During the day today, November 26, the prototype of the new domestically built Hai Kun submarine (hull number SS-711), constructed and developed for the Taiwanese Navy, carried out its sixth sea trial after completing a series of surface evaluations in waters near the port of Kaohsiung. During this new trial, focused on verifying key elements such as sonar functions, the propulsion system, and submarine logging, there had been speculation about the potential execution of the submarine’s first dive, which ultimately did not take place. However, various local Taiwanese media outlets have indicated that the delivery of the unit could occur during the upcoming month of June.
Preparations ahead of Hai Kun’s future first dive
Although the submarine’s first dive did not take place, CSBC detailed the procedures for this maneuver in order for the submarine to operate safely at depth for extended periods. To this end, it is necessary to complete a series of prior procedures before each dive. These include four main stages: load planning, load inspection, systems verification, and practical drills.
The load planning process defines the required capacity for fuel, personnel, drinking water, food, pressurized air, armament, ammunition, and lifesaving and damage-control equipment, based on the distance, duration, and meteorological conditions of the mission. Subsequently, the total weight and its distribution are calculated to ensure the vessel’s stability and to prevent loss of control or dangerous listing.
During the inspection phase, the items are loaded and checked one by one in accordance with checklists, after which a complete inventory of the vessel is conducted to remove any temporary or excess loads. Finally, the data are updated to confirm the submarine’s overall stability.
System verification and drills
The shipyard noted that systems verification is comparable to “an aircraft’s pre-flight inspection.” At this stage, the proper sealing of doors and watertight compartments is checked, along with the operation of hydraulic, electrical, air, and control systems, as well as the functionality of fire suppression systems, leak detection, emergency lighting, liferafts, and escape routes.
CSBC emphasized that any failure underwater can prove critical, making safety a central aspect of the process. The final step consists of conducting drills, during which the crew practices basic navigation, weapons, and communications operations, as well as emergency response exercises such as engine failures, power outages, flooding, or fires.
During the test voyages, in addition to the regular crew, technical personnel are also embarked, significantly increasing the number of people on board. CSBC indicated that, as this is the first submarine built in Taiwan, the company initially did not have enough qualified submarine personnel to serve as a test crew, which is why personnel from the Navy’s 256th Fleet were exceptionally brought in.
Program background
The Hai Kun was originally scheduled to begin sea trials in April of the previous year and be delivered by the end of November. However, the first trial was delayed until June 17, with delays accumulating due to various factors. Finally, on November 28, after completing its fifth surface trial, CSBC announced that the submarine had entered the submerged testing phase.
In November, the Chung-Shan Institute of Science and Technology (NCSIST) and Navy sources confirmed that the submarine had carried out additional navigation trials, system calibrations, and stability evaluations, including turning maneuvers, directional control, and verification of the performance of its diesel-electric propulsion system. According to officials cited by local media, the prototype continued to be “on schedule” despite the accumulated delays.
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