Okinawa Special units The JCG maintains three national-level elite units for each specialized fields: . Rescue swimmers and public safety diving team. Regional counterparts are . Offshore oil spill and chemical hazard response team. The Japanese counterpart of the National Strike Force (NSF) of the USCG. Counter-terrorism tactical team. Regional counterparts are . Ranks Equipment Vessels Immediately after its creation, the MSA operated the second-hand ships of the former Japanese Navy, but it was only allowed to use smaller and slower vessels. The designations of PL, PM, PS and PC were used to classify ships as being: Patrol Ship – Large, Medium, Small and "Craft" = very small. From FY1949 the construction of new ships began. Because GHQ instructed the service to model its ships after those of the USCG, the 700-ton PL Daiou-class was based on Cactus-class buoy tenders, the 450-ton PM Awaji-class patrol vessel was based on Thetis-class patrol boats, the 270-ton PS Kuma-class patrol vessel was based on Active-class patrol boats, and the 23-meter PC Hatsunami-class patrol craft used a USCG 75-foot patrol boat as a model. However, these copies of American ship types were found wanting as they neither suited the actual operational work of the MSA nor the sea conditions around Japan. As a result, when the Treaty of San Francisco came into force, MSA's own patrol ship's design work began. The PL type patrol vessels increased in size to the 900-ton Nojima-class patrol vessel, PS type patrol vessels differentiated into the 350-ton PS Tokachi-class patrol vessel and the 130-ton PS Hidaka-class patrol vessel. Later, the 350-ton class PS's were reclassified as PM type. In the late 1970s, it was clear that the new international rules on national exclusive economic zones would demand a considerable increase in the size of the Maritime Safety Agency fleets. To cope with this dramatic increase in workload, the 1,000-ton PL Shiretoko-class patrol vessels, 500-ton PM Teshio-class patrol vessels and 30-meter PC Murakumo-class patrol craft were built in large quantities. In addition, the Japan MSA also began protecting shipping operations by deploying air-sea rescue helicopters on-board PLHs. Since the 1980s, criminal ships had advanced into Japan's ocean spaces and were showing high speeds, also North Korean armed trawlers (fushin-sen) began to appear. For this reason, the MSA designed and built the 180-ton PS Mihashi-class patrol vessels that combined both ocean-going capability and high-speed performance. In addition, upping the speed of