Submarines Resurgent

Type 094A
Pictured here are Type 094A nuclear-powered ballistic missile submarines of the PLA Navy. China presently has six Type 094 Jin-class SSBNs. (Chinese MND)

Submarines are undergoing a renaissance in the Asia-Pacific region. Excluding mini-submarines, approximately 230 are in service.

With a growing naval superpower present in the Asia-Pacific region, demand for submarines is expected to increase, as a ThyssenKrupp Marine Systems (TKMS) spokesperson explained, they have “…the capability to occupy large numbers of opposing forces through their mere presence in any given sea area.”

“Specifically, in the Asia-Pacific region demand is clearly on the rise, as many countries strive to improve and modernise existing submarine fleets or even build up their initial capability for submarine warfare. With regional security challenges becoming increasingly complex in the maritime environment, the advantages of a sophisticated submarine capability, from conventional diesel-electric through to air-independent propulsion (AIP) submarines, are clearly going to grow in the years to come.” Of course the rapid recent growth of the People’s Liberation Army Navy (PLAN) and China Coast Guard (CCG) – each with an array of well armed vessels of all sizes – is a major concern for many nations in the region.

China’s Challenge

Asia’s largest submarine operator is the PLAN. The United States predicts that numbers of Chinese diesel-electric submarines will remain at a constant 55 through till 2030. However, the nuclear-powered fleet will see some growth, with ballistic missile submarines (SSBN) growing from the current six to eight by 2030, and attack submarines (SSN) doubling to 13 boats.

The PLAN owns six Type 094 Jin-class SSBNs, but Admiral Sam Paparo, head of the US Pacific Fleet, surprised many last year when he said Type 094As are now “equipped with JL-3 intercontinental ballistic missiles”, a reference to 5,400+ nautical mile (10,000+km) range submarine-launched ballistic missiles (SLBM) presumed to have multiple warheads. It was thought that JL-3s would only appear on next-generation Type 096 SSBNs currently under development; JL-3s allow the PLAN to target the continental USA from China’s littoral waters.

The Pentagon confirms that Type 096 SSBNs “likely began construction in the early 2020s”. Satellite imagery showed a 105 foot (32 metre) long and 36-39ft (11-12m) diameter hull section at the Bohai shipyard in Huludao in February 2021, this likely belonging to a Type 096.

Some analysts claim that China launched an eighth Shang-class SSN at Huludao in January, with a seventh launched in May 2022. If these reports are correct, and they are not just older boats being refurbished, then they may be the latest Type 093B SSNs that the US military expects to arrive in the mid-2020s.

China is improving its conventional submarines too, with at least 17 of the 3,600-tonne AIP-equipped Type 039 in service. A next-generation Type 039C was observed in June 2021 – it has a redesigned sail with raked front edge and chine, a stern-mounted reelable passive towed-array sonar and potentially photonics masts.

China is exporting submarines, Bangladesh having commissioned two second-hand Type 035G boats in 2017.

Japan’s Innovation

The Japan Maritime Self-Defense Force (JMSDF) has 22 diesel-electric submarines, and Japan was first to introduce lithium-ion (Li-ion) battery-powered vessels. Indeed, JS Oryu, which was commissioned on 5 March 2020, was the first of its kind in the world. Powered by long-life Li-ion batteries from GS Yuasa, their advantage is longer endurance at higher speeds thanks to their higher capacity. Rechargeable at sea via snorkelling, these Li-ion batteries have a shorter indiscretion time due to a high charge current.

The JMSDF then commissioned a new Li-ion-powered Taigei-class in March 2022 from Mitsubishi Heavy Industries (MHI), doing away with previous lead-acid batteries and Stirling AIP systems. The 3,000t JS Taigei cost $760 million to build. Four more in the class are presently under construction, with the JMSDF receiving one annually.

