The construction of a mothership for China's first deep-sea submersible has been completed at a shipyard in Zhejiang Province.

The submersible is capable of surveying more than 10,000 meters under water, the Shanghai Ocean University, which is leading a research project, said.

With 200-million-yuan (US$30 million) investment from private investors, the ship, Zhang Jian, named after an entrepreneur and educationist in modern China, is expected to be put into service in July.

"It is not only China's first dedicated hadal research ship, but also its first scientific research ship built with private investment," said Cui Weicheng, director of the university's center of hadal science and technology.

"With government investment, we may need more than 10 years to finish the construction (of the ship)."

Zhang Jian was completed in a year's time.

The research ship will go through trial voyages and equipment tests until June 30. It can hold 60 people and is equipped with devices for sea research, including three seabed landers, one manned submersible and one unmanned one, both of which can dive into more than 10,000 meters underwater.

The 4,800-ton ship will carry more than 10 researchers on its first official voyage to the 8,000-meter-deep New Britain Trench in Pacific Ocean in July and August. Its second trip will be in December to the world's deepest trench — Mariana Trench, where the lowest point is about 11,000 meters deep.