Module 5 - COLREGs

Yachtmaster Offshore Standard: COLREGs

What you will learn

Run a multi-contact collision-avoidance command cycle that separates evidence, applicable rules, action, crew roles and proof of safe clearance.

At Yachtmaster level, naming the encounter rule is only the start. The skipper must keep an accurate traffic picture, apply the correct framework to each contact, act while options remain and show that the manoeuvre actually worked.

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.

Worked example

At night, a visually acquired power-driven vessel remains near 040° relative while range falls from 4.5 to 3.1 to 2.0 miles. A second target is detected astern on radar, and rain is reducing visibility ahead.

1Treat the repeated near-steady bearing and decreasing range as collision risk; verify the visual contact and radar association rather than relying on its AIS name.
2Classify the first encounter from the actual geometry and in-sight rules, while assessing the astern contact independently for overtaking or a separate developing risk.
3Choose an early, substantial and rule-compliant action that leaves sea room and does not turn the second contact into a new close-quarters situation.
4Allocate visual and radar monitoring, state the expected bearing or CPA trend and set the next observation time.
5If visual contact is lost in the rain, reassess the relevant contact under Rule 19 rather than preserving an old stand-on or give-way label by habit.

Sense check: The response is incomplete if it names one Rule correctly but ignores the second contact, changing visibility or proof that safe clearance is developing.

Yachtmaster Offshore Standard: COLREGs
Contact record	Command question	Useful evidence
Detection	Is the vessel visually in sight, radar-only, heard or uncertain?	Lookout report, relative bearing, range, sound and sensor association
Rule framework	Which visibility, channel, TSS, overtaking and encounter rules apply?	Rules 4–10, 11–19 and current local information
Risk	What trend shows risk or close quarters, and what remains uncertain?	Repeated visual bearings and systematic radar observation
Action	What early action is lawful, apparent and clear of other contacts?	Ordered course or speed, sea room and predicted response
Proof	What observation shows safe passing distance is developing?	Bearing, range, CPA/TCPA trend and finally-past-and-clear check

Use one command record for each contact

A yacht is approaching a traffic lane at night with a ship visually in sight, a radar-only target inside rain and a small craft close on the quarter.

1. Evidence
Record visual status, bearing and range trend, radar association, uncertainty and the conditions affecting detection for each contact.
2. Framework
Name the applicable visibility, routeing, overtaking and encounter rules separately; a ship following a traffic lane has no automatic priority.
3. Action
State the ordered course or speed change, why it is lawful and apparent, and which secondary conflict it must avoid.
4. Verification
Name the next timed observation, the safe-clearance evidence and the trigger for a different action or skipper call.

Sense check: A single instruction such as 'alter to starboard' is not a multi-contact plan until it is checked against every relevant contact and routeing constraint.

Common mistake or limitation

Applying one stand-on or give-way label to every contact ignores the visual-sight boundary and the separate Rule 19 framework.
A traffic-lane vessel has no automatic priority, and a right-angle TSS crossing is a heading requirement rather than a course-over-ground target.
Rule 2 does not excuse an avoidable late manoeuvre, and a VHF agreement does not replace compliance with the COLREGs.
A completed alteration is not proof of clearance; continue systematic observation until the result is safe and every contact is controlled.

Recap

Build a time-sequenced picture and state uncertainty before selecting a rule.
Apply the correct visibility and encounter framework to each contact separately.
Choose early, substantial action that does not create another close-quarters situation.
Delegate observation and verify safe passing distance until finally past and clear.

Optional quick check

Section 13 of 14

A ship is visually in sight while a second contact is detected only by radar inside a rain squall. What is the strongest command approach?

Sources and factual review

Reviewed 2 September 2026 - Compass Revision editorial review.

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