USCG General Navigation: Master's License

This is an interactive test. Read each question and select the proper answer by clicking on the appropriate answer. If a "Y" appears, your choice is correct. If a "N" appears, more study may be in order.


65: The LMT of LAN is 1210. Your longitude is 70°30'E. Which time would you use to enter the Nautical Almanac to determine the declination of the Sun at LAN?


83: All Loran-C transmitting stations are equipped with cesium frequency standards which permit __________.


92: When utilizing a Pacific Coast chart, the reference plane of soundings is __________.


110: A millibar is a unit of __________.

    N a. humidity
    N b. precipitation
    Y c. pressure
    N d. temperature

114: All echo-sounders can measure the __________.

    N a. actual depth of water
    Y b. actual depth of water below keel
    N c. average depth from waterline to hard bottom
    N d. average depth of water to soft bottom

133: The line connecting the Loran-C master station with a secondary station is called the __________.

    N a. focus line
    Y b. base line
    N c. side line
    N d. center line

137: Priming of the tides occurs __________.

    N a. at times of new and full Moon
    N b. when the Earth, Moon, and Sun are lying approximately on the same line
    N c. when the Moon is between first quarter and full and between third quarter and new
    Y d. when the Moon is between new and first quarter and between full and third quarter

193: In using Loran-C, skywave reception gives greater range but is __________.

    N a. only accurate during daylight hours
    Y b. much less accurate
    N c. only accurate at twilight
    N d. more accurate than using ground waves

199: Civil twilight occurs at 0558 zone time on 30 December 1981. Your DR position at that time is LAT 15°02'N, LONG 46°02'W. Which statement concerning the planets available for morning sights is TRUE?

    Y a. At 0558, Mars can be used for an ex-meridian observation.
    N b. Venus, Jupiter, and Mars sights will yield a good three line fix.
    N c. Saturn will be near the prime vertical.
    N d. Venus will be visible low in the western sky.

207: An important lunar cycle affecting the tidal cycle is called the nodal period. How long is this cycle?

    N a. 16 days
    N b. 18 days
    N c. 6 years
    Y d. 19 years

302: Which symbol represents a 20-fathom curve?

    Y a. -..-..-..-..-
    N b. - - - - - - - -
    N c. - - . - - . - - . - - .
    N d. - - - - - - - -

316: According to Buys Ballot's law, when an observer in the Northern Hemisphere experiences a northwest wind, the center of low pressure is located to the __________.

    Y a. northeast
    N b. west-southwest
    N c. northwest
    N d. south-southeast

327: When daylight savings time is kept the times of tide and current calculations must be adjusted. One way of doing this is to __________.

    N a. subtract one hour from the times listed under the reference stations
    Y b. add one hour to the times listed under the reference stations
    N c. apply no correction, as the times in the reference stations are adjusted for daylight savings time
    N d. add 15° to the standard meridian when calculating the time difference

412: If you were sailing in the North Pacific and were interested in the ice and iceberg limits, you could find this information in the __________.

    Y a. Pilot Chart
    N b. Coast Pilot
    N c. Notice to Mariners
    N d. None of the above

458: The prevailing westerlies of the Southern Hemisphere blow 18-30 knots __________.

    Y a. all year long
    N b. during the summer months only
    N c. during the winter only
    N d. during spring only

643: When using the radar for navigating __________.

    N a. the best fix is obtained by using a tangent bearing and a range
    N b. and using two radar ranges for a fix, the objects of the ranges should be close to reciprocal bearings
    Y c. and using ranges, the most rapidly changing range should be measured last
    N d. and crossing a radar range of one object with the visual bearing of a second object, the two objects should be 80° to 110° apart

664: Which ARPA data should you use in order to determine if a close quarters situation will develop with a target vessel?

    N a. Set and drift of the current
    Y b. Relative track information
    N c. Predicted time of CPA
    N d. Initial range of acquisition

709: A sea breeze is a wind __________.

    N a. that blows towards the sea at night
    Y b. that blows towards an island during the day
    N c. caused by cold air descending a coastal incline
    N d. caused by the distant approach of a hurricane

719: You are on course 209°T. In order to check the longitude of your vessel, you should observe a celestial body on which bearing?

    N a. 209°
    Y b. 270°
    N c. 299°
    N d. 000°

720: Which change in the condition of the seas could indicate the formation of a tropical storm or hurricane several hundred miles from your location?

