Taiwan’s Indigenous Submarine Program: An Overview

In May, Taiwan for the first time revealed a miniature model of the Republic of China Navy’s (ROCN’s) first domestically-designed and produced diesel-electric attack submarine (SSK) during a groundbreaking ceremony for a new shipyard to construct and repair the service’s new underwater force in the southern port city of Kaohsiung.

The ROCN’s so-called Indigenous Defense Submarine (IDS) program was initiated in 2014 following a decision by the Obama administration to not support Taiwanese efforts to modernize the country’s aging submarine force. The administration of George W. Bush had initially pledged its commitment to support Taipei in procuring or building eight SSKs by the middle of the 2020s; the reversal under Obama was supposed to help improve U.S.-China ties.

Taiwan’s push for an expanded and more modern submarine force comes amid a shift in the balance of naval power in the Taiwan Strait. Over the past three decades, the ROCN has shifted from a sea control to a sea denial strategy to deny the Chinese People’s Liberation Army Navy (PLAN) control of waters adjacent to Taiwan. A modern fleet of SSKs is key to such a denial strategy and constitutes one of the most effective deterrents to any Chinese attempts to take Taiwan by force via an amphibious landing operation.

At its narrowest point, the Taiwan Strait is just 225 kilometers wide. However, the shallow depth and jagged sea floor enables quiet SSKs to better hide from enemy sonar detection. The new ROCN submarine force could severely disrupt any PLAN attempts to land an invasion force on Taiwanese shores. The PLAN currently fields around six nuclear-powered attack subs (SSNs) and over 50 SSKs.

The ROCN currently deploys two Hai Lung-class (improved Dutch Zwaardvis-class) and two U.S.-built Guppy II-class SSKs. The latter two subs are only used for training purposes. The Hai Lung SSKs will be retrofitted by Dutch maritime systems integrator RH Marine with a new combat management system and other upgrades between 2020 and 2023. The ROCN has also been pushing to modernize the Guppy-class SSKs.

The ROCN has operated the Hai Lung and Hai Hu for over 30 years, with the two SSKs first entering service in 1987 and 1988, respectively. The upgrades to the subs are expected to extend their operational lifespan into the late 2030, according to the Taiwanese Ministry of National Defense (MND). The life extension program is overseen by the military-run Chung-shan Institute of Science and Technology and will cost around $13 million.

Upgrading the older boats is only a stopgap measure until the first new SSKs will be deployed in the middle to late 2020s. According to the MND, the IDS program is divided into two phases. The first phase comprises completing design work of the new SSK class for an estimated $66 million. This phase was reportedly completed in March of this year. The second stage will be the actual construction of the new SSKs. While the ROCN has over 30 years of experience in operating, maintaining, and repairing submarines, Taiwan’s shipbuilding industry has no practice in building them.

The MND, in cooperation with U.S. defense contractors, has been evaluating design proposals from seven foreign shipbuilders, including European and U.S. companies, as well as an Indian firm and a Japanese firm. According to Taiwanese media reports, the ministry selected a European company, Gibraltar-based Gavron Limited, to supply the design for the new ROCN SSK fleet.

The miniature model of the new submarine class, which was revealed on May 9, features an X-form rudder system and a more current sail, but otherwise closely resembles the Hai Lung-class. According to naval analyst HI Sutton, the design “implies that [the new sub class] will be double-hulled with a relatively conventional internal arrangement.” Few other technical details have been revealed. For example, it is unclear whether the estimated 1,200-1,500-ton subs will be fitted an indigenous air-independent propulsion (AIP) system.

Notably, the U.S. Department of State approved licenses for U.S. defense contractors to sell U.S.-made submarine technology to Taiwan in April 2018, facilitating closer collaboration between the United States and Taiwan on submarine construction. It should be noted, however, that no American shipyard has built a SSK since the 1950s. U.S. defense contractor Lockheed Martin will serve as systems integrator and reportedly also supply the SSKs’ combat management system.

The submarines will reportedly be built using Japanese construction techniques. Retired submarine builders from Mitsubishi and Kawasaki Heavy Industries have been supporting the MND as technical consultants since the inception of the IDS program in 2014. Construction of the submarines will be overseen by the China Shipbuilding Corporation (CSBC), Taiwan’s main ship-building company.

Construction of the first SSK is slated to begin in 2021, with sea-trials of a prototype to commence by 2024 and a commissioning date of the first-of-class boat tentatively set for 2026. Without any notable delays caused by construction and development problems, the ROCN could operate four SSKs by 2030 with an estimated per-unit cost of around $1 billion.