ARLINGTON, Va. – China’s expanding submarine production and seabed-mapping challenge the U.S. undersea advantage that underpins both conventional operations and the nation’s deterrent, as Beijing is increasingly targeting areas around key American operating locations, according to Vice Adm. Chris Cavanaugh.
Cavanaugh, commander of U.S. Pacific Fleet Submarine Forces, said China has launched eight Shang-class submarines in less than four years and could produce 20 to 30 similar submarines over the next decade as Beijing expands its capabilities and industrial base.
“China is doing the engineering work and the industrial base development to narrow that gap significantly,” Cavanaugh said during the Naval Submarine League’s annual symposium here Thursday.
In terms of nuclear security implications, China is expanding both its attack and ballistic-missile submarine forces, while also developing the infrastructure and information needed to operate across the undersea domain. Cavanaugh said China is conducting seabed mapping and oceanographic collection around areas where the U.S. operates and maintains critical infrastructure.
A Reuters investigation cited by Cavanaugh traced Chinese seabed mapping activities involving dozens of vessels near Taiwan, the Philippines, Guam and Hawaii.
“The work takes place in areas where they assess that we operate,” Cavanaugh said. “It takes place in areas they assess we have infrastructure.”
For U.S. strategic forces, greater Chinese undersea surveillance could complicate efforts to maintain the secrecy and freedom of movement that have historically helped protect the nation’s ballistic-missile submarines and sustain a credible sea-based nuclear deterrent.
Cavanaugh said the proliferation of sensors, underwater gliders and uncrewed systems is challenging longstanding assumptions about U.S. access and freedom of movement. “The ocean is not becoming transparent,” he said, but the changes are placing a premium on persistent, distributed surveillance.
The U.S. Pacific submarine force conducted more than 100 uncrewed-system missions and logged more than 10,000 hours of integrated undersea surveillance in 2026, Cavanaugh said. He added the U.S. retains an undersea advantage based on its equipment, crews and operational experience, but warned that the advantage “is real, but it is not guaranteed.”
