China's manned submersible, Jiaolong, made its first dive in the Mariana Trench on Friday, as part of a bid to attempt the country's deepest-ever 7,000-meter manned dive.

The dive, which is the first of a series of six ones and began at 9 a.m. local time (2300 GMT Thursday), will try to reach the depth of 5,000 meters and last eight hours.

Three sea divers Ye Cong, Cui Weicheng and Yangbo are inside the submersible, whose first dive was delayed several days due to a tropical storm.

"It is the first dive Jiaolong took after its successful dive to 5,188 meters last July and the attempt is to test the submersible's functionality and performance at the depth of over 5,000 meters after its technical improvement in the past year," said Cui, who is also deputy on-scene commander.

"Much remains uncertain, especially for the first try. But we are well prepared. If everything goes well, we will go deeper," Cui said.

The on-scene dive headquarter is expected to have a press conference on the latest diving information.

Jiaolong, depending on local weather and sea conditions, will try another five dives, deeper and deeper, in the coming days. The fifth and sixth are scheduled to challenge the depth of 7,000 meters.

The six dives will test various functions and performances of the manned submersible at great depths. Each dive may last for eight to 12 hours.

Experts say, for safety, sea dives can only be conducted in daylight under no-more-than-four-class wind and no-more-than-three-class wave.

Xiangyanghong-09, the submersible's oceanographic mother ship, reached the designated dive zone on Monday morning.

(Xinhua News Agency June 15, 2012)