Ballistic Missile Submarine (SSBN)

A ballistic missile submarine (hull symbol SSBN, colloquially a boomer) is a nuclear-powered boat carrying submarine-launched ballistic missiles, the most survivable leg of a nuclear triad because it can hide in the ocean’s vastness. Crews are often rotated as Blue and Gold to maximize patrol time, sustaining a continuous at-sea deterrent. The boat’s value is precisely that it is never found: detection by anti-submarine warfare is the principal threat to the deterrent it provides.