Final answer:
On ICW's, encountering yellow markers signifies navigational aids indicating caution areas. Yellow triangles and squares on channel markers also guide navigators which side to pass when following the preferred channel direction.
Step-by-step explanation:
When you are on Inland Waterways (ICW) and encounter some yellow markers, these are navigational aids indicating that you are approaching a caution area. Yellow markers are typically used in the United States to mark areas where special caution is advised. They serve as a visual guide for those navigating the waterways.
On the Intracoastal Waterway, you may see a yellow square or triangle on channel markers. These yellow symbols indicate which side of the marker you should pass on when following the preferred channel. For instance, a yellow triangle should be kept to the starboard (right) side of the vessel, while a yellow square should be kept to the port (left) side when going in the preferred channel direction.
For example, a yellow buoy with an anchor symbol indicates a safe anchorage area, while a yellow buoy with a crossed diamond symbol warns of an obstruction in the water. It's important for boaters to understand and follow these markers to avoid potential dangers.