Taiwan’s first domestically built submarine, the Hai Kun, encountered a technical failure during recent sea acceptance trials, raising concerns about system readiness. The incident occurred during the second round of surface trials conducted on June 26.
During the trial, the submarine suffered a failure in its stern hydraulic systems, affecting control of the X-rudder. Crew members manually operated the rudder to steer the vessel safely back to port. Tugboats accompanying the submarine helped prevent potential collisions with nearby ships.
The malfunction took place as the Hai Kun approached the next testing phase, which includes shallow-water diving and surfacing trials. The X-rudder system uses four diagonal fins to enhance maneuverability, stealth, and operational efficiency during navigation.
Navy Command Headquarters said sea trials aim to identify technical weaknesses and allow engineers to correct them. Officials explained that the submarine supports automatic, semi-automatic, and manual operation modes to ensure operational safety.
The navy stated that the crew followed established procedures and maintained safety throughout the incident. Engineers addressed the hydraulic problem immediately after the submarine returned to port. Officials confirmed that the issue has not reappeared since the repair.
Navy Chief of Staff Vice Admiral Chiu Chun-jung acknowledged delays in the Hai Kun development timeline. He said the project now runs at least two months behind schedule. Authorities transferred the submarine to the CSBC Corp shipyard in Kaohsiung for final calibration and equipment checks.
Chiu emphasized that the navy continues to monitor testing progress closely before approving diving trials. He stressed that safety standards take precedence over delivery deadlines. Officials plan to conduct further inspections before authorizing the next testing phase.
CSBC Corp faces financial penalties for delivery delays starting last month. The government will deduct accumulated fines from the project’s final payment. Despite setbacks, officials said construction and testing efforts remain ongoing.
Defense analysts view the Hai Kun project as a critical step in strengthening Taiwan’s domestic defense manufacturing capacity. As testing continues, authorities expect further refinements before full operational deployment.

