Chinese team successfully tests saturation diving system

Chinese divers set a national record with a dive of 313.5 meters in the South China Sea using the saturation diving technique on Sunday.

The technique, which allows safe deep dives, has been developed to increase the country's capability to conduct offshore rescues.

Wang Zhenliang, director of the China Rescue and Salvage of the Ministry of Transport, told Xinhua News Agency on Sunday that development of the saturation diving system will help the country handle emergencies in offshore resources exploration quickly and effectively, especially on offshore oil drilling platforms.

Wang said most oil exploration in the South China Sea is less than 300 meters beneath sea level, which prompted the country to establish a saturation diving team to handle potential problems.

Saturation diving allows divers to work at great depths underwater for a long time while reducing the risk of decompression sickness. Saturation diving is commonly used in offshore exploration, rescues and construction.

In the four-day diving experiment that began on Thursday, six divers dived about 300 meters in the South China Sea on Sunday in two groups after more than two days living in a pressurized habitat, a living chamber, on the diving support vessel Shenqian.

On Sunday morning, the first three divers - Hu Jian, Guan Meng and Dong Meng - were deployed into the water in a closed diving bell, or a personnel transfer capsule, which is clamped to the accommodation transfer chamber.

The pressure in the capsule is adjusted to suit the ocean depth while the capsule is lowered, so that the pressure change can be slow without delaying operations.

The men wore diving suits that had hot water flowing inside to keep the divers' bodies at normal temperature under the sea.

The other three divers - Li Hongjian, Luo Xiaoming and Tan Hui - began another diving attempt later.

Two of them stayed about two hours under the sea, about 300 meters deep.

Shen Hao, director of the Shanghai Rescue and Salvage Center, told Xinhua the divers will stay in the living chamber until Jan 24, which is a long enough decompression process to let the inert gas in their tissues return to normal.

Without proper decompression, divers may suffer decompression sickness, more commonly known as "the bends" - a potentially fatal condition.

China is now working to develop saturation diving technology that can work at a depth of 500 meters, Wang said.

About nine countries in the world have conducted saturation dives at depths beyond 400 meters, China Central Television reported.

Humans were first found to be able to handle prolonged exposure to different breathing gases and high-pressure environments in 1957, through US scientist George F Bond's Genesis project.

In 1962, the US Navy's "Man-in-the-Sea" Program conducted the first saturation dive in the world.

In 1988, French divers reached a depth of 534 meters using the saturation diving technique.

(China Daily USA 01/13/2014 page6)