Soryu-class submarine
This is a Soryu-class submarine (note the X-configured rudder) of the JMSDF. Japan operates a fleet of 22 modern diesel-electric submarines. (Gordon Arthur)

South Korea is pursuing Li-ion batteries too. Samsung SDI began developing such batteries in 2016, and these will be fitted in KSS-III Batch 2 submarines from 2027. The batteries allegedly last three times longer than lead-acid ones when sailing at full speed.

Preceding KSS-III Batch I boats, meanwhile, have a 20-day underwater endurance via lead-acid batteries and hydrogen fuel cell AIP. Constructed by jointly by Daewoo Shipbuilding and Marine Engineering (DSME) and Hyundai Heavy Industries (HHI), the first of three boats was commissioned in August 2022. Some 76 percent of ROKS Dosan Ahn Changho’s content is sourced indigenously. Significantly, the 3,358t vessel fired a Hyunmoo 4-4 SLBM from one of its six vertical-launch tubes for the first time in 2021.

South Korea has progressively accumulated experience as a submarine builder, starting with nine 1,290t KSS-I/Type 209 submarines and then nine 1,860t KSS-II/Type 214 boats, with assistance from TKMS.

Three future KSS-III Batch 3 boats will be the largest yet. In fact, thanks to North Korea’s pursuit of nuclear-tipped SLBMs, there is a growing chorus for Seoul to obtain nuclear-powered boats. Thus, Batch III could potentially be 4,000t SSNs.

North Korea operates dozens of mini-submarines, one of which torpedoed a South Korean corvette in a deadly 2010 incident. In an April 2022 parade, Pyongyang unveiled a 14m-long SLBM, even larger than the Pukguksung-5 debuting a year earlier. North Korea is modifying a Sinpo-C/Romeo-class submarine to carry 2-3 SLBMs as part of its nuclear-deterrence strategy.

Son Won-il-class submarines
The Republic of Korea Navy has nine Son Won-il-class submarines acquired under the KSS-II programme. These Type 214 boats were license-built under TKMS. (Gordon Arthur)

Yet another East Asian nation building submarines is the Republic of China (Taiwan). It was forced into its eight-boat Indigenous Defense Submarines (IDS) programme because nobody was willing to build them on Taiwan’s behalf. Taiwan International Shipbuilding (CSBC) started construction of the first IDS in November 2021, and it is slated for delivery in 2025. Despite tapping foreign workers and American expertise, the IDS project is technologically challenging for Taiwan. The octet is urgently needed to deter Chinese aggression.

Subcontinental Divide

The Pakistan Navy (PN) is upgrading three Agosta 90B submarines. STM in Turkey returned the second boat recently, while media reported last year that STM was also carrying out customisation work on its STM 500 mini-submarine on behalf of the PN.

Pakistan awaits eight 2,800t Hangor-class submarines. The keel of the fifth boat was laid, and steel was cut on the sixth vessel, at Karachi Shipyard & Engineering Works (KSEW) on 24 December 2022. China is building the first four boats, while KSEW is responsible for the remainder by 2028. Based on the Chinese Yuan class, the Hangor programme is running slightly behind schedule, since China was supposed to deliver its boats in 2022-23.

As for the Indian Navy (IN), it must contend with bureaucratic ineptitude. This is best illustrated by Project 75I, a labyrinthine $5.6 billion effort to build six AIP-equipped submarines. In mid-2021, India issued a request for proposals (RfP) to five foreign shipbuilders (DSME, Naval Group, Navantia, Rubin Design Bureau and TKMS), seeking a partner for either Mazagon Dock Limited (MDL) or Larsen & Toubro under the Strategic Partnership model.

Project 75I’s acceptance of necessity was granted back in 2007, illustrating the programme’s glacial pace. The RfP required a fuel cell-based AIP, but despite deadlines being pushed back twice, no company seems willing to respond.

Asked about its offering, a TKMS spokesperson claimed to have the only sea-proven AIP system with zero emissions of reissuing gases into areas surrounding the submarine. “The current version of our AIP is in the fourth generation, and we are continually investing in perfecting this technology for reliability, longevity and ease of operation. Emerging technologies such as Li-ion batteries for submarines, together with our AIP, offer a significantly superior capability to reduce the indiscretion rate, better stealth characteristics and improved maintenance of the submarine.”

