China’s newest nuclear-powered submarine sank earlier this year, US officials say

China’s newest nuclear-powered submarine sank pierside in the spring and the Chinese Navy tried to conceal the loss, according to two US defense officials.

The attack submarine was the first of its new Zhou-class line of vessels, the official said, under construction at a shipyard near the city of Wuhan. The Zhou-class submarines have a distinctive X-shaped stern, designed to improve maneuverability underwater.

A satellite image from March 10, taken by Maxar Technologies, shows the Zhou-class sub, with its signature x-shape tail, docked at the port. Additional Maxar imagery reviewed by CNN from later in June shows that the sub did not return to the pier.

“It’s not surprising that the PLA Navy would try to conceal the fact that their new first-in-class nuclear-powered attack submarine sank pierside,” said the senior US defense official.

The unusual activity at the shipyard was first noticed by Tom Shugart, an adjunct senior fellow at the Center for a New American Security who routinely studies satellite imagery of Chinese shipyards.

“I’ve never seen a bunch of cranes clustered around (one spot),” Shugart told CNN. “If you go back and look at historical imagery, you can see one crane, but not a bunch clustered there.” In looking at older satellite images of the same shipyard, Shugart also noticed the submarine’s larger size and its distinctive tail, indicating a new class of submarine.

“Usually, those submarines, after they get launched, they’re there at the shipyard for several months in outfitting. And it wasn’t there anymore,” Shugart said.

Beijing has made the modernization of the People’s Liberation Army (PLA) Navy and its submarine force one of its highest priorities as it seeks to build a world-class military on par with the United States. According to the latest China military power report from 2023, the PLA Navy operates six nuclear-powered ballistic missile submarines, six nuclear-powered attack submarines, and 48 diesel-powered attack submarines.

The US Navy has 53 fast attack submarines, 14 ballistic-missile submarines and four guided-missile submarines. The entire US submarine fleet is nuclear-powered.

The senior defense official said it is unclear whether nuclear fuel had already been loaded onto the submarine or if the vessel was unfueled when it sank.

The Wall Street Journal first reported news of the submarine’s sinking.

A spokesperson from the Chinese embassy in Washington, DC, said: “We are not familiar with the situation you mentioned and currently have no information to provide.”

China is also working on expanding its ability to produce new submarines. Even as the PLA Navy retires older submarines, China is expected to have 65 submarines in 2025 and 80 in 2035 because of the growth in its submarine construction capacity, according to the Congressional Research Service (CRS).

China has the world’s largest Navy by number of ships. The PLA Navy has 370 platforms, which includes 234 warships, according to CRS, while the US has 219 warships. The US has identified China as its long-term “pacing challenge.”

In a swipe at the Chinese industrial base, the defense official said, “The incident raises deeper questions about the PLA’s internal accountability and oversight of China’s defense industry—which has long been plagued by corruption.”