Taiwan’s first domestically produced submarine prototype, the “Narwhal” (hull number 711), held its naming and launching ceremony on September 28, 2023. Following this, it underwent Harbour Acceptance Trials (HAT) and on February 27 of this year, it was moved from the CSBC Corporation to the Naval Shipyard for the final phase of HAT testing.
According to reports from the Central News Agency, CSBC Chairman Cheng Wen-Lung mentioned recently that safety is the top priority in submarine testing, and there is still a schedule to follow from a project perspective. HAT is expected to be completed by the end of April, followed by Sea Acceptance Testing (SAT). Let’s delve into what HAT and SAT entail, as well as the planning for subsequent mass production ships and their strategic tactical significance.
The process includes collaboration between CSBC, the Navy, and foreign countries for the construction of the submarine – launching, joint Harbour Acceptance Testing (HAT), joint Sea Acceptance Testing (SAT), launching torpedoes to verify combat systems, naval operational evaluations, transitioning the vessel to the Navy, pre-commissioning training by the Navy, formal commissioning, and deployment into operational service.
Harbour Acceptance Trial (HAT) involves a series of tests conducted in the port area after the completion of submarine construction in the shipyard to ensure that the submarine meets the expected performance and functionality criteria set during design. These tests are typically carried out by the Navy and the shipyard.
The main components of HAT testing include system testing (power, weapons, sonar, air conditioning, etc.), port operation tests (berthing, mooring, power connection), environmental adaptation tests, safety tests, communication tests (frequency range tests), and more.
Sea Acceptance Test (SAT) occurs after the completion of Harbour Acceptance Testing, where the submarine is taken into the sea for a series of related tests. This includes tactical maneuvers such as diving, surfacing, and other actions to ensure the submarine performs at the expected levels of performance and safety standards in actual sea conditions.
SAT testing comprises most components of HAT testing and adds additional tests like navigation quality, control system (submersion and resurfacing, rudder, depth control), weapons system testing, sonar testing, stability testing, and emergency situation testing including fire response and pressure changes. Additionally, the Narwhal submarine is expected to conduct live torpedo firing to verify the combat system’s performance.
Former Director of the Naval Research and Development Center and current Defense Ministry adviser, Vice Admiral Shao Wei-yang, mentioned during a parliamentary session on April 17 that HAT is still in progress with no definite end date, as each test must be completed before proceeding to the next stage.
Vice Admiral Shao Wei-yang also expressed hopes that CSBC can deliver the submarine by the year 2025. The initial plan involves the construction of 7 additional submarines, with a projected progress of “3+2+2”.
The purpose of the prototype submarine is to identify issues and make improvements. For instance, the follow-up ships to the domestically produced Tuojiang-class vessel, represented by the Narwhal, are currently in production and exhibit superior performance compared to the prototype.
The Narwhal submarine is equipped with 6 torpedo launch tubes capable of carrying MK48 heavyweight torpedoes. It is understood that the subsequent ships will not only optimize related equipment but also potentially carry submarine-launched UGM-84 Harpoon missiles.
It is noteworthy that the United States has sold MK-48 Mod6 AT heavyweight torpedoes (MK-48 Mod6 AT HWT) to Taiwan, along with relevant equipment. These torpedoes can cruise at speeds exceeding 52 kilometers per hour, with a maximum sprint speed of 102 kilometers per hour. They utilize MK-48 sonar detectors, guidance, and control systems, along with new power systems and stealth technology to reduce detection, effectively enabling stealth attacks, thereby enhancing the domestically produced submarine’s combat capabilities.
The strategic applications of submarines primarily involve disrupting shipping, attacking enemy shorelines, and strategic deterrence. Tactical uses include surveillance, targeting maritime vessels, escort defense, anti-submarine hindrances, and hunting operations.
Given Taiwan’s narrow geographical layout and lack of extensive hinterland, submarine capabilities can extend Taiwan’s maritime defense line further out to sea, enhancing maritime depth. This forces potential adversaries to be vigilant against potential “ambushes” by Taiwanese submarines, achieving the military strategic goal of “defensive hold, layered deterrence.”
Upon the completion of the subsequent 7 domestically produced submarines, including the prototype Narwhal and the existing 2 Hai Lung-class submarines, there will be a total of 10 submarines. However, when the 7 additional domestically produced submarines are completed, the Hai Lung-class submarines will have been in service for over 40 years by then. As such, the decision to increase the submarine numbers remains to be seen.