What navigational aid is employed in the middle of a channel?

Range markers are navigational aids specifically designed to assist with safe navigation through channels, particularly in locations where precise alignment is crucial. They consist of two or more devices that are typically positioned at different elevations or locations, which must be aligned by the navigator to ensure the vessel stays on a safe course through the channel. When the front and rear markers are in line, it indicates that the vessel is on the proper track.

This method of navigation is especially effective in narrow channels where navigation can be tricky, as it helps to prevent groundings or collisions by guiding mariners safely along the navigable route. The use of range markers is a standard practice in marine navigation, allowing for consistency and safety in navigating through congested waterways.

Other navigational aids mentioned, such as port markers, lighted buoys, and regulatory signs, serve different purposes in aiding navigation and safety. Port markers generally indicate the left or right side of the channel and are employed primarily in the context of lateral navigation aids. Lighted buoys provide a visual signal with illumination but don't offer the same precise alignment guidance as range markers. Regulatory signs inform mariners of rules and regulations, rather than assisting with navigation through a specific channel. Thus, range markers are uniquely suited for guiding