China's been steadily upgrading its submarine fleet and weapons to detect those of the US should the two nations go to war.

In this handout photo taken in Jan. 2020 and provided by Nekton, a diver helps a crew member onboard “Limiting Factor” submarine, part of sea trials of the Nekton Mission begins in mid-March. A team ...

Inside the effort to deliver a ‘transformational improvement’ in how the US builds submarines, vital to preserving its undersea advantage.