Final answer:
Red buoys are the lateral markers that indicate the edge of the channel on your right side as a boater heads upstream.
Step-by-step explanation:
When navigating a boat upstream, the lateral markers that indicate the edge of the channel on your right side are known as red buoys. Red buoys have odd numbers and may be shaped like cones or cans. They are used to mark the right side of the channel, known as the starboard side, as you travel upstream.