Question 45 AB01 - Able Seafarer

The Correct Answer is B **Explanation for Option B (Red triangle):** In the United States Aids to Navigation System (Lateral System, often referred to as the IALA Region B system), the convention for marking a channel when entering from sea follows the rule "Red Right Returning." This means: * **The starboard (right) side of the channel** when returning (entering from sea) is marked by **red buoys and marks**. * **Preferred shape for non-lateral regulatory markers:** While buoys are typically cylindrical or nun-shaped, fixed daymarks marking the starboard side are characterized by a **red color and a triangular shape**. The triangle points toward the navigable water. Therefore, a **Red triangle** is the standard daymark used to mark the starboard side of the channel when entering from sea. **Explanation of Incorrect Options:** **A) Red and white octagon:** This description typically refers to a non-lateral regulatory marker, specifically a **"Stop" or "Restricted Operation"** marker (like a stop sign) that indicates an exclusion or hazard, not a lateral channel boundary. **C) Black and white diamond:** The black and white diamond is a standard non-lateral regulatory marker used to indicate **Hazards** (rocks, shoals, submerged objects). It is never used to mark the starboard side of a channel boundary. **D) Green square:** In the US Lateral System (Red Right Returning), **Green** marks the **port (left) side** of the channel when entering from sea. The characteristic shape for a green daymark is a **square** (or a can-shape for buoys). Therefore, a green square marks the opposite side of the channel (port side).