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 PL and PM type patrol vessels became important and this has also been achieved. As a final measure, by equipping JCG ships with remote control turrets incorporating automatic tracking functions applied to the ship's machine cannon, precise shooting became possible.