[Geoje = E-Daily Reporter kim kwanyong ] On the 15th, I visited the special-purpose vessel construction area at Hanwha Ocean’s Geoje facility in Geoje, South Gyeongsang Province. The “Pyeongtaek,” a state-of-the-art 3,600-metric-ton frigate that was launched last month, was visible at the quay. The Setting To Work (STW) process—verifying that all equipment and systems are functioning properly—was in full swing. Berthing trials are set to begin this coming October. Next to it, final work was underway on the “Seohee,” the second vessel of the Jang Bogo-III Batch-II class, a 3,600-metric-ton submarine. Within the same shipyard, the ROK Navy’s latest surface ships and submarine forces are simultaneously taking shape.

This is also a place where the history of the Republic of Korea Navy’s vessels has been carried forward. Hanwha Ocean—formerly Daewoo Shipbuilding & Marine Engineering—began by building the Republic of Korea’s first domestically produced destroyer, the KDX-I “King Gwanggaeto the Great,” followed by the KDX-II “Admiral Yi Sun-sin” and the KDX-III “Yulgok Yi I,” equipped with the Aegis combat system.

Now, the Korean Next-Generation Destroyer (KDDX) continues that legacy. Last July, Hanwha Ocean signed a contract with the Defense Acquisition Program Administration (DAPA) worth 838 billion won for the detailed design and construction of the KDDX lead ship. The KDDX project, with a total budget of approximately 7.8 trillion won, aims to procure six 7,000-metric-ton-class destroyers using domestic technology. The lead ship is scheduled for delivery to the Navy in 2032.

◇“Time Savings” Proven on the Pyeongtaek: Applied to the KDDX

Prior to the construction of the KDDX, the Pyeongtaek was the vessel that demonstrated Hanwha Ocean’s surface ship production capabilities. The Navy is currently carrying out the Ulsan-class Batch III project to replace aging patrol ships and frigates. In 2023, Hanwha Ocean secured orders for the fifth and sixth ships, the final vessels in this program. The fifth ship is the Pyeongtaek. Preparations are also underway for the sixth ship, with the goal of launching it early next year. Following trial and evaluation, the Pyeongtaek is scheduled to be delivered to the Navy in December 2027, and the sixth ship around June 2028.

The Ulsan-class Batch III is a 3,600-metric-ton frigate measuring approximately 130 meters in length and 15 meters in beam. It is equipped with a 5-inch gun, the Korean Vertical Launch System (KVLS), ship-to-ship guided missiles, tactical ship-to-ground guided missiles, and long-range anti-submarine torpedoes.

A composite sensor mast (ISM), which serves as the ship’s “eyes,” is positioned atop the bridge. It houses infrared detection and tracking equipment, as well as a multifunction phased-array radar (MFR) developed with domestic technology. As a four-face fixed radar, it can detect and track air and surface targets in all directions and simultaneously engage multiple aerial targets.

Its submarine detection capabilities have also been enhanced. The ship operates a hull-mounted sonar (HMS) and a towed array sonar (TASS), both developed using domestic technology. Another key feature is the application of a hybrid propulsion system to reduce underwater radiated noise.

A notable aspect of the Pyeongtaek-class construction is that the shipbuilding method itself is changing. While building the Pyeongtaek-class, Hanwha Ocean increased the size of the hull blocks placed on the assembly line compared to previous practices. In exchange for larger blocks, the number of blocks used was reduced by about half. According to the company, this eliminated the process of individually joining multiple small blocks on the assembly line, thereby shortening the construction period by about 1 to 2 months.

This construction method is scheduled to be applied to the KDDX program, following its use on the first and second ships of the Ulsan-class Batch IV, which Hanwha Ocean secured the contract for. Given that the KDDX project has been delayed compared to the original plan, shortening the time required not only for the design but also for the actual construction process is crucial to ensuring the timely delivery of the lead ship, scheduled for 2032.

