USCG Exam Practice · Passing distance and CPA from chart plot
A vessel equipped with ARPA is required by 33 CFR §164.40 to also carry a device to indicate speed and distance. What is the maximum allowable error in indicated speed for such a device under normal operating conditions?
- A2 percent of vessel speed or 0.2 knot, whichever is greater
- B5 percent of vessel speed or 0.5 knot, whichever is greater✓ correct
- C5 percent of vessel speed or 0.5 knot, whichever is less
- D10 percent of vessel speed or 1.0 knot, whichever is greater
Why B is correct
33 CFR §164.40(b)(2) specifies that errors in indicated speed should not exceed 5 percent of the speed of the vessel or 0.5 knot, whichever is greater. Option C uses the same numbers but applies the wrong comparator ('less' instead of 'greater'), which would impose a far more restrictive standard.
Cited:33 CFR §164.40
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