News outlet BusinessKorea reported earlier this week that the Republic of Korea Navy's (ROKN) Daegu-class frigates are confirmed to have a number of structural defects, with some of these requiring maintenance more frequently than what the service initially expected.
The ROKN has confirmed that the eight frigates, which were built between 2015 and 2023 by Hanwha Ocean (when it was still operating as Daewoo Shipbuilding and Marine Engineering) and HD Hyundai Heavy Industries, had design flaws that were discovered only last year.
Navy officials conducted a review of the frigates' construction processes after receiving reports of cracking and leaks in their respective fuel lines.
This then led to the discovery that low-strength alloys that differed from those in the design drawings and therefore did not meet design requirements were nonetheless used in the manufacture of the fuel lines on all eight ships in the class.
As all the frigates would have been rendered inoperative by the defects, thus resulting in a gap in South Korea's warfighting capability, the navy allocated funds from its own emergency budget to facilitate the immediate replacement of the affected fuel lines as an interim measure.
An official of the Defence Acquisition Program Administration (DAPA), the South Korean military's main procurement arm, confirmed that the funds allocated by the navy for the repairs totalled, "several billion won" (one billion won is equivalent to approximately US$700,000, ed).
The same official said Hanwha Ocean has acknowledged that there were indeed flaws in the frigates' design and construction, and that the company has reportedly pledged to cover all repair costs.
An investigation revealed that Hanwha Ocean, which was responsible for the detail design and construction of class lead ship ROKS Daegu, had used low-strength piping materials that differed from what was stipulated in the design drawings during construction, thus resulting in cracks.
No problems were found during the operation of Daegu after it was built, delivered, and put into service in 2018. However, the cracks and related problems began to manifest about five years later.
Hanwha Ocean said that a subcontractor had, "arbitrarily used a different pipe material [from] what the design drawings specified, and only realised that there was a problem," after an engine fuel leak had occurred.
DAPA argued that Hanwha Ocean had overall responsibility for the subcontractor's management and construction practices, and so there is no excuse for the defects.
DAPA has demanded that Hanwha Ocean shoulder all repair costs incurred due to the latter's culpability.
The request was initially rejected by Hanwha Ocean, and DAPA announced that it would impose sanctions. In response, Hanwha Ocean relented and agreed to cover the repair costs.
Another identified structural defect that led to fuel leaks was related to the frigates' seawater pipes.
Due to space constraints, the ships' seawater pipes were laid out in such a way that they inevitably passed through the fuel tanks. DAPA alleges that although Hanwha Ocean knew this arrangement would increase the risk of corrosion in the engines due to the high salt content of seawater, the company proceeded with this arrangement.
DAPA said that the Defense Agency for Technology and Quality, as auditing agency, had approved this design arrangement on the frigates and is therefore partly responsible for the defect and the resulting fuel leaks.