BEIJING -- An optical cable winch system applicable to all sea depths has completed its first deep-sea survey mission in the South China Sea, according to Science and Technology Daily on Tuesday.

During the survey, the cable length of the towing operation was more than 11,000 meters, and the operation depth reached more than 4,000 meters below the water surface. The stability and operation capability of the domestic deep-sea winch system were fully verified.

The safe working load of the winch was greater than or equal to 15 tonnes, said Li Wenhua, the project's chief scientist. With the maximum working water depth of 11,000 meters, the winch can conduct scientific research operations in the deepest of all seas, said Li.

Developed by the Dalian Maritime University and some machinery and sci-tech companies, this is the first set of whole-sea deep optical cable winch systems in China, said Li.

The winch will conduct regular deep-sea and polar survey operations in the future.

An optical cable winch system is used to deploy, recover, and tow large systems such as cable-controlled underwater robots. It is the basic configuration equipment for scientific research ships and is indispensable during deep-sea resource exploration and development.