Which of the following is not a navigational aid?

A mooring buoy serves a different purpose than navigational aids that guide vessels through waterways. While right and left channel markers, as well as mid-channel markers, provide specific information about safe navigation routes by marking the edges of navigable channels or directing vessels to stay in the correct part of the waterway, a mooring buoy is designed for temporarily securing a boat rather than guiding navigation. It helps boaters tie off their vessels safely when they are not in motion but does not contribute to navigation by indicating channels or hazards. The other options are distinctly part of the navigational system, marking safe passage for boats and preventing accidents in busy waterways.