USCG Exam PracticeRadar fundamentals and ARPA basics
A vessel required to carry ARPA under 33 CFR §164.38 must also carry a speed and distance device per 33 CFR §164.40. What is the maximum allowable speed error for that device when operating free from shallow water effect and 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) 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 applies the wrong comparative ('less' instead of 'greater'), which would impose a far more restrictive standard than the regulation requires.
Cited:33 CFR §164.40