Radar Observer · Collision Avoidance — Scanty Information
Rule 7(c) specifically cautions that:
- AAssumptions shall not be made on the basis of scanty information, especially scanty radar information✓ Correct
- BRadar may be ignored if AIS is available
- CA single observation is enough to determine risk
- DPlotting is unnecessary at long range
Explanation
A single radar observation gives range and bearing but not the target's course, speed, CPA, or TCPA — acting on it alone is acting on scanty information. Rule 7(c) prohibits this; the officer must take a series of observations (plot/track) before judging risk and deciding on action.
Authority: Navigation Rules, Rule 7(c)
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