'We do not compromise on safety.'
Before entering the Hanwha Ocean shipyard in Geoje, a large sign on the building's exterior caught the eye. As the bus carrying reporters passed between the massive vessels under construction, the company’s fire station, '2119,' came into view. Upon arriving at the special shipbuilding area, security was emphasized in addition to safety. Each reporter's phone was affixed with a security sticker. This shipyard, where naval combat ships and submarines are built, was under strict control.
After undergoing thorough security procedures, we encountered the next-generation submarine 'Seohee.' Descending a ladder into the submarine, a long corridor unfolded before us, slightly wider than an adult man's shoulder. On either side of the narrow passage were living quarters, a medical room, a dining area, as well as restrooms and showers. The daily lives of crew members, who must eat, sleep, and engage in combat underwater, were tightly packed along this single corridor.
Launched on September 15 at the Hanwha Ocean shipyard, Seohee is the second vessel of the Batch-II Jangbogo-III class. Set to be commissioned in the second half of this year, this submarine weighs approximately 3,600 tons and measures about 89 meters in length. In comparison, the Batch-I Jangbogo-III class Dosan Ahn Chang-ho is about 84 meters long, indicating an increase in hull size. However, what struck us first was the density of the space rather than its size.
Inside the submarine, explanations were provided regarding the horizontal torpedo launchers at the bow and the vertical launch system for submarine-launched ballistic missiles (SLBMs) at the rear. The living and resting spaces for the crew coexist with armaments designed to respond to underwater and surface targets within the same hull. The challenge of submarine design is evident in balancing various functions within a limited space while ensuring the crew's living and working flow.
The key advancements in Seohee extend beyond the visible size of the hull. Hanwha Ocean has combined an air-independent propulsion (AIP) system with lithium-ion batteries developed by Hanwha Aerospace to enhance underwater operational endurance.
AIP is a system that generates the power needed for propulsion without relying on external air while submerged. By integrating lithium-ion batteries, the energy available for underwater operations has been significantly increased. The ability to remain submerged for extended periods reduces the need to surface, allowing for more discreet mission execution. Hanwha Ocean claims this propulsion system is the world's first of its kind, providing one of the longest underwater endurance capabilities among diesel submarines.
Detection and strike capabilities have also been improved. The combat system, which serves as the submarine's brain, and the sonar system, which acts as its eyes and ears, have been enhanced to strengthen information processing and target detection capabilities. The submarine is also equipped with the ability to strike land targets using SLBMs. Overall performance, including stealth and survivability, has been improved compared to the previous Batch-I, with a domestic production rate of about 80%.
Stepping out of Seohee and onto the Ulsan-class Batch-III escort ship 'Pyeongtaek,' the sense of space felt different. After navigating the narrow corridors of the submarine, the escort ship felt relatively spacious and comfortable. The contrast between the stealthy movements of a submarine and the diverse threats faced by an escort ship was evident in the experience.
Launched in mid-August, Pyeongtaek is currently undergoing Setting To Work (STW) to check the operation of its equipment and systems. It is scheduled to enter dock trials in October and will undergo testing before being delivered to the navy in December 2027.
Weighing approximately 3,600 tons, Pyeongtaek measures about 130 meters in length and 15 meters in width. It is designed to respond to threats at sea, underwater, and on land, equipped with a 5-inch gun, a Korean vertical launch system (KVLS), anti-ship and land-attack guided missiles, and long-range anti-submarine torpedoes.
The composite sensor mast is equipped with infrared detection and tracking equipment, as well as multifunctional phased array radar developed with domestic technology. The radar is fixed on four sides to detect and track aerial and maritime targets from all directions, allowing simultaneous engagement of multiple aerial threats. The hybrid propulsion system reduces noise, and the combination of hull-mounted and towed array sonars enhances anti-submarine warfare capabilities.
On-site, the speed of construction was highlighted as a competitive advantage alongside performance. A Hanwha Ocean representative explained that the construction period from the start of building Pyeongtaek to its sea trials and delivery is about 30 months. By increasing the size of the hull blocks used in construction, the number of blocks has been reduced by about half, shortening the construction time by 1 to 2 months. This method is planned to be applied to future Ulsan-class Batch-IV and Korean next-generation destroyer (KDDX) constructions.
Changes are also underway in the production facilities supporting the construction of both vessels. The special shipbuilding plant No. 4, visited before boarding, stood out with its high ceilings. Completed in October last year, this latest facility at the Geoje shipyard covers over 12,000 square meters and can be used for both submarine construction and indoor assembly of surface ships. Hanwha Ocean states that such facilities capable of simultaneously handling surface and submarine work are unique in the country.
The core of the plant's operation is an AI-based smart integrated control system. The smart crane features automatic obstacle avoidance, stabilization, and load alignment functions. This equipment is designed to reduce accident risks and assist in precise operations when moving heavy ship structures. The pipe manufacturing plant has automated processes such as cutting and bending.
Securing indoor workspace is also linked to construction schedules. It allows work to continue with reduced weather impact and enables the indoor production and assembly of large blocks. Hanwha Ocean plans to utilize the No. 4 plant for the construction of the 5th and 6th Ulsan-class Batch-III vessels and the 1st and 2nd Batch-IV vessels.
In a separate launch tube factory, which has been operational for about a year, two autonomous robots were seen transporting materials. Barcodes have been applied to materials that were previously managed manually. This reflects a shift in the management and movement of materials in the construction of large vessels, enhancing production efficiency.
* This article has been translated by AI.
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