COLREGs Lights & Shapes Practice Test 2025 - Free Maritime Navigation Practice Questions and Guide

The correct choice is a sailing vessel under 20 meters. According to the COLREGs (International Regulations for Preventing Collisions at Sea), specific lighting requirements are established for various types of vessels to ensure safe navigation and prevent collisions.

For a sailing vessel that is under 20 meters in length, the regulations allow for a simplified lighting configuration. This vessel can combine the sidelights (which indicate the port and starboard sides) and the stern light (which indicates the rear of the vessel) into a single all-around white light. This combination is acceptable because it simplifies the lighting requirements for smaller vessels, making it easier for them to equip and operate without compromising safety.

In contrast, other vessel types listed do not have the same flexibility. For example, fishing vessels at anchor are required to display specific lights that indicate they are engaged in fishing and they cannot combine lights in the same manner. Power-driven vessels, regardless of their size, must display separate sidelights and a stern light to maintain clear identity and visibility at night. Similarly, a seaplane at rest on the water must comply with different lighting regulations that pertain specifically to aircraft, which do not allow for a combination of sidelights and stern lights in a single lantern.

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