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.


46: What wind reverses directions seasonally?


85: Your longitude is 179°59'W. The LMT at this longitude is 23h 56m of the 4th day of the month. Six minutes later your position is 179°59'E longitude. Your LMT and date is now __________.


107: The average height of the surface of the sea for all stages of the tide over a 19 year period is called __________.


111: Green lights may appear on __________.

    Y a. horizontally banded buoys
    N b. vertically striped buoys
    N c. yellow buoys
    N d. spherical buoys

181: Which navigational mark may only be lettered?

    N a. An unlighted, green, can buoy
    Y b. A spherical buoy
    N c. A red buoy
    N d. A port side day-shape

185: A ship is in longitude 54°00'W on a true course of 270°. The ship's clocks are on the proper time zone. At what longitude should the clocks be changed to maintain the proper zone time?

    N a. 45°00'W
    N b. 52°30'W
    N c. 60°00'W
    Y d. 67°30'W

309: You are underway on course 050°T and your maximum speed is 12 knots. The eye of a hurricane bears 120°T, 110 miles from your position. The hurricane is moving towards 285°T at 25 knots. What course should you steer at 12 knots to have the maximum CPA?

    N a. 332°
    N b. 339°
    Y c. 346°
    N d. 357°

328: The direction of prevailing winds in the Northern hemisphere is caused by the __________.

    N a. magnetic field at the North Pole
    N b. Gulf Stream
    Y c. Earth's rotation
    N d. Arctic cold fronts

337: To predict the actual depth of water using the Tide Tables, the number obtained from the Tide Tables is __________.

    N a. the actual depth
    Y b. added to or subtracted from the charted depth
    N c. multiplied by the charted depth
    N d. divided by the charted depth

350: When making landfall at night, the light from a powerful lighthouse may sometimes be seen before the lantern breaks the horizon. This light is called the __________.

    N a. diffusion
    N b. backscatter
    Y c. loom
    N d. elevation

429: A great circle crosses the equator at 127°W. It will also cross the equator at what other longitude?

    N a. 127°E
    Y b. 53°E
    N c. 27°E
    N d. 27°W

438: Your longitude is 124°E, and your local mean time is 0520 on the 5th of the month. The mean time and date at Greenwich is __________.

    N a. 1336 on the 4th
    N b. 1336 on the 5th
    Y c. 2104 on the 4th
    N d. 2104 on the 5th

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

491: A special purpose buoy shall be __________.

    N a. lighted with a white light
    N b. striped black and red
    N c. lighted with a red light
    Y d. yellow

721: Under the IALA Buoyage System, a red and white vertically-striped buoy would NOT indicate __________.

    N a. a landfall
    Y b. the extreme end of an islet
    N c. a mid-channel
    N d. a center line

769: What does not contribute to the commercial GPS receiver position error?

    N a. Satellite clock
    Y b. Ship's speed
    N c. Atmospheric/Ionospheric propagation
    N d. Satellites' orbits

783: Magnetism which is present only when the material is under the influence of an external field is called __________.

    N a. permanent magnetism
    Y b. induced magnetism
    N c. residual magnetism
    N d. terrestrial magnetism

797: Which statement is TRUE concerning the current of the Gulf Stream?

    N a. It reaches its daily maximum speed a few hours before the transit of the Moon.
    N b. It is slower at the time of neap tides than at spring tides.
    N c. When the Moon is at its maximum declination the stream is narrower than when the Moon is on the equator.
    Y d. Variations in the trade winds affect the current.

799: In Region A of the IALA Buoyage System, when entering from seaward, the starboard side of a channel would be marked by a __________.

    N a. green can buoy
    N b. red can buoy
    Y c. green conical buoy
    N d. red conical buoy

832: What is the most important source of information to be used in correcting charts and keeping them up to date?

    N a. Fleet Guides
    Y b. Notice to Mariners
    N c. Sailing Directions
    N d. Pilot Charts

845: During one synodic rotation, a body makes one complete turn relative to the __________.

    N a. Earth
    Y b. Sun
    N c. stars
    N d. vernal equinox

862: The U.S. Coast Guard publishes __________.

    Y a. Light Lists
    N b. U.S. Coast Pilots
    N c. Radio Navigational Aids
    N d. All of the above

912: The Light List Does NOT contain information on __________.

