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.


13: Most modern Loran-C receivers, when not tracking properly, have a(n) __________.


27: Spring tides are tides that __________.


51: In the U.S. Aids to Navigation System, red and green horizontally-banded buoys mark __________.


145: The standard time meridian for zone description -1 is __________.

    N a. 0°
    N b. 7 1/2°W
    N c. 7 1/2°E
    Y d. 15°E

167: When the Moon's declination is maximum north, which of the following will occur?

    N a. Mixed-type tides
    N b. Higher high tides and lower low tides
    Y c. Tropic tides
    N d. Equatorial tides

169: You want to transit Hell Gate on 23 July 1983. What is the period of time around the AM (ZD +4) slack before ebb when the current will be less than 0.5 knot?

    Y a. 0939 to 0957
    N b. 0943 to 0953
    N c. 0844 to 0852
    N d. 0348 to 0356

296: The wind flow from the horse latitudes to the doldrums is deflected due to __________.

    Y a. Coriolis force
    N b. the mid-latitude, semi-permanent high
    N c. differing atmospheric pressures
    N d. the prevailing westerlies

336: You are steaming eastward in the North Atlantic in an extratropical cyclonic storm and the wind is dead ahead. According to the law of Buys Ballot, the center of the low pressure lies __________.

    N a. ahead of you
    N b. astern of you
    N c. to the north
    Y d. to the south

395: If the Sun's observed altitude is 27°12', the zenith distance is __________.

    Y a. 62°48'
    N b. 27°12'
    N c. 152°48'
    N d. 43°12'

414: The barometer is an instrument for measuring the __________.

    N a. temperature
    N b. relative humidity
    N c. dew point
    Y d. atmospheric pressure

418: In most cases, the direction of the apparent wind lies between the bow and __________.

    Y a. the direction of the true wind
    N b. true north
    N c. the beam on the windward side
    N d. the beam on the lee side

425: 90° - Ho = __________.

    N a. sextant altitude
    N b. co-latitude
    N c. LHA
    Y d. zenith distance

548: When the declination of the Moon is 0°12.5'S, you can expect some tidal currents in Gulf Coast ports to __________.

    N a. have either a double ebb or a double flood
    N b. become reversing currents
    Y c. become weak and variable
    N d. exceed the predicted velocities

575: The horizontal plane, perpendicular to the zenith-nadir axis, that intersects with the celestial sphere and is tangent to the earth is called the __________.

    N a. celestial horizon
    N b. sensible horizon
    N c. visible horizon
    Y d. geoidal horizon

632: You must construct a Mercator projection for an area bounded by latitudes 40° - 47°N and longitudes 176°E to 176°W on a paper 28 X 36 inches. Allow a neat line of one inch. What will be the separation between meridians?

    N a. 3.190 inches
    Y b. 3.249 inches
    N c. 3.529 inches
    N d. 3.714 inches

749: You are enroute to assist vessel A. Vessel A is underway at 4.5 knots on course 233°T, and bears 264°T at 68 miles from you. What is the course to steer at 13 knots to intercept vessel A?

    N a. 249°
    Y b. 256°
    N c. 262°
    N d. 268°

823: The greatest directive force is exerted on the magnetic compass when the __________.

    N a. needles are nearly in line with the meridian
    N b. vessel is near the magnetic poles
    N c. variation is near zero
    Y d. vessel is near the magnetic equator

858: Your ship is proceeding on course 320°T at a speed of 25 knots. The apparent wind is from 30° off the starboard bow, speed 32 knots. What is the relative direction, true direction and speed of the true wind?

    Y a. Relative 80°true 040°T, 16.2 knots
    N b. Relative 40°true 080°T, 16.4 knots
    N c. Relative 80° true 060°T, 15.2 knots
    N d. Relative 60°true 040°T, 18.6 knots

881: Under the IALA-A Buoyage System, when entering from seaward, a buoy indicating the preferred channel is to starboard may have a __________.

    N a. green light
    N b. long-flashing light characteristic
    Y c. square topmark
    N d. conical shape

901: Under the IALA-A Buoyage System, a buoy indicating that the preferred channel is to port when entering from seaward, can have a __________.

    N a. can shape
    N b. group-flashing (2) light
    N c. red-and-green vertical stripes
    Y d. green light

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

958: You are preparing a weather report form. Twenty-five percent of the sky is covered with clouds, and the anemometer indicates that the apparent wind is from 062° relative at 13 knots. You are on course 238°T at 22 knots. How should you encode group Nddff? (D041NG )

    Y a. 20220
    N b. 20613
    N c. 30219
    N d. 32413

963: To center a compass bowl in its binnacle, you should have the ship on an even keel, heading north or south, and adjust the screws until __________.

