Pass Benchmark: 70% (21/30) • Standard: USCG NMC / 46 CFR
USCG Navigation Problems (Set 39)
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Question 1 of 30
On 1 July your 0515 ZT fix gives you a position of LAT 24°36.0'S, LONG 151°42.0'W. Your vessel is on course 300°T, and your speed is 10.0 knots. Local apparent noon (LAN) occurs at 1215 ZT, at which time a meridian altitude of the Sun's lower limb is observed. The observed altitude (Ho) for this sight is 42°55.0'. What is the calculated latitude at LAN?
Browse Questions in Set 39
30 MCQs #1 On 1 July your 0515 ZT fix gives you a position of LAT 24°36.0'S, LONG 151°42.0'W. Your vessel is on course 300°T, and your speed is 10.0 knots. Local apparent noon (LAN) occurs at 1215 ZT, at which time a meridian altitude of the Sun's lower limb is observed. The observed altitude (Ho) for this sight is 42°55.0'. What is the calculated latitude at LAN? #2 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? #3 On 7 November your 0830 zone time fix gives you a position of LAT 27°36.0'N, LONG 162°19.0'W. Your vessel is on course 289°T and your speed is 19.0 knots. Local apparent noon (LAN) occurs at 1138 zone time, at which time a meridian altitude of the Sun's lower limb is observed. The observed altitude (Ho) for this sight is 45°35.0'. What is the latitude at 1200 ZT? #4 On 20 November your 0612 zone time (ZT) position was LAT 25°38.0'N, LONG 166°54.0'W. Your vessel was steaming on course 126°T at a speed of 20.0 knots. An observation of the Sun's lower limb was made at 0854 ZT. The chronometer read 07h 51m 14s and was slow 02m 52s. The observed altitude (Ho) was 27°58.3'. LAN occurred at 1147 ZT. The observed altitude (Ho) was 45°35.0'. What was the longitude of your 1147 ZT running fix? #5 On 13 October your 0515 zone time fix gives you a position of LAT 26°53.0'N, LONG 90°05.0'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 54°51.5'. What is the latitude at 1200 ZT? #6 On 16 December your 1810 zone time DR position is LONG 129°46.5' W. At that time you observe Polaris with a sextant altitude (hs) of 23°56.8'. The chronometer time of the sight is 03h 12m 31s, and the chronometer error is 02m 16s fast. The index error is 2.5' off the arc, and the height of eye is 52.6 feet. What is your latitude by Polaris? #7 On 24 September your 1841 zone time DR position is LAT 25°15.0' N, LONG 129°34.5' E. At that time you observe Polaris with a sextant altitude (hs) of 25°20.8'. The chronometer time of the sight is 09h 38m 12s, and the chronometer error is 03m 12s slow. The index error is 4.3' off the arc, and the height of eye is 52.0 feet. What is your latitude by Polaris? #8 On 29 April your 1913 zone time DR position is LAT 22°09.0' N, LONG 56°16.0' W. At that time you observe Polaris with a sextant altitude (hs) of 22°25.8'. The chronometer time of the sight is 11h 11m 14s, and the chronometer error is 02m 18s slow. The index error is 1.5' off the arc, and the height of eye is 61.5 feet. What is your latitude by Polaris? #9 On 14 March your 1846 ZT DR position is LAT 21°57.6' N, LONG 132°16.2' W. At that time you observe Polaris with a sextant altitude (hs) of 22°16.8'. The chronometer time of the sight is 03h 45m 10s, and the chronometer error is 01m 32s slow. The index error is 3.2' off the arc, and the height of eye is 44.9 feet. What is your latitude by Polaris? #10 On 15 July at 0447 ZT, your vessel's DR position is LAT 22°42' N, LONG 126°36' E. At approximately this time, you obtain a sextant altitude (hs) of Polaris reading 23°46.2' with an index error of 1.6' off the arc. Your chronometer reads 08h 48m 28s, and is 1m 16s fast. What is your latitude by Polaris, given a height of eye of 33 feet? #11 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 index error is 2.5' off the arc. The height of eye is 54 feet. What is the latitude at the time of the sight? #12 On 22 May at 0440 ZT, your vessel's DR position is LAT 23°24' N, LONG 110°24' W. At approximately this time, you obtain a sextant altitude (hs) of Polaris reading 23°40.9' with an index error of 1.6' on the arc. Your chronometer reads 11h 42m 14s, and is 2m 36s fast. What is your latitude by Polaris, given a height of eye of 24 feet? #13 On 13 October at 1847 ZT, your vessel's DR position is LAT 42°17.4' N, LONG 138°46.2' W. At approximately this time, you obtain a sextant altitude (hs) of Polaris reading 42°16.8', with an index error of 3.2' on the arc. Your chronometer reads 03h 45m 20s and is 1m 32s slow. What is your latitude by Polaris, given a height of eye of 44 feet? #14 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'. Your chronometer reads 04h 42m 36s, and the chronometer error is 02m 24s slow. Your height of eye is 24 feet, and the index error is 1.3' off the arc. Determine the latitude by Polaris. #15 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 height of eye is 36', and the index error is 3.3' off the arc. What is the latitude at the time of the sight? #16 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 reading 28°42.6', with an index error of 2.4' on the arc. Your chronometer reads 09h 50m 00s, and is 4m 14s slow. What is your latitude by Polaris, given a height of eye of 28 feet (8.5 meters)? #17 On 5 May at 1953 zone time, you take a sextant observation of Polaris. Your vessel's DR position is LAT 29°30.0' N, LONG 66°25.7' W, and your sextