Rule 4 clarifies that the rules in Section I (Rules 4–10) apply in any condition of visibility, whether clear or restricted. This is distinct from Section II rules which only apply when vessels are in sight of one another, and Section III which applies in restricted visibility.
STCW Bridge Watch Lens
Decide applicability before manoeuvring: Rules 4-10 apply in any visibility, Rules 11-18 only when vessels are in sight, and Rule 19 governs radar-only encounters in restricted visibility.
Build the traffic picture with sight, hearing, radar/ARPA and chart context.
Do not let AIS or one isolated bearing replace systematic observation.
After manoeuvring, keep monitoring bearing, range, CPA/TCPA and passing distance until the other vessel is finally past and clear.
Exam Focus
Start every scenario by classifying the encounter: overtaking, head-on, crossing, narrow channel, traffic separation, or restricted visibility.
If two rules seem to conflict, check the order carefully: overtaking duties still apply, and Rule 2 still requires ordinary seamanship.
Key Takeaways
Section I rules apply in ALL visibility conditions
These are the fundamental steering and sailing rules
Must be followed regardless of weather or visibility
Common Mistakes
Thinking different steering rules apply in fog vs clear weather for Section I
Test Your Knowledge
Test your knowledge and prove your mastery.
More rules in this Part
- Safe SpeedEvery vessel shall at all times proceed at a safe speed so that proper and effective action can be taken to avoid collision.
- Risk of CollisionEvery vessel shall use all available means to determine if risk of collision exists. If in doubt, such risk shall be deemed to exist.
- Action to Avoid CollisionAny action to avoid collision shall be positive, made in ample time, and with due regard to good seamanship.
- Narrow ChannelsA vessel proceeding along the course of a narrow channel shall keep as near to the outer limit of the channel which lies on her starboard side.
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