It has been confirmed that all eight 3,600-ton Daegu-class frigates (FFG-II) built between 2015 and 2023 at a total cost of 3.2 trillion won (about $3.2 billion) have design and construction defects and have undergone unprecedented continuous repairs. Hanwha Ocean (formerly Daewoo Shipbuilding & Marine Engineering, DSME) and HD Hyundai Heavy Industries each built four frigates.
The Daegu-class frigate is one of the new combat ships that replaced the old frigates of the South Korean Navy – the Ulsan-class frigate (FF), the Pohang-class frigate (PCC) and the patrol boat. Eight frigates have been built through the “Ulsan-class Batch II” construction project. The detailed design and construction of the first frigate “Daegu” was undertaken by Hanwha Ocean. It was launched at the Geoje Shipyard of DSME in June 2016 and entered service in March 2018. The eighth frigate “Chuncheon” was launched at the Ulsan Shipyard of HD Hyundai Heavy Industries in March 2022 and officially entered service on October 24, 2023.
All 8 frigates have major defects
At the end of last year, the South Korean Navy discovered that all eight frigates that had been delivered had major defects: the engine fuel pipelines were made and installed with “off-the-shelf, low-strength” alloys, which did not meet the design requirements and caused pipeline cracking and fuel leakage. Currently, the eight warships are undergoing temporary repairs.
At the end of last year, the South Korean Navy discovered that all eight commissioned frigates had major defects: the engine fuel pipelines were manufactured and installed using “off-the-shelf, low-strength” alloys, which did not meet the design requirements, resulting in pipeline cracking and fuel leakage. Currently, all eight warships are successively undergoing temporary repairs.
South Korean media reported that the Daegu-class frigates frequently had power system problems, which puzzled the South Korean Navy. Later, during self-inspection, it was found that there were engine leaks and a small amount of oil leakage. If the South Korean Navy had not discovered this problem in time and continued to operate as usual, it would have most likely caused the suspension of operations of 8 frigates and paralyzed the South Korean Navy.
After confirming the problem, the South Korean Navy took “temporary repair” measures, urgently investing billions of won of its own budget to carry out pipeline repairs on eight frigates, and immediately made clear the severity of the problem to the Defense Acquisition Program Administration of South Korea, which is responsible for the large frigate project, including design defects during the DSME period.
A person from the South Korea Defense Acquisition Program Administration (DAPA) said: “At the end of last year, the South Korean Navy conducted a comprehensive inspection of the Daegu-class frigates and found that all eight frigates had the same problem of leaking due to damaged engine fuel pipelines, and allocated funds from its own emergency budget to replace the pipelines. Regarding this issue, we have asked Hanwha Ocean, which obtained the detailed design and built the main ship, whether it is responsible, but the shipyard has always refused to admit it. Recently, Hanwha Ocean admitted that there were major defects in design and construction, and said it would cover all repair costs.”
Eight frigates were reported to have major flaws at both the construction and design levels.
Hanwha Ocean, which was responsible for the detailed design and construction of the first Daegu-class frigate, used a pipe material that was different from the design drawings and had low strength during construction, causing cracks in the pipes. No problems were found during the operation of the first ship after it was built, delivered and commissioned, but problems began to occur about five years after it was deployed.
In response, Hanwha Ocean blamed the outsourcer, saying that “the outsourcer arbitrarily used piping materials different from those specified in the design drawings, and only realized that there was a problem after the engine fuel leak occurred.”
However, DAPA believes that Hanwha Ocean is responsible for the management and construction of the outsourced contractor, so there is no excuse for the defects. In response, the agency asked Hanwha Ocean to pay all repair costs incurred due to its fault. This request was initially rejected by Hanwha Ocean, and DAPA immediately announced that it would take “fraudulent contractor sanctions.” Forced by this move, Hanwha Ocean said it would bear all repair costs.
The second reason for the engine fuel leak was design flaws, for which DAPA believes both the shipbuilder and the auditor are to blame.
Generally speaking, it is considered an unwritten rule in ship design to minimize the number of pipes entering the fuel tank, but Hanwha Ocean passed the seawater pipe through the fuel tank due to lack of space. Hanwha Ocean designed a seawater pipeline to pass through the fuel tank even though it knew that the seawater had a high salt content and that the seawater pipe would inevitably rust. The Korea Research Institute for defense Technology and Quality Research Institute approved this design, so it also needs to be held responsible for this major defect.
Although the leakage problem of the Daegu-class frigate has been temporarily solved by replacing the pipeline, due to the long service life of the ship design, if it leaks again, what hidden dangers will it cause in the future is still unknown. If all eight frigates face serious problems, it will lead to the worst situation of interruption of South Korean naval operations.
According to other reports, the South Korean Defense Technology and Quality Research Institute raised the severity of the issue to the South Korean Navy last year. However, fearing exposure as the supervisory body that gave the final approval for the design and construction of the warships, the institute chose to adopt a passive attitude and did not take strong restrictive measures against Hanwha Ocean.
However, what worries the South Korean industry the most is that if the review reveals that it is not simply a matter of leakage, but that structural adjustments are needed, it would mean that South Korea’s naval power would be significantly affected.