Navigation General practice test

20 questions. Pick an answer to see its rule.

1. Question 1, Electronics, International and Inland

   Which information must automatic identification systems (AIS) automatically provide to appropriately equipped shore stations, vessels and aircraft?

   ANavigational statusBVessel's typeCVessel's courseDAll of the above
   Show the answer

   D. All of the above

   AIS automatically broadcasts identity, type, position, course, speed and navigational status.

   33 CFR 164.46. Source: NMC sample exam.

2. Question 2, Electronics, International and Inland

   On which of the following does an automatic identification system (AIS) transponder transmit and receive information?

   A3 cm, X-band radarB10 cm, S-band radarCVHF maritime bandDUHF L-band
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   C. VHF maritime band

   AIS works on the VHF maritime band, not on radar frequencies.

   33 CFR 164.46. Source: NMC sample exam.

3. Question 3, Aids to Navigation, International and Inland

   When trying to sight a lighthouse you notice a glare from a town in the background. How does this affect the range at which the light may be sighted?

   AIncreased slightly due to extra lightingBConsiderably reduced and difficult to distinguishCIncreased if the light is red or green due to contrast with the glareDUnchanged
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   B. Considerably reduced and difficult to distinguish

   Background lighting makes a light much harder to pick out, so it may be seen far later than its range suggests.

   Bowditch; Light List. Source: NMC sample exam.

4. Question 4, Aids to Navigation, International and Inland

   What is the characteristic of a quick flashing light?

   AShows quick flashes for about 5 seconds followed by a 1 second dark periodBShows groups of 2 or more flashes at regular intervalsCDurations of light and darkness are equalDShows not less than 60 flashes per minute
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   D. Shows not less than 60 flashes per minute

   A quick flashing light shows at least 60 flashes per minute, without a break.

   Light List. Source: NMC sample exam.

5. Question 5, Aids to Navigation, International and Inland

   What does a white buoy with an orange rectangle on it indicate?

   AA controlled areaBAn exclusion areaCGeneral informationDDanger
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   C. General information

   On a white regulatory mark, an orange rectangle gives information. A diamond warns of danger, a crossed diamond marks exclusion and a circle marks a controlled area.

   33 CFR Part 62. Source: NMC sample exam.

6. Question 6, Charts & Publications, International and Inland

   The compass rose on a nautical chart indicates both variation and which other information?

   AAnnual rate of variation changeBDeviationCCompass errorDAnnual rate of precession change
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   A. Annual rate of variation change

   The compass rose shows variation for a stated year and the annual change, so you can update it.

   Chart No. 1; Bowditch. Source: NMC sample exam.

7. Question 7, Charts & Publications, International and Inland

   The depth of water on a chart is indicated as 23 meters. What does that depth convert to?

   A11.5 fathomsB12.6 fathomsC69.0 feetD78.6 feet
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   B. 12.6 fathoms

   23 meters is about 75.5 feet. Divide by 6 feet per fathom to get 12.6 fathoms.

   Unit conversion. Source: NMC sample exam.

8. Question 8, Charts & Publications, International and Inland

   A HYDROLANT warning would normally be sent for all of the following EXCEPT __________.

   AThe presence of a large unwieldy tow in congested offshore waterBUnexploded ordinance in ocean waters at a depth of 78 fathoms (143 meters)CExtinguishment of Robbins Reef Light in New York City's Upper BayDA report of a ship in distress in mid-ocean
   Show the answer

   C. Extinguishment of Robbins Reef Light in New York City's Upper Bay

   HYDROLANT warnings cover high-seas hazards. A harbor light out in Upper New York Bay belongs in local notices instead.

   Bowditch. Source: NMC sample exam.

9. Question 9, Compass, International and Inland

   What must change for the compass deviation to change?

   AThe geographical position of the vesselBThe speed of the vesselCThe longitude of the vesselDThe heading of the vessel
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   D. The heading of the vessel

   Deviation comes from the vessel's own magnetism, so it changes with heading.

   Bowditch. Source: NMC sample exam.

10. Question 10, Compass, International and Inland

    How does the standard magnetic compass heading differ from the true heading?

    ABy variationBBy latitudeCBy deviationDBy compass error
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    D. By compass error

    Compass error is the combined effect of variation and deviation, and it separates a compass heading from a true heading.

    Bowditch. Source: NMC sample exam.

11. Question 11, Compass, International and Inland

    A magnetic compass card is marked in how many degrees?

