NK-Sub1 
 
 The US and South Korea are reporting that North Korea is believed to have lost one of its submarines. The vessel was operating off the coast of North Korea when it disappeared, and the North Korean navy has been observed engaged in search and rescue operations in the area where the sub is believed to have been stationed.

North Korea’s navy (formally called the Korean People’s Navy) fields a wide range of vessels, including amphibious landing craft, over 400 patrol boats, and 70 submarines. Most of the country’s subs, however, could charitably be described as “ancient.”

North Korea’s arsenal includes:

50 Romeo-class submarines: These are based on a post-WW2 1950s Soviet design, which was in turn based on the WW2-era Type-XXI German U-Boat. History buffs may recognize the Type XXI as the absolute cutting-edge of WW2 submarine warfare. It was the first submarine designed to remain submerged rather than as a surface vessel that submerged to attack or evade the enemy. It could travel for days on battery, recharge in less than five hours via snorkel, and featured advanced hull designs and silent running capabilities that exceeded the other submarines of its day.

CHinese-Type33
North Korea’s Romeo-class subs are believed to be based on the Chinese Type 033.

The Romeo enhanced some of these capabilities further and the KPN is using Chinese designs built between 1973 and 1995, but the oldest of these vessels is still over 40 years old.

40 Sang-O submarines: These are much smaller than the Romeo class, at just 300 tons. These are the largest submarines that North Korea is known to have put into domestic mass production. These are small ships, suitable for local patrols and domestic defense, but not for significant force projection. A boat of this type was captured by the South Koreans in the 1996 Gangneung submarine infiltration incident.

10 Yono-class submarines: These are midget subs, at 130 tons. They have a crew of two with 6-7 special forces onboard. A ship of this class is believed to have been involved in an October 2010 incident in which a South Korean corvette was destroyed by an unknown North Korean submarine.

In addition, North Korea is believed to have fielded a new submarine as recently as 2014. Little is known about this new, Sinpo-class design — it may be based on older vessels from Yugoslavia or incorporate technology from newer Russian vessels. South Korean sources suggested at one point that it could be built from old Golf II-class hulls that North Korea imported in the early 1990s, but this has not been confirmed. If rumors are true, it would be North Korea’s first ballistic missile submarine, though it lacks the ability to project force much outside of NK’s territorial waters.

As of this writing, the KPN has not requested outside assistance or aid with any rescue efforts. It could be some time before we know which submarine was lost and whether or not any survivors were rescued by the recovery crews.