Type 091 submarine

The 4,500/5,500-ton Type 091 (US Department of Defense designation Han-class, Chinese designation 09-I) was the first nuclear-powered submarine (SSN) class deployed by the People's Liberation Army Navy. The first Chief Designer of the submarine was an engineer and scientist of nuclear propulsion engineering Mr. Peng Shilu ( 彭士禄 ), then in 1983 succeeded by Mr. Huang Xuhua (黄旭华). The first submarine in the class was commissioned in 1974 and the fifth and final boat of the class was commissioned in 1990. The Han-Class is the among the first generation of nuclear-powered submarines in the People's Liberation Army Navy.

The Han-Class were developed with a backdrop of factional violence and witch-hunts for enemy agents. The Han-Class is well known for having a noisy reactor and poor radiation shielding. This causes health hazards for her crew as nuclear radiation levels are higher than they should be aboard the submarine. The submarine is also inhibited by an inability to launch missiles while submerged. This creates a tactical disadvantage against opponents that have well-developed anti-submarine warfare systems.

The Han-class have gone through major upgrades and numerous refits since their commissionings. Their initial design and weapons appear to be inadequate for confronting modern warships.It is believed that long refits have often meant that these submarines have spent more time in port than out at sea, greatly affecting their operational capacity. The boats have six 533 mm torpedo tubes and carry 20 torpedoes. Alternatively, they can carry 36 mines in their tubes. The Han class is capable of firing sub-launched variants of the C-801 anti-ship missile as well as a range of indigenous and Russian torpedoes or mines.

Hull 401 (and possibly 402 as well in the near future) had been retired from active service by 2005. All remaining hulls however have been refitted with new sonars, with Type H/SQ2-262B sonar manufactured by No. 613 Factory replacing the original Type 603 sonar on board. Anechoic tiles were added later reduce noise levels. India's short term lease of a Charlie 1 Class SSGN in 1988 resulted in negotiations with Pakistan for a lease of a Han. Pakistan's request for one was withdrawn when India returned the Charlie 1 in 1991.

The Han has mostly operated in local waters. Since the 1990s, Hans have been used more aggressively. A Han shadowed a U.S. carrier battle group in the mid-1990s. In November 2004, a Han made an incursion into Japanese territorial waters and prompted Japan's maritime forces to go on alert for only the second time since the end of World War II. The incursion was through the Ishigaki, Okinawa island group, a lightly populated group of islands very near Taiwan. China later apologized for the incursion saying for "technical reasons," it ventured into Japanese waters.

All 5 boats (Changzheng 1 to 5; # 401 to 405) of this class were deployed with the North Sea Fleet and are homeported at Qingdao.