QSZ class submersible

QSZ-II submersible is a type of diving equipment developed in the People's Republic of China, and in addition to being used as an ordinary Newtsuit type diving gear, it can also be used as a remotely operated underwater vehicle (ROUV), an application frequently practiced by one of the users of QSZ-II submersible, the People's Liberation Army Navy (PLAN). QSZ-II submersible is developed by the 702nd Research Institute (中国船舶重工集团公司第702研究所) of China Shipbuilding Industry Corporation (CSIC).

Type I diving bell
The origin of the QSZ-II dates back in 1970s, when the requirement was first issued, but it was too ambitious for the Chinese industrial capability back then to achieve. Due to the political turmoil in China, namely, the Cultural Revolution, work did not begin until 1980. When work finally begun, Chinese designers took a much more practical approach by proceed in several stages, realizing the limitation of the backward Chinese industrial capability. Type-I diving bell was the very first stage of the approach.

Type I diving bell, short for Type I rescue diving bell (Yi-xing Jiu-sheng Zhong, I型救生钟), is used mainly for submarine rescue, and it is also capable of being used to carryout some underwater work. For rescue operations, it is primarily used for wet rescue, but when the sea state is calm and the submarine at the bottom of the ocean is not tilted too much, Type I diving bell can be used for dry rescue operation as well by docking and mating with bottomed submarine.

Due to the effects of political turmoil, the development of Type I diving bell is protracted as the Chinese industrial capability had to take time to recover. Type I diving bell was first completed in 1985, but it was not five years later after further extensive trials and civilian service, did it finally enter the service with PLAN. Type I diving bell is capable of performing its designed functions at a depth of 130 meters and up to 8 (usually 6) submariners can be rescued at each dive.

QSZ-I ADS
Experience gained in the development of the Type I diving bell had greatly helped the development of QSZ-I, and this planned second stage of development began even before the completion of the Type I diving bell. Development of QSZ-I atmospheric diving suit (ADS) took four years, from 1982 to 1986, and unlike its predecessor Type I diving bell that had to go through half a decade of civilian use to prove its worth, QSZ-1 ADS was immediately pressed into service in 1987 after its completion. QSZ-I has a tether management system (TMS). Specifications:
 * Length: 2.08 meter
 * Width: 1.3 meter
 * Height: 1.5 meter
 * Weight: 609 kg
 * Maximum depth: 300 meters

QSZ-II submersible
QSZ-II submersible is the development of QSZ-I ADS. There are three major upgrades over the original QSZ-I. The first upgrade is the addition of four propellers and additional sensors such as underwater television, and this enables the diver to operate to an extended range with radius up to 50 meters. The control system and computerization is consequently upgraded to enable to diver to move more agilely and easily with these newly added equipment. The third upgrade is that in addition to being used as an ordinary Newtsuit type diving gear, it can also be used as a remotely operated underwater vehicle (ROUV), a favorite practice of PLAN. The maximum operational depth of QSZ-II submersible is identical to its predecessor QSZ-I ADS, at 300 meters. The general designer of QSZ-II submersible is Mr. Xu Huangnan (徐芑南), a professor at Shanghai Jiao Tong University, who is also the future deputy general designer of Explorer AUV, and the future general designer of other Chinese unmanned underwater vehicles including Sea Dragon class ROUV, and CR class AUV.

Mobile diving bell
Mobile diving bell (Yi-dong-shi Jiu-Sheng-Zhong, 移动式救生钟) is the latest development of QSZ series, and it is an upgrade of Type I diving bell utilizing the experience gained from QSZ-II submersible. The skirt of the mobile diving bell is greatly modified so that it can dock and mate with the submarine hatch when the submarine is tilted at a greater angle. The addition of propulsion system enables the mobile diving bell to perform rescue mission in fast flowing ocean currents and it can perform both wet rescue and dry rescue. Tests of mobile diving bell completed in Qingdao and it subsequently entered service with PLAN. Specifications:
 * Diameter: 3 meters
 * Height: 4.2 meters
 * Weight: 10.5 ton
 * Maximum operating depth: 200 meters
 * Maximum number of rescues at each dive: 10