Taiwan will begin sea acceptance testing (SAT) of its first locally built submarine prototype in April, marking a critical step in bolstering undersea combat capabilities as Beijing steps up military pressure on the island.
Taiwan’s defence ministry confirmed on Tuesday that the submarine, named Hai Kun, or Narwhal, will proceed with the sea trials as scheduled, dismissing concerns about delays in earlier phases of testing.
Unveiled in September 2023, the prototype entered its harbour acceptance test (HAT) phase in November. While the SAT is set for April, local media reports suggest that the HAT process has encountered unexpected challenges.
Do you have questions about the biggest topics and trends from around the world? Get the answers with SCMP Knowledge, our new platform of curated content with explainers, FAQs, analyses and infographics brought to you by our award-winning team.
Reports cite instability in the shore-based power supply, causing voltage fluctuations that damage multiple subsystem components. The vessel’s optical-electronic periscope system is also reported to have experienced hydraulic instability, requiring ongoing calibration. Both factors are potentially contributing to delays.
The defence ministry rejected the reports on Tuesday. “There are no issues with unstable shore power voltage, and the submarine’s battery installation is proceeding as planned,” ministry spokesman Sun Li-fan said.
Certain components may need to be replaced during testing, but this was “a normal part of the process”, Sun said, emphasising that “based on the navy’s assessment, the next phase [SAT] will proceed according to the planned timeline”.
Under the timeline, the SAT will wrap up by October, ahead of the submarine’s planned delivery in November.
The sea trials will include live-fire torpedo testing, weapons and sonar system validation, and assessments of combat readiness. Other evaluations will cover diving and surfacing manoeuvres, navigation performance, control system reliability, and emergency response drills, according to the defence ministry.
The SAT will be followed by operational assessments and combat evaluations ahead of active service commission. Pre-commissioning training for the submarine’s crew will also take place before its formal induction.
According to former navy commander Chen Yung-kang, who is also a lawmaker from Taiwan’s main opposition Kuomintang (KMT), the biggest challenge during the SAT will be coordination between the navy and the builder of the submarine – CSBC Corporation, Taiwan.
“People might assume the submarine will simply set sail for testing, but it’s not that simple,” Chen said. “There are logistical and operational issues, including long hours for personnel underwater and even basic matters like using the specially designed submarine restrooms.”
Effective collaboration between CSBC and the navy was essential for a smooth testing process, he emphasised.
CSBC was awarded the contract to design and build the submarine in 2016, after Taiwan failed to secure a foreign supplier due to pressure and obstruction from Beijing, which sees Taiwan as part of China to be reunited by force if necessary.
Most countries – including the United States, Taipei’s main international backer and weapons supplier – do not recognise Taiwan as an independent state. However, Washington is opposed to any attempt to take the self-governed island by force and is committed to arming it for defence.
Built at a cost of NT$26 billion (US$792.6 million), the diesel-electric-powered prototype features an X-shaped rudder configuration for operation in shallow waters, complemented by additional small horizontal fins. It is equipped with a combat system from US weapons giant Lockheed Martin and will carry US-made MK-48 heavyweight torpedoes.
In August last year, Taiwan’s cabinet approved a NT$284 billion project proposed by the island’s leader William Lai Ching-te, to build seven more submarines over the next 14 years.
However, lawmakers from the opposition KMT and the smaller Taiwan People’s Party have raised concerns over the project’s progress. Last month, they passed a motion to freeze half of the NT$2 billion funding proposed for 2025 to continue work on the project until the prototype successfully completes its SAT this year.
The expansion of Taiwan’s submarine fleet comes amid escalating tensions with Beijing. The People’s Liberation Army has ramped up military activities around the island, including frequent war games, fly-bys and naval manoeuvres.
More from South China Morning Post:
- Photo suggesting US major general joined Taiwanese tabletop drills triggers debate
- Taiwan coastguard detains mainland China crew after undersea cable damaged
- PLA steps up Taiwan military patrols over Lunar New Year holiday
For the latest news from the South China Morning Post download our mobile app. Copyright 2025.
