Collision Avoidance, Lights, Shapes and Sound Signals
The collision regulation framework
Candidates must understand the structure of the collision regulations: conduct in any condition of visibility, conduct in sight of one another, lights and shapes, and sound and light signals. Know the concepts of safe speed, risk of collision, action to avoid collision, narrow channels, traffic separation schemes and the give-way and stand-on hierarchy.
Lights and shapes
Learn the arcs of visibility and the meaning of masthead, sidelights, sternlight and all-round lights. Know the configurations for power-driven vessels underway, sailing vessels, vessels at anchor, vessels not under command, restricted in ability to manoeuvre, constrained by draft, fishing, towing and pushing. Shapes follow the same logic: ball, cylinder, cone, diamond, and combinations.
Sound signals
Know the manoeuvring and warning signals, fog signals by vessel type, and the distress signals. Understand that a signal must be unambiguous and given in good time.
Traps
- Mixing up the sidelight colours and their arcs.
- Forgetting that a vessel at anchor shows an all-round white light, not a masthead light.
- Confusing the fog signal for a power-driven vessel making way with one stopped.
- Assuming a stand-on vessel never acts; it must act when collision is imminent.
Worked rule of thumb
For any lights question, identify three things: vessel type, activity status, and length. Then apply the required configuration. If two answers differ only by an extra light, check whether the vessel is underway or at anchor.