Checkpoint Asia

North Korea Has Converted a Conventional Submarine to Fire Its Nuclear Missiles

Now has at least some sea-based deterrence

Might be a 1950s design but can level a city

North Korea released a number of images of Kim Jong-un inspecting a new submarine. The images show the North Korean leader touring what appears to be a submarine in drydock, under construction. Experts believe the new sub will carry nuclear-tipped missiles that could be used to threaten U.S. military bases in Japan and throughout the Asia-Pacific region.

The photos, released via the state-run KCNA news agency, show Kim and an entourage touring a submarine inside a massive construction building. The submarine appears similar to existing North Korean subs—but with a catch. The submarine appears to have an expanded sail with launch tubes for Pukgeukseong-1 ballistic missiles.

KCNA, reporting on the event, stated that Kim Jong-un, “visited the newly built submarine and detailed the operational tactical specifications of the ship and the weapon combat systems. (Kim) expressed great satisfaction about the design and construction of the submarine so that it can smoothly carry out the military strategic wishes of our party even in the context of each situation.” The submarine will operate in the Sea of Japan.

The Project 633 class Soviet diesel electric submarine, nicknamed “Romeo” by NATO forces, was introduced in the late 1950s. The Soviets shared plans for the submarines with China, who transferred seven of them to North Korea in the 1970s and supplied parts for another 13 in kit form. Although very obsolete in 2019, the Romeos make up a substantial portion of North Korea’s large submarine fleet. In 2014, Kim Jong-un was photographed taking a ride on one of the submarines.

In the mid-1990s, North Korea acquired a large number of outdated ex-Soviet Navy submarines, many of which were reportedly in poor condition. Ostensibly bought for scrap, the purchase included a small number of Project 629A ballistic missile submarines, known to NATO as the Golf II class. The Golf II class was based on the same Romeo-class submarines used by North Korea but modified to carry three missile tubes in the submarine’s sail. The similarity of design of the Golf II to the new North Korean submarine suggests that although North Korea never managed to get a Golf II in service, the new submarine incorporates technology from the old Soviet subs.

The new submarine is a successor to the Gorae (Whale), a technology demonstrator that concealed one missile in the sail. Underwater warfare expert H.I. Sutton, author of the Covert Shores submarine blog, told Popular Mechanics the missile submarine is likely a conversion of one of North Korea’s Romeo-class submarines, “Although it was described as newly built by North Korea’s state media, there are very clear signs that this is a modification of a previously built boat. So the submarine was built at least twenty years ago.”

A man on the subway in Seoul, South Korea watches footage of a Pukgeukseong missile test, April 2016

As propaganda the photos attempt to show the size and scale of the submarine without showing off too many details. Sutton has noticed several small, seemingly minor details of the sub that point to its lineage. In the photo above, the lower arrow points to one of two shrouded propellers—standard on Romeo-class submarines—with one located on each side of the hull. The upper arrow shows what generally looks like the Romeo submarine with an enlarged topside. That topside is almost certainly meant to support a larger, wider sail with missile launch tubes inside.

Sutton believes the new submarine can carry two, possibly three Pukgeukseongmissiles. First tested in 2016, Pukgeukseong (called KN-11 by U.S. intelligence)is thought to have a range of 1,200 kilometers (745 miles) and is nuclear-tipped. Launched from the Sea of Japan, such a missile could hold U.S. and Japanese targets at risk of nuclear attack. The new submarine could later embark future missiles with even longer ranges—the ideal target is the U.S. island territory of Guam, a regional hub for U.S. Air Force nuclear-capable bombers and U.S. Navy nuclear submarines.

A submarine equipped with nuclear-tipped missiles could be a surprise first strike weapon, inching quietly towards its target undetected and then launching a barrage of missiles. [Only if they are suicidal.] Most nuclear powers however use sub-based nukes as a strictly defensive weapons meant to deter such surprise attacks. A submarine on patrol could evade enemy forces, riding out a nuclear attack on its home country and then firing its missiles in retaliation.

North Korea’s conversion of an existing submarine into a missile-firing one appears to have come with performance compromises. “The missile tubes appear to be located in what was the second battery compartment,” Sutton says. “This may mean that the boat carries fewer batteries meaning that she cannot submerge for as long.”

The “new” North Korean submarine is relatively primitive by modern standards. Nevertheless, Sutton tells Popular Mechanics, “although the submarines is old fashioned, the armament is very potent and will be taken very seriously by other navies.”

Source: Popular Mechanics