Rule 7 — Risk of Collision
You must use all available means to determine if a risk of collision exists. If there is any doubt, assume it does exist.
The most reliable technique is compass bearings: if the bearing of an approaching vessel does not change appreciably, a risk of collision exists. This is called a 'constant bearing, decreasing range' (CBDR) situation.
Key Points
- If in doubt, risk of collision EXISTS
- Constant bearing + decreasing range = collision risk
- Use compass bearings to assess risk
Tip: Take a series of compass bearings on an approaching vessel. If the bearing stays roughly the same but the vessel is getting closer, you are on a collision course.