Commercial satellite imagery of the Sinpho South Shipyard from September 18 reveals six barges and vessels gathered around the construction hall quay, suggesting that the North Koreans are preparing to launch a new submarine.
Construction of what is believed to be a new ballistic missile submarine (SSB) began in early 2016. In 2019, Kim Jong Un visited the shipyard; images from his guidance visit raised questions about what the North Koreans were actually building—a new SSB or a modified ROMEO-class (or both)—but suggested construction was nearing completion. The parts yard adjacent to the construction halls has been empty since late summer of 2020, but so far there have been no indications in North Korean media about when the new submarine might be launched.
While barges and a dry dock have been occasionally observed around the submarine launch quay at the main construction hall, the presence of six vessels and barges in this area has not been observed before.
Figure 1. Areas of new activity at the Sinpho South Shipyard.
Figure 2. Vessels and barges observed around submarine launch quay on September 18.
There is also an apparent tow fixture on the launch quay rollout rails that could be used to ensure the barges tow the submarine out along the rails. Since the quay abruptly drops into the water, the floating drydock could be used to receive the submarine as it comes off the quay and then gently set it into the water.
These barges were not present on imagery from September 12, reported by CSIS’ Beyond Parallel, indicating that the preparations are likely still at an early stage.
This raises the question of where a new submarine would be berthed once it is launched. The secure boat basin is one possible choice, although only one submarine can fit under the covered area of the quay. Another potential area would be the probable submarine pen and L-shaped pier that have been under slow construction in recent years.
Figure 3. Construction materials observed near probable submarine pen.
If that area is intended to be a submarine pen, a water channel would still need to be excavated from the shore to the pen. Alternatively, it is also possible this new area is intended to be a facility to conduct repairs that cannot be done on a floating drydock.
Additionally, this image provides a clear view of the GORAE/SINPO-Class experimental ballistic missile submarine’s missile launch hatch.
Figure 4. Clear view of the SINPO-Class SSB’s missile-launch hatch.
The hatch, located in the sail of the submarine, is estimated to be 1.8 meters in diameter, which can readily accommodate at least a Pukguksong-1 or Pukguksong-3 submarine-launched ballistic missiles’ launch canisters. The Pukguksong-1 ( KN-11) has a reported diameter of 1.1 meters, and the Pukguksong-3, 1.4 meters.