    Y a. A long swell from an unusual direction
    N b. A lengthy lull in the wind and seas
    N c. Large seas coming from different directions
    N d. A brisk chop from the southeast

728: In the Bay of Fundy, during twilight, you a take sight of Mars. The sextant altitude (hs) is 03°35.5'. Your height of eye is 32 feet and there is no index error. The air temperature is -10°C and the barometer reads 1010 millibars. What is the observed altitude (Ho)?

    N a. 03°14.5'
    Y b. 03°15.8'
    N c. 03°16.2'
    N d. 03°28.8'

770: You are plotting a running fix in an area where there is a determinable current. How should this current be treated in determining the position?

    Y a. The course and speed made good should be determined and used to advance the LOP.
    N b. The drift should be added to the ship's speed.
    N c. The current should be ignored.
    N d. The set should be applied to the second bearing.

855: Which condition exists at the summer solstice in the Northern Hemisphere?

    N a. The north polar regions are in continual darkness.
    N b. The Northern Hemisphere is having short days and long nights.
    Y c. The Southern Hemisphere is having winter.
    N d. The Sun shines equally on both hemispheres.

920: What is the average speed of the movement of a hurricane following the recurvature of its track?

    N a. 5 to 10 knots
    Y b. 20 to 30 knots
    N c. 40 to 50 knots
    N d. Over 60 knots

983: Error may be introduced into a magnetic compass by __________.

    N a. making a structural change to the vessel
    N b. a short circuit near the compass
    N c. belt buckles
    Y d. All of the above

996: Warm air masses will generally have __________.

    N a. turbulence within the mass
    Y b. stratiform clouds
    N c. heavy precipitation
    N d. good visibility

1064: The dew point temperature is __________.

    N a. always higher than the air temperature
    N b. always lower than the air temperature
    N c. equal to the difference between the wet and dry bulb temperatures
    Y d. the temperature at which the air is saturated with water vapor

1104: Which condition(s) is(are) necessary for the formation of dew?

    N a. Clear skies
    N b. Calm air
    N c. Earth's surface cooler than the dew point of the air
    Y d. All of the above

1169: The symbols shown are used on radio facsimile weather charts. The symbol indicated at letter "O" represents __________. (D042NG )

    Y a. sandstorms
    N b. thunderstorms
    N c. snow
    N d. rain showers

1188: The magnitude of three stars is indicated. Which star is the brightest?

    N a. Antares + 1.2
    N b. Altair + 0.9
    Y c. Vega + 0.1
    N d. Cannot be determined; magnitude indicates size not brightness

1272: What are the colors of a mid-channel daymark?

    N a. Black and red
    Y b. Red and white
    N c. Green and red
    N d. Green and white

1390: The fog most commonly encountered at sea is called __________.

    N a. conduction fog
    N b. radiation fog
    N c. frontal fog
    Y d. advection fog

1470: The Illustration shows the symbols used on radio facsimile weather charts. Which symbol indicates a hurricane? (D042NG )

    N a. M
    N b. I
    N c. L
    Y d. K

1493: You are running parallel to the coast and estimate that the current is against you. In plotting a running fix using bearings from the same object on the coast, the greatest safety margin from inshore dangers will result if what speed is used to determine the fix?

    Y a. Minimum speed estimate
    N b. Maximum speed estimate
    N c. Average speed estimate
    N d. A running fix should not be used under these conditions.

1520: The diurnal inequality of the tides is caused by __________.

    Y a. the declination of the Moon
    N b. changing weather conditions
    N c. the Moon being at apogee
    N d. the Moon being at perigee

1614: Hot air can hold __________.

    N a. less moisture than cold air
    Y b. more moisture than cold air
    N c. the same amount of moisture as cold air
    N d. moisture independent of air temperature

1625: A sling psychrometer is used to measure __________.

    N a. seawater temperature
    N b. engine temperature
    Y c. dry bulb and wet bulb temperatures
    N d. barometric pressure

1628: As the temperature of the air reaches the dew point, __________.

    N a. rain must develop
    Y b. fog may form
    N c. it begins to snow
    N d. water freezes

1755: Which weather system produces strong cold winds called "Northers" during the winter months in the Gulf of Mexico?

    N a. An anticyclone
    N b. A high pressure system
    N c. A cyclone
    Y d. Both A and B

1759: Which magnetic compass corrector(s) can be set while the vessel is on a heading of magnetic north or magnetic south?

    N a. Quadrantal spheres
    Y b. Heeling magnets
    N c. Flinders bar
    N d. Fore-and-aft magnets

1796: Which weather element cannot be measured accurately while on board a moving vessel?

