USCG Exam PracticeRadar fundamentals and ARPA basics
A vessel required to carry an ARPA under 33 CFR §164.38 must also carry a speed and distance device under 33 CFR §164.40. What is the maximum permissible speed error for that device when operating free from shallow water effect and free from 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) states 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 the wrong comparator ('whichever is less'), which would impose a far more restrictive standard not stated in the regulation.
Cited:33 CFR §164.40