COLREGs Rule 7: Risk of collision — Explained

Rule 7 says you must use every available means to decide whether risk of collision exists, and if in doubt assume it does. If the compass bearing of an approaching vessel does not change appreciably, risk of collision exists.

What Rule 7 says

Use all available means to decide if risk of collision exists. If there is any doubt, assume it does.
Use radar properly if fitted, including long-range scanning and radar plotting to get early warning.
Do not make assumptions on scanty information, especially scanty radar information.
Risk of collision exists if the compass bearing of an approaching vessel does not appreciably change. It may exist even with a changing bearing, especially with a very large vessel, a tow, or at close range.

This is a plain-English summary, not the official wording. For the exact text, see the IMO convention. In UK waters the rules are given legal force by the Merchant Shipping (Distress Signals and Prevention of Collisions) Regulations.

What it means on a yacht

Take a hand-bearing compass bearing of the ship, or line it up with a stanchion while you sit still. If it stays on the same bearing while the range closes, you are on a collision course.

Practise it

Test yourself on who gives way in the free COLREGs trainer, or print the rules of the road cheat sheets for the chart table.

Other rules in Part B

Frequently asked questions

How do you tell if there is a risk of collision?

Take repeated compass bearings of the other vessel. If the bearing stays steady while it gets closer, there is a risk of collision. With large ships or at close range, even a slowly changing bearing can mean risk.