In 1986, the ROK Navy reorganized its patrol forces into three fleets: the First Fleet, Second Fleet, and Third Fleet. The three numbered fleets, each is led by a rear admiral (upper half), are responsible for protecting the coastal water around South Korea: The First Fleet is for the eastern naval sector, the Second Fleet is for the western naval sector and the Third Fleet is for the southern naval sector including Jeju Island. Each fleet includes a Maritime Battle Group, Logistics Squadron, Base Squadron, and Training Squadron. The Maritime Battle Group comprises squadrons of patrol forces composed of "Kwanggaeto the Great"-class destroyers, "Daegu"-class and "Incheon-class" frigates, "Ulsan"-class frigates, "Pohang"-class corvettes, and patrol vessels ("Yoon Youngha-"class fast missile craft, "Chamsuri 211-"class fast rocket craft, "Chamsuri-"class fast patrol boats).