    N a. the Global Positioning System (GPS)
    Y b. aeronautical lights useful for marine navigation
    N c. radio beacon systems
    N d. radio direction finder calibration stations

959: What is the index error of sextant B in illustration D050NG? (D050NG )

    N a. 0'30" off the arc
    N b. 1'00" off the arc
    Y c. 3'30" off the arc
    N d. 1'30" on the arc

988: You are preparing a weather report form, WS Form B-80. One-half of the sky is covered with clouds, and the anemometer indicates that the apparent wind is from 340° relative at 14 knots. You are on course 307°T at 12.6 knots. How should you encode group Nddff? (D041NG )

    N a. 53414
    N b. 54013
    Y c. 42205
    N d. 43013

1062: What is the approximate geographic range of Horton Point Light, NY, if your height of eye is 40 feet (12.2 meters)? Refer to "Reprints from the LIGHT LISTS AND COAST PILOTS" .

    N a. 18.8 nm
    Y b. 19.3 nm
    N c. 20.3 nm
    N d. 24.8 nm

1077: A current will develop between areas of different density in ocean waters. If you face in the same direction the current is flowing, the water of __________.

    N a. high density will be on the left in the Northern Hemisphere
    N b. high density will be on the right in the Southern Hemisphere
    Y c. low density will be on the left in the Northern Hemisphere
    N d. low density will be on the left in the Southern Hemisphere

1087: The velocity of a rotary tidal current will increase when the Moon is __________.

    N a. new
    N b. full
    N c. at perigee
    Y d. All of the above

1110: To make sure of getting the full advantage of a favorable current, you should reach an entrance or strait at what time in relation to the predicted time of the favorable current?

    N a. At the predicted time
    Y b. 30 minutes before the predicted time
    N c. One hour after the predicted time
    N d. 30 minutes before flood, one hour after an ebb

1156: When cold air displaces warm air you have a(n) __________.

    Y a. cold front
    N b. occluded front
    N c. stationary front
    N d. warm front

1163: The total magnetic effects which cause deviation of a vessel's compass can be broken down into a series of components which are referred to as __________.

    N a. divisional parts
    Y b. coefficients
    N c. fractional parts
    N d. equations

1168: Which type of cloud is indicated by the number 4? (D039NG )

    N a. Altocumulus
    N b. Cirrostratus
    N c. Cumulus
    Y d. Altostratus

1173: When adjusting a magnetic compass for error, a deviation table should be made __________.

    N a. before correcting for any deviation
    N b. after correcting for variation
    Y c. after adjusting the fore-and-aft and athwartships permanent magnets
    N d. before the quadrantal correctors are placed on the compass

1180: You are on course 238°T. To check the course of your vessel you should observe a celestial body on which bearing?

    N a. 180°
    N b. 238°
    Y c. 328°
    N d. 090°

1332: The longitude of the upper vertex of a great circle track is 169°E. What is the longitude of the lower vertex?

    N a. 076°E
    N b. 169°W
    N c. 101°W
    Y d. 011°W

1537: Which sextant in illustration D043NG reads 29°47.5'? (D043NG )

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

1544: The height of a tide can be increased by __________.

    Y a. a storm surge
    N b. a high pressure area
    N c. the jet stream
    N d. a cold front

1551: In order to get the maximum benefit from the Gulf Stream, on a voyage between Houston and Philadelphia, you should navigate __________.

    Y a. about 75 miles east of Ormond Beach, FL
    N b. close inshore between Jupiter Inlet and Fowey Rocks, FL
    N c. along the 50-fathom curve while off the east coast of Florida
    N d. about 10 miles east of Cape Canaveral, FL

1728: If a hurricane several hundred miles away is moving in your general direction your barometer would __________.

    N a. start to rise rapidly
    Y b. start to fall gradually
    N c. rise slowly, begin "pumping" and then start a slow, steady fall
    N d. remain steady

1730: If you observe the point of cloud convergence shifting to the right and the "bar" of the storm appears to move along the horizon __________.

    Y a. the center of the storm will by-pass you
    N b. the storm will strike you on the starboard side
    N c. you are in the direct path of the storm and should take immediate steps to batten down loose gear
    N d. the storm is starting to break up

1785: Which factor(s) is/are used to develop the charted information of a lighthouse?

    N a. Height of the light and the observer
    Y b. Height and brightness of the light
    N c. Brightness of the light and height of the observer
    N d. Height of the light only

1812: The line of position should be plotted as a circle around the GP of the body when the Ho exceeds what minimum value?

