Conduct in any visibility
The core conduct rules apply in every condition: keep a proper lookout (Rule 5), proceed at a safe speed (Rule 6), use all available means including radar to judge whether a risk of collision exists (Rule 7), and take avoiding action that is early, substantial and obvious (Rule 8). Risk of collision is judged by the compass bearing of an approaching vessel — a steady bearing with a closing range means a collision is developing. These rules are the foundation on which the give-way rules sit.
| Encounter (power) | Give-way vessel | Action |
|---|---|---|
| Head-on | Both | Each alters to starboard, passes port to port |
| Crossing | Vessel with the other on her starboard side | Alter to starboard; avoid crossing ahead |
| Overtaking | The overtaking vessel | Keep clear until finally past and clear |
| The power-driven encounters (Rules 13-15). |
Responsibilities between vessels
Rule 18 sets the order of giving way: a power-driven vessel keeps out of the way of a sailing vessel, a fishing vessel, a vessel restricted in her ability to manoeuvre, and one not under command. In or near restricted visibility, Rule 19 applies and there is no stand-on vessel — both proceed at a safe speed and avoid a close-quarters situation. The Master applies these without hesitation, because the rules exist to be predictable.
WARNING — Early, large and to starboard In a crossing or head-on meeting the action the examiner expects is an alteration to starboard that is early and big enough to be obvious to the other vessel — never a small nudge and never (in these cases) a turn to port.