Pass Benchmark: 70% (21/30) • Standard: USCG NMC / 46 CFR
USCG Navigation Problems (Set 6)
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Question 1 of 30
On 22 April your 1852 DR position is LAT 23°54.5'N, LONG 117°36.8'W. You observe an unidentified star bearing 077°T at an observed altitude (Ho) of 18°58.7'. The chronometer reads 02h 54m 53s, and is 02m 51s fast. What star did you observe?
Browse Questions in Set 6
30 MCQs #1 On 22 April your 1852 DR position is LAT 23°54.5'N, LONG 117°36.8'W. You observe an unidentified star bearing 077°T at an observed altitude (Ho) of 18°58.7'. The chronometer reads 02h 54m 53s, and is 02m 51s fast. What star did you observe? #2 On 22 April your 1852 DR position is LAT 23°54.5'N, LONG 117°36.8'W. You observe an unidentified star bearing 259°T at an observed altitude (Ho) of 41°15.2'. The chronometer reads 02h 54m 53s, and is 02m 51s fast. What star did you observe? #3 On 22 March your 0519 DR position is LAT 27°20.6'N, LONG 69°25.6'W. You observe an unidentified star bearing 200°T at an observed altitude (Ho) of 33°05.5'. The chronometer reads 10h 16m 47s, and is 02m 15s slow. What star did you observe? #4 On 27 August your 0900 zone time DR position is LAT 24°25.0'N, LONG 94°20.0'W. Your vessel is on course 071°T at a speed of 20.0 knots. What is the zone time of local apparent noon (LAN)? #5 On 14 January your 0550 DR position is LAT 25°26.0'N, LONG 38°16.0'W. You observe an unidentified star bearing 192°T at an observed altitude (Ho) of 06°15.2'. The chronometer reads 08h 48m 51s, and is 01m 22s slow. What star did you observe? #6 On 22 March your 0519 DR position is LAT 27°20.6'N, LONG 69°25.6'W. You observe an unidentified star bearing 051°T at an observed altitude (Ho) of 50°03.7'. The chronometer reads 10h 16m 47s, and is 02m 15s slow. What star did you observe? #7 On 6 March at 0550 zone time, morning stars were observed, and the vessel's position was determined to be LAT 23°56.0'N, LONG 27°19.0'W. Your vessel is steaming at 25.0 knots on a course of 149.0°T. A sextant observation of the Sun's lower limb is made at 0830 zone time. The chronometer reads 10h 32m 05s, and the sextant altitude is 31°31.5'. The index error is 2.5' on the arc, and the chronometer error is 01m 45s fast. Your height of eye on the bridge is 76.0 feet. What is the azimuth (Zn) of this sight using the assumed position? #8 On 22 February your 1857 DR position is LAT 23°46.0'S, LONG 93°16.5'E. You observe an unidentified star bearing 126°T at an observed altitude (Ho) of 40°21.5'. The chronometer reads 01h 00m 35s and is 03m 25s fast. What star did you observe? #9 On 8 February your 0800 zone time position is LAT 21°55'S, LONG 52°27'W. Your vessel is on course 056°T at a speed of 17.5 knots. An observation of the Sun's lower limb is made at 0938 zone time, and the observed altitude (Ho) is 46°06.5'. The chronometer reads 12h 37m 23s, and the chronometer error is 1m 24s slow. LAN occurs at 1243 zone time, and a meridian altitude of the Sun's lower limb is made. The observed altitude (Ho) for this sight is 83°56.1'. Determine the vessel's 1200 zone time position. #10 On 22 March your 1834 DR position is LAT 26°13.5'S, LONG 108°36.5'W. You observe an unidentified star bearing 062°T at an observed altitude (Ho) of 23°22.0'. The chronometer reads 01h 32m 37s, and is 01m 50s slow. Which star did you observe? #11 On 22 June your 0424 ZT DR position is LAT 26°18.5' N, LONG 124°18.2' W. You observe an unidentified star bearing 031°T at an observed altitude (Ho) of 49°26.0'. The chronometer reads 00h 23m 24s and is 01m 32s slow. What star did you observe? #12 On 22 July your 0442 ZT DR position is LAT 26°35.6' N, LONG 22°16.7' W. You observe an unidentified star bearing 112°T, at an observed altitude (Ho) of 44°16.0'. The chronometer reads 05h 39m 03s and is 03m 14s slow. What star did you observe? #13 On 22 March your 1834 DR position is LAT 26°13.5'S, LONG 108°36.5'W. You observe an unidentified star bearing 315°T at an observed altitude (Ho) of 66°01.2'. The chronometer reads 01h 32m 37s, and is 01m 50s slow. What star did you observe? #14 On 23 May your 0628 zone time position was LAT 28°18.0'S, LONG 102°42.0'E. Your vessel was steaming on course 040°T at a speed of 20.0 knots. An observation of the Sun's lower limb was made at 0758 ZT. The chronometer read 01h 02m 06s and was fast 04m 04s. The observed altitude (Ho) was 13°16.7'. LAN occurred at 1201 zone time. The observed altitude (Ho) was 42°32.0'. What