Observe and identify
Developing level, about 2 min. IALA worldwide marks.
The situation
A navigation light lies ahead. Start playback and watch at least one complete cycle. Its period is an illustrative charted example; identify the combination of colour and rhythm.
Which mark matches the light you observe?
- Isolated danger
- Port-hand mark · Region A
- Starboard-hand mark · Region A
Answers and explanations
Lookout: Two black balls above black and red; two white flashes at night.
The sound answer
Isolated danger
Black with broad red horizontal bands and two black spheres. A white group-flashing (2) light. A danger of limited extent has navigable water around it; the mark does not specify a safe distance from the danger.
Why the other options fall short
Port-hand mark · Region A
Red can-shaped lateral mark. In the conventional direction of buoyage, leave it to port. In the opposite direction, leave it to starboard. Read the charted buoyage direction rather than assuming every passage is inward. Here the observed cue identifies isolated danger. Black with broad red horizontal bands and two black spheres. A white group-flashing (2) light. A danger of limited extent has navigable water around it; the mark does not specify a safe distance from the danger.
Starboard-hand mark · Region A
Green conical lateral mark. In the conventional direction of buoyage, leave it to starboard; travelling against that direction reverses the side of your vessel on which you leave it. Here the observed cue identifies isolated danger. Black with broad red horizontal bands and two black spheres. A white group-flashing (2) light. A danger of limited extent has navigable water around it; the mark does not specify a safe distance from the danger.
Isolated danger marks
Black with broad red horizontal bands and two black spheres. A white group-flashing (2) light. A danger of limited extent has navigable water around it; the mark does not specify a safe distance from the danger.