8A4-class ROUV

8A4 class remotely operated underwater vehicle (ROUV) is a class of Chinese ROUV used to perform various underwater tasks ranging from oil platform service to salvage and rescue missions, and it is a member of a series of related ROUVs developed in People's Republic of China. Original order included two units, and it is rumored (yet to be confirmed) that more follow-on units were also ordered after the delivery of the original order.

RECON-IV ROUV

The origin of 8A4 traces back to RECON-IV ROUV. Since the 1980’s, China begun to operate ROUVs to support its offshore oil drill operations and salvage operations, such as Hysub 10 ROUVs and Hysub 40 ROUVs supplied by Canadian firm International Submarine Engineering in British Columbia. Hysub 40 ROUVs was deployed by Shanghai Salvage Bureau and proved its worth not only in oil drilling operations, but also in salvage and rescue missions. However, these foreign built ROUVs were simply too expensive to be adopted in significant numbers, and the salvage operational need of People's Liberation Army Navy (PLAN) could not be met. As a result, China decided to develop its own version of ROUVs with similar capability.

One of the first ROUVs domestically built in China was RECON-IV ROUV, which is based on American RECON-III ROUV built by Perry Oceanographic (later purchased by Lockheed Martin) based in Riviera Beach, Florida. Based on the technology transfer, Shenyang Institute of Automation(沈阳自动化所) of Chinese Academy of Science and Perry Oceanographic jointly developed RECON-IV ROUV, which was adopted by PLAN for salvage and rescue operations. However, like earlier ROUVs, RECON-IV is primarily designed for civilian operations and had its limitations in performing certain military operations, such as cutting through specialized steel used to build certain compartments of submarines that were stranded, and opening some valves on sinking vessels, thus a more capable follow-up was needed.

8A4 ROUV

To develop a ROUV that meet the special need of military salvage and rescue operations that was not commercially available on the market, China organized a design team in the late 1980’s including the 702nd Research Institute of China Shipbuilding Industry Corporation (CSIC), Shipbuilding Engineering Institute(船舶工程学院) of Harbin Engineering University (HEU), and Institute of Underwater Engineering(水下工程研究所) of Shanghai Jiao Tong University (SHJTU), with a professor of SHJTU, Mr. Xu Huangnan (徐芑南), and the future deputy general designer of Explorer AUV, and the future general designer of other Chinese unmanned underwater vehicles including Sea Dragon class ROUV, CR class AUV, and SJT class ROUV, was named as the general designer of 8A4 ROUV. The goal was to develop a ROUV that is primarily used for military applications, while also capable of performing civilian tasks as the secondary mission.

To shorten the time needed, decision was made to develop a ROUV based on existing technology by first selecting a system available o the market with performance closest to the requirement, and then improving the commercially available system based on the experienced gained from RECON-IV ROUV developed earlier. AMETEK 2006, an American ROUV used to support offshore oil drilling operations, was selected because it was the one that met the requirement best, while also being the one China could purchase on the international market at the time. However, despite meeting Chinese requirements better than all of the rest available systems, it was far from getting close, so extensive improvement was needed. One of the major upgrades needed was the complete redesign and incorporation of two manipulators that were required to operate around half a dozen tools underwater. These manipulators were completed by the main subcontractor, Huazhong University of Science and Technology (HUST), and eventually won the 1st Place in CSIC Scientific and Technological Advancement Award in 1996.

The first 8A4 ROUV completed in the sea trials in 1993 and subsequently entered service. During its evaluation in trials, 84A ROUV successfully opened the submarine compartment constructed of special steel, a feat no other ROUV in Chinese inventory could achieve, and 8A4 was thus dubbed as the most capable salvage and rescue ROUV in Chinese service. 8A4 is capable of operating a depth up to 600 meters, with cruising radius up to 150 meters, and it was one of the first ROUV in Chinese inventory to incorporate a tether management system (TMS). In 1996, 8A4 ROUV won a 3rd Place in CSIC Scientific and Technological Advancement Award. Despite the success and awards received, 8A4 class ROUV is severely limited in its capability during actual deployment due to financial constraint: with the exception of the very first unit, all of the remaining 8A4 ROUVs have their TMS deleted due to the budget cuts, resulting in significant reduction in performance. For example, the maximum operational depth is reduced by more than a half. It would not be until the early 2010’s during the scheduled overhaul would the TMS be planned to be reintroduced to all 8A4 ROUVs to achieve their full capability.

7B8 ROUV

7B8 ROUV is a further development of 8A4 ROUV, and it is a Chinese transition from ROUV to Autonomous underwater vehicle (AUVs). Designed by Shipbuilding Engineering Institute(船舶工程学院) of Harbin Engineering University (HEU) based on the experience of 8A4 ROUV with Mr. Deng Sanrui (邓三瑞) as the general designer, 7B8 ROUV was first revealed to the Chinese public in Beijing during the National Science and Technology Exhibition of the People's Liberation Army at Military Museum of the Chinese People's Revolution in 1995 while still under development, and members of the Central Military Commission headed by General Liu Huaqing was among those special guests.

7B8 ROUV is unique in that in comparison to other Chinese ROUVs, it can also operate independently as an AUVs in addition of being able to operated remotely via tether/cable like an ordinary ROUVs. 7B8 first completed its trials as a ROUV in the 1990’s and in 2000, it completed AUV trials including autonomously searching underwater targets and autonomous underwater work, and subsequently entered service. When 7B8 is operated as an AUV, the maximum operating depth is less than when operating as a ROUV. Specifications:

Length: 4.33 meter
Width: 1.27 meter
Height: 1.76 meter
Weight: 1.69 ton
Operating depth: 100 meter (when operating as an AUV)

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