Question 36 AB01 - Able Seafarer

The Correct Answer is C **Explanation for Option C (Correct):** Buoys and day beacons exhibiting a yellow triangle or a yellow square painted on them (often affixed to lateral marks) are used to specifically delineate the route of the Intracoastal Waterway (ICW). * **Yellow Triangle:** When displayed on a mark (usually a green lateral mark), it indicates that the ICW route is proceeding to the right (starboard side) of the vessel when heading generally south or west along the ICW route. * **Yellow Square:** When displayed on a mark (usually a red lateral mark), it indicates that the ICW route is proceeding to the left (port side) of the vessel when heading generally south or west along the ICW route. These distinctive yellow symbols are crucial at **locations where the ICW coincides with, crosses, or diverges from another navigable channel or waterway** (like a major inlet, river, or local channel). They help mariners differentiate the primary ICW route from the intersecting channel, especially where the lateral numbering systems of the two channels might conflict or cause confusion. **Explanation for Incorrect Options:** * **A) In minor harbors where the controlling depth is 10 feet (3 meters) or less:** The yellow triangle/square marking system is designed for route delineation on the major, federally maintained Intracoastal Waterway. Depth requirements do not dictate the use of these specific ICW symbols; they are functional symbols indicating route direction. * **B) Only at particularly hazardous turns of the channel:** While these marks are important for navigation, their primary purpose is route identification, not solely hazard warning (which is typically handled by conventional lateral or safe water marks). They are used continuously along the ICW, not just at hazardous turns. * **D) On isolated stretches of the ICW to mark undredged areas:** Undredged or potentially dangerous areas are typically marked using traditional lateral marks (red/green) or sometimes isolated danger marks, depending on the system in use. The yellow ICW symbols indicate the navigable channel route itself, not specific undredged areas outside the channel.