Collision Regulations (COLREG) and Safe Navigation
This domain tests whether you can apply the 1972 Collision Regulations under time pressure: lookout and safe speed, the order of precedence between steering rules, lights, shapes, sound signals and conduct in restricted visibility. Greek examiners favour short scenario questions where the distractors are plausible but wrong about which rule takes priority.
The framework rules
Rule 5 lookout by all available means; Rule 6 safe speed allowing for visibility, traffic, draught and stopping distance; Rule 7 risk of collision - a steady bearing with decreasing range means risk, and if in doubt, assume risk; Rule 8 action in good time, substantial, and avoiding a succession of small alterations.
Order of application
- Overtaking (Rule 13): any vessel overtaking keeps clear, and this overrides crossing rules.
- Head-on (Rule 14): both alter to starboard.
- Crossing (Rule 15): the vessel with the other on her own starboard side gives way.
- Rule 18 responsibility: power-driven gives way to sailing, fishing, not under command and restricted in ability to manoeuvre.
- Rule 17: the stand-on vessel holds course and speed but must act when collision cannot be avoided by the give-way vessel alone; if power-driven and crossing, she should not turn to port if that is practicable.
- Rule 19 restricted visibility: no stand-on vessel; reduce to a safe speed, use radar and sound signals.
Lights, shapes and arcs
Power-driven under 50 m: one masthead light, sidelights, sternlight; 50 m and over: a second, higher aft masthead light. Arcs: masthead 225°, sidelights 112.5° each, sternlight 135°. Sailing vessels show sidelights and sternlight only, with an optional red-over-green. Fishing vessels trawling show green over white; other fishing red over white. At anchor, an all-round white (<50 m) or two all-round whites (≥50 m), plus a black ball by day.
Worked example
You are power-driven at 10 kn on 000°T; another power-driven vessel bears 110°T at 4 NM, bearing steady and range closing at 15 kn. Reasoning: steady bearing and falling range means risk of collision (Rule 7); she is on your starboard side crossing, so you are the give-way vessel (Rule 15). Alter clearly to starboard and pass astern of her - at 15 kn closing speed the range halves in under 8 minutes, so act now and confirm the bearing is opening.
Traps that cost marks
- Using "right of way": the rules give-way and stand-on.
- Calling a crossing situation when you are actually overtaking.
- Showing a masthead light on a sailing vessel, or reversing the fishing light order.
- A stand-on vessel that does nothing at close quarters.
- Quoting Rule 19 as if a stand-on vessel exists in fog.