Everything You Need to Know: North Korea's Submarine Fleet

I can describe it in one word, Junk. Romeos and Whiskeys were junk prior to the Soviet collapse and North Korea has no idea how to maintain them. The problem with North Korea is Soul. In any type of military confrontation hundreds of thousand of people are going to die in South Korea before we can flatten the north. We can flatten them in short order but in those few minutes or hours they will rain down hell on Soul. It will be the worse catastrophe in mankind's history. Diplomacy is the only option.

North Korea's armed forces aren't the problem. They won't defeat anyone. They are capable of inflicting significant hurt on some poor civilian population but never defeat anyone militarily. The real problem is that North Korea's Fat Boy gets to threaten anyone and everyone while standing under the protective umbrella of Japan.

Diesel boats on the battery are supremely quiet and very hard to track, so they always pose a threat.