IALACOLREG
7

Risk of Collision

Every vessel shall use all available means to determine if risk of collision exists. If in doubt, such risk shall be deemed to exist.

Rule 7 explains how to decide whether risk of collision exists. Every vessel shall use all available means appropriate to the prevailing circumstances and conditions to make that assessment. If there is any doubt, such risk shall be deemed to exist.

a
Risk of collision is often indicated when the compass bearing of an approaching vessel does not appreciably change.
b
A noticeable bearing change does not automatically remove the risk. Collision risk may still exist, especially when approaching a very large vessel, a tow, or a vessel at close range.
c
Assumptions shall not be made on the basis of scanty information, especially scanty radar information.
d
If radar is fitted and operational, it must be used properly. That includes long-range scanning for early warning and radar plotting or equivalent systematic observation of detected targets.

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.

3

Steady or nearly steady bearing is the classic trigger, but close range, a large vessel or a tow can still mean risk even when bearing change seems small.

Key Takeaways

1

A steady or nearly steady bearing is a classic collision-warning sign

2

If there is doubt, the Rules tell you to treat the risk as real

3

Scanty radar information is not a safe basis for assumptions

4

Radar must be used systematically, not casually

Common Mistakes

Assuming a slight bearing drift means there is no danger

Failing to plot or systematically track a target before deciding the situation is safe

Treating AIS data as if it replaces Rule 7 assessment

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