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Taiwan island's first 'indigenous' submarine revealed to have sea trial without anchor; repeated problems expose boat's vulnerability: expert

Global Times

By Chen Yang and Ma Jun Published: Dec 01, 2025 07:14 PM

The island of Taiwan's "indigenous" submarine Hai Kun, which the armed forces on the island had confidently claimed would be delivered in November, has not only failed to complete basic underwater navigation tests but has recently been reported to have problems such as "uninstalled anchors" and "unintegrated watertight door systems." This has drawn sharp criticism within the island for "endangering crew members' lives."

A military affairs expert told the Global Times that whether it is the severe delays in the testing progress or the continuous problems with its onboard equipment, these issues have fully exposed the vulnerability of the island's so-called "indigenous" submarine.

According to reports by media outlets on the island, after completing its third surface test in July this year, the Hai Kun submarine immediately underwent over four months of dock and port maintenance, adjustments, and calibrations, finally setting out to sea for its fourth surface test on Thursday. CSBC Corporation, Taiwan, the company responsible for constructing the submarine, claimed that the main objective of this sea trial was to test systems such as power, navigation instruments, periscopes, and sonar. However, contrary to expectations, on Friday morning the Hai Kun departed from the second port of Kaohsiung Harbor for another sea trial, marking the first time and an unusual move of going out to sea for two consecutive days.

According to the original plan, the submarine was supposed to complete sea trials in September and be delivered by the end of November, but it is still undergoing the most preliminary surface tests. There is speculation that due to the confirmed delay in delivery, CSBC Corporation, Taiwan may be accelerating its tests in response to potential breach-of-contract issues, according to Taiwan media.

Media on the island reported that the next sea trial of the Hai Kun is expected to move into the underwater navigation test phase, yet it is far behind the schedule. Military observers on the island noted that the tight schedule of two consecutive days of sea trials indicates the Hai Kun is getting ready for subsequent underwater tests, but the scenarios are unprecedented - returning to port by dusk or conducting trials for two consecutive days. As a result, opinions divided over whether the previous surface navigation test phase is drawing to a close or if it is in need of further system integration.

A report by the island's Mirror Daily revealed on Saturday that the anchor windlass system of the Hai Kun submarine malfunctioned during tests in the dry dock. Consequently, for the first five sea trials, the submarine set sail without an anchor installed. "The Taiwan naval authorities were fully aware of this situation yet insisted that the shipbuilding company proceed with sea trials without the anchor, in violation of relevant regulations."

Mirror Daily further disclosed that the watertight doors of the Hai Kun had not undergone complete system integration testing, leaving uncertainty as to whether each compartment could maintain watertight isolation under extreme pressure conditions.

The report said that relevant regulations within the island explicitly require vessels to be equipped with anchors, anchor chains, and mooring lines, among other necessary equipment. However, the naval authorities on the island have demanded CSBC Corporation, Taiwan proceed with testing "even without anchors," in an attempt to create the illusion that the Hai Kun project is proceeding normally. Sources also revealed that the naval authorities claimed those regulations only apply to civilian vessels, arguing that submarines, as military vessels and specialized ships, are exempt from such restrictions - a stance described as "utterly lawless."

Apart from numerous problems during its sea trials, the Hai Kun submarine has also faced a variety of other issues. The island's Liberty Times revealed on Sunday that the diesel engines selected for the Hai Kun are not specialized models for submarines. Citing analysis by a military observer on the island, the report said that due to Taiwan's inability to procure high-power main engines suitable for submarines, it ultimately opted for a "commercial diesel generator manufactured by a Nordic factory," whose output power falls below a certain level and is therefore not subject to export controls. As a result, the Hai Kun submarine relies on six commercial diesel generators connected in parallel to meet the requirement for originally designed power output, charging capacity, and charging speed. Should Taiwan's naval authorities seek to mass-produce submarines of the same model in the future, they would have to switch to high-power generators and redesign the system, essentially starting from scratch.

A military affairs expert told the Global Times that the Hai Kun has, from the very beginning of its construction, faced challenges including the lack of core technologies and heavy reliance on imported main equipment. Photos taken during the vessel's launch have revealed numerous issues in the submarine construction techniques. More importantly, frequent interruptions to planned sea trials and repeated returns to dry dock for repairs during the testing phase have exposed significant discrepancies between the submarine's actual performance and its original design, demanding major modifications.

This has not only delayed the development timeline of the Hai Kun but also introduced various risks that are difficult to eliminate. That is fundamentally why concerns have arisen within the island about the submarine's ability, the expert said, noting that the island of Taiwan lacks both the capability to develop core equipment - forcing reliance on overseas procurement - and the essential system integration skills needed to effectively coordinate equipment from diverse sources.