Visitors look at the model of the China's manned submersible Jiaolong at the 2019 China Marine Economy Expo in Shenzhen, south China's Guangdong Province, October 15. The expo, under the theme of "Sharing Blue Economy Opportunities, Building a Shared Future," opened here on Tuesday. It has attracted more than 450 companies and institutions to participate and is expected to present China's achievements in the marine economy and the latest progress in the global marine industry. Photo: Xinhua

The spherical shell of China's domestically manufactured deep-sea manned submersible has completed and passed inspection in a development that Chinese analysts said would aid China exploit resources and improve the nation's overall technological capability.

The homemade submersible is the world's largest and capable of carrying three people to depths of more than 10,000 meters.

The titanium alloy shell passed a simulation where the pressure matched that of 10,000 meters underwater, equivalent to that of a car on a fingernail.

"Although the spherical shell is thick, its shape also changes and shrinks under such pressure," said the chief designer Ye Cong. 

"Through the experiments, we have found that such deformation is elastic and this indicates the safety of the spherical shell," Ye said. 

Song Zhongping, a military expert and TV commentator, said that the titanium alloy material - resistant to pressure and corrosion - was a major technological highlight in the construction of the submersible. "Exploring the deep sea will boost the development of many subjects including marine geology, geography, deep-sea communication technology and biology," Song said.

The previous Chinese manned submersible Jiaolong is capable of diving to around 7,000 meters in the Mariana Trench. 

"Chinese people hope to dive to any deep point in any ocean worldwide, and we should explore and utilize the deep sea from the perspective of a shared destiny," Song said.

"We need to understand our planet and know more of the unknown parts under the sea," he said. "The US and other Western countries already explored the deep sea in the 20th century, and China also hopes to contribute to human technological advances."