Questions

The type of buoy indicated by the letter D depends on the specific characteristics and context shown in your reference, which you haven't provided. However, I can describe these types of buoys for you:

• Nun Buoy (A): This type of buoy is conical and typically red in color with even numbers. It marks the right side of the channel when returning from the sea (red, right, returning).

• Can Buoy (B): This buoy is cylindrical and typically green with odd numbers. It marks the left side of the channel when returning from the sea.

• Spar Buoy (C): This is a tall, thin buoy that is anchored vertically in the water. It can be used for various purposes, including marking channels and special areas.

• Pillar Buoy (D): This buoy has a tall body that may be shaped like a pillar or tower and equipped with lights or other navigational aids. It can serve as a hazard marker, safe water marker, or other types of markers as needed.

Without the specific visual reference, it's difficult to provide a definitive answer. Could you provide more context or a description of the buoy marked by "D"?