Taiwan’s undersea submarine base plan resurfaces as cross-strait tensions rise
- As new submarines come into service, experts refloat idea to build secret undersea naval base on island’s east coast
- Despite defence advantages, Taipei torpedoed the 90s proposal after military purchases fell through
Taipei’s government is being urged to reconsider a proposal to use underwater caves as part of a naval base for a new fleet of submarines that could begin commissioning in 2025.
The island’s mountainous east coast – with steep cliffs and deep sea terrain – would provide an ideal base for such warships, according Taiwanese defence experts.
In particular, geological structures along the eastern coast of Hualien county and its adjacent natural underwater terrain could provide ideal cover for submarines, said Lu Li-shih, a former instructor at the island’s Republic of Taiwan Naval Academy in Kaohsiung.
“Just 100 metres (328 feet) from Hualien’s coastline, the sea is 1,000 metres (3,300 feet) deep, and 10km (6.2 miles) from the coast, the water is more than 4,000 metres deep, allowing submarines to dive stealthily into the oceanic trench of the Pacific soon after sailing from the base,” Lu said.
“The geological structures of the sea cliffs in Hualien are composed of hard rock, which is suitable to dig deep caves or tunnels.”
Taiwan plans to develop and build a fleet of at least eight diesel-electric powered attack submarines under its Indigenous Defence Submarine (IDS) Programme, with the first vessel expected to launch in September and go into service in the first half of 2025, according to Taiwanese media.
The shelved proposal for an underwater submarine base has recently been making waves in Taiwan’s military circles.
An article published by Taiwanese online news portal Up Media called on Taipei to reconsider the naval base cave project, which was originally named “Antung Plan”, or “Secure the East”, since the existing Zuoying Naval Base in southern Kaohsiung is not a deep port and would not be concealed enough even after expansion.
Taiwan’s navy began studying the proposal in 1991 after Washington promised to sell eight diesel-electric submarines and 12 P-3C anti-submarine patrol aircraft to Taipei.
The pledges prompted the island’s navy to make plans for an underwater U-shaped tunnel inside a coastal ridge in Hualien that would have housed a comprehensive logistics and maintenance underground facility, according to a report published in 2004 by Zhu Xianlong, former deputy director of the Taiwan Research Institute at Beijing Union University.
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The island’s air force has two underground hangars in Hualien and Taitung, which could shield up to 400 fighter jets in the event of a first strike, thanks to a 500km mountain range.
“It’s not safe for subs to berth in naval bases in the island’s south and north ports, where waters are shallow and it is easy to be detected,” Chang said.
“A cave sub facility for the Taiwanese navy should be a kind of sloping underwater tunnel inside Hualien’s rocky cliff that is similar to the Swedish underwater submarine base, which cannot be detected by [anti-submarine] aircraft and satellites.”
Muskö Naval Base, a Swedish underwater naval facility south of Stockholm, has an area of several square kilometres and is connected by 20km of underground roads, and a 3km-long tunnel, part of which runs under the sea.
The PLA Navy also has an underground base in Yalong bay on the south of the island of Hainan, which is situated near an oceanic trench that can offer protection.
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“The PLA has devised many scenarios for a possible war over Taiwan, including the involvement of aircraft carrier strike groups, in which the ship-borne fighter jets and missiles would be deployed to bombard the island’s key military bases,” Ni said.
“But attack subs that are hidden in an underwater submarine base and oceanic trench may drag down or even ruin the PLA’s plan to seize the island in a quick fight.”
Arthur Ding, an honorary professor at National Chengchi University in Taipei, said it would be too costly for the navy to build an underwater submarine base, even though “it sounds like a good idea”.
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“Diesel-electric subs have limited endurance, so it might be better to let the vessels station in the northern and southern ports.”
Taiwan’s new IDS submarines will eventually replace the four older submarines currently in service in the navy.
Two of the vessels are diesel-electric submarines bought from the Netherlands in the 1980s, while the other two are used US Navy GUPPY submarines.
The vessels, which were designed several decades ago, are used for training only.