OVERVIEW: The Chang Bogo-class submarine is a variant of the Type 209 diesel-electric attack submarine initially developed by Howaldtswerke-Deutsche Werft (HDW) of Germany, 

DETAILS: The South Korean Chang Bogo-class submarines, originally based on Type 209/1200, had reportedly been heavily upgraded from a time early in the 21st century, which if properly undertaken was supposed to include domestic hull stretch augmentation from 1,200 tons to 1,400 tons, and installment of domestically developed Torpedo Acoustic Counter Measures (TACM).

SOURCES:Wikipedia, the Free Encyclopedia. "Chang Bogo-class Submarine - Wikipedia." n.d. Accessed September 8, 2017. https://en.wikipedia.org/wiki/Chang_Bogo-class_submarine. 