Green is a square shaped daymark buoy.
In Region B a "green can shaped buoy" stands for the edge of a channel on a boaters left side when entering from open sea or heading upstream, the opposite applies in Region A.
The left edge of a navigation channel as you are heading in.
The left edge of a navigation channel as you are heading in.
The left edge of a navigation channel as you are heading in.
The left edge of a navigation channel as you are heading in.
The left edge of a navigation channel as you are heading in.
The left edge of a navigation channel as you are heading in.
The left edge of a navigation channel as you are heading in.
A red cone shaped buoy, called a nun buoy, usually marks the right side of the channel when you are returning from the sea or going upstream. Remember it by saying, red, right, returning.
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Preferred channel markers are buoys showing red and green bands.