Which buoy is used to mark the beginning of a preferred channel?

The choice of a Nun buoy as the marker for the beginning of a preferred channel is grounded in the specific function and characteristics associated with navigational buoys. Nun buoys are typically conical in shape and are used in the lateral system of buoyage. In this system, they are placed to indicate the safe passage through a channel, particularly on the starboard side when entering from the sea.

When navigating inland waters or coastal channels, mariners rely on these buoys to determine their course, and a Nun buoy specifically signifies the right side of the channel, thus denoting where the preferred channel starts. This helps in guiding vessels safely and efficiently through potentially hazardous waters.

Other buoy types serve different purposes. For example, a Safe Water mark indicates that there is navigable water all around the buoy and is often used for fairways, while an Isolated danger mark indicates a specific hazard that should be avoided. Can buoys, on the other hand, typically mark the left side of a channel when entering from the sea. Through this understanding, it's clear why the Nun buoy is identified as the correct marker for the beginning of a preferred channel.