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Deck · 2,005 questions

Navigation Problems - USCG Exam Questions

Worked chart problems: plotting courses and fixes, time, speed, and distance, set and drift, and compass error corrections.

Every question below is a real U.S. Coast Guard exam question with four choices. Answer one and the correct choice is revealed instantly, with the USCG reference and illustration where the question uses one.

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All Navigation Problems questions

Questions 1–100 of 2,005 · page 1 of 21

  1. #1 On 2 February your 0400 zone time DR position is LAT 24°14.0' N, LONG 163°28.0' W. You are on course 322°T at a speed of 22 knots. Considering their m...
  2. #2 You observe the lower limb of the Sun at a sextant altitude (hs) of 34°51.4' on 18 October. The index error is 2.0' off the arc. The height of eye is...
  3. #3 You are underway on course 160°T at 10 knots. The current is 210°T at 0.9 knots. What is the course made good?
  4. #4 On 16 January your 0930 ZT DR position is LAT 26°07.0'S, LONG 51°43.0'E. Your vessel is on course 238°T at a speed of 17.0 knots. What is the ZT of lo...
  5. #6 Your vessel is steering course 299°psc, variation for the area is 7°W, and deviation is 4°W. The wind is from the southwest, producing a 3° leeway. Wh...
  6. #7 On 25 June at 0612 zone time, morning stars were observed, and the vessel's position was determined to be LAT 28°13.0'S, LONG 49°34.0'E. Your vessel i...
  7. #8 On 24 January your 0700 zone time DR position is LAT 22°25.0'N, LONG 46°10.0'W. Your vessel is on course 110°T at a speed of 12.0 knots. What is the z...
  8. #9 On 22 July at 0448 ZT, morning stars were observed, and the vessel's position was determined to be LAT 21°43.0'N, LONG 158°39.0'E. Your vessel is stea...
  9. #10 At 0600 ZT on 24 July your DR position is LAT 22°37'N, LONG 32°45'W. You are steering 185°T at a speed of 20.0 knots. Determine the computed altitude...
  10. #11 On 28 October at 1754 ZT, your vessel's DR position is LAT 28°30' N, LONG 63°24' W. At this time, you obtain a sextant altitude (hs) of Polaris readin...
  11. #13 While enroute from Cape Town to Rio a vessel's course is 281°pgc. The variation for the locality is 24°W. The deviation is 4°E. The gyro error is 2°W....
  12. #14 You observe the lower limb of the Sun at a sextant altitude (hs) of 50°26.9' on 9 November. The index error is 1.5' on the arc. The height of eye is 5...
  13. #15 The true course between two points is 194°. Your gyrocompass has an error of 2°W and you make an allowance of 1° leeway for a southwest wind. What gyr...
  14. #17 On 2 October your 1845 DR position is LAT 28°09.2'S, LONG 167°48.1'E. You observe a faint star through a hole in the clouds at a sextant altitude (hs)...
  15. #18 On 22 June your 0400 zone time DR position is LAT 23°00'N, LONG 81°45'W. You are steaming on course 110°T at a speed of 8.6 knots. What will be the zo...
  16. #19 On 2 April your 0830 zone time fix gives you a position of LAT 20°16.0'S, LONG 004°12.0'E. Your vessel is steaming a course of 143°T at a speed of 18....
  17. #20 You are taking a time tick using the 1930 signal from Rio de Janeiro, Brazil. You hear the preparatory signal "CQ DE PPE" repeated several times follo...
  18. #22 On 25 February at 0622 ZT, you observe the upper limb of the Moon with a sextant altitude of 59°58.6'. Your DR position is LAT 30°28.3'S, LONG 102°39....
  19. #23 You observe the lower limb of the Sun at a sextant altitude (hs) of 41°29.8' on 11 January. The index error is 2.4' off the arc. The height of eye is...
