China's independently-developed large amphibious aircraft AG600, codenamed Kunlong, slides on the water surface of a reservoir near Zhanghe Airport in Jingmen, Central China's Hubei province, Oct 20, 2018. (XINHUA)

China's second amphibious assault ship was launched in Shanghai on Wednesday, according to footage published on Chinese websites.

Video clips posted on Chinese news portals and military-themed websites showed the colossal vessel moving into the water and being towed by several tugboats to a nearby berth at Hudong-Zhonghua Shipbuilding, a major shipbuilder under China State Shipbuilding Corp.

Video clips posted on Chinese news portals and military-themed websites showed the colossal vessel moving into the water and being towed by several tugboats to a nearby berth at Hudong-Zhonghua Shipbuilding, a major shipbuilder under China State Shipbuilding Corp

The move indicated that construction of the second Type 075 amphibious assault ship, which is also regarded as a landing dock for helicopters, has basically finished.

The launch of the first Type 075 vessel, which is now berthed next to its sister ship, took place in September at Hudong-Zhonghua.

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In shipbuilding, launch refers to the process during which a nearly-finished ship is moved into water. It is one of the most important stages in a ship's construction because once a ship is launched, it means that its major structures have been put in place and that the major work of the construction project has been completed.

In the next phase, engineers will start outfitting and fine-tuning the vessel's equipment while conducting mooring tests and sea trials.

The People's Liberation Army Navy and China State Shipbuilding Corp have yet to publish information about Wednesday's launch, but weapons fans speculated it was a gift to mark the 71st anniversary of the founding of the PLA Navy, on Thursday.

The PLA Navy was founded on April 23, 1949, in Baimamiao township of Jiangsu province. In 1989, April 23 was designated as the Navy's foundation day.

Science and Technology Daily previously reported that the Type 075 is about 250 meters long, around 30 meters wide and will displace nearly 40,000 metric tons.

The United States, Britain, France, Spain, Italy and South Korea have also developed and built modern amphibious assault ships.

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Type 075 ships will extensively boost the PLA Navy's amphibious operational capability, according to Cui Yiliang, editor-in-chief of industry magazine Modern Ships.

The Navy now has Type 071 amphibious transport dock ships in operation, but they are capable of carrying only several helicopters－far from enough for massive amphibious landing operations, he explained.

"By comparison, the Type 075 will be able to carry many more helicopters and a stronger force of landing craft, allowing the Navy to execute low-altitude, over-the-horizon projection of a large quantity of troops."

With the new Type 075 ships, the Navy will be able to rapidly conduct large-scale landing operations, according to the editor.