On February 15, after 18 days' blue water training, the PLA Navy North Sea Fleet's pelagic training formation parked a naval port in Qingdao. Since departured from Qingdao on January 29, the formation sailed through Yellow Sea, East China Sea, Miyako strait to western pacific, from Bashi Channel to South China Sea, then across Bashi Channel again, and finally returned through Miyako Strait after trained in the western Pacific. During the 18 days, the formation sailed more than 5800 nm and experienced complex weather and navigation conditions such as thick fog, reef island area, waves and so on.