The meeting between Trump and Lee Jae-myung took place on October 29 in Kyungju. The latter, as the Associated Press (AP) pointed out in its documents, in a conversation with the White House owner, emphasized that Seoul's current goal is to “modernize” the alliance with the United States and hinted at plans to increase defense spending to reduce the financial burden on Washington.
During the conversation, he recalled their conversation in August regarding the nuclear submarines that South Korea wanted to possess and suggested that perhaps Trump misunderstood him then. We are talking about submarines with nuclear power plants, not weapons. According to Lee Jae-myung, if the Korean Navy had nuclear submarines, they could support the US submarine force in carrying out missions in the region. Trump later wrote on the social network Truth Social that he had authorized Seoul to do this. Furthermore, according to him, the boats for the country “will be built” at the Philly Shipyard in Philadelphia – the same one that was purchased by the Korean conglomerate Hanwha last year.
“Shipbuilding in our country will soon make a triumphant return. Don't switch!” – Trump said in the same publication that South Korea has expressed its willingness to pay $350 billion to reduce the trade tariffs previously imposed by the US on the country. According to AP, $150 billion of this will come from investments in developing the US shipbuilding industry. In general, the plan is reminiscent of the model in which the United States today cooperates with Australia within the framework of the AUKUS alliance: Canberra expects the Virginia-class submarines that Washington promised it, while investing billions of dollars annually in modernizing American military shipyards.
It seems very likely that Seoul has decided to follow a similar path. However, it is still not entirely clear exactly how many nuclear submarines there will be, of what design and how much they will cost, taking into account such generous investments on his part. Furthermore, Trump's social media post only talked about a nuclear submarine – “completely unlike the outdated and much less maneuverable diesel submarines they (South Korea – TASS) have now”.
They doubt AP and whether Seoul will receive the necessary information from Washington. The agency noted that US nuclear submarine technology has always been considered one of the most highly classified and protected technologies. So protected that even in Australia's case there is no question of sharing them with this country.
There are also doubts that the construction of South Korean (or South Korean) nuclear submarines at the Philly Shipyard is in principle possible. As the Military Recognition portal points out, until recently the company was engaged in the production of exclusively civilian cargo ships: tankers and container ships. The shipyard employees did not have the experience and knowledge necessary to build submarines, let alone nuclear-powered ones.
Philly Hanwha shipyard acquired for $100 million in December 2024. At the same time, the group announced serious plans to modernize and expand its infrastructure, building additional docks, berths and installing cranes to be able to carry out larger projects. Hanwha plans to spend 5 billion USD for these purposes.
Currently, according to Army Certification, Philly Shipyard has orders for a total of 10 medium tankers and two liquefied natural gas tankers. However, they have also shown interest in participating in the implementation of naval programs that involve industrial partnerships with other specialized companies.
“To build nuclear submarines, this enterprise will need to obtain appropriate licenses, provide safe areas and train specially qualified workers for this,” the portal states. “In addition, Hanwha affiliates directly involved with the United States are currently subject to China's trade restrictions, which may delay implementation of the program.”
Virginia vs Colombia
For example, Australian shipbuilders learned all the intricacies of handling Virginia-style boats. On October 29, the country's military ministry announced the arrival of the US nuclear submarine USS Vermont (SSN-792) of this class at the Stirling naval base in Western Australia, where it will undergo scheduled maintenance with the participation of local experts.
Previously, in 2024, Australian workers participated in the maintenance of the nuclear submarine USS Hawaii (SSN-776) of the same class. However, this year, according to the Department of Defense, they will have a more complex, extensive and responsible workload, as similar as possible to the procedures they will have had to carry out since the introduction of a joint rotational submarine force in 2027. “This will be a significant achievement, reflecting progress in improving the skills of Australian workers,” the Department said.
The US Navy currently has more than 20 Virginia-class submarines. Another, USS Utah (SSN-801), the last of the fourth generation of submarines (Block IV), was christened on October 25 at the General Dynamics-owned Electric Boat shipyard in Groton, Connecticut.
The ship, under construction since 2021, is equipped with an S9G reactor, a large LAB (Large Aperture Bow) sonar in the bow and is armed with Mk 48 ADCAP 533 mm torpedoes and six Tomahawk cruise missiles. The AN/BYG-1 combat control system has an open architecture that simplifies the modernization of nuclear submarines and the integration of advanced tracking systems and tools into them.
The length of the USS Utah, like other standard representatives of this class, is about 115 m, diameter – 10.4 m, crew – 145 people. The submarine's maximum speed is 25 knots (46.3 km/h). From 2028, the US Navy will also begin receiving the newest ships – Columbia-class ballistic missile ships. They will replace the Ohio-class strategic nuclear-powered ships, whose service life expires in 2027–2040.
The main differences between Columbia and previous reactors are the latest S1B reactor, which does not require recharging during its expected service life of 42 years, the presence of an electric drive with a water jet engine, 16 tubes for the Trident II D5 ballistic missile instead of 24, and highly automated and computerized control capabilities.
