USCG Exam PracticePassing distance and CPA from chart plot
A vessel is required to be fitted with an ARPA under 33 CFR §164.38. What is the maximum allowable speed error for the required speed and distance indicating device when the vessel is operating free from shallow water effect and free from the effects of wind, current, and tide?
- A. 2 percent of vessel speed or 0.2 knot, whichever is greater
- ✓ 5 percent of vessel speed or 0.5 knot, whichever is greaterCorrect
- C. 5 percent of vessel speed or 0.5 knot, whichever is less
- D. 10 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 ('whichever is less'), which would impose a far more restrictive standard than the regulation requires.
Cited:33 CFR §164.40