2025 USCG Captain's License Practice Exam – Comprehensive Prep Guide

The correct choice of displaying one all-round white light for a power-driven vessel under 7 meters in length at night is based on the regulations outlined in the Navigation Rules. For vessels of this size, the regulations allow for a simplified lighting configuration to ensure safety while still complying with maritime law.

An all-round white light, which can be seen from all directions, suffices to indicate the presence of the vessel to others and helps to prevent collisions. This is particularly important for smaller vessels that navigate in areas with a lot of traffic, as it provides necessary visibility without the complexity of additional lights.

In contrast, displaying sidelights and a sternlight would be requirements for larger vessels, and showing all the lights required for a vessel more than 7 meters would not be necessary or practical for a smaller vessel. Sidelights only would not provide the full range of visibility required by navigation rules, as they are meant to meet specific lighting regulations for different vessel sizes. Therefore, using one all-round white light is both permissible and practical for power-driven vessels under 7 meters in length at night.