🔍 Key Concepts

• IALA cardinal buoyage system characteristics (North, South, East, West) • What parts of a buoy’s light characteristic can be changed to avoid confusion when two systems are close together • The difference between color, pattern, numbering, and light period as identifiers

💭 Think About

• If two separate cardinal systems are close together, what feature of the lights can be varied so mariners can tell which hazard a particular buoy belongs to, even at night? • Do cardinal buoys normally rely on color differences between nearby systems, or on differences in how the light behaves over time? • Which answer choices describe something that is actually standardized and fixed in the cardinal system, and which describe something that can be adjusted locally?

✅ Before You Answer

• Review how cardinal buoys are normally painted and top‑marked in the IALA system (these do NOT change between nearby systems). • Check which characteristic of a buoy’s light rhythm (flash pattern and timing) can be altered for different installations without breaking the basic cardinal meaning. • Verify whether numbering is a standard feature of cardinal marks, or more common with lateral marks.