the last, USS Port Royal.

Aegis Combat System

The Aegis Combat System is an American integrated naval weapons system developed by the Missile and Surface Radar Division of RCA, and now produced by Lockheed Martin. It uses powerful computer and radar technology to track and guide weapons to destroy enemy targets.

Initially used by the United States Navy, Aegis is now used also by the Japan Maritime Self-Defense Force, Spanish Navy, Royal Norwegian Navy, Republic of Korea Navy and Royal Australian Navy. Over 100 Aegis-equipped ships have been deployed. It is also part of NATO's European missile defence system.

Chungmugong Yi Sun-sin-class destroyer

Chungmugong Yi Sun-sin class destroyers (Korean: 충무공 이순신급 구축함, Hanja: 忠武公李舜臣級驅逐艦) are multipurpose destroyers of the Republic of Korea Navy. The lead ship of this class, ROKS Chungmugong Yi Sunsin, was launched in May 2002 and commissioned in December 2003. Chungmugong Yi Sun-sin-class destroyers were the second class of ships to be produced in the Republic of Korea Navy's destroyer mass-production program named Korean Destroyer eXperimental, which paved the way for the navy to become a blue-water navy. Six ships were launched by Hyundai Heavy Industries and Daewoo Shipbuilding & Marine Engineering in four years.

Combined gas and gas

Combined gas turbine and gas turbine (COGAG) is a type of propulsion system for ships using two gas turbines connected to a single propeller shaft. A gearbox and clutches allow either of the turbines to drive the shaft or both of them combined.

Using one or two gas turbines has the advantage of having two different power settings. Since the fuel efficiency of a gas turbine is best near its maximum power level, a small gas turbine running at its full power is more efficient compared to a twice as powerful turbine running at half power, allowing more-economical transit at cruise speeds.

Compared to Combined diesel and gas (CODAG) or Combined diesel or gas (CODOG), COGAG systems have a smaller footprint but a much lower fuel efficiency at cruise speed and for CODAG systems it is also somewhat lower for high speed dashes.

General Electric LM2500

The General Electric LM2500 is an industrial and marine gas turbine produced by GE Aviation. The LM2500 is a derivative of the General Electric CF6 aircraft engine.

The LM2500 is available in 3 different versions:

The LM2500 delivers 33,600 shaft horsepower (shp) (25,060 kW) with a thermal efficiency of 37 percent at ISO conditions. When coupled with an electric generator, it delivers 24 MW of electricity at 60 Hz with a thermal efficiency of 36 percent at ISO conditions.

The improved, 3rd generation, LM2500+ version of the turbine delivers 40,500 shp (30,200 kW) with a thermal efficiency of 39 percent at ISO conditions. When coupled with an electric generator, it delivers 29 MW of electricity at 60 Hz with a thermal efficiency of 38 percent at ISO conditions.

The latest, 4th generation, LM2500+G4 version was introduced in November 2005 and delivers 47,370 shp (35,320 kW) with a thermal efficiency of 39.3 percent at ISO conditions.As of 2004, the U.S. Navy and at least 29 other navies had used a total of more than one thousand LM2500/LM2500+ gas turbines to power warships. Other uses include hydrofoils, hovercraft and fast ferries.

In 2012, GE developed an FPSO version to serve the oil and gas industry's demand for a lighter, more compact version to generate electricity and drive compressors to send natural gas through pipelines.

Guided missile destroyer

A guided-missile destroyer is a destroyer designed to launch guided missiles. Many are also equipped to carry out anti-submarine, anti-air, and anti-surface operations. The NATO standard designation for these vessels is DDG. Nations vary in their use of destroyer D designation in their hull pennant numbering, either prefixing or dropping it altogether. The U.S. Navy has adopted the classification DDG in the American hull classification system.

In addition to the guns, a guided-missile destroyer is usually equipped with two large missile magazines, usually in vertical-launch cells. Some guided-missile destroyers contain powerful radar systems, such as the United States’ Aegis Combat System, and may be adopted for use in an anti-missile or ballistic-missile defense role. This is especially true of navies that no longer operate cruisers, so other vessels must be adopted to fill in the gap.

Gwanggaeto the Great-class destroyer

The Gwanggaeto the Great-class destroyers (Hangul: 광개토대왕급 구축함, Hanja: 廣開土大王級 驅逐艦), often called KD-I class, are destroyers, but are classified by some as frigates, operated by the Republic of Korea Navy. It was the first phase of ROKN's KDX program, in moving the ROK Navy from a coastal defence force to a blue-water navy.

Hong Sang Eo

The Hong Sang Eo (Red Shark) torpedo (Hangul: 홍상어 어뢰), also called the K-ASROC, is a vertically launched anti-submarine missile successively developed and tested by South Korea's University of Science and Technology, the Korea Agency for Defense Development (ADD) and the Republic of Korea Navy in 2009. The Red Shark missile has a range of 12 miles (19 km) and carries a K745 Blue Shark torpedo that is deployed by parachute near the intended target. After release, the Blue Shark independently searches for the target.

The missiles are planned to be deployed on KDX-II and KDX-III destroyers starting in 2010. Each destroyer will carry between 8 (KDX-II) and 16 (KDX-III) of the missiles. The development cost of the program was around US$ 80 million, with a production cost of about $14 million. They were designed in order to combat the potential threat of North Korean submarines.