◇From the 1,200-metric-ton Jang Bogo-class to the 3,600-metric-ton Seo Hee-class

While surface ships are preparing for a generational shift from the KDX to the KDDX, the Jang Bogo-III Batch II is playing that role in the submarine sector.

Hanwha Ocean’s history of submarine construction dates back to 1983. At that time, the company was awarded the contract to build the first 1,200-metric-ton submarine for the Navy, the Jang Bogo-I (Class 209), Ship No. 1, the “Jang Bogo.” Since then, the company has built 17 of the 24 submarines ordered by the South Korean Navy to date, including nine Jang Bogo-I submarines, three 1,800-metric-ton Jang Bogo-II (Class 214) submarines, and five Jang Bogo-III submarines.

Previously, with the delivery of the first ship of the Batch I class, the *Dosan Ahn Chang-ho*, designed and built using domestic technology, to the Navy in 2021, South Korea joined the ranks of nations capable of independently developing submarines of 3,000 metric tons or more. The *Seohee*, currently under construction at the Geoje Shipyard, is the second ship of the Jangbogo-III Batch II class, representing a further evolution from its predecessor.

With a displacement of approximately 3,600 metric tons and a length of about 89 meters, it is larger than the Dosan Ahn Chang-ho-class submarines. The performance of the combat system—which serves as the submarine’s “brain”—and the sonar system—which acts as its “eyes and ears”—has also been improved. Target detection and information processing capabilities have been enhanced, and the submarine’s ability to strike land-based targets has been strengthened. The localization rate stands at approximately 80 percent.

In particular, the propulsion system has been upgraded. It combines an Air-Independent Propulsion (AIP) system developed by Hanwha Ocean with lithium-ion batteries developed by Hanwha Aerospace. This approach enhances underwater endurance by utilizing both the AIP system—which generates power without external air while submerged—and lithium-ion batteries, which have a higher energy density than conventional lead-acid batteries.

Hanwha Ocean plans to utilize the Jang Bogo-III Batch II as a strategic platform targeting not only the South Korean Navy’s capabilities but also the overseas submarine market. The company explains that its competitive edge lies in its design capabilities—which can accommodate the varying weaponry, sensors, and operational requirements of different nations—and its ability to localize the system.

◇AI Management and Robot Material Handling

Hanwha Ocean’s newly constructed Special Vessels Plant No. 4, with a total area of approximately 12,000 square meters, is used not only for submarine construction but also as an indoor assembly facility for surface ships. Since large blocks can be produced and assembled indoors, the facility minimizes the impact of weather conditions such as rain and wind. It is also being utilized for work on the Ulsan-class Batch III Ships No. 5 and 6, as well as the subsequent Batch IV Ships No. 1 and 2.

Automated equipment has been implemented throughout the plant. An AI-based smart integrated control system manages production status, while smart cranes automatically avoid obstacles and position loads with precision while minimizing sway. In the piping fabrication shop, manufacturing processes such as cutting and bending have been automated. Smart logistics robots also move materials to the workstations.

Around the ship blocks, foldable work platforms were installed to allow workers to safely perform welding and assembly tasks even at heights. Dust collection systems, which immediately extract the smoke and fine metal particles generated during welding, were also deployed throughout the facility. This approach improves not only automation but also worker safety and the work environment.

Hanwha Ocean plans to continue expanding its production facilities through 2030. The company will construct a new indoor assembly hall for surface ships and expand its fleet, while also pursuing the acquisition of additional quay capacity depending on order volume.

Kim Kyu-baek, Senior Vice President in charge of Business Management at Hanwha Ocean’s Special Vessels Division, stated, “Through large-scale investment and research and development, we will continue to secure and strengthen ‘next-generation defense solutions’ to carry on our legacy as a leading shipbuilder.” He added, “To respond to the rapidly changing maritime security environment, we will proactively expand our production facilities and maximize our technological competitiveness.”