Sea Dragon class ROV

Sea Dragon (海龙) class remotely operated underwater vehicle is a class of Chinese ROV used to perform various underwater tasks ranging from oil platform service to salvage and rescue missions, and it is a class of ROUV developed in People's Republic of China with the deepest diving capability: up to 3,500 meters.

Background
Although numerous types of ROUVs have been developed in China in the 1980s and 1990s, these ROUVs are limited in that their maximum operating depth is restricted within 1,000 meters, which is not sufficient enough for deepwater explorations and other tasks. To meet the urgent need of a ROUV that is capable of deepwater operations, China decided to develop the Sea Dragon (海龙) class ROUV on its own since it was too costly and thus impractical to obtain foreign assistance on the international market.

The funding of the development of Sea Dragon class ROUV was provided by COMRA (中国大洋协会, short for China Ocean Mineral Resource Research and Development Association, 中国大洋矿产资源研究开发协会), and Institute of Underwater Engineering (水下工程研究所) of Shanghai Jiao Tong University (SHJTU) was named as the contractor. Mr. Ren Ping (任平), a professor at School of Naval Architecture, Ocean and Civil Engineering of SHJTU was named as the general designer. Other important design team members included Mr. Zhu Jimao (朱继懋), another SHJTU professor, who was the general designer of earlier Type 7103 DSRV and the general designer of earlier HR-01 ROUV.

Sea Dragon-1 ROUV
Sea Dragon-1 ROUV is equipped with half a dozen underwater cameras with one of them specifically for stationary objects, and half a dozen underwater lights for illumination. Additionally, there are two high-intensity discharge lamps for additional illumination, and a sonar is also present for additional search capability. A 125-horsepower propulsion powers four thrusters for horizontal movements and another pair of thrusters for vertical movements. There are two manipulators, one with 7 degree of freedom (DOF), and another of 5-DOF, capable of handling several hundred kilograms of weight, and able to perform a variety of tasks underwater.

The tether management system (TMS) weighs 2.5 tons, while the cable spool with steel cables weighs over 40 tons. To avoid the loss of ROUV in bad weather as in the case of Kaikō in 2003, a specially designed mechanism was incorporated to prevent such mishaps. On July 29, 2004, Sea Dragon-1 ROUV begun its final sea trials and after the completion, it subsequently entered Chinese service in the same year.

Sea Dragon-2 ROUV
Sea Dragon-2 ROUV is the successor of Sea Dragon-1 ROUV, developed by the same designer and also funded by COMRA, the funding provider of Sea Dragon-1 ROUV. During the deployment of Sea Dragon-1 ROUV, valuable information is obtained based on the feedback, and this info became the base for upgrading Sea Dragon-1 ROUV, which eventually became Sea Dragon-2 ROUV. From April 29, 2008 thru May 17, 2008, Sea Dragon-2 ROUV successfully completed its final sea trials in South China Sea under the leadership and supervision of Professor Zhu Jimao, and subsequently entered Chinese service.

The most obvious improvement that differentiates Sea Dragon-2 ROUV from Sea Dragon-1 ROUV is that Sea Dragon-2 is almost as twice fast as Sea Dragon-1 ROUV in reaching the maximum operating depth of 3,500 meters: it would only take less than 30 minutes for Sea Dragon-2 ROUV to achieve so, as opposed to nearly 50 minutes for Sea Dragon-1. Other physical characteristics and performance parameters remain the same as that of Sea Dragon-1, but reliability, maintainability and availability are improved for Sea Dragon-2, based on the feedback from the service of Sea Dragon-1. It's reported that due to such improvements, the planned series production of Sea Dragon class ROUV would be only consisted of Sea Dragon-2 ROUVs.

Specification
The following specification applies to Sea Dragon-1 ROUV. Specifications of Sea Dragon-1 ROUV and Sea Dragon-2 ROUV are similar except that Sea Dragon-2 ROUV can reach the maximum operating depth much faster than Sea Dragon-1 ROUV, while other differences are minor.
 * Length: > 3 meter
 * Width: 1.8 meter
 * Height: 1.8 meter
 * Weight: 3.25 ton
 * Speed: 3.5 kt (forward and back)
 * Sideway speed: 2.5 kt (left and right)
 * Ascending speed: 1.8 kt
 * Descending speed: 2.2 kt