Taiwan’s first domestically built submarine faces delays

The delivery of Taiwan's Hai Kun (Narwhal) submarine will be delayed due to testing.

Taiwan's defense minister Koo Li-Hsiung (顧立雄) was invited by the Foreign Affairs and National Defense Committee of the Legislative Yuan, Taiwan’s legislature, to attend a special briefing on October 20 regarding the “Current Status and Corresponding Measures for the Sea Acceptance Trials (SAT) of the Indigenous Defense Submarine Prototype, the Hai Kun.”

Speaking to the media before the meeting, Minister Koo stated that the construction of the Hai Kun submarine prioritizes quality and safety, and that SAT will proceed as planned.

However, he acknowledged that completing the required tests and delivering the submarine by November “poses a considerable challenge,” adding that he will continue to urge the Navy and CSBC (Taiwan’s shipbuilding corporation) to work diligently.

According to the special report presented in the meeting, the Hai Kun submarine entered the SAT phase on June 17, 2025. The SAT is divided into three stages conducted sequentially: surface navigation trials, shallow dive trials, and deep dive trials.

The report noted that three surface navigation trials have been completed. Current efforts are focused on two items, the “Main Engine and Power Management System” and the “Integrated Platform Management System (IPMS)”, followed by performance calibration and verification of surface navigation, after which the shallow dive phase will begin.

Shallow dive trials primarily involve functional verification in areas such as vessel maneuvering, detection and reconnaissance equipment, emergency functions, and combat management.

Deep-dive trials mainly involve functional verification in areas such as vessel maneuvering, vessel performance, emergency functions, detection and reconnaissance equipment, and combat management.

The report did not specify the expected timeline for the shallow dive and deep dive trials.

Testing needs more time

The impending delay in the delivery of the Hai Kun submarine has drawn attention from both ruling and opposition legislators in the Legislative Yuan.

Loh Meei-ling (羅美玲), a legislator from the ruling Democratic Progressive Party (DPP), asked: “Was there a problem with the initial timetable?”

Minister Koo responded:

“During construction, there were times when relevant equipment or technical assistance from the original manufacturers could not be provided immediately. This shows that the scheduling was not as easily achievable as we had imagined; things were not ‘available on demand.’ We are indeed experiencing delays in this area.”

Loh then asked when the deep-dive trials would be completed and whether there is currently no timetable.

Koo replied: “At present, we must conduct additional surface navigation trials to meet the standards required before diving. Once those are completed, we will proceed with the shallow and deep-dive trials. Safety and quality take priority.”

Ma Wen-chun (馬文君), a legislator from Taiwan's opposition Kuomintang (KMT) party, questioned why, despite regular construction-inspection meetings repeatedly stating that there were no problems and that progress was on schedule, delivery was nevertheless being delayed.

The Ministry of National Defense (MND) replied that “The current delay is due to equipment and engineering issues encountered during the testing phase that must be addressed. The construction milestones were met; however, the testing phase requires more time to make improvements based on deficiencies identified.”



A flexible timeline is suggested

KMT legislator and retired ROC Navy Admiral Chen Yeong-kang (陳永康) suggested during interpellation that the Navy should appropriately relax the timeline.

He said, “Safety cannot be compromised. Performance can be discussed and refined, but the timeline must be flexible. The so-called milestones should not be fixed at a single point in time.”

He continued, “Many items remain to be tested on the first vessel. Given the current schedule, CSBC and the Navy should allow for a flexible margin of time for the delivery of the subsequent seven vessels.”

Chen further highlighted the practical constraints the Navy and CSBC will face, stating:

“Since every vessel’s major overhaul must return to CSBC, and intermediate maintenance must also return to CSBC. While the Navy’s dry docks are limited, once the third vessel is delivered, there will permanently be one vessel under construction and one vessel undergoing major overhaul.”

Admiral Chen also pointed out that overall project expenditures must be properly calculated.

He said, “When the budget was first planned, were economic factors such as fluctuations in the NTD-USD exchange rate and inflation taken into account? The Navy and CSBC must manage this proactively.”

Regarding subsequent testing, Chen referenced the 2003 tragedy of the PLA Navy’s Submarine No. 361, in which a mechanical failure killed all 70 crew members.

“In 2003, when the CCP Navy’s Type 035 Ming-class Submarine No. 361 was conducting a dive using its snorkel, the crew started the main engine, but the air intake valve failed to open. The air inside the submarine was completely exhausted within two minutes, and all personnel on board perished,” he said.

“When our submarine conducts surface and diving trials, we should not rely solely on the periscope; we must also conduct navigation using the snorkel,” he added.

Minister Koo agreed with Chen’s advice, replying: “We will proceed accordingly.”

CSBC may incur penalties

Legislator Ma asked how penalties would be imposed if CSBC fails to deliver the submarine as per the contract in November, and whether there is a cap on the fine.

Minister Koo replied that the daily penalty is approximately NT$190,000 (about US$6,200).

The MND Defense Procurement Office added that the ceiling to delay penalties is 20% of the construction cost. Since the construction cost is about NT$19.3 billion, the cap would be roughly NT$4 billion.