  20. #24 You are underway on course 106°T at a speed of 15.3 knots. You sight a buoy bearing 109°T at a radar range of 3.6 miles at 1725. If you change course...
  21. #25 The propeller on a vessel has a diameter of 24.0 feet and a pitch of 21.3 feet. What would be the slip if the vessel cruised 510 miles in a 24 hour da...
  22. #26 On 14 March at 1845 ZT, you take a sextant observation of Polaris. Your DR position is LAT 29°10' N, LONG 154°30' W, and your sextant reads 29°53.5'....
  23. #28 On 27 March your 0730 zone time position is LAT 28°16'N, LONG 56°37'W. Your vessel is on course 158°T at a speed of 15.0 knots. An observation of the...
  24. #29 On 12 March your 1846 zone time DR position is LONG 129°16.5' W. At that time you observe Polaris with a sextant altitude (hs) of 28°01.5'. The chrono...
  25. #31 On 25 April your 0930 zone time position is LAT 28°35'S, LONG 82°30'W. Your vessel is on course 300°T at a speed of 20.0 knots. Determine the zone tim...
  26. #32 On 22 May your 0437 DR position is LAT 25°18.5'N, LONG 51°18.0'W. You observed an unidentified star bearing 233°T at an observed altitude (Ho) of 29°4...
  27. #33 On 29 April your 0300 ZT DR position is LAT 28°39' N, LONG 168°03' E. You are on course 108°T at a speed of 22 knots. Considering their magnitude, azi...
  28. #34 You are steering 154° per gyrocompass. The wind is northeast by east, causing 4° leeway. The gyro error is 3° east, variation is 11° west, and deviati...
  29. #35 If the pitch of the propeller is 21.5 feet, and the revolutions per day are 96,666, calculate the day's run allowing 9% negative slip.
  30. #36 You desire to make good a true course of 129°. The variation is 7°E, magnetic compass deviation is 4°E, and gyrocompass error is 2°W. An easterly wind...
  31. #37 On 12 June your 1845 DR position is LAT 21°47'N, LONG 46°52'W when you observe a faint unidentifiable star through a break in the clouds. The star bea...
  32. #38 On 9 February your 0830 zone time DR position is LAT 22°19.0'N, LONG 64°37.0'E. Your vessel is on course 128°T at a speed of 19.0 knots. What is the z...
  33. #39 On 12 February your 0930 zone time DR position is LAT 25°20.0'N, LONG 30°40.0'W. Your vessel is on course 135°T at a speed of 11.2 knots. What is the...
  34. #40 You observe the lower limb of the Sun at a sextant altitude (hs) of 62°22.2' on 6 June. The index error is 1.2' on the arc. The height of eye is 28 fe...
  35. #41 On 3 October your 0830 ZT position is LAT 26°15.0'S, LONG 73°16.0'E. Your vessel is on course 280°T at a speed of 19.0 knots. What is the ZT of local...
  36. #43 On 22 February your 1857 DR position is LAT 23°46.0'S, LONG 93°16.5'E. You observe an unidentified star bearing 108°T at an observed altitude (Ho) of...
  37. #44 The true course between two points is 078°. Your gyrocompass has an error of 2°E. You make an allowance of 3° leeway for a north wind. What gyro cours...
  38. #45 On 2 October your 1845 DR position was LAT 28°09.2'S, LONG 167°48.1'E. You observe a faint star through a hole in the clouds at a sextant altitude (hs...
  39. #47 On 15 November your 0813 zone time (ZT) fix gives you a position of LAT 22°30.0'N, LONG 67°28.0'W. Your vessel is on course 164°T, and your speed is 1...
  40. #48 On 10 October your 1500 zone time DR position is LAT 27°35.6' S, LONG 44°49.0' W. You are on course 342°T at a speed of 24 knots. Considering their ma...
  41. #49 On 22 June your 0424 DR position is LAT 26°18.5' N, LONG 124°18.2' W. You observe an unidentified star bearing 154°T at an observed altitude (Ho) of 1...
