IALACOLREG
4

Application

Rules in Section I apply in any condition of visibility.

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

1

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.

2

Build the traffic picture with sight, hearing, radar/ARPA and chart context. Do not let AIS or one isolated bearing replace systematic observation.

3

After manoeuvring, keep monitoring bearing, range, CPA/TCPA and passing distance until the other vessel is finally past and clear.

Exam Focus

1

Start every scenario by classifying the encounter: overtaking, head-on, crossing, narrow channel, traffic separation, or restricted visibility.

2

If two rules seem to conflict, check the order carefully: overtaking duties still apply, and Rule 2 still requires ordinary seamanship.

Key Takeaways

1

Section I rules apply in ALL visibility conditions

2

These are the fundamental steering and sailing rules

3

Must be followed regardless of weather or visibility

Common Mistakes

Thinking different steering rules apply in fog vs clear weather for Section I

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