🔍 Key Concepts

• Rule 20 – Application of Lights and Shapes in the Navigation Rules • The purpose of navigation lights: to indicate type of vessel, status, and motion to others • How extra lights might affect the ability of other vessels to correctly interpret your lights

💭 Think About

• What could happen if additional lights look similar to, or are in the same position as, required navigation lights? • How might bright or poorly placed extra lights affect another vessel’s ability to see and correctly identify your sidelights, masthead light, or stern light? • Besides identification, what other safety concern is involved when there are many or very bright lights on a vessel at night?

✅ Before You Answer

• Verify what Rule 20 says about no interference with prescribed lights • Check that any additional lights do not change the distinctive pattern or visibility range of the required lights • Confirm that extra lights cannot reasonably be confused with any light combination described elsewhere in the Rules