In 1992 the world undersea-research community was surprised by the news that the People’s Republic of China intended to build various types of submersibles, platforms, and the supporting infrastructure to do deep-ocean exploration for resources.
The optimistic government press releases became reality, however, with the development of the Harmony 7000 manned submersible in 2002. She was designed, built, and tested by the China Ship Scientific Research Center at Wuxi. By the time she began diving trials in 2009, she was called the Harmony; one year later she had acquired a more appropriate name, the Jiaolong (Sea Dragon).
Capable of diving to a depth of 23,000 feet, she became the world’s deepest-diving manned submersible. Previously, Japan’s Shinkai 6500 had held the record at 21,325 feet.
The U.S. Navy’s 20,000-foot capability ended when its manned submersible Sea Cliff was retired in 1998. Today the deepest U.S. diving capability is the Woods Hole Oceanographic Institution’s Alvin, which can dive to 14,700 feet. The Alvin is being upgraded over time to have a 21,325-foot depth capability.
Note that the depth capability of all these submersibles is clustered around 20,000 feet. The reason is that 98 percent of the World Ocean seafloor is at or less than 20,000 feet. Even though maximum ocean depth is about 36,000 feet, the depths beyond 20,000 feet represent only 2 percent of the seafloor. This is the “hadal zone,” and that 2 percent is important as it represents all 37 deep-sea trenches. The zone is about the size of the surface area of the United States, Alaska, Hawaii, and perhaps half of Mexico. New deep-diving systems are needed to do productive research work in the great trench depths.
China’s Shanghai Ocean University recognized this need and established the Hadal Science and Technology Research Center (HAST). It has launched an ambitious program to develop a multi-vehicle deep-diving exploration system consisting of a dedicated mother ship; three full-ocean-depth “landers” (vertical probes for imagery, data, and sample collecting); a hybrid autonomous and remotely operated vehicle (ARV), the Rainbowfish ARV; and a human-occupied vehicle (HOV), the Rainbowfish HOV. All are designed to operate down to the full ocean depth of 36,000 feet. Professor Weicheng Cui, dean of HAST, is program manager (he previously oversaw the Jiaolong project).
The 4,800-ton mother ship Zhang Jian became operational in July 2016. One of the three landers was sea-tested to 13,000 feet, and the Rainbowfish ARV was tested to 7,000 feet, in October 2015. Full-ocean-depth tests in the Challenger Deep (the deepest point in Earth’s seafloor) are to be conducted in January 2017.
A primary mission of the ARV is to permit HAST to test various components that will be used in the Rainbowfish HOV. The ARV will have the same hydrodynamic shape as the manned vehicle, and many of its components will be the same material and design as those on board the HOV. Like the HOV, the ARV is fully powered by on-board lithium ion batteries. About 95 percent of the vehicles’ components will be manufactured in China.
Construction of the manned submersible is slated for completion by 2019, with sea trials to follow. She should be fully operational by 2020.
There are two unique features of this developmental program. First, it is a system of deep-diving platforms living together on board a built-for-the-purpose mother ship. HAST calls this its “movable laboratory.” It offers a great deal of flexibility and enhanced safety as the team of landers, ARV, and HOV can operate together and assist each other at the seafloor. Using this multi-vehicle approach will increase at-sea productivity greatly.
The second feature is equally remarkable. The program is supported by a flexible combination of public and private funding. This is probably a first in China, where normally the national government plans and funds all such major programs. The resulting bureaucracy can be extremely difficult. In this case, both the national and Shanghai regional governments are investors along with the privately held Shanghai Rainbowfish Ocean Technology Ltd. (hence the rather unusual names of the ARV and HOV submersibles).
Soon, the dragon will be diving deeper—with what promises to be a very productive suite of submersibles.