851 (originally known as Dongdiao 232) is the electronic surveillance and missile tracking ship built by Shanghai-based Qiuxin Shipyard for the PLA Navy. The first and only hull was commissioned into the East Sea Fleet in 1999. The ship was observed collecting electronic intelligence (ELINT) off the coast of Japan during February 2000, shortly before several PLA Navy warships conducted an exercise in the East China Sea area.
The ship is armed with a manual dual-37mm AAA gun, two manual dual-25mm AAA guns, and a 3-cell 324mm torpedo launcher. A helicopter flight deck is located at the stern of the ship.
Originally there were two large radar dishes located on the deck, possibly for missile tracking purpose. Following a recent refit, these dishes were replaced by three large radomes housing unknown equipment.