    N a. 80°
    N b. 83°
    N c. 85°
    Y d. 87°

1815: Which weather system produces strong cold winds called "Northers" during the winter months in the Gulf of Mexico?

    Y a. An anticyclone
    N b. A polar maritime air mass
    N c. A cyclone
    N d. A low pressure system

1815: Which weather system produces strong cold winds called "Northers" during the winter months in the Gulf of Mexico?

    Y a. An anticyclone
    N b. A polar maritime air mass
    N c. A cyclone
    N d. A low pressure system

2068: The illustration represents a movable dam. If there is high water and the wickets are down so that there is an unobstructed navigable pass through the dam, what light(s) will be shown at D if the lock walls and piers are not awash? (D037NG )

    Y a. One red light
    N b. Two red lights
    N c. Three red lights
    N d. One amber light

2254: A rock and sand structure extending from the bank of the river toward the channel is known as a __________.

    Y a. wingdam
    N b. towhead
    N c. cutoff
    N d. landwall

2271: What is the definition of height of tide?

    N a. The vertical distance from the surface of the water to the ocean floor
    Y b. The vertical distance from the tidal datum to the level of the water at any time
    N c. The vertical difference between a datum plane and the ocean bottom
    N d. The vertical difference between the heights of low and high water

2335: The Light List indicates that a light has a nominal range of 13 miles and is 36 feet high. If the visibility is 17 miles and your height of eye is 25 feet, at what approximate distance will you sight the light?

    N a. 10.0 miles
    Y b. 12.9 miles
    N c. 14.2 miles
    N d. 17.0 miles

2348: Under the IALA cardinal system, a mark with a quick light showing 9 flashes every 15 seconds indicates that the safest water is on the __________.

    N a. north side of the mark
    Y b. west side of the mark
    N c. east side of the mark
    N d. south side of the mark

2462: Under ideal viewing conditions, the dimmest star that can be seen with the unaided eye is of what magnitude?

    N a. First
    N b. Third
    N c. Fourth
    Y d. Sixth

2481: The letter D as shown represents the __________. (D006NG )

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

2566: When the time is based on the movement of the visible Sun along the ecliptic the time is known as __________.

    N a. real time
    N b. visible time
    Y c. apparent time
    N d. mean time

2651: Low pressure disturbances which travel along the intertropical convergence zone are called __________.

    Y a. tropical waves
    N b. tropical disturbances
    N c. permanent waves
    N d. tidal waves

2740: When one upbound vessel is overtaking another vessel and both are pushing a tow ahead, what reaction may you expect?

    N a. Both towheads will tend to drift apart, and the overtaking vessel will be slowed down.
    N b. Both towheads will tend to drift together, and the overtaking vessel will be slowed down.
    Y c. Both towheads will tend to drift apart, and the overtaken vessel will be slowed down.
    N d. Both towheads will tend to drift together, and the overtaken vessel will be slowed down.

2769: If your vessel must pass through a draw during a scheduled closure period, what signal should you sound to request the opening of the draw?

    N a. One prolonged blast followed by one short blast
    N b. Three short blasts
    N c. One prolonged blast followed by three short blasts
    Y d. Five short blasts

2780: You are pushing a tow ahead and passing close to another towboat which is pushing ahead in the same direction (you are overtaking). After the towheads pass close alongside __________.

    N a. you will gain speed
    N b. both boats will gain speed
    N c. the tows will tend to drift apart
    Y d. the tows will tend to drift together

2927: The position labeled C, as shown, was plotted because __________. (D051NG )

    N a. the vessel's course changed from due North to due East
    Y b. running fixes are better estimates of true position than dead-reckoning positions
    N c. the vessel's speed changed
    N d. All of the above are correct

3006: You are outbound in a channel marked by a range astern. The range line is 309°T. You are steering 127°T and have the range in sight as shown. What action should you take? (D047NG )

    N a. Come right to 129°T.
    N b. Come left until the range comes in line then alter course to 129°T.
    N c. Come left until the range comes in line then alter course to 125°T.
    Y d. Come right to close the range then when on the range steer 129°T.

3054: In illustration D051NG, the position labeled C was plotted because __________.

    Y a. running fixes are better estimates of true position than dead-reckoning positions are
    N b. the vessel's course changed from due North to due East
    N c. the vessel's speed changed
    N d. All of the above are correct

3055: A single line of position combined with a dead-reckoning position results in a(n) __________.

    N a. running fix
    N b. fix
    Y c. estimated position
    N d. assumed position