Submersible's developers reveal winning formula

Coming off a recent epic expedition to the world's deepest location, the developers of China's new deep-sea manned submersible shared their reactions on the monumental underwater experience.

"It's incredible," said Zhang Wei, one of three pilots of the submersible Fendouzhe (Striver), describing his maiden trip to the Mariana Trench, the deepest natural frontier on Earth.

The vehicle completed 13 dives in October and November, eight of which exceeded a depth of 10,000 meters, including a national-record depth of 10,909 meters on Nov 10.

"The seafloor, where we landed, is actually very flat. There is such a thick layer of sediment that objects sink easily. I've also seen some marine life, such as sea cucumbers and a kind of gammarid species," Zhang said.

For veterans, however, the fact of reaching 10,000 meters is simply a difference of number.

"It means we have a five-digit number instead of four-digit," answered Ye Cong, 41, Fendouzhe's chief designer.

"It was not my first time aboard a deep-sea manned sub, after all. I was more relaxed than 10 years ago. My focus was more on the improvements of the vehicles' general performance," said Zhang.

He added that the 36-ton vehicle impressed him with more reliability and comfort than previous submersibles.

Fendouzhe was developed by the China Ship Scientific Research Center based in Wuxi, a modern manufacturing hub in East China's Jiangsu province.

The 800-million-yuan ($122.5 million) project was launched in 2016 as a vital part of the country's deep-sea technology and equipment blueprint plan for the 13th Five-Year Plan period (2016-20).

Being China's largest ship and ocean engineering research institute, the center is behind the success of all of the country's three deep-sea manned submersibles, including Jiaolong, Shenhai Yongshi (Deep Sea Warrior) and Fendouzhe.

Fendouzhe has shown significant improvements over its predecessors in almost every facet of the game, including descending and ascending speeds, material toughness and battery capacity. It is said to have reached a localization rate of 96.5 percent for its parts and components.