  42. #50 On 7 March at 1838 ZT, in DR position LAT 34°26.9' N, LONG 58°16.2' W, you observe Polaris for latitude. The sextant altitude (hs) is 35°08.4'. The in...
  43. #51 On 16 January at 1804 zone time, you take a sextant observation of Polaris. Your vessel's DR position is LAT 36°12' N, LONG 124°36' W, and your sextan...
  44. #52 If the pitch of the propeller is 26.7 feet, and the revolutions per day are 131,717, calculate the day's run allowing 4% negative slip.
  45. #53 If the pitch of the propeller is 19.4 feet, and the revolutions per day are 96,713, calculate the day's run allowing 6% positive slip.
  46. #54 On 25 April your 1130 DR position is LAT 24°50.0'N, LONG 61°25.0'W. Your vessel is on a course of 300°T at a speed of 16.0 knots. Determine the zone t...
  47. #56 At 1300 ZT on 9 May your DR position is LAT 24°00'N, LONG 83°26'W. Determine the computed altitude (Hc) of the Sun for the assumed position nearest to...
  48. #57 Your vessel is steering course 166°psc, variation for the area is 8°W, and deviation is 3°W. The wind is from the west-southwest, producing a 2° leewa...
  49. #58 You desire to make good a true course of 329°. The variation is 13° W, magnetic compass deviation is 4°E, and gyrocompass error is 2°W. A southerly wi...
  50. #59 If the speed necessary for reaching port at a designated time is 17.4 knots and the pitch of the propeller is 25.6 feet, how many revolutions per minu...
  51. #60 On 3 December evening twilight for your vessel will occur at 1901 zone time. Your vessel's DR position will be LAT 24°18.5' S, LONG 110°30.6' W. Consi...
  52. #64 If the pitch of the propeller is 25.1 feet, and the revolutions per day are 91,591, calculate the day's run allowing 7% positive slip.
  53. #65 If the speed necessary for reaching port at a designated time is 23.7 knots and the pitch of the propeller is 20.8 feet, how many revolutions per minu...
  54. #66 On 12 June your 1945 DR position is LAT 21°47.0'N, LONG 46°52.0'W when you observe a faint unidentifiable star through a break in the clouds. The star...
  55. #67 On 28 July your 0800 zone time fix gives you a position of LAT 25°16.0'N, LONG 71°19.0'W. Your vessel is on course 026°T, and your speed is 17.5 knots...
  56. #68 The true course between two points is 057°. Your gyrocompass has an error of 3° east and you make an allowance of 1° leeway for a north-northwest wind...
  57. #69 On 2 January you are on a course of 094°T at a speed of 20 knots. At 0430 ZT, your DR position is LAT 24°12'N, LONG 71°24'W. Determine the zone time o...
  58. #70 On 3 February your 0451 zone time DR position is LAT 24°15.0' S, LONG 124°24.0' W. Considering their magnitude, azimuth and altitude, which group incl...
  59. #71 On 12 June your 1845 DR position is LAT 21°47'N, LONG 46°52'W when you observe a faint unidentifiable star through a break in the clouds. The star bea...
  60. #73 On 16 July your 1810 zone time DR position is LAT 24°16.5' S, LONG 162°52.0' E. Considering their magnitude, azimuth, and altitude, which group includ...
  61. #74 The propeller on a vessel has a diameter of 21.5 feet and a pitch of 24.5 feet. What would be the apparent slip if the vessel cruised 458 miles in a 2...
  62. #75 On 26 November your 0535 DR position is LAT 27°18.9' S, LONG 30°18.4' E. You observe an unidentified planet bearing 085°T at an observed altitude (Ho)...
  63. #76 On 15 October your 0300 zone time DR position is LAT 27°14' S, LONG 99°46' E. You are on course 128°T at a speed of 19 knots. Considering their magnit...