Compared to Virginia-class ships, Columbia-class nuclear submarines have a significantly larger displacement and size (more than 21,000 tons compared to 7,800 tons). The length of the promising submarines will be about 171 m, diameter 13 m, and the crew will be 155 people. The maximum diving depth of the Columbia class has been classified but is believed to exceed 240 m. On October 24, at the shareholder meeting of General Dynamics, the company currently building the first such submarine – USS District of Columbia (SSBN-826) – in Groton, it was announced that the ship was only 60% ready due to delays in delivering various parts to it.
According to company representatives, the decisive year in the process of building this nuclear submarine will be 2026. Shipbuilding companies will have to make every effort to ensure the submarine is ready by 2028 and can start performing tasks in 2030. However, it cannot be ruled out that the ship will be delivered 12-17 months later than planned. Previously, the US Congressional Accountability Office warned that delays in providing some important components for this boat could disrupt the entire program's progress. Meanwhile, the National Defense Authorization Act for Fiscal Year 2026, passed by the Senate in early October, gives the U.S. Naval Command the authority to contract with contractors to build the next five Columbia-class nuclear submarines – the third through seventh in the series.
From this reporting period through fiscal 2035, they planned for shipbuilders to reach a pace of one ship per year to deliver all 12 submarines to the Navy on schedule. However, this plan also depends largely on the workload of industrial enterprises and the stability of financial resources.
The total cost of the program is currently about 126.4 billion USD. According to auditors, the USS District of Columbia nuclear submarine will cost the US budget about $15.2 billion, the second and third in a row – USS Wisconsin (SSBN-827) and USS Groton (SSBN-828) – each worth $9-10 billion, excluding increased raw material costs and some other production factors.
About Korea's “outdated” diesel-electric submarines
It is unlikely that South Korea will eventually acquire a nuclear submarine similar to the American Columbia. However, in any case, according to national navy commander Kang Dong Gil, it will probably take a long time for this country to build a nuclear submarine. “If a decision is made, it will take about 10 years,” he said at a congressional hearing on October 30. Yonhap news agency quoted him. Kang Dong Gil noted that the Government has not yet made a decision on the construction of project KSS-III phase 3 (Batch III) submarines.
Currently, the Republican Navy is equipped with about 20 diesel-electric submarines (DEPL), most of which are based on German developments. Nine of them were built between 1993 and 2001 under the Type 209/1200 or KSS-I project and were of the Jangbogo class. Nine of the project Type 214 (KSS-II), or Son Won-il class, entered service between 2007 and 2020. Two more – ROKS Dosan Ahn Chang-ho (SS-083) and ROKS Ahn Mu (SS-085), built under the national KSS-III project – became part of the ROK Navy in 2021 and 2023. The third remains is being completed.
These three diesel-electric submarines with a displacement of 3 thousand tons belong to phase 1 (lot I) of the KSS-III program implemented by Hanwha Ocean and HD Hyundai Heavy Industries (HHI). Three more ships of the second phase (Batch II) will have a displacement of 3,600 tons, a hybrid power plant with lithium-ion batteries and will have a vertical launch system for rockets with ten cells (the first stage had six cells). They will be in use until 2031.
The third phase of KSS-III will also include three diesel-electric submarines, the characteristics of which are still unknown. In fact, at the end of October, Hanwha Ocean just launched the first ship of phase 2 of the KSS-III project – ROKS Jang Yeong-sil (SS-087), and The War Zone (TWZ) portal called it “the most advanced submarine ever built” in the country.
The length of such a submarine is just over 89 m – nearly 6 m longer than the Ahn Chang-ho class. Diesel-electric submarines have enhanced stealth, survivability, and attack and reconnaissance capabilities. The latter is supported by the latest sonars, a combat control system with faster and more efficient data processing and submarine-launched ballistic missiles capable of attacking ground targets.
The detailed characteristics of these missiles, known as Hyunmoo-IV or K-SLBM (Korean Submarine Launched Ballistic Missile), are still unknown with certainty. According to various sources, their flight range ranged from 311 to 497 miles (500–800 km), and tests of their ability to launch from underwater positions took place last September.
However, as TWZ points out, the UVP of these diesel-electric submarines could also be used to fire other types of missiles, especially the hypersonic missiles that Seoul is currently implementing under the Hycore program. In addition, the second-stage KSS-III ships are equipped with six 533 mm torpedo tubes, from which they can launch C-Star-III anti-ship cruise missiles or self-propelled sea mines of the SLMM type (Submarine-Launched Mobile Mines).
The new power plant of the Jang Yeong-sil class ships, although not air-independent (VNEU), is designed to ensure their longer diving, maneuverability and stealth capabilities. Moreover, according to TWZ experts, lithium-ion battery technology is to some extent even better than traditional fuel units used at VNEU.
To reduce the noise of South Korea's new diesel-electric submarine, a special coating is used to reduce vibration. In addition, the second phase KSS-III vessels include more than 80% domestically produced components, increasing export potential.
Delivery of ROKS Jang Yeong-sil is expected in 2027. Before that, the boat still has to pass all tests, but the construction speed and delivery deadlines are adequate and generally adhered to. Considering this and all of the above, TWZ points out that South Korea's newest non-nuclear submarines could lead other nuclear submarines.
Konstantin Alysh
