Navy’s new “sea flatbed” debuts: 711-type semi‑submersible Yinmahu (饮马湖船) conducts first night loading and semi‑submersion drills

New platform unveiled and tested

The People’s Navy (人民海军) has publicly unveiled its newest 711‑type semi‑submersible transport, the Yinmahu ship (饮马湖船), hull number 834, and it has been reported that the vessel has completed its first nighttime loading and semi‑submersion training since entering service. CCTV and Chinese media said the ship moved from familiar to unfamiliar waters within a day and, under both general and complex adverse border weather conditions, completed sequential transits, loading and diving‑up tasks to test precision delivery and multi‑domain sustainment in extreme environments.

Design tailored for heavy lift and precision handling

Unlike a submarine, a semi‑submersible does not fully submerge; it floods ballast tanks to lower the main deck to a preset depth so heavy boats, tanks or other equipment can be floated aboard. The Yinmahu reportedly has a main deck longer than 100 metres and a beam in excess of 30 metres. Designers adopted an aft‑castle (艉楼船型) layout — living quarters and propulsion concentrated at the stern to free the forward deck — and fitted dozens of keel ballast tanks with inlet/outlet valves plus a real‑time monitoring and control system to maintain longitudinal and transverse stability as draft changes dynamically during submersion and surfacing.

What this means strategically

A “sea flatbed” like Yinmahu can retrieve damaged warships for repair, rapidly deliver armored units, hovercraft or helicopters to distant islands, or act as a mid‑sea transfer platform between large transports and small landing craft. Why does that matter to Western readers? Because improved maritime sealift and offshore transfer capabilities directly enhance the People’s Navy’s operational reach for island logistics and amphibious operations—an increasingly sensitive factor amid regional disputes and heightened U.S.–China strategic competition. Observers note that nighttime, low‑visibility handling is a key test of command‑and‑control and seamanship; it has been reported that crews completed securing embarked vessels late at night to ensure stability before the ship steamed again, highlighting both the human and technical demands of this class.