North Korea’s Diesel-Electric Ballistic Missile ‘Frankensub’ Emerges

A very deep rework of an ancient Cold War-era Romeo class diesel-electric submarine that North Korea has ‘Frankensteined’ into a conventionally-powered missile submarine has been officially unveiled and launched. The ceremony, which Kim Jong Un attended, took place at Sinpo submarine yard on North Korea’s eastern shore on September 6th. The submarine is named Hero Kim Kun Ok and carries the hull number 841.

Kim inspects his ballistic missile submarine in Sinpo. (KCNA)
The boat’s Romeo-class origins are more clear in this image. Note it appears the submarine’s rudder and screw have been totally photoshopped out of the image. (KCNA)

We first saw parts of the so-called Gorae/Sinpo-C class ‘SSB’ as it was being modified on land back in 2019. The grafted-on missile compartment behind its sail gave it a bizarre look. While it isn’t perfectly clear if that was the same boat that we are seeing here, it seems highly likely, especially considering North Korea had years to fiddle with it to make it a workable design.

As for the submarine’s capabilities, its missile compartment extension aft of the sail clearly features five doors on each side, for a total of ten compartments. The forward four are larger than the rear six. This does make sense, with the boat being designed to carry multiple types of missiles, specifically a mix of short-range and longer-range submarine-launched ballistic missiles (SLBMs), and/or SLBMs and submarine-launched cruise missiles (SLCM). In particular, the Hermit Kingdom’s new nuclear-capable sea-launched cruise missile, the Hwasal-2, adapted for submarine launch would be the top cruise missile contender for this submarine, as we previously posited.

The submarine’s very dated hull design and grafted-on missile compartment are apparent here. (KCNA)
Here we see the boat post-launch alongside the pier. (KCNA)

North Korea has been openly pursuing a second-strike nuclear deterrent in the form of sub-launched ballistic missiles of various types for many years. Still, assuming North Korea can get their deeply modified SSB to work, just having a boat or two capable of nuclear patrols does not ensure a credible nuclear second-strike deterrent. These submarines will be very noisy by modern standards and will be tracked from the second they leave North Korean piers. Still, the very existence of such a capability would be viewed as another major step for North Korea along its unbridled nuclear weapons development adventure. Persistent patrols could also tie up significant South Korean, U.S., and Japanese anti-submarine resources.

Kim touring the Sinpo submarine yards back in 2019, the first time we got a glimpse of the regime’s Romeo class turned SSB ‘Frankensub’ ambitions. (KCNA)
Kim riding on a Romeo class years ago. The type dates back to the 1950s and still makes up the backbone of the North Korean Navy’s submarine fleet. (KCNA)

One discrepancy that is worth mentioning is that supposedly the launch took place on September 6th. Yet high-resolution satellite imagery from that day shows nothing of the sort, including any obvious preparations for an event. It is possible that the launch occurred and the pier area was reset quickly or preparations happened very fast and the satellite pass did not pick up any of them, but it does seem a bit odd.

As for Kim’s remarks on the big unveiling, writes:

The DPRK leader outlined a “plan to remodel existing medium-sized submarines into offensive ones loaded with tactical nuclear weapons to play an important role in the modern warfare” in his speech Wednesday, the Rodong Sinmun reported, calling it a “low-cost ultra-modernization strategy.”

The country “will accelerate the nuclear armament of the navy without letup” in a scheme that is “separate from our developmental and prospective plan for building nuclear submarines,” the report added, part of North Korea’s “advance toward the attainment of the grandiose goal for turning the country into an advanced maritime power.”

The next big milestone for this very unique boat will be actually test-firing an SLBM, that is if it survives its shakedown operations.

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