    N a. the compass heading is in line with the lubber's line
    N b. there is no lost motion in the gimbal rings
    Y c. no change of heading by compass is observed if you raise and lower the heeling magnet
    N d. the gimbal rings do not strike the compass frame when they are tilted

991: You are underway in the North Sea on course 328°T when you sight a buoy broad on your port bow. You are in the best navigable water if the buoy __________.

    N a. has a topmark of two cones with points down
    N b. is a western quadrant buoy
    N c. is painted yellow on the top half and black on the bottom
    Y d. exhibits a light with the characteristic of VQ(3)5s

1020: The Light List shows that a navigational light has a nominal range of 6 miles and a height above water of 18 feet (5.5 meters). Your height of eye is 40 feet (12.2 meters) and the visibility is 27.0 miles. At which approximate range will you first sight the light?

    N a. 5.6 miles
    N b. 6.4 miles
    Y c. 9.8 miles
    N d. 12.1 miles

1060: Isobars on a weather map are useful in predicting __________.

    N a. temperature
    N b. dew point
    Y c. wind velocity
    N d. relative humidity

1231: Some lights used as aids to marine navigation have a red sector to indicate a danger area. How are the limits of a colored sector of light listed in the Light List?

    N a. Geographical positions outlining the area of the sector
    N b. True bearings as observed from the light toward a vessel
    Y c. True bearings as observed from a vessel toward the light
    N d. Bearings given in the Light List are always magnetic

1242: Daymarks marking the starboard side of the channel when going towards the sea are __________.

    Y a. green squares
    N b. green triangles
    N c. red squares
    N d. red triangles

1295: The best estimate of the wind direction at sea level can be obtained from observing the direction of the __________.

    N a. cloud movement
    N b. vessel heading
    Y c. waves
    N d. swells

1311: What is the characteristic of a quick light?

    N a. Shows groups of 2 or more flashes at regular intervals
    N b. Durations of light and darkness are equal
    Y c. Shows not less than 60 flashes per minute
    N d. Shows quick flashes for about 5 seconds followed by a 1 second dark period

1347: What will be the velocity of the tidal current south of Doubling Point, ME, at 1357 EST (ZD +5) on 3 April 1983?

    N a. 0.9 knot
    N b. 1.3 knots
    Y c. 2.0 knots
    N d. 2.6 knots

1369: Which of the following is the most useful factor for predicting weather?

    N a. The present reading of the barometer
    N b. The previous reading of the barometer
    N c. The difference in the barometric readings within the past 24 hours
    Y d. The rate and direction of change of barometric readings

1380: Which type of weather could you expect soon after seeing "hook" or "comma" shaped cirrus clouds?

    Y a. Rain with the approach of a warm front
    N b. Clearing with the approach of a cold front
    N c. Continuing fog and rain
    N d. The formation of a tropical depression

1384: Which type of cloud is indicated by number 9? (D039NG )

    N a. Cumulus
    Y b. Cumulonimbus
    N c. Altostratus
    N d. Stratocumulus

1444: Stratocumulus clouds are indicated by which number? (D039NG )

    N a. 1
    N b. 4
    Y c. 6
    N d. 7

1488: What defines a great circle?

    N a. A curved line drawn on a Mercator Chart
    N b. A course line that inscribes a loxodromic curve
    Y c. The shortest distance between any two points on the earth
    N d. The smallest circle that can be drawn on the face of a sphere

1547: Which light combination does NOT indicate a navigational channel passing under a fixed bridge?

    Y a. Red lights on the LDB and green lights on the RDB
    N b. Three white lights in a vertical line
    N c. Two green lights in a range under the span
    N d. A fixed red light on each pier at the channel edge

1642: Which type of cloud formation should be of immediate concern to small craft operators?

    N a. cirrus
    N b. altostratus
    N c. nimbostratus
    Y d. cumulonimbus

1649: If you count 20 seconds between seeing lightning and hearing the thunder, how far is the storm away from you?

    N a. 2 miles
    Y b. 4 miles
    N c. 6 miles
    N d. 8 miles

1705: Two well-developed low pressure areas may be separated by a __________.

    N a. trough of higher pressure
    N b. hill of higher pressure
    Y c. ridge of higher pressure
    N d. valley of higher pressure

1732: The eye of a hurricane is surrounded by dense black cumulonimbus clouds which are called the __________.

    Y a. wall cloud
    N b. nimbostratus cloud
    N c. bar
    N d. funnel

1768: A flashing red light displayed at a single lock means that the lock __________.

