8A4-class ROUV

The 8A4 class ROUV is a remotely operated underwater vehicle (ROUV), a Chinese ROUV used to perform various underwater tasks ranging from oil platform service to salvage and rescue missions. The 8A4 is a member of a series of related ROUVs developed in the People's Republic of China, with improved versions designed using earlier versions or commercially available versions as a starting point. The predecessor to the 8A4 is the RECON-IV, which is an improved version of the American RECON-III. The 8A4 is an improved version of the American AMETEK 2006. The 7B8 is an improved version of the 8A4.

Recon-IV Rouv
The origin of 8A4 traces back to the RECON-IV ROUV. Since the 1980s, 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 the 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 needs of the 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 the RECON-IV ROUV, which is based on the American RECON-III ROUV built by Perry Oceanographic (later purchased by Lockheed Martin) based in Riviera Beach, Florida. Based on the technology transfer, the Shenyang Institute of Automation of the Chinese Academy of Science and Perry Oceanographic jointly developed the RECON-IV ROUV, which was adopted by People's Liberation Army Navy for salvage and rescue operations. However, like earlier ROUVs, the 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 meets the special needs of military salvage and rescue operations that was not commercially available on the market, China organized a design team in the late 1980s including the 702nd Research Institute of China Shipbuilding Industry Corporation (CSIC), the Shipbuilding Engineering Institute of Harbin Engineering University (HEU), and the Institute of Underwater Engineering 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 the 8A4 ROUV. The goal was to develop an ROUV primarily used for military applications, while also capable of performing civilian tasks as the secondary mission.

To shorten the time needed, the decision was made to develop an ROUV based on existing technology by first selecting a system available on the market with performance closest to the requirements, and then improving the commercially available system based on the experienced gained from the RECON-IV ROUV developed earlier. The AMETEK 2006, an American ROUV used to support offshore oil drilling operations, was selected because it was the one that met the requirements 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 improvements were 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, the Huazhong University of Science and Technology (HUST), and eventually won 1st Place in the Scientific and Technological Advancement Award of the China Shipbuilding Industry Corporation in 1996.

The first 8A4 ROUV completed sea trials in 1993 and subsequently entered service. During its evaluation, the 8A4 ROUV successfully opened a submarine compartment constructed of special steel, a feat no other ROUV in Chinese inventory could achieve, and the 8A4 was thus dubbed as the most capable salvage and rescue ROUV in Chinese service. The 8A4 is capable of operating at a depth of up to 600 meters, with a cruising radius of up to 150 meters, and it was one of the first ROUVs in Chinese inventory to incorporate a Tether Management System (TMS). In 1996, the 8A4 ROUV won 3rd Place in the Scientific and Technological Advancement Award of the China Shipbuilding Industry Corporation. Despite the success and awards received, the 8A4 class ROUV is severely limited in its capability during actual deployment due to financial constraints. 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 half. It is not until the early 2010s during the scheduled overhaul would the TMS be planned to be reintroduced to all the 8A4 ROUVs to achieve their full capability.

7B8 ROUV
The 7B8 ROUV is a further development of the 8A4 ROUV, and it is a Chinese transition from ROUV to Autonomous underwater vehicle (AUV). Designed by the Shipbuilding Engineering Institute of Harbin Engineering University (HEU) based on the experience of the 8A4 ROUV with Mr. Deng Sanrui (邓三瑞) as the general designer, the 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 the 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.

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

Specifications:
 * Length: 4.33 meters
 * Width: 1.27 meters
 * Height: 1.76 meters
 * Weight: 1.69 tons
 * Operating depth: 100 meters (when operating as an AUV)