VESSEL REVIEW | ROKS Chamsuri-231 – Rocket-armed fast patrol boat for Republic of Korea Navy
The Republic of Korea Navy (ROKN) has taken delivery of ROKS Chamsuri-231 (참수리-231), the first fast patrol craft built under the PKX-B batch-II programme.
The vessel is intended to defend the Northern Limit Line (NLL), the de facto maritime boundary in the Yellow Sea that separates the two Koreas.
The South Korean Defense Acquisition Program Administration (DAPA) held the vessel’s delivery ceremony at HJ Shipbuilding and Construction's Yeongdo Shipyard in Busan on August 14, 2026.
The craft is currently being prepared via the ROKN's operational deployment procedures before her assignment to the NLL area to protect territorial waters.
Enhancement of an earlier proven naval design
Chamsuri-231 is designated a patrol killer medium rocket (PKMR) vessel. The PKX-B programme is the navy's next-generation fast patrol craft initiative and is replacing the ageing Chamsuri-class patrol killer medium craft. The batch-II vessels will serve alongside the batch-I PKMRs and the larger Yoon Young-ha-class patrol vessels.
The navy plans to acquire 18 PKX-B batch-II craft.
The PKMR is a domestically designed and built 230-tonne-class craft. It is 44 metres (140 feet) long with a beam of seven metres (23 feet) and a crew of between 20 and 23. The batch-II vessels have the same overall dimensions as their batch-I predecessors.
A combined diesel-and-gas propulsion arrangement drives waterjets to deliver a maximum speed of 40 knots.
Armed for countering small surface and coastal threats
Chamsuri-231’s weapons include a Hyundai Wia KP-76L/62 76mm main gun, K6 12.7mm machine guns mounted on two S&T Dynamics remote weapon stations, and a stern-mounted 12-cell launcher for LIGNex1/Hanwha 130mm Biryong guided rockets.
The guided rockets give the PKMR a means of engaging small, fast craft, including boats and landing craft, as well as coastal targets. When the navy launched the first PKMR in 2016, it said the rockets were intended to counter North Korean hovercraft, which it described as difficult to hit with conventional naval guns.
The batch-II vessels leave the batch-I boats’ principal weapons fit unchanged but alters how they are operated. The combat system now integrates fire control for the 130mm guided rocket system and the 12.7mm machine guns. Their consoles have also been consolidated, enabling operators to switch quickly between weapons during intense, close-range engagements.
DAPA said the vessels also have enhanced anti-jamming capability for responding to electronic warfare threats. Each batch-II boat will also carry the improved SPS-560K 3D air surveillance radar, which can cut interference among other onboard systems to improve performance.
The craft's weapons use the LIG Nex1 SAQ-560K electro-optical targeting sight. This sensor also includes an anti-icing function, ensuring improved availability during winter operations.
The PKMR's soft-kill system is the Rheinmetall MASS decoy launcher.
Additional safety features and improved interior layout
Other batch-II changes drew on the ROKN’s operational experience with the batch-I craft. The helm station has been raised to give the seated coxswain a better forward view, and a fire damper is now fitted in the ventilation duct serving the 76mm ammunition magazine to prevent flames from entering this space.
DAPA plans to deliver the three other PKX-B batch-II craft launched with Chamsuri-231 sequentially by the end of 2026. The vessels will operate primarily along the west coast of the Korean Peninsula.
