(ZHANG YONGFENG)

Research vessel Dayang Yihao departs from Sanya on south China's island province of Hainan on December 2, making the country's 30th oceanic exploration mission.

The voyage, which will last 180 days and cover 19,000 nautical miles, will take the vessel across the Indian Ocean. A total of 339 people are on board, including 254 scientists and engineers.

Among the experiments, scientists will test a remotely operated underwater vehicle on a series of oceanic surveys mainly on polymetallic sulphide and bioresources.