In the meantime, Project 75, a $3.6 billion contract with Naval Group for six Scorpenes, is nearing completion. Signed up for in 2005, deliveries are about seven years behind the original schedule. Nonetheless, Naval Group told Asian Military Review: “The P75 programme is well on track, with five submarines already in service within the Indian Navy … The last one is currently completing her sea trials in order to be delivered in 2024.”

“This programme is not only a first of its kind for India, but in the world. Indeed, there are no other submarine-building projects where transfer of technology was made for all the submarines to be constructed locally, including the first-of-class. The P75 is an obvious industrial success, and above all it is performing extremely well for the Indian Navy.”

In a surprise move, India announced on 23 January that Naval Group had received a contract for detailed design and integration of AIP onto INS Kalvari, the first Scorpene. Rather than Naval Group’s patented MESMA AIP, Kalvari and sister ships will instead receive a Defence Research & Development Organisation (DRDO) AIP, which the MoD claims will enhance submerged endurance several-fold.

Incidentally, the French shipbuilder said of its own MESMA: “Thanks to tests carried out for several years on a full-scale land-based demonstrator, Naval Group guarantees a reliable and safe system, as well as a diving autonomy of 2-3 weeks depending on the use. At the end of 2019, this demonstrator had accumulated more than 7,000 hours of operation, the equivalent of more than six years of use.”

While fitting AIP into the Kalvari class will give India invaluable experience, and does involve immense technological risk, it does not solve the impasse with P75I. MDL’s submarine workforce will be left redundant after the final Scorpene is finished and, currently, the IN has just 14 conventional submarines instead of the 24 mandated.

INS Arihant, the first of four Indian SSBNs, was commissioned in 2016, while introduction of a second is imminent. Delhi has also approved a programme to build six SSNs, though their timeline is unclear. In 2021 the IN returned an Akula II SSN to Russia a year short of its ten-year lease expiring. The IN might lease another Russian Akula vessel after 2025.

Southeast Asia

The sorry plight of Thailand’s submarine acquisition brings into sharp relief the importance of due diligence in contractual details. The Royal Thai Navy (RTN) is facing significant delays in obtaining an S26T from China. Originally, the maker proposed using MTU 12V 396 SE84 diesel engines, but Germany refused to sell them because of an EU arms embargo on China.

S26T submarine
This cutaway model shows an S26T submarine. Thailand wanted to buy three such submarines from China, but it is struggling to obtain the first because of engine procurement troubles. (Gordon Arthur)

Last year, German military attaché Philipp Doert confirmed that no export licence had been issued, plus, “China did not ask/coordinate with Germany before signing the Thai-China contract, offering German MTU engines as part of their product.” Asian Military Review approached MTU for comment, but could not elicit any response.

China therefore cannot fulfil the Thai contract, so is offering a Chinese-built, but unproven, CHD620 engine instead. This has not impressed the RTN, which has embarked on a series of technical reports, meetings, certification demands and sending a delegation to China. The RTN will conclude its deliberations by June. Construction on the $430 million vessel halted last year, with more than 50 percent of the 1,850t S26T completed. This boat cannot be delivered before 2024.

Indonesia suffered the tragic loss of KRI Nanggala in April 2021, a stark reminder of the risks inherent in operating submarines. The backbone of the Indonesian Navy’s underwater fleet is three Type 209/1400 Nagapasa-class boats from DSME. Indonesia appears dissatisfied with its South Korean boats, and seems to have walked away from a $1.02 billion contract for three submarines signed in 2019.

In February 2022, Jakarta inked a memorandum of understanding with PT PAL for two Scorpenes. Although not yet a done deal, a Naval Group spokesperson elaborated: “Our strategic partnership agreement with the state-owned shipyard PT PAL is not just about submarines, but also about building Indonesian sovereignty to the benefit of the Indonesian Navy and local defence industry.”