    N a. is ready to use but vessels must stand clear
    N b. is ready to use and vessels may approach
    Y c. cannot be made ready immediately and vessels shall stand clear
    N d. cannot be made ready immediately but vessels may approach

1955: The letter A in illustration D006NG represents the __________.

    N a. geoidal horizon
    Y b. sensible horizon
    N c. celestial horizon
    N d. visible horizon

2078: If a towboat requires a double lockage it shall give which sound signal at a distance of not more than one mile from the lock?

    N a. One short blast followed by two long blasts
    N b. One long blast followed by one short blast
    N c. Two long blasts followed by one short blast
    Y d. One long blast followed by two short blasts

2143: What lights would you see on the Illinois water way 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?

    Y a. Red over amber (yellow)
    N b. Green over amber (yellow)
    N c. Red over Green
    N d. Green over Red

2258: The primary use of apparent time in marine navigation is to __________.

    N a. calculate sunrise or sunset
    N b. determine zone time
    N c. enter an almanac
    Y d. determine the time of meridian transit

2351: A position obtained by applying ONLY your vessel's course and speed to a known position is a __________.

    N a. running fix
    N b. probable position
    N c. fix
    Y d. dead-reckoning position

2396: Perihelion is the point where the Sun __________.

    Y a. is nearest to the Earth
    N b. is farthest from the Earth
    N c. is on the opposite side of the Earth from the Moon
    N d. and Moon and Earth are in line

2416: An orange and white buoy indicating a vessel-exclusion area will be marked with what symbol?

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

2418: While proceeding downriver, you sight a red triangular-shaped daymark on the left bank. Under the U.S. Aids to Navigation System on the Western Rivers this is a __________.

    N a. special purpose signal
    Y b. passing daymark
    N c. mark with no lateral significance
    N d. crossing daymark

2474: A vessel is heading magnetic north and its magnetic compass indicates a heading of 356°. What action should be taken to remove this error during compass adjustment?

    N a. If the blue ends of the magnets are to port, and the athwartships tray is at the top, you should remove some of the magnets.
    Y b. If the blue ends of the magnets are to starboard, and the athwartships tray is at the bottom, you should remove some magnets.
    N c. If the red ends of the magnets are to starboard, and the athwartships tray is at the bottom, you should reverse the magnets.
    N d. If the blue ends of the magnets are to starboard, you should raise the athwartships tray.

2505: At the approaches to Savannah, GA, with the wind coming out of the west, the wind-driven current will be flowing approximately __________.

    N a. 280°
    N b. 260°
    N c. 100°
    Y d. 080°

2512: In the time diagram shown __________. (D005NG )

    Y a. you are in east longitude
    N b. your time is about 1000
    N c. your date is a day earlier than the date at Greenwich
    N d. you must be in the Northern Hemisphere for it to be accurate

2520: When correcting the sextant altitude to apparent altitude you are correcting for inaccuracies in the reference level and __________.

    N a. the equivalent reading to the center of the body
    N b. the equivalent reading from the center of the Earth
    Y c. for inaccuracies in the instrument
    N d. the bending of the rays of light from the body

2582: You must construct a Mercator plotting sheet on a piece of paper measuring 32" by 36". The area includes latitude 31°S to 37°S and longitude 005°W to 002°E. Allow a three-quarter inch neat line on all sides. What is the maximum distance between each degree of longitude that will permit the area of the plotting sheet to be drawn within the stated limitations?

    N a. 4.00 inches
    N b. 4.11 inches
    N c. 4.25 inches
    Y d. 4.36 inches

2604: A sidereal day is approximately how much shorter than a solar day?

    Y a. 4 minutes
    N b. 8 minutes
    N c. 12 minutes
    N d. 16 minutes

2606: The measurement of local time is based on the passage of the Sun over the __________.

    N a. upper branch of the observer's meridian
    Y b. lower branch of the observer's meridian
    N c. upper branch of the Greenwich meridian
    N d. lower branch of the Greenwich meridian

2670: The angle that is measured westward from the first point of Aries to the hour circle of the body along the celestial equator is the __________.

    N a. Greenwich sidereal angle
    N b. local sidereal time
    Y c. sidereal hour angle
    N d. azimuth angle

2680: The angle measured eastward from the vernal equinox along the celestial equator often expressed in time units is the __________.

    N a. Greenwich sidereal time
    Y b. right ascension
    N c. local sidereal time
    N d. sidereal hour angle

2738: While navigating in fog off a coastline of steep cliffs, you hear the echo of the ship's fog horn 3 seconds after the signal was sounded. What is the distance to the shore?

    N a. 1100 yards
    N b. 872 yards
    Y c. 550 yards
    N d. 792 yards