🔍 Key Concepts

• IALA Maritime Buoyage System (safe water mark characteristics) • Differences between shapes, colors, and topmarks used for lateral, cardinal, isolated danger, and safe water marks • Purpose of retroreflective material on aids to navigation at night

💭 Think About

• Think about what makes a safe water mark distinct from other buoys: how is it shown on charts and how does it look in reality? • Which option describes something that would be clearly visible at night when illuminated by a vessel’s searchlight? • Among the choices, which feature is specifically associated with safe water marks in the IALA system, rather than with general buoy numbering or shapes used for other marks?

✅ Before You Answer

• Review the standard colors and patterns of safe water marks (daymark appearance). • Check which topmark shape is used for safe water marks in the IALA system. • Confirm which feature would most directly help identification at night using a vessel’s lights.