On November 10th there was a brief clash between North and South Korean gunboats off the west coast. The result was a humiliating defeat for the north. The main reason for this was the quality of the weapons on each side. The South Korea ship was a 150 ton patrol boat, armed 40mm and 20mm autocannon, and a computerized fire control system. The North Korean vessel was a 131 ton patrol boat with 37mm and 25mm cannon, and no computers. The South Korean ship was able to quickly put accurate fire on the North Korea ship, even though there were in rough seas (2 meter/six foot waves) and the ships were 3,200 meters (two miles) apart. The North Korean gunboat was using 1960s technology, and their guns were firing manually. While the South Korean boat was hit by fifteen shells, the North Korean boat was hit by many more, and was burning as it limped back across the NLL (Northern Limit Line). Apparently at least three North Korean sailors were killed, and several more wounded.
Moving the maritime border, the NLL (Northern Limit Line), south, has been a North Korean goal for decades. The reason is the lucrative crab fishing grounds off the west coast. North Korea currently makes $100 million from crabs taken north of the NLL. Only military families (mostly from the navy) are allowed to take crabs, and the crab catch is a major part of the income of these loyal officers. North Korea wants more crab fishing grounds, to make more of its naval officers happy. Thus, every few years, North Korean patrol boats cross the NLL, get shot up by superior South Korean warships, and honor is satisfied. The northerners also believe the waters south of the NLL contain oil deposits as well, but this appears to be mostly rumor.
The crabs are real, and so is the combat superiority of the southern naval and air forces. Although North Korea about 400 ships in its navy, compared to 120 in the South Korean Navy, most of the North Korean vessels are old and small (like the patrol boat shot up on the 10th). South Korea has more larger ships (ten that are over 1,000 tons, compared to three for North Korea) and much better weapons and equipment.