Undersea infrastructure and peacetime shadowing

Undersea communications infrastructure creates a less visible struggle than surface transits through contested waters. States and commercial actors may seek to tap networks, monitor traffic, or gather information from systems on the seabed. A defending navy may put its own submarine in the way or use a frigate's sonar to make surveillance unmistakable. These encounters are contests of intelligence and positioning rather than declared battles, yet they still demand ships and crews able to operate close to a rival. Maritime security therefore includes protecting infrastructure that most people never see.