Layered Security

Layered security, or defense in depth, combines independent procedural, physical, and electronic controls so that defeating one does not compromise the ship or facility. ISPS does not name the term but builds the concept into the ship security plan: ISPS Code Part A Section 9.4 requires measures across access control, restricted areas, cargo and stores handling, monitoring, and security-level escalation. Layers include perimeter barriers, access checks, lookouts, lighting, CCTV, the ship security alert system, and citadel hardening against piracy under BMP5. Each layer adds detection or delay against an intruder.