Yachtmaster Offshore Standard: COLREGs

Start with control and evidence. Maintain a proper lookout, safe speed and a time-sequenced picture from visual bearings, hearing, systematic radar observations and every other appropriate available means. Record uncertainty rather than filling it with an AIS label. AIS can be absent or wrong and normally reports course and speed over the ground; collision-avoidance decisions remain primarily based on systematic visual and/or radar observation.

Treat every contact separately. Decide whether it is visually in sight, whether risk of collision or a close-quarters situation exists, and whether Rules 9, 10 or 13 shape the encounter before applying the ordinary responsibilities in Rules 12–18. A vessel not visually in sight when navigating in or near restricted visibility is handled under Rules 4–10 and Rule 19. A radar or AIS symbol does not create an in-sight stand-on or give-way role.

Choose action that complies with the relevant Rules and is early, substantial and readily apparent when circumstances admit. Check sea room, secondary contacts, routeing constraints, vessel response and the risk of creating a new close-quarters situation. A VHF passing conversation, target name or single CPA prediction cannot replace that decision. Continue the observation until safe passing distance is established and the contact is finally past and clear.

Brief the watch in operational language: who has the con, who keeps the visual lookout, who observes or plots each radar contact, what action is ordered, what evidence must prove it effective and what trigger calls the skipper or changes the plan. Rule 2 preserves responsibility and permits departure only when necessary to avoid immediate danger; it is not a shortcut around predictable Rule 8, Rule 16, Rule 17 or Rule 19 action.