Navigation General · Radar Plotting
On a relative-motion radar display, a contact whose relative motion line points directly at your own ship's position (center) indicates:
- AA collision or very close CPA — the contact is on a steady bearing closing✓ Correct
- BThe contact will pass well clear astern
- CThe contact is stationary
- DThe contact is overtaking and opening
Explanation
On a relative-motion display, if the contact's relative track passes through the center, its CPA is essentially zero — risk of collision exists. A bearing that does not appreciably change while range decreases is the classic Rule 7 indication of risk of collision.
Authority: Radar plotting; Navigation Rules, Rule 7
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