If a navigation marker has a red light, what type of marker is it likely to be?

A navigation marker with a red light is typically used to designate a danger mark. These types of markers are employed to alert mariners to hazardous conditions, such as submerged rocks, reefs, or other obstacles that could pose a risk to navigation. The red light serves as a clear warning and is universally recognized in maritime navigation to indicate areas that require caution.

In contrast, regulatory marks are designed to convey specific rules and regulations, such as speed limits or no-wake zones, while safe water marks indicate that there are navigable waters in all directions around the marker. Channel markers, usually green or red, help to delineate the safe navigable channel for vessels. The use of a red light specifically correlates with safety and hazard awareness, reinforcing that the primary function of such a marker is to signal danger to approaching vessels.