China's second manned submersible, an underwater vehicle capable of descending to depths of 4,500 meters, begun testing at China Ship Scientific Research Center, a China Shipbuilding Industry Corporation affiliate in Wuxi, East China's Jiangsu province, on May 28.

The live coverage from CCTV shows the submersible lowering into a basin for test operations in Wuxi, on May 28. [Photo provided to wuxinews.com.cn]

Unlike Jiaolong, an earlier model capable of diving to 6,699 meters, the still unnamed submersible made its debut at a test basin for system debugging and regulation training.

According to Hu Zhen, chief designer of the 20-ton submersible, with 8 meters in length and 3.5 meters in height, it has a similar size to Jiaolong and can accommodate three people at a time.

Though inferior to Jiaolong in terms of maximum diving capacity, it has received a number of important improvements including the installment of a more efficient lithium battery, an innovative Ti80 titanium alloy frame, and two more windows which offer those inside the cabin better sightlines.