was the longitude of your 1201 zone time running fix? #15 On 8 February your 0800 zone time (ZT) position was LAT 28°55.0'S, LONG 52°27.0'W. Your vessel was steaming on course 036°T at a speed of 19.0 knots. An observation of the Sun's lower limb was made at 0938 ZT. The chronometer read 12h 37m 23s and was slow 01m 24s. The observed altitude (Ho) was 45°29.2'. Local Apparent Noon (LAN) occurred at 1240 ZT. The observed altitude (Ho) was 77°10.5'. What was the longitude of your 1200 ZT running fix? #16 On 23 September your 1836 DR position is LAT 25°18'S, LONG 162°23'E. You observe an unidentified star bearing 000°T at an observed altitude (Ho) of 26°18'. The chronometer reads 07h 34m 12s, and is 01m 54s slow. What star did you observe? #17 On 22 March your 1834 DR position is LAT 26°13.5'S, LONG 108°36.5'W. You observe an unidentified star bearing 294°T at an observed altitude (Ho) of 33°02.7'. The chronometer reads 01h 32m 37s, and is 01m 50s slow. What star did you observe? #18 On 9 November at 0426 ZT, your position was LAT 25°17.0'S, LONG 154°16.0'E. Your vessel is steaming at 14.0 knots on course 066°T. A sextant observation of the Sun's lower limb is made at 0837 ZT. The chronometer reads 10h 35m 21s, and the sextant altitude (hs) is 50°26.9'. The index error is 1.5' on the arc, and the chronometer error is 01m 48s slow. Your height of eye on the bridge is 56.0 feet. What is the observed altitude (Ho) and azimuth (Zn) of this sight using the assumed position? #19 On 22 February your 1857 DR position is LAT 23°46.0'S, LONG 93°16.5'E. You observe an unidentified star bearing 150°T at an observed altitude (Ho) of 42°15.0'. The chronometer reads 01h 00m 35s, and is 03m 25s fast. What star did you observe? #20 On 14 January your 0550 DR position is LAT 25°26.0'N, LONG 38°16.0'W. You observe an unidentified star bearing 043°T at an observed altitude (Ho) of 37°12.1'. The chronometer reads 08h 48m 51s, and is 01m 22s slow. What star did you observe? #21 On 28 July your 0800 zone time (ZT) 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. Local apparent noon (LAN) occurs at 1150 ZT, at which time a meridian altitude of the Sun's lower limb is observed. The observed altitude (Ho) for this sight is 82°28.7'. What is the latitude at 1200 ZT? #22 On 14 January your 1922 DR position is LAT 27°18.5'S, LONG 67°18.0'E. You observe an unidentified star bearing 250°T at an observed altitude (Ho) of 31°01.2'. The chronometer reads 03h 25m 43s, and is 03m 15s fast. Which star did you observe? #23 On 2 January you observe the lower limb of the Sun at a sextant altitude (hs) of 35°50.4'. The index error is 0.8' on the arc. The height of eye is 24 feet (7.3 meters). What is the observed altitude (Ho)? #24 On 14 January your 1922 DR position is LAT 27°18.5'S, LONG 67°18.0'E. You observe an unidentified star bearing 054°T at an observed altitude (Ho) of 07°52.1'. The chronometer reads 03h 25m 43s, and is 03m 15s fast. What star did you observe? #25 On 14 January your 1922 DR position is LAT 27°18.5'S, LONG 67°18.0'E. You observe an unidentified star bearing 295°T at an observed altitude (Ho) of 13°50.7'. The chronometer reads 03h 25m 43s, and is 03m 15s fast. What star did you observe? #26 On 17 March your 0520 DR position is LAT 27°23.0'N, LONG 39°42.0'W. You observe an unidentified star bearing 110°T at an observed altitude (Ho) of 50°47.2'. The chronometer reads 08h 22m 15s, and is 01m 45s fast. What star did you observe? #27 On 22 March your 0519 ZT DR position is LAT 27°20.6' N, LONG 69°25.6' W. You observe an unidentified star bearing 094°T, at an observed altitude (Ho) of 30°15.0'. The chronometer reads 10h 16m 47s and is 02m 15s slow. What star did you observe? #28 On 17 March your 0520 DR position is LAT 27°23.0'N, LONG 39°42.0'W. You observe an unidentified star bearing 313°T at an observed altitude (Ho) of 43°03.8'. The chronometer reads 08h 22m 15s and is 01m 45s fast. What star did you observe? #29 On 17 March your 1845 DR position is LAT 25°10.0'N, LONG 66°48.0'W. You observe an unidentified star bearing 340°T at an observed altitude (Ho) of 66°25.1'. The chronometer reads 10h 47m 49s, and is 1m 54s fast. What star did you observe? #30 On 17 March your 1845 DR position is LAT 25°10.0'N, LONG 66°48.0'W. You observe an unidentified star bearing 320°T at an observed altitude (Ho) of 50°02.9'. The chronometer reads 10h 47m 49s, and is 1m 54s fast. What star did you observe?
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