    N a. Relative humidity
    N b. Atmospheric pressure
    N c. Temperature
    Y d. Wave period

1818: In order to utilize the capacity of a lock to its maximum, pleasure craft are locked through with all of the following EXCEPT __________.

    N a. coal barges
    Y b. oil barges
    N c. sand barges
    N d. cement barges

1824: The illustration represents a fixed C of E lock and dam. What navigational light(s) is(are) exhibited at the position indicated by the letter C in the illustration? (DO36NG )

    N a. One red light
    N b. Two green lights
    Y c. Three green lights
    N d. No light

1960: Astronomical refraction causes a celestial body to appear __________.

    N a. to the left of its position in the Northern Hemisphere and to the right in the Southern Hemisphere
    N b. to the right of its position in the Northern Hemisphere and to the left in the Southern Hemisphere
    Y c. higher than its actual position
    N d. lower than its actual position

2016: Which statement about the Flinders bar of the magnetic compass is CORRECT?

    Y a. It compensates for the error caused by the vertical component of the Earth's magnetic field.
    N b. It compensates for error caused by the heeling of a vessel.
    N c. It compensates for quadrantal deviation.
    N d. It is only needed in equatorial waters.

2061: Fog is likely to occur when there is little difference between the dew point and the __________.

    N a. relative humidity
    Y b. air temperature
    N c. barometric pressure
    N d. absolute humidity

2147: What lights would you see on the Illinois waterway when any wickets of the dam or bear traps are open, or partially open, which may cause a set in the current conditions in the upper lock approach?

    N a. Green over blue
    Y b. Red over amber (yellow)
    N c. Red over green
    N d. None of the above

2252: The vertical angle between the horizontal and the magnetic line of force is the __________.

    N a. elevation
    N b. magnetic angle
    N c. vertical angle
    Y d. dip

2369: Which magnetic compass corrector(s) CANNOT be set on a heading of magnetic east or magnetic west?

    Y a. Heeling magnet
    N b. Flinders bar
    N c. Fore-and-aft magnets
    N d. All of the above can be set on magnetic east or magnetic west headings.

2386: The path that the Sun appears to take among the stars is the __________.

    N a. zodiac
    N b. Tropic of Cancer in the Northern Hemisphere
    Y c. ecliptic
    N d. line of apsides

2424: Under the IALA-B Buoyage System, when entering from seaward a lateral system buoy to be left to starboard may display which of the topmarks shown? (D046NG )

    Y a. A
    N b. B
    N c. C
    N d. D

2452: The permanent magnetism of a vessel may change in strength due to __________.

    N a. the nature of the cargo being carried
    N b. changes in heading
    Y c. major structural repair
    N d. All of the above

2456: An orange and white buoy marking an area where operating restrictions are in effect will be marked with which symbol?

    N a. Open-faced diamond
    N b. Diamond with a cross
    Y c. Circle
    N d. Rectangle

2527: In the doldrums you can expect __________.

    N a. steady, constant winds
    Y b. frequent rain showers and thunderstorms
    N c. steep pressure gradients
    N d. low relative humidity

2962: While navigating in fog off a coastline of steep cliffs, you hear the echo of the ship's fog horn 4 1/2 seconds after the signal was sounded. What is the distance to the shore?

    N a. 405 yards
    N b. 628 yards
    N c. 730 yards
    Y d. 825 yards

2966: You take a bearing of 264° of a lighthouse. Which bearing of another object would give the best fix?

    N a. 291°
    N b. 059°
    Y c. 182°
    N d. 239°

2991: When using a radar in an unstabilized mode, fixes are determined most easily from __________.

    N a. objects that are close aboard
    Y b. ranges
    N c. tangent bearings
    N d. center bearings

3016: The radar control that shortens all echoes on the display and reduces clutter caused by rain or snow is the __________.

    N a. sensitivity time control (sea clutter control)
    N b. receiver gain control
    N c. brilliance control
    Y d. fast time constant (differentiator)

3101: The typical operating range of automatic identification systems (AIS) at sea is nominally __________.

    N a. 2 nm
    N b. 8 nm
    Y c. 20 nm
    N d. 40 nm

3130: When may the automatic identification system (AIS) be switched off?

    N a. At anytime as long as it is properly logged.
    Y b. At the Master's professional judgment.
    N c. Only when the vessel is at anchor or in port.
    N d. Under no circumstance.