DEFENSE/Sea trials begin for Taiwan's indigenous defense submarine prototype

Kaohsiung, June 17 (CNA) Taiwan's first indigenous defense submarine the Narwhal began sea trials Tuesday as it sailed out of the Port of Kaohsiung, according to a military source.

The Narwhal, also known as Hai Kun, was seen sailing out to sea at around 8 a.m. from CSBC Corp. Taiwan's shipyard, where it had been moored. More than 10 technicians and military personnel were on the boat's deck, while several other people stood on the sail.

A harbor acceptance test (HAT) of the submarine has recently concluded, and the vessel will now undergo various tests, including of its propulsion and navigational systems, while part of it is above the surface, a source with knowledge of the matter told CNA.

The Narwhal underwent test sails in the port from Saturday to Monday as its propulsion system was being fine-tuned, the source said.

The submarine will be heavily guarded by other Navy vessels during sea trials, with M109 assault boats, Kuang Hua VI-class missile boats, and Cheng Kung-class frigates being deployed to the areas where the tests will take place, according to the source.

A sea trial, or a sea acceptance test (SAT), is a formal series of trials conducted at sea to evaluate whether a newly built or significantly upgraded ship meets its contractual performance specifications before it is delivered to the customer.

For submarines, sea trials usually involve testing of its propulsion, steering and navigation, depth capabilities, and acoustic signature.

Part of the tests require the submarine to be fully submerged, but the Navy declined to comment Tuesday on when submerged tests for the Narwhal would begin.

Despite that reluctance to comment on the testing timetable, Navy Chief of Staff Chiu Chun-jung (邱俊榮) said the contractual deadline for the submarine to be delivered to the Navy in November remained unchanged.

The program has faced repeated delays based on public stated commitments.

Program convener Huang Shu-kuang (黃曙光) originally said in September 2023, when the submarine prototype was unveiled at a photo op, that the submarine could be delivered to the Navy before the end of 2024, which did not happen.

The Narwhal then missed its deadline of April 30, 2025 for completing harbor trials amid reports of technical issues, including components and parts failing due to voltage surges from an onshore power supply the ship was attached to during testing in February.

Former advisor to the Navy Kuo Hsi (郭璽) made several allegations in his online show that the Narwhal was suffering from leaking. The Navy declined to comment when asked to respond to Kuo's allegation on April 30.