Read the lights
Night identification. Foundation level, about 2 min. COLREGs Rules 21 & 23.
The situation
A contact is approaching ahead at night. Use the bridge view and binoculars to observe the lights before revealing the vessel information.
Which configuration are you observing?
- Power-driven vessel, seen ahead: A masthead light and both sidelights.
- Sailing vessel, seen ahead: Sidelights without a masthead light.
- Vessel at anchor: An all-round white anchor light.
Lookout: Look for the white masthead light above the red and green sidelights. Light visibility depends on your aspect.
The sound answer
Power-driven vessel, seen ahead
The authored contact carries a single white masthead light and red and green sidelights, seen from ahead. This is the under-50 m power-driven profile in this exercise. Assess collision risk separately.
Why the other options fall short
Sailing vessel, seen ahead
An ordinary sailing vessel’s underway lights do not include the white masthead light used by a power-driven vessel. Revisit the elevated white light in this scene.
Vessel at anchor
An anchor light alone does not account for the two sidelights visible here. This scene explicitly uses the power-driven vessel light profile.
Rules 21 & 23 · Power-driven vessel lights
A masthead light is white and shows through an arc of 225°. Sidelights are red to port and green to starboard. In this authored under-50 m configuration, one masthead light is shown.