National Maritime Center Providing Credentials to Mariners Q127 Navigation Problems-Oceans (Sample Examination) Page 1 of 5
Choose the best answer to the following Multiple Choice questions. 1. You depart LAT 28 55.0'N, LONG 89 10.0'W, enroute to LAT 24 25.0'N, LONG 83 00.0'W. What is the true course and distance by mid-latitude sailing? (A) 427 miles, 129 T o (B) 442 miles, 122 T o (C) 436 miles, 133 T o (D) 418 miles, 122 T 2. On 29 October in DR position LAT 41 12.0'N, LONG 50 18.9'W, you take an ex-meridian observation of the Sun's lower limb, near upper transit. The chronometer time of the sight is 03h 21m 12s, and the chronometer error is 01m 50s slow. The sextant altitude (hs) is 34 54.2'. The index error is 2.0' on the arc, and your height of eye is 45 feet. What is the latitude at meridian transit? o (A) 41 12.0'N (B) 41 16.0'N o (C) 41 20.2'N o (D) 41 23.6'N 3. On 11 February your 1832 zone time DR position is LONG 110 52.6'W. At that time you observe Polaris with a sextant altitude (hs) of 26 19.8'. The chronometer time of the sight is 01h 34m 56s, and the chronometer error is 02m 16s fast. The index error is 2.7' off the arc, and the height of eye is 60.2 feet. What is your latitude by Polaris? (A) 25 27.2'N o (B) 25 34.2'N o (C) 26 27.2'N o (D) 26 34.2'N 4. Determine the great circle distance and initial course from LAT 35 08.0'S, LONG 19 26.0'E to LAT 33 16.0'S, LONG 115 36.0'E. (A) 4559 miles, 121 T o (B) 4457 miles, 126 T o (C) 4688 miles, 126 T o (D) 4682 miles, 059 T Page 2 of 5
5. On 15 November your 1030 ZT DR position is LAT 17 25'S, LONG 42 12'W. You are on course 059 T, speed 22 knots. Determine your 1200 position using the following observations of the Sun. Zone Time GHA Declination Ho 1128 40 50.4' S 18 33.6' 88 18.4' 1133 42 05.4' S 18 33.6' 88 37.7' o (A) LAT 17 00.0'S, LONG 41 45.8'W o (B) LAT 17 02.1'S, LONG 41 48.4'W (C) LAT 17 06.8'S, LONG 41 44.3'W o (D) LAT 17 08.9'S, LONG 41 40.4'W 6. On 4 December your 1500 ZT DR position is LAT 18 06.0' N, LONG 75 42.0' W. You are on course 020 T at a speed of 15.0 knots. You observed 3 celestial bodies. Determine the latitude and longitude of your 1548 running fix. Body Zone Time GHA Observed Altitude Declination Venus 1500 73 51.1' 48 29.5' S 23 22.1' Sun L/L 1524 128 25.7' 24 24.9' S 22 18.6' Moon L/L 1548 37 54.1' 43 24.8' S 9 43.0' o (A) LAT 18 10.3'N, LONG 75 34.5'W o (B) LAT 18 12.6'N, LONG 75 42.0'W o (C) LAT 18 14.0'N, LONG 75 40.0'W (D) LAT 18 17.3'N, LONG 75 37.7'W 7. 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 magnitude, azimuth, and altitude, which group includes the three stars best suited for a fix at star time? o (A) Procyon, Antares, Sirius (B) Acrux, Procyon, Arcturus o (C) Acrux, Canopus, Regulus o (D) Sirius, Procyon, Regulus Page 3 of 5
8. On 4 October your 1907 zone time DR position is LAT 25 15.0'S, LONG 105 44.0'E. At that time, you observe Deneb bearing 011.5 psc. The chronometer reads 00h 07m 42s, and the chronometer error is 00m 36s fast. The variation is 7.5 W. What is the deviation of the standard compass? (A) 3.2 E o (B) 4.3 W o (C) 2.1 E o (D) 2.1 W 9. The true course from point A to point B is 317. A SSW wind causes a 4 leeway, variation is 6 W and deviation is 1 E. What is the magnetic compass course to steer to make good the true course? o (A) 308 psc o (B) 313 psc o (C) 326 psc (D) 318 psc 10. The upper vertex of a great circle track is in LONG 156 00'E. Sailing eastward, the great circle track will cross the equator in LONG. o (A) 110 00'W o (B) 66 00'W o (C) 66 00'E (D) 114 00'W 11. You are planning a voyage by great circle from the mouth of the Delaware River (LAT 38 40'N, LONG 75 00'W) to Lisbon, Portugal. Which statement is TRUE? (Use gnomonic tracking chart WOXZC 5274.) o (A) The Northern Hemisphere vertex lies to the east of Lisbon. o (B) You must plot a composite sailing to remain south of icebergs reported north of 44 N. (C) You will reach the northernmost latitude of the voyage in the vicinity of LONG 42 30'W. o (D) The distance is measured in 60-mile segments using the length of the degree of latitude crossed by the track line. Page 4 of 5
12. On 26 September your 0830 zone time DR position is LAT 23 04.0'N, LONG 129 16.0'E. Your vessel is on course 119 T at a speed of 20.0 knots. What is the zone time of local apparent noon (LAN)? o (A) 1158 o (B) 1205 (C) 1210 o (D) 1214 13. 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 bears 270 T at a sextant altitude (hs) of 65 41.7'. The index error is 0.5' on the arc, and the height of eye is 45 feet. The chronometer reads 09h 43m 27s, and the chronometer error is 1m 46s slow. What star did you observe? o (A) Epsilon Leonis (B) Algeiba o (C) Merak o (D) Scheat 14. On 17 April your vessel is enroute from the Panama Canal to Kobe, Japan. Your 0400 zone time DR position is LAT 26 12.0'N, LONG 126 12.0'W. Your vessel is on course 285 T at a speed of 18 knots. What will be the zone time of sunrise at your vessel? o (A) 0535 o (B) 0541 o (C) 0552 (D) 0602 15. At 0800 ZT on 29 June your DR position is LAT 26 00.0'N, LONG 75 29.5'W. Given a chronometer time of 01h 00m 00s, determine the computed altitude (Hc) of the Sun for the assumed position nearest to the above given latitude and longitude. o (A) Hc 34 38.6' o (B) Hc 34 48.6' (C) Hc 34 58.6' o (D) Hc 35 18.6' Page 5 of 5