What does Rule 23 address?

Rule 23 specifically addresses the requirements for vessel signals and lights for various types of vessels. It outlines the visibility and display of navigation lights that vessels must use to indicate their presence, size, and activity to others on the water. This rule is crucial for ensuring safe navigation, particularly during periods of reduced visibility, such as at night or in adverse weather conditions. Proper signaling is essential for preventing collisions and enhancing communication between vessels at sea.

In contrast, other options do not pertain to the scope of Rule 23. For instance, vessel registration processes are covered under different regulations, as is the case for rules specific to fishing vessels which have their own set of guidelines. Emergency signaling procedures also fall outside the focus of Rule 23, which revolves specifically around the requirements for the display of lights and signals while underway.