National Maritime Center

Transcription

1 National Maritime Center Providing Credentials to Mariners (Sample Examination) Page 1 of 5

2 Choose the best answer to the following Multiple Choice questions. 1. 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 magnitude, azimuth, and altitude, which group includes the three bodies best suited for a fix at star time? o (A) Mars, Regulus, Canopus o (B) Jupiter, Alphard, Betelgeuse o (C) Achernar, Suhail, Alphard (D) Achernar, Procyon, Aldebaran 2. On 23 July your 2100 ZT position is LAT 'N, LONG 'W, when you observed an azimuth of Polaris to determine the compass error. Polaris bears per gyrocompass. At the time of the observation, the helmsman noted that he was heading per gyrocompass and per standard compass. Variation is 12.0 W. Which of the following statements is TRUE? o (A) The gyro error is 0.7 E. o (B) The gyro error is 1.7 W. (C) The deviation is 1.7 E. o (D) The compass error is 13.7 W 3. You are on a voyage from Cape May (LAT 39 50'N, LONG 74 45'W) to the English Channel (LAT 49 00'N, LONG 05 00'W). What will NOT prohibit the use of a great circle track from departure to arrival? (Use gnomonic chart WOXZC 5274.) (A) The high latitude in which the vertex lies o (B) Icebergs north of 48 N and west of 49 W o (C) Newfoundland o (D) Islands approximately 50 miles south of Cape Cod 4. In which voyage, between two points, is the rhumb line distance NOT approximately the same as the great circle distance? o o (A) The two points are in low latitudes in the same hemisphere. (B) One point is near the equator, one point is in a high latitude, and both are near the 180th meridian. (C) The two points are in high latitudes in the same hemisphere. o (D) The two points are near the equator, but in different hemispheres. Page 2 of 5

3 5. On 18 May your 1030 ZT DR position is LAT 20 41'N, LONG 63 32'W. You are on course 106 T, speed 24 knots. Determine your 1200 position using the following observations of the Sun. Zone Time GHA Declination Ho ' N ' ' ' N ' ' (A) LAT 'N, LONG 'W o (B) LAT 'N, LONG 'W o (C) LAT 'N, LONG 'W o (D) LAT 'N, LONG 'W 6. On 16 July at 2000 zone time, you take a sextant observation of Polaris. Your vessel's DR position is LAT 'N, LONG 'W, and your sextant reads '. Your chronometer reads 05h 59m 16s, and your chronometer error is 01m 28s slow. Your height of eye is 48 feet, and the index error for your sextant is 1.3' off the arc. What is the latitude of your vessel from your observation of Polaris? o (A) 'N o (B) 'N (C) 'N o (D) 'N 7. Determine the distance from LAT 'N, LONG 'E to LAT 'N, LONG 'W by parallel sailing. o (A) miles o (B) miles o (C) miles (D) miles Page 3 of 5

4 8. At 2221 your course is 222 pgc at a speed of 11.2 knots, when radar detects a buoy bearing 355 relative, at a range of 5.8 miles. The gyro error is 2 E. If you change course at 2226, what course should you steer to leave the buoy 1.0 mile abeam to port? o (A) 210 pgc (B) 228 pgc o (C) 231 pgc o (D) 206 pgc If choice B is selected set score to On 13 September your 1830 ZT DR position was LAT 23 03'S, LONG 'E, when you observed a faint unidentifiable star through a hole in the clouds. The star bore T at a sextant altitude (hs) of '. The chronometer read 11h 24m 39s and is 05m 08s slow. The index error is 1.0' off the arc, and the height of eye is 52 feet. What star did you observe? o (A) Alpha Indi o (B) Beta Aquarii o (C) Beta Gruis (D) Alpha Tucanae 10. On 13 October your 0515 zone time fix gives you a position of LAT 'N, LONG 'W. Your vessel is on course 068 T, and your speed is 7.8 knots. Local apparent noon (LAN) occurs at 1145 zone time, at which time a meridian altitude of the Sun's lower limb is observed. The observed altitude (Ho) for this sight is '. What is the latitude at 1200 ZT? (A) 'N o (B) 'N o (C) 'N o (D) 'N 11. On 10 April, your 1630 ZT DR position is LAT 'N, LONG 'W. You are on course 324 T at a speed of 22 knots. What will be the zone time of sunset at your vessel? o (A) 1805 o (B) 1814 o (C) 1818 (D) 1833 Page 4 of 5

5 12. On 12 July your 0800 ZT DR position is LAT 'N, LONG 'W. Your vessel is on course 045 T at a speed of 15.0 knots. What is the ZT of local apparent noon (LAN)? o (A) 1146 o (B) 1148 (C) 1152 o (D) You observe the lower limb of the Sun at a sextant altitude (hs) of ' on 11 October. The index error is 3.0' off the arc. The height of eye is 63 feet (19.2 meters). What is the observed altitude (Ho)? o (A) ' o (B) ' o (C) ' (D) ' 14. On 20 November your 1030 ZT DR position is LAT ' N, LONG ' E. You are on course 060 T at a speed of 20 knots. You observed 3 celestial bodies. Determine the latitude and longitude of your 1200 running fix. Body Zone Time GHA Observed Altitude Declination Moon ' ' N ' Sun ' ' S ' Venus ' ' S ' o (A) LAT 'N, LONG 'E o (B) LAT 'N, LONG 'E (C) LAT 'N, LONG 'E o (D) LAT 'N, LONG 'E 15. The great circle distance from LAT 'S, LONG 'E to LAT 'S, LONG 'E is 4559 miles and the initial course is 121 T. Determine the longitude of the vertex. o (A) 'E o (B) 'E (C) 'E o (D) 'E Page 5 of 5