Not to be outdone, another shipbuilder explained: “Currently, TKMS remains actively in pursuit of new submarine acquisition projects in India (P75I) and Indonesia. We are aware of other opportunities that are not as mature in their definition as the aforementioned, and are active to support both existing and prospective new customers in the region with the acquisition of new submarines.”

Manila is a potential first-time buyer, as it mulls two submarines. The Philippine Navy activated a Submarine Group in 2016, and issued a request for information to shipbuilders the same year. Nothing has eventuated to date.

One contender said: “Naval Group stands ready to support the Philippines in the development of their naval capabilities. For the submarine fleet, Naval Group has unique know-how to help the customer create a submarine force, which is very different than merely buying submarines, since it is also necessary to take into account the training, logistics and fleet support aspects.”

Singapore gained experience with Swedish-built Challenger- and Archer-class submarines. Then, in 2013 it ordered two 70m-long Type 218SGs with fuel cell AIP from TKMS, plus a second pair in 2017; their acquisition cost is $1.8 billion. The first Invincible-class submarine was launched in February 2019, and two more last year. These 2,200t boats need just 28 crewmen thanks to automation and decision management systems.

TKMS would not be drawn on Type 218SG technologies, other than to say the design has increased underwater endurance, minimised magnetic signature, increased processing power for AI and analysis, new weapon integration and enhanced self-defence.

Elsewhere in Southeast Asia, Malaysia operates two Scorpenes, Vietnam possesses six Kilo-class boats and Myanmar received a second-hand Kilo from India.

Scorpene submarines
The Royal Malaysian Navy procured two Scorpene submarines from Naval Group in France. With both commissioned in 2009, one is pictured here. (Gordon Arthur)


Australia’s September 2021 cancellation of the 12-vessel Attack-class programme cost the Australian taxpayer a $583 million cancellation fee to Naval Group. However, the true cost was in the vicinity of $2.35 billion thanks to monies already spent. Nonetheless, Royal Australian Navy (RAN) officials refuse to describe Project Sea 1000 as a huge mistake.

Star-struck at the feasibility of obtaining nuclear-powered engineering capability under the AUKUS alliance, Canberra conducted an 18-month study seeking “an optimal pathway” to build SSNs in conjunction with the UK and USA. A decision on the way forward could be made in March.

The RAN desires at least eight SSNs built locally, but when this will occur is anyone’s guess. It is inconceivable that the first boat could be available before 2040, given the nuclear stewardship learning curve that Australia must learn, and tight production schedules in the UK and USA.

Despite initial protestations from the RAN that a capability gap would not occur, there is growing acknowledgement that an interim platform might be required. Perhaps the RAN also sees salvation in several extra-large unmanned underwater vehicle projects currently ongoing.

In the interim, ASC will perform a life-of-type extension on six Australian Collins-class submarines from 2026-35. HMAS Farncomb will be the first to undergo the two-year refit, adding 10 years to its life. Each submarine will have its hull cut in half and various systems replaced. Furthermore, Thales Australia is upgrading its sonar suite, and Safran will provide optronic masts.

HMAS Rankin
HMAS Rankin, an Australian Collins-class submarine, conducts a helicopter transfer. The six vessels were inducted from 1996-2003. (Australian Department of Defence)

Saab Kockums, who helped build the Collins class, told Asian Military Review: “There are hundreds of conventional submarines worldwide that are close to end-of-life and will need to be replaced in the years to come. The Asia-Pacific region is no exception. Saab Kockums is continually supporting Singapore for the Archer class, and we have close cooperation with ASC in Australia for Collins-class submarines. Based on our experience and close customer relationships in Asia-Pacific…we continue to follow market development and are positive for more opportunities in the future.”

Europe has been the traditional powerhouse for conventional submarines. However, Asia is emerging as a serious builder too, especially with both China and South Korea having achieved exports. Add in the likes of India, Japan and Taiwan, and it is obvious that Asia has a tremendous repository of submarine-building skills.

by Gordon Arthur