Hyunmoo-3 is a new cruise missile that is to be fielded with the military of Republic of Korea. It is designed by Agency for Defense Development (ADD). The name Hyunmoo (Hangul: 현무) comes from a mythical beast described as the "Guardian of the Northern Sky", perhaps hinting North Korea.

Kidd-class destroyer

The Kidd-class destroyers were a series of four guided missile destroyers (DDGs) based on the Spruance class. The Kidds were designed as more advanced multipurpose ships, in contrast to their predecessor's focus on anti-submarine warfare, adding considerably enhanced anti-aircraft capabilities. Originally ordered for the former Imperial Iranian Navy, the contracts were canceled when the 1979 Iranian Revolution began, and the ships were completed for the United States Navy. Because they were equipped with heavy-duty air conditioning and other features that made them suitable in hot climates, they tended to be used in the Middle East, specifically the Persian Gulf itself. During their service with the U.S. Navy from the 1980s to the late 1990s, the ships were popularly known as the "Ayatollah" class. They were decommissioned and sold to the Republic of China Navy as the Kee Lung class.

Korean Destroyer eXperimental

KDX (Korean Destroyer eXperimental) is a substantial shipbuilding program embarked on by the Republic of Korea Navy.

It is a three-phased program consisting of three individual classes of ships:

KDX-I (3,800 tons),

KDX-II (5,500 tons),

Aegis Combat System-enabled KDX-III (11,000 tons).

KDX-IIA, planned derivative of KDX-II with Aegis combat system (5,500 ~ 7,500 tons)

Korean Vertical Launching System

The Korean Vertical Launching System (K-VLS or KVLS) is a vertical launch weapon system developed by South Korea to be deployed by the Republic of Korea Navy. It is used in the Sejong the Great-class destroyer, and is scheduled to be added to the Daegu-class frigate. The K-VLS can deploy the Cheolmae-2 air defense missile, Hong Sang Eo anti-submarine missile, Haeseong-II, Hyunmoo-3 land attack cruise missiles and even SLBMs.

Mark 41 Vertical Launching System

The Mark 41 Vertical Launching System (Mk 41 VLS) is a shipborne missile canister launching system which provides a rapid-fire launch capability against hostile threats. The Vertical Launch System (VLS) concept was derived from work on the Aegis Combat System.

ROKS Munmu the Great (DDH-976)

ROKS Munmu the Great (DDH-976) is a Chungmugong Yi Sun-sin-class destroyer in the South Korean navy. It was named after the Korean king Munmu of Silla.

Stealth ship

A stealth ship is a ship which employs stealth technology construction techniques in an effort to ensure that it is harder to detect by one or more of radar, visual, sonar, and infrared methods.

These techniques borrow from stealth aircraft technology, although some aspects such as wake and acoustic signature reduction (Acoustic quieting) are unique to stealth ships' design. Though radar cross-section (RCS) reduction is a fairly new concept many other forms of masking a ship have existed for centuries or even millennia.

Type 052D destroyer

The Type 052D destroyer (NATO/OSD Luyang III-class destroyer) is a class of guided missile destroyers in the Chinese People's Liberation Army Navy Surface Force. The Type 052D is a larger variant of the Type 052C; the Type 052D uses a canister-type, instead of revolver-type, vertical launching system (VLS) and has flat-panelled active electronically scanned array (AESA) radar. The new VLS is not limited to anti-air missiles, making the Type 052D China's first dedicated multi-role destroyer.Chinese media informally calls the Type 052D the Chinese Aegis, portraying it as a peer of contemporary United States Navy ships equipped with the Aegis Combat System. The appearance of the Type 052D, with flat-panelled radar and canister-based VLS, has encouraged the moniker's use.

Vertical launching system

A vertical launching system (VLS) is an advanced system for holding and firing missiles on mobile naval platforms, such as surface ships and submarines. Each vertical launch system consists of a number of cells, which can hold one or more missiles ready for firing. Typically, each cell can hold a number of different types of missiles, allowing the ship flexibility to load the best set for any given mission. Further, when new missiles are developed, they are typically fitted to the existing vertical launch systems of that nation, allowing existing ships to use new types of missiles without expensive rework. When the command is given, the missile flies straight up long enough to clear the cell and the ship, and then turns on course.

A VLS allows surface combatants to have a greater number of weapons ready for firing at any given time compared to older launching systems such as the Mark 13 single-arm and Mark 26 twin-arm launchers, which were fed from behind by a magazine below the main deck. In addition to greater firepower, VLS is much more damage tolerant and reliable than the previous systems, and has a lower radar cross-section (RCS). The U.S. Navy now relies exclusively on VLS for its guided missile destroyers and cruisers.

The most widespread vertical launch system in the world is the Mark 41, developed by the United States Navy. More than 11,000 Mark 41 VLS missile cells have been delivered, or are on order, for use on 186 ships across 19 ship classes, in 11 navies around the world. This system currently serves with the US Navy as well as the Australian, Danish, Dutch, German, Japanese, New Zealand, Norwegian, South Korean, Spanish, and Turkish navies, while others like the Greek Navy preferred the similar Mark 48 system.The advanced Mark 57 vertical launch system is used on the new Zumwalt-class destroyer. The older Mark 13 and Mark 26 systems remain in service on ships that were sold to other countries such as Taiwan and Poland.

When installed on an SSN (nuclear-powered attack submarine), a VLS allows a greater number and variety of weapons to be deployed, compared with using only torpedo tubes.

Sejong the Great-class destroyers
Patrol vessels
warfare ships
Mine warfare
Auxiliary ships


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