🔍 Key Concepts
• Recall the IALA buoyage system shapes and meanings for lateral, cardinal, isolated danger, and safe water marks.
• Think about which buoy type indicates navigable water all around (center of channel, landfall mark) and what its topmark shape is.
• Compare the shapes in the figure with the standard safe water mark topmark, paying attention to whether it’s single or paired and whether it’s a ball or cones.
💭 Think About
• Which type of mark tells you that you are in or near the middle of safe water, rather than warning you to stay away from a danger?
• Look at each choice: which ones look like cardinal mark topmarks (used to indicate direction of safe water) and which one looks like something that might stand alone to mark safe water all around?
• Among the options, which topmark would be easiest to recognize at a distance as a single, distinctive shape associated with safe water buoys in IALA diagrams?
✅ Before You Answer
• Verify from your study materials what the standard IALA safe water mark looks like (color, pattern, and topmark shape).
• Double‑check which options in the illustration show cones versus spheres (balls).
• Before choosing, confirm that the topmark you pick is not used for cardinal marks (north, south, east, or west) or isolated danger marks.