What should you do when approaching a boat in darkness or reduced light?

When approaching a boat in darkness or reduced light, ensure that you have proper navigation lights on to make your presence known. Use radar and sound signals to communicate your position and intentions, and maintain a safe speed to allow for maneuvering if necessary. Keep a vigilant lookout for other vessels and obstacles, and be prepared to adjust your course as needed to avoid collisions. Always prioritize safety by following established maritime rules and guidelines.