The letter R followed by one or more numbers indicates what?

The designation of the letter R followed by one or more numbers specifically indicates distance in the context of maritime navigation. In navigational terms, when you see the letter R, it typically refers to "range," which represents the distance from a particular point or object. For example, "R5" would indicate a range of five nautical miles.

This understanding of R as distance is anchored in common maritime practices and conventions for communication on navigational charts and in the operation of vessel systems. Recognizing this designation is crucial for effectively interpreting navigational data, which is essential for safe and efficient passage planning and marine operations.