Upgraded Sang-O (Shark) class subs in service with North Korea

This is a working file for the recently revealed improved Sang-O class small submarines in service with North Korea.

Length: 39m (+5m vs original Sang-O)
Speed: X+10kph submerged

Armament: Likely 4 x 533mm (21") torpedo tubes

More info on DPRK small/midget subs:
http://covertshores.blogspot.com/2010/06/north-korean-small-submarines-file.html