Country of origin
Dimensions and displacement
7 700 tons
Displacement, full load
11 000 tons
Propulsion and speed
10 186 km at 20 knots
4 x General Electric LM2500 gas turbines driving
2 shafts with 100 000 shp
2 x Super Lynx of SH-60 Seahawk
1 x 127 mm/62 Mk-45 Mod 4, 1 x 30 mm Goalkeeper
1 x RAM Block 1, 16 x SSM-700K Hae Sung AShM,
RIM-66M-5 Standard SAM, Hyunmoo III cruise missiles, Red Shark SUwM
6 x K745 Blue Shark torpedoes
The Sejong the Great class
destroyers are among the most
advanced warships afloat today. They were developed under the KDX-III
program, which sought to provide the South Korean Navy with a
world-class destroyer capable of meeting virtually any threat at
sea, on land, or in the air.
The design of these vessels borrows heavily from features of
Arleigh Burke class and the Japanese Atago class, and
shares numerous common components and systems as well, but has a
largely original construction and composition. Moreover, with a
combat displacement of some 11 000 tons (practically making these
vessels Cruisers), the Sejong the Great class destroyers are
substantially heavier. The wider hull flare and bulkier
superstructure are also very different from the Arleigh Burke class,
though the Atago class has a similar shape. Also as with the Arleigh
Burke class, the structural components (hull, bulkheads, decks,
hatches, etc.) of the Sejong the Great class are almost entirely
steel in composition.
There are three vessels in the class; the DDG-991 Sejong the
Great, DDG-992 Yulgok Yi I, and DDG-993 Seoae Ryu Seong-ryong. Named
after prominent figures of the Joseon Dynasty, they were
commissioned in 2008, 2012, and 2014, respectively. The DDG-991
Sejong the Great and DDG-993 Seoae Ryu Seong-ryong were constructed
by the Hyundai Heavy Industries (HHI) shipyard in Ulsan, while the
DDG-992 Yulgok Yi I was constructed by the Daewoo Shipbuilding &
Marine Engineering shipyard in Opko.
Likely owing to the use of only fully-developed technologies
and subsystems, the Sejong the Great class destroyers cost only $923
million per-vessel. It is worth noting that his price tag makes
these among the most inexpensive Aegis warships ever constructed.
Sensors consist of four AN/SPY-1D(V) phased array radar sets,
an AN/SPG-62 fire control radar, a DSQS-21BZ hull mounted sonar, an
MTeQ towed array sonar system, and a Sagem Infrared Search &
Track (IRST) system. The AN/SPY-1D(V) is capable of being used as a
passive radar, and the Sagem IRST is already a passive system,
giving the Sejong the Great class immense situational awareness
capabilities even at a maximum Emissions Control (EMCON) state,
giving it substantial stealth capability.
Propulsion for the Sejong the Great class is four General
Electric LM2500 gas turbines driving two shafts with 100 000 shp.
Additional power for the ship's systems is provided by three
Rolls-Royce AG9140RF gas turbine generators, as the electrical power
demand of the class' systems is too great for the LM2500's
alternators alone. Enough fuel bunkerage is provided for a 10 186 km
(5 500 nm)
range at 20 knots, and the full speed of the class is approximately
30 knots. Two rudders are fitted, allowing for a relatively small
minimum turning circle.
The weapons, sensors, fire controls, propulsion, and other
systems are fully-automated, and networked together via the Aegis
combat information system; the version currently used in the Sejong
the Great class is Baseline 7 Phase 1. This system allows the ship
to detect, identify, evaluate, and engage targets with no input from
the crew, other than the decision to engage. The system can also
display several-thousand contacts, and track and/or engage up to 100
simultaneously. It is also possible for the crew to operate these
systems manually, as in earlier guided missile warships, without
using the Aegis system. The class also has a Maritime Air
Support Operation Centre (MASOC) system, allowing it to coordinate the
operations of all friendly tactical aircraft in the vicinity.
The stern is covered by a large helicopter landing pad, and
there are two hangars. The total capacity is two helicopters, which
can be expanded to three, if an additional helicopter is kept on the
landing pad. The maintenance and storage facilities have space and
equipment for either the Super Lynx or
The missile battery of the Sejong the Great class is
exceptional. Not even including the 21-cell RAM launcher, or even
the 16 Hyunmoo III anti-ship missiles, they carry an incredible 128
missiles in three different VLC launch cell pads (one forward with
48 cells, one aft with 32 cells, and another 48-cell pad aft). This
is a much larger stock of missiles than the 96 cells found on the
Arleigh Burke class, though it is still second-place to the
class battlecruisers (which have the world's largest missile
battery, at 352 missiles).
The variety of missiles carried by the Sejong the Great class
is staggering as well. These include the RIM-66M-5/SM-2ER Block IV
Standard SSM-700K Haeseong with a range of 240 km, the Hyunmoo IIIB
land attack cruise missile with a range of 1 000 km, the SSM-700K Haeseong anti-ship missile with a range of
150 km, the Red Shark (also
called the K-ASROC) anti-submarine missile with a 18.5 km range, and
the RIM-116B RAM surface to air missile with a range of 7.4 km. The
K745 Blue Shark torpedo has an effective range of 18.5 km.
Though only two gun systems are carried, these are also quite
formidable. The Mk-45 Mod 4 127-mm/62 dual-purpose gun fires 30.7 kg
projectiles at a rate of fire of 20 rounds/minute, with a maximum
range of 38.4 km, and is capable of engaging land targets, ships,
aircraft, and even missiles. The Goalkeeper 30 mm CIWS fires 0.4 kg
projectiles at up to 4 200 rounds/minute, with an effective range of
3 km, and can be used against watercraft as well as aircraft and
The complete ammunition loadout for the Sejong the Great
class includes (but is likely not limited to) 680 127 mm shells, 1 190
30 mm shells, 21 RAM missiles, 6 Blue Shark torpedoes, and 16x
SSM-700K Hae Sung missiles. The VLS load-out is variable, but the
standard configuration consists of 80 SM-2 Standard missiles, 32
Hyunmoo IIIB missiles, and 16 Red Shark missiles. The loadout for
the additional munitions carried by the helicopters is unknown.
In 2012, the ROKN formally made a request to the government
for three additional Aegis warships, with an eye toward having them
in commission by 2027. If these vessels are authorized, it is likely
that they will be additional Sejong the Great class destroyers, or
possibly an evolved version of the design.
The manufacturers retain the ability to construct additional
Sejong the Great class, but it is unknown as of late 2015 if any
other will be ordered by the ROKN, and very unlikely that KDX-III
type vessels would be offered for export, as many of its key
technologies are classified and/or barred from further proliferation
by the US government.
Barring unforeseen developments, the Sejong the Great class
destroyers will remain in service until at least the mid-2030s.
Arleigh Burke class: US Destroyer class, and the design basis
of the Sejong the Great class.
Kongo class: Japanese variant of the Arleigh Burke class.
Atago class: Japanese destroyer class, with a similar design
to the Sejong the Great class.
Type 052D class: Chinese destroyers,
generally considered to be comparable in capability to Aegis
warships. They are also similar in layout to the Sejong the Great
Type 055 class: New class of Chinese destroyers in
development, with a similar design to the Sejong the Great class.
Sejongdaewang (Sejong the Great) (DDG-991)
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