June 7, 2017 · Noble Prowl Gwisin Sea of Japan

Strikepod Engages Probable Gwisin


Today at 1812Z, Strikepod Tango-1, operating approximately 3km southeast of Mayang-Do, engaged what we believe to be a North Korean Gwisin-class microsubmarine.

Tango-1 continued around the clock monitoring of Minnow-2 at a range of approximately 1.2km, and a depth of 3.5m, reporting on its position every two hours.

  • The vessel remained on a fixed patrol pattern off the coast of Mayang-Do, maintaining a speed of approximately 2-3kts, and rising to periscope depth at regular intervals, presumably to transmit contact data and to receive orders from its KPN handlers.

  • At 1807Z today, Strikepod Command received a flash transmission from Tango-1 indicating that Minnow-2 had turned abruptly and accelerated to 10kts, and was now approaching on a collision course with active sonar pinging.

  • Tango-1 altered course three times, and each time was met with a corresponding course change by Minnow-2.

  • Strikepod Command determined that Minnow-2 was acting in a hostile manner, and ordered Tango-1 to prepare for combat.

At 1810Z, Tango-1 altered course a final time, with Minnow-2 changing course to follow.

  • Tango-1 accelerated and assumed a combat formation. Two relays remained at or near the surface, while remora-1, remora-2, remora-3, and the rogue moved to positions approximately 100m apart.

  • Minnow-2 continued to close at a rate of 10kts, on a course to engage the Tango-1 rogue.

  • The Tango-1 rogue increased speed to 12kts and made for a depth of 20m, hoping to outrun or out-dive Minnow-2.

  • As Minnow-2 turned and dove to pursue, remora-1 accelerated to 15 kts and closed.

  • Once within range, remora-1 detonated its explosive payload, resulting in the destruction of Minnow-2 (and remora-1).

Why did the Gwisin attack?

  • At no time was there any indication that the Gwisin had detected Tango-1, though it is possible that another vessel or undersea sensor, perhaps even another microsubmarine operating in the area, had detected the Strikepod and communicated its position to the KPN who in turn communicated it to the Gwisin.

  • Whether the Gwisin was ordered to attack once Tango-1 was detected, or whether it was aware of Tango-1's presence for an extended period of time before attacking is unclear.

  • One possibility is that Tango-1 was under surveillance, and that the Gwisin was ordered to attack in order to provoke a reaction by the Strikepod, resulting in valuable intelligence for the KPN.

  • It is also possible that Pyongyang hoped to send Washington a message: North Korea is aware of Strikepod activity within its territorial waters, and will respond accordingly.

At this time, there has been no official response from Pyongyang.

  • While an incident of this magnitude could provide the DPRK with a significant propaganda windfall, leveraging it for political gain would mean revealing knowledge of U.S. micronaval activities, and by extension, the state of its own micronaval capability.

  • Though a weaponized Atom-class is designed for complete destruction, we cannot rule out the possibility that, given the relatively shallow depth where the engagement occurred, a thorough KPN salvage operation could recover debris from remora-1 on the sea floor. Pyongyang could use this debris as the basis for a more broad-based, public indictment of U.S. undersea activities in DPRK territorial waters.

What We Know of the Gwisin-class

  • As we previously noted, the Gwisin incorporates several technologies found in the Shāyú-class microsubmarine, including signal processing, communications, and propulsion, but is powered by a high energy density battery, not a micronuclear reactor like the Shāyú.

  • Sensor data collected during the engagement suggests that, while highly maneuverable, the Gwisin's top speed is less that 15kts, and is likely only between 10-12kts.

  • The Gwisin is a solo actor. That is, there is no indication of network capability or collaboration with other microsubmarines.

  • Though it incorporates powerful signal processing technology, we believe that the Gwisin is only marginally autonomous.

Strikepod Command


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