🔍 Key Concepts

• Defense readiness conditions (DEFCON) and National Security Zones that can affect aids to navigation and radio/navigation systems • Differences between visual navigation (piloting), radio/electronic navigation, and celestial navigation • How governments can control or degrade electronic signals for security while still allowing basic navigation methods

💭 Think About

• Ask yourself: Which type of navigation depends most on signals or systems that a government can turn off, scramble, or restrict for security reasons? • Consider which method relies on equipment that receives information from outside the vessel, and which methods mostly use information you already have onboard (charts, almanacs, sextant, visual landmarks). • Think about historical wartime or security situations: what has often been limited or intentionally degraded to prevent an enemy from using it?

✅ Before You Answer

• Identify which option(s) rely on externally controlled systems or signals (like satellites, shore stations, or transmitted radio signals). • Confirm which methods can still be practiced using only paper charts, publications, and natural bodies (sun, stars, planets) with no outside transmissions. • Before picking an answer, eliminate any method that the government cannot actually ‘turn off’ because it depends only on what you can see or calculate yourself.