ROKS Dosan Ahn Changho: South Korea’s first KSS III Submarine

The KSS-III submarine, also classified as the Dosan Ahn Changho-class submarines – is a series of diesel-electric attack submarines currently being built for the Republic of Korea Navy.

On August 16, ROKS Dosan Ahn Changho, South Korea’s first KSS III submarine, was deployed for the first time. The feat is the culmination of three years of testing and trials following the submarine’s launch in 2018. Many consider the deployment of the vessel an important milestone, marking the first time that a ballistic missile submarine is in operational readiness. ROKS Dosan Ahn Changho, which was commissioned in August 2021, has already made headlines multiple times for conducting submarine-launched ballistic missiles tests.

The KSS-III submarine, also classified as the Dosan Ahn Changho-class submarines – is a series of diesel-electric attack submarines currently being built for the Republic of Korea Navy. The KSS-III initiative consists of the development of nine diesel-electric attack submarines, capable of firing submarine-launched ballistic missiles, to be built in three batches, between 2014–2029.

The KSS-III are the largest submarines to ever be built by South Korea and are reportedly based on the design of the German-origin Type 214 submarine. And the ROKS Dosan Ahn Changho is the lead ship of the class. The class are equipped with the Korean Vertical Launching System which will be able to carry up to ten indigenous “Chonryong” land-attack cruise missiles and “Hyunmoo” submarine-launched ballistic missiles, becoming the first submarines in the South Korean navy to have this kind of capability. They will also have many other improvements compared to their predecessors built with a greater degree of South Korean technology, especially in the later batches, which will include Samsung SDI lithium-ion batteries.

As designed, the class has a surfaced displacement of 3,358 tons, and a submerged displacement of 3,705 tons. Dimensions include a running length of 83.5 meters, a beam of 9.6 meters, and a draught of 7.62 meters. Power is a diesel-electric arrangement involving 4 x Bumhan Industry PH1 PEM fuel cell systems, developing 150 kW each, driving a single, low-noise propeller at the rear in typical fashion. Acoustic dampening is used where possible to maintain stealthiness for the boat.

Dosan Ahn Changho has a superior performance compared to a conventional submarine. A maximum underwater speed of 20 knots and a top-side speed of 12 knots. Range is 10,000 nautical miles which will help the service maintain protection of the vast South Korean coastline. Aboard is a complement of fifty personnel – making for one relatively compact attack submarine.

The boat’s profile is conventional with a blunt, rounded nose, tubular hull, and tapered aft section. the hull sides are noticeably bulged and the conning tower sits ahead of midships. The tower is home to the dive planes as well as the required collection of periscopes, sensors, and communications masts. The tail section of the boat incorporates the multi-bladed propeller unit as well as a cruciform tailplane arrangement.

In terms of armament, Dosan Ahn Changho is equipped with a range of the most modern Korean weapons, including 6 x 533mm bow-facing torpedo tubes, supporting the “Tiger Shark” torpedo fasmily, as well as the submarine-launched “Harpoon” anti-ship missile. Beyond this is are six Vertical Launching Systems embedded aft of the conning tower and these house land-attack cruise missiles as well as ballistic missiles as needed.

The submarines carry continuous active sonar and flank array sonar for detection, classification and localisation of targets. The KSS-III-class is also integrated with a combat management system developed by Hanwha for the armament assignment, target detection and tracking, and engagement in linkage with the sensors.

ROKS Dosan Ahn Changho (SS-083) launches Hyunmoo 4-4 SLBM