What does "close aboard" signify for ships in terms of distance?

"Close aboard" is a term used in naval operations to describe the distance between two ships, specifically indicating that they are within a specific range of each other that allows for direct communication and coordination without the need for additional navigational aids. The standard distance that defines "close aboard" is typically understood to be within 600 yards.

This range is significant in maritime operations for various reasons, including the ability to utilize lifeboats, conduct personnel transfer operations, and ensure effective visual or verbal communication between vessels. Conditions such as the visibility, weather, and the tactical situation may also influence the operational readiness and maneuvering decisions when ships are in close proximity. Thus, referring to the distance as 600 yards provides a clear benchmark for sailors and officers managing ships in a fleet or during specific missions.