š Key Concepts
ā¢ IALA Buoyage System (Regions A and B) and which marks are the same in both regions
ā¢ Characteristics and purpose of a special mark (color, light, and especially its topmark)
ā¢ Differences between special mark topmarks and those used for isolated danger and safe water buoys
š Think About
ā¢ First, recall what a special mark is used for (e.g., military areas, cables, recreation zones). What distinctive shape or symbol is placed on top to show it is not a normal lateral or cardinal mark?
ā¢ Look at each option: one ball, two balls, diamond, and a yellow X shape. Which of these is associated with hazard or safe water, and which is associated with areas or features of special use?
ā¢ Ask yourself: in both Region A and Region B, does the special mark keep the same topmark, or does it change like the lateral marks do?
ā
Before You Answer
ā¢ Verify which symbol is the universal special mark topmark in IALA (same for Regions A and B).
ā¢ Eliminate the topmark you know belongs to an isolated danger mark (two black balls vertically) and the one for safe water buoys (a red-and-white vertical stripes with a specific topmark).
ā¢ Confirm that the correct choice matches the yellow-colored special mark used to mark areas such as spoil grounds, pipelines, or recreation zones.