    A90B180C360D400
    Show the answer

    C. 360

    A compass card is marked through 360 degrees.

    Bowditch. Source: NMC sample exam.

12. Question 12, Weather, International and Inland

    What does a steep barometric gradient indicate?

    ACalmsBStrong windsCPrecipitationDLight winds
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    B. Strong winds

    Tightly packed isobars mean a steep pressure gradient, which drives strong winds.

    Bowditch. Source: NMC sample exam.

13. Question 13, Weather, International and Inland

    Which term is given to the dense black cumulonimbus clouds surrounding the eye of a hurricane?

    AFunnel cloudsBWall cloudsCSpiral rainbandsDCyclonic spirals
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    B. Wall clouds

    Wall clouds are the dense ring around the eye, where the strongest winds are found.

    Bowditch. Source: NMC sample exam.

14. Question 14, Tides & Currents, International and Inland

    A rotary current sets through all directions of the compass. How much time does it take to complete one of these cycles, in a locale off the East coast of the U.S.?

    A2 1/2 hoursB3 1/2 hoursC6 1/4 hoursD12 1/2 hours
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    D. 12 1/2 hours

    A rotary current on a semidiurnal coast completes a cycle in about 12 1/2 hours, one tidal cycle.

    Bowditch. Source: NMC sample exam.

15. Question 15, Tides & Currents, International and Inland

    When daylight savings time is kept, the times of tide and current calculations must be adjusted. How can this be accomplished?

    ASubtract one hour from the times listed for the subordinate stationsBApply no correction as the times at the reference stations are adjusted for daylight savings timeCAdd 15° to the standard meridian when calculating the time differencesDAdd one hour to the times listed for the reference stations
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    D. Add one hour to the times listed for the reference stations

    Tide tables use standard time, so add one hour when daylight saving time is in effect.

    NOAA tide tables. Source: NMC sample exam.

16. Question 16, Tides & Currents, International and Inland

    What describes a flood current?

    AHorizontal movement of the water away from the land following low tideBHorizontal movement of the water away from the land following high tideCHorizontal movement of the water toward the land after high tideDHorizontal movement of the water toward the land after low tide
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    D. Horizontal movement of the water toward the land after low tide

    Flood is the horizontal flow toward land after low tide. Ebb flows away from land.

    Bowditch. Source: NMC sample exam.

17. Question 17, Piloting, International and Inland

    You are steering 349°T, and a light is picked up dead ahead at a distance of 17.2 miles at 2122. You change course to pass the light 4.5 miles off abeam to port. If you are making 19.5 knots, what is your ETA at the position 4.5 miles off the light?

    A2216B2213C2207D2210
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    B. 2213

    Distance to the passing point is root (17.2 squared - 4.5 squared), about 16.6 miles. At 19.5 knots that takes 51 minutes, and 2122 + 51 is 2213.

    Speed, time, distance. Source: NMC sample exam.

18. Question 18, Piloting, International and Inland

    Your vessel is on a course of 221°T at 15 knots. At 0319 a light bears 198.5°T, and at 0353 the light bears 176°T. At what time and distance off will your vessel be when abeam of the light?

    A0417, 6.0 milesB0427, 7.4 milesC0410, 5.2 milesD0407, 4.3 miles
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    A. 0417, 6.0 miles

    Bow angle goes from 22.5 to 45 degrees, so use 7/10 of the run. The run is 34 minutes at 15 knots, or 8.5 miles. 0.7 x 8.5 is 6 miles abeam, 24 minutes after 0353.

    Bow and beam bearings. Source: NMC sample exam.

19. Question 19, Piloting, International and Inland

    You are underway on course 215°T at 12 knots. The current is 000°T at 2.3 knots. What is the course made good?

    A209°TB217°TC222°TD232°T
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    C. 222°T

    Add the vectors: 12 knots on 215 and 2.3 knots setting north. You end up about 6.9 miles west and 7.5 miles south per hour, a course made good of about 222.

    Current sailing. Source: NMC sample exam.

20. Question 20, Electronics, International and Inland

    Which level of accuracy can be obtained utilizing the U.S. Coast Guard's Maritime Differential GPS in an established coverage area?

    A10 metersB20 metersC50 metersD92 meters
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    A. 10 meters

    The accepted answer is that DGPS gives accuracy of about 10 meters in its coverage area.

    Bowditch. Source: NMC sample exam.