COLREGs: Steering and Sailing Rules, Lights, Shapes and Signals
Domain 2 examines rule-by-rule application. Scenarios ask who gives way, what action is required, which lights or shapes are displayed, and what sound signal is made.
Steering and sailing rules
Rule 5 requires a proper lookout by sight, hearing and all available means. Rule 6 sets safe speed; Rule 7 covers risk of collision; Rule 8 requires action that is positive, made in ample time and large enough to be readily apparent. Rule 13: the overtaking vessel keeps out of the way until finally past and clear. Rule 14: head-on power vessels both alter course to starboard. Rule 15: in a crossing situation, the vessel with the other on her starboard side gives way. Rule 16 requires early, substantial give-way action; Rule 17 restricts the stand-on vessel. Rule 18 sets responsibilities toward sailing vessels, fishing vessels and vessels not under command. Rule 19 applies in restricted visibility and removes stand-on and give-way roles.
Lights and shapes
A power-driven vessel underway shows masthead light(s), sidelights and a sternlight. At anchor: an all-round white light and, by day, a black ball. Not under command: two all-round red lights and two balls. Restricted in ability to manoeuvre: red-white-red all-round lights and ball-diamond-ball shapes.
Worked example
Power vessel A on course 000°T sees power vessel B bearing 045°T with a steady bearing and decreasing range. B is on A's starboard side, so this is a crossing situation and A must give way. A should avoid crossing ahead, preferably by a large early alteration to starboard to pass astern of B; A must not turn to port across B's bow.
Traps
Assuming AIS or VHF resolves the rule; standing on too long; turning to port for a vessel on your port side; confusing the in-sight rules with Rule 19; forgetting sound signals and day shapes; misidentifying lights at night.