On October 7, 2021, we learned that one of the U.S. Navy's prized Seawolf class nuclear fast attack submarines — one of just three ever built — had suffered a serious underwater collision. Credit: US Navy photo.

Did nuclear-powered attack submarine USS Connecticut (SSN-22) hit an uncharted underwater massif while patrolling in the South China Sea on October 2?

That is what US Navy investigators concluded early this week, but not everyone is buying into that story— in particular, Chinese state media outlet, The Global Times.

Other questions are also being asked: Did the collision result in a nuclear leakage that the US is trying to conceal? And what were they doing there in the first place.

A Beijing-based think tank said last week it had satellite evidence showing that US spy planes, including a “nuke sniffer,” recently flew over the South China Sea, according to the South China Morning Post.

Experts told the SCMP that the aircraft were likely establishing whether there was any nuclear fallout from the collision.

Meanwhile, US military authorities are holding their cards close.

“The investigation determined USS Connecticut grounded on an uncharted seamount while operating in international waters in the Indo-Pacific region,” Cdr. Haley Sims, a 7th Fleet spokesperson, told Insider.

“Commander, US 7th Fleet will determine whether follow-on actions, including accountability, are appropriate.”

The damage to the forward section of the Seawolf class submarine damaged its ballast tanks and prompted Connecticut to make a week-long voyage on the surface to Guam.

The Navy has said repeatedly that the submarine’s nuclear reactor and propulsion system are undamaged.

The collision caused a small number of moderate and minor injuries to the crew.

USNI News, which was first to report that the sub had struck a seamount, said damage to the forward section of the submarine damaged its ballast tanks.

The incident happened on Oct. 2 but was not reported by the Navy until five days later.

Submerged objects, such as mines, wrecks, and other submarines are plainly visible to a trained sonar operator. Credit: US Navy photo.

The vessel made its way to Guam for a damage assessment, where it is undergoing initial repairs overseen by Naval Sea Systems Command, personnel from the Puget Sound Naval Shipyard and submarine tender USS Emory S. Land.

According to Forbes, at a minimum, the USS Connecticut will be out of service for years, and there is a creeping realization that the damage may be significant enough to force its premature retirement. 

China claims the South China Sea as its own, and objects to other nations sailing military craft in that region.

The US rejects Chinese claims to the waters, and makes a point of sailing there in so-called freedom of navigation missions, as do other Western nations, often angering Beijing.

The presence of a US Navy submarine in the South China Sea represents an aggression to Beijing, and Chinese state media were quick to attack the official US narrative.

On Tuesday, Global Times published claims from Chinese military experts who said the collision may have resulted in nuclear leakage that the US is trying to conceal.

“A nuclear leakage could have taken place, and a recent flight of a US nuclear material detection aircraft to the South China Sea shows the US understands the possibility,” the Global Times wrote. 

Zhang Junshe, a senior research fellow at the Naval Research Academy of China’s People’s Liberation Army, told the Global Times the US justification for the collision “lack sincerity, transparency and professionalism.”

Other outlets also cast doubt on the US version of events.

“Covering up the truth is a tradition of the US military,” the People’s Daily newspaper wrote Monday, referring to the collision as an “accident.”

The newspaper previously referred to the crash as an “example of the superpower’s reckless military presence.”

After the Navy first reported the collision on October 7, five days after it happened, Chinese officials accused the US of a cover-up.

Zhao Lijian, the Chinese Ministry of Foreign Affairs spokesman, said on on October 26 that the US was “irresponsible” and “cagey.”

The Seawolf-class fast-attack submarine USS Connecticut (SSN 22) departs Puget Sound Naval Shipyard for sea trials following a maintenance availability. (U.S. Navy photo by Thiep Van Nguyen II)

Zhao added that China had “every reason to question the truth and the intention of the US.”

“What was USS Connecticut up to do secretively in the South China Sea this time? What did it collide with? Why did that collision happen?” he said.

“Was there a nuclear leak that creates nuclear contamination in the marine environment?”

Many have expressed their utter puzzlement to us as to how a multi-billion dollar nuclear submarine that is laden with some of the most capable sensors on the planet — literally one of the most advanced vehicles mankind has ever built — can just run into something below the waves. 

Meanwhile, the damage and subsequent repairs to the attack submarine have caused renewed attention on the Navy’s attack submarine maintenance backlog.

“If we ended up doing [the Connecticut work] in one of the public shipyards, that would certainly cause perturbations in all the other work in the shipyards,” Jay Stefany, acting assistant secretary of the Navy for research, development and acquisition, told the House Armed Services Committee readiness subcommittee.

“Right now, it’s in Guam, that’s public record, there is no dry dock in Guam, hopefully, a sub tender can do the work, but that remains to be seen,” he said.

“It just shows how … the world gets a vote and things change and unexpected incidents create more demand for repairs. … The attack subs have always been the poor cousin in the public shipyards in terms of getting priority, but we know particularly a Seawolf-class submarine is extremely valuable in terms of the mission in that part of the world.”

Connecticut is one of three Sea Wolf-class attack nuclear boats that were developed for deep-water operations to take on Soviet submarines in the open ocean.

Since the end of the Cold War, the trio has been upgraded and modified to carry out some of the Navy’s most sensitive missions.

The complicated topography of the South China Sea that submarines of all nations, including the US and China, must navigate. Credit: NASA.

Many have expressed their utter puzzlement to us as to how a multi-billion dollar nuclear submarine that is laden with some of the most capable sensors on the planet — literally one of the most advanced vehicles mankind has ever built — can just run into something below the waves. 

According to experts, highly accurate charts are always the first choice. Active sonar transmissions are used to confirm the water depth checks with the chart.

These active sonar pulses can be transmitted in front and to the sides of modern submarines. These short-range, high-frequency sonar systems reveal nearby underwater objects with great clarity.

Submerged objects, such as mines, wrecks, and other submarines are plainly visible to a trained sonar operator. 

The downside to the use of active sonar is that it is detectable and at approximately two times the range it allows the operator to search, in most ocean environments.

A typical high-frequency, high-resolution sonar may see out to 5,000 yards and is vulnerable to detection out to least 10,000 yards or farther in good conditions.

This means an adversary can localize a submarine’s position, and it can remain undetected while trailing the active-sonar emitting submarine for as long as it uses its high-resolution sonar.

If a submarine is operating in an area where they suspect the presence of adversary submarines, they may choose to not use high-frequency active sonar to verify surrounding topography.

This, as described earlier, is because the sonar transmissions will give away their position if detected. This means the submarine relies on accelerometer dead-reckoning for the ship’s position.  

This type of navigation has very small errors that compound over time. Eventually, the submarine can be out of position by hundreds of yards or more. The error grows with time until the next navigational fix.

There are ways to fix the submarine’s position that doesn’t involve sonar, but they don’t reveal what topography is hidden between soundings on a chart.

Sources: Insider, The Global Times, South China Morning Post, USNI News, People’s Daily, US Department of Defense, The Drive, Forbes