North Korea building new, larger submarine pens | IHS Jane's 360

The massive investment North Korea is making into building the new submarine bunker at Sinpo suggests it will be used to protect its most prized naval asset - the SSB capability it is currently developing - rather than its existing fleet of Romeo and far smaller Sang-O-class boats.

North Korea is known to currently have one SSB, which South Korea's official Yonhap news agency calls the Sinpo class, while other sources refer to it as the Gorae class. Measuring approximately 67 m in length, the SSB houses one ballistic missile launch tube that extends through its sail. This has been used to test Pukgeukseong (Polaris) submarine-launched ballistic missiles.

At 150 m, each of the new pens in the Sinpo submarine bunker would be able to accommodate two such SSBs, but would have to be sufficiently high to enable their missiles to be loaded into their launch tubes from above.