What color marking is often associated with obstruction on the port side?

The color marking that is commonly associated with obstructions on the port side is red. In the IALA Maritime Buoyage System, red typically signifies a mark that indicates a danger or an obstruction that should be passed on the other side—in this case, the starboard (right) side when approaching from seaward. This is a critical aspect of maritime navigation, as it helps mariners identify hazards and navigate safely around them.

In maritime buoyage, red marks are often used in lateral buoyage systems to indicate that vessels should keep these markers to starboard. Thus, when a mariner sees a red marker, they understand that this represents an obstruction or hazard on their port side. This knowledge is essential for maintaining safe passage in navigable waters, especially in crowded or hazardous areas. The significance of color in navigation is a fundamental part of IALA buoyage practices, ensuring consistent and clear communication of navigational information.