OR so says the Chosun Ilbo:
South Korean patrol boats and corvettes are able to detect a mere 30 percent of submarines at a time when North Korea is increasing the frequency of submarine infiltration drills.
The article continues in typical Korean fashion; many statistics with little background. The problem with so many of the Korean numbers is there is no real basis or understanding the measurement. What is an “exercise?” Are they counting individual subs or days? For instance, if you have two subs out for two days, is it 2 exercises (2x subs), 4 exercises (2x subs x2 days) or what.
There is also a bit of intel “I’m telling you now so you can’t blame me latter” going on here:
This year’s submarine exercises in the West Sea were reportedly concentrated between June and August. “There’s a likelihood that the North will seek a chance for provocation as a lot of North Korean and Chinese fishing boats are busy in the West Sea during the blue crab harvest season” that began in early September, Shin said.
Take a look at the geography and oceanography of the Northwest Islands some time. Makes for a very interesting Harpoon scenario!
The definition of a midget submarine is also interesting. The NorKs have apparently been developing semi-submersible craft with torpedoes. This is part of the detection challenge the article alludes to.