  64. #78 On 13 November at 0438 ZT, morning stars were observed and the vessel's position was determined to be LAT 22°14.0'S, LONG 79°23.0'E. Your vessel is st...
  65. #79 On 5 May your 1800 ZT DR position is LAT 26°11.5'N, LONG 65°35.0'W. You are on course 270°T at a speed of 12 knots. What will be the ZT of sunset at y...
  66. #81 On 10 June your 1712 zone time DR position is LAT 25°10.0' S, LONG 06°58.0' E. You are on course 213°T at a speed of 9.0 knots. Considering their magn...
  67. #82 On 16 March your 0330 ZT DR position is LAT 22°36.0'S, LONG 76°16.0'E. You are on course 098°T at a speed of 16 knots. What will be the ZT of sunrise...
  68. #83 On 7 May you observe Polaris for latitude at 0303 ZT. Your DR position is LAT 56°35.4' N, LONG 05°38.9' W. The sextant altitude is 56°11.1'. The heigh...
  69. #84 On 24 March your vessel is enroute from Cadiz to Norfolk. Evening twilight will occur at 1830 zone time and your vessel's DR position will be LAT 35°0...
  70. #85 On 6 March your 1854 zone time DR position is LAT 23°51.5' N, LONG 73°14.0' W. At that time you observe Polaris with a sextant altitude (hs) of 24°16....
  71. #86 On 3 February your 0547 zone time DR position is LAT 24°18.5' N, LONG 167°25.0' E. Considering their magnitude, azimuth, and altitude, which group inc...
  72. #87 On 12 September your 0600 zone time (ZT) fix gives you a position of LAT 22°51.9'N, LONG 133°40.1'W. Your vessel is on course 062°T, and your speed is...
  73. #89 On 10 October your 0930 zone time position is LAT 25°00.0'S, LONG 164°38.6'W. Your vessel is on course 180°T at a speed to 10.0 knots. What is the zon...
  74. #90 On 2 October your 1845 DR position is LAT 28°09.2'S, LONG 167°48.1'E. You observe a faint star through a hole in the clouds at a sextant altitude (hs)...
  75. #91 You are turning 105 RPM, with a propeller pitch of 17 feet, and an estimated slip of -1%. What is the speed of advance?
  76. #92 On 22 April your 1852 ZT DR position is LAT 23°54.5' N, LONG 117°36.8' W. You observe an unidentified star bearing 129°T at an observed altitude (Ho)...
  77. #93 On 4 January your 0800 zone time DR position is LAT 25°25.0 S, LONG 16°09.0'W. Your vessel is on course 290°T at a speed of 13.5 knots. What is the zo...
  78. #94 On 11 November your 0200 zone time DR position is LAT 26°32' S, LONG 154°16' E. You are on course 058°T at a speed of 21 knots. Considering their magn...
  79. #95 On 28 October morning twilight will occur around 0524 ZT. Your DR position is LAT 25°25.0' N, LONG 32°33.3' W. Considering their magnitude and locatio...
  80. #96 On 17 May at 0501 zone time, morning stars were observed, and the vessel's position was determined to be LAT 22°16.0'S, LONG 103°46.0'W. Your vessel i...
  81. #97 On 14 January your 0550 DR position is LAT 25°26.0'N, LONG 38°16.0'W. You observe an unidentified star bearing 212°T at an observed altitude (Ho) of 4...
  82. #99 On 22 July your 1759 ZT DR position is LAT 24°50.2' S, LONG 05°16.0' E. You observe an unidentified star bearing 231°T, at an observed altitude (Ho) o...
  83. #100 On 23 March your 1600 ZT DR position is LAT 27°16.3' N, LONG 156°48.2' W. You are on course 063°T at a speed of 18.0 knots. Considering their magnitud...
  84. #101 On 24 September your 1841 zone time DR position is LONG 129°34.5' E. At that time you observe Polaris with a sextant altitude (hs) of 25°20.8'. The ch...
  85. #102 On 20 June your 1742 zone time DR position is LAT 24°55.0' S, LONG 8°19.6' E. Considering their magnitude, azimuth, and altitude, which three stars ar...
  86. #103 On 30 October an ex-meridian altitude of the Sun's lower limb at upper transit was observed at 1144 ZT. Your DR position is LAT 22°42.0'S, LONG 137°16...
  87. #104 On 22 July your 1759 DR position is LAT 24°50.2' S, LONG 05°16.0' E. You observe an unidentified star bearing 293°T at an observed altitude (Ho) of 17...
  88. #105 On 22 July your 0442 DR position is LAT 26°35.6' N, LONG 22°16.7' W. You observe an unidentified star bearing 149°T at an observed altitude (Ho) of 12...
  89. #106 On 12 July your 0800 ZT DR position is LAT 24°15.0'N, LONG 132°30.0'W. Your vessel is on course 045°T at a speed of 15.0 knots. What is the ZT of loca...
  90. #107 On 16 February your 0300 ZT DR position is LAT 28°32.0'S, LONG 176°49.0'E. You are on course 082°T at a speed of 21 knots. What will be the zone time...
  91. #108 On 24 August your vessel is enroute from Perth, Australia, to Bombay, India. Evening twilight will occur at 1807 zone time and your vessel's DR positi...
  92. #109 On 1 October you determine the zone time of evening twilight will be 1835. Your DR position will be LAT 27°18.0' N, LONG 48°52.0' W. Considering their...
  93. #110 On 22 March your 1834 ZT DR position is LAT 26°13.5' S, LONG 108°36.5' W. You observe an unidentified star bearing 077°T, at an observed altitude (Ho)...
  94. #111 On 3 February your 0550 zone time DR position is LAT 26°16.0' N, LONG 112°05.0' W. Considering their magnitude, azimuth, and altitude, which group inc...
  95. #112 On 11 March your 1846 zone time DR position is LAT 25°05.7' N, LONG 124°29.0' W. At that time you observe Polaris with a sextant altitude (hs) of 25°5...
  96. #113 On 22 May your 0437 ZT DR position is LAT 25°18.5' N, LONG 51°18.0' W. You observe an unidentified star bearing 097°T at an observed altitude (Ho) of...
  97. #114 On 27 March your 0330 zone time DR position is LAT 23°32'N, LONG 154°47'E. Your vessel is on a course of 105°T at a speed of 20 knots. What will be th...
  98. #115 If the speed necessary for reaching port at a designated time is 16.8 knots and the pitch of the propeller is 22.3 feet, how many revolutions per minu...
  99. #117 You observe the lower limb of the Sun at a sextant altitude (hs) of 46°20.3' on 1 April. The index error is 4.5' off the arc. The height of eye is 57...
  100. #118 On 12 June your 1845 DR position is LAT 21°47'N, LONG 46°52'W when you observe a faint unidentifiable star through a break in the clouds. The star bea...

Navigation Problems questions: what to expect

Q How many Navigation Problems questions are in the Deck pool?

There are 2,005 Navigation Problems questions on this site, every one released by the U.S. Coast Guard or taken from the National Maritime Center's sample examinations, with its correct answer. The exam draws its Navigation Problems module from the same pool.

Q What score do I need to pass the Navigation Problems module?

Most USCG exam modules, including Navigation Problems, require 70 percent to pass. Rules of the Road modules require 90 percent.

Q Are these the real USCG Navigation Problems exam questions?

Yes. They are the published U.S. Coast Guard questions, matched to the National Maritime Center's 2026 sample examinations. Answer any question to see the correct choice, the USCG reference and the illustration where the question uses one.

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About the Deck question pool

The Deck pool holds the current U.S. Coast Guard questions for every deck credential, from Able Seaman and the OUPV six-pack up to unlimited Master. Each question is multiple choice with four options, graded instantly, with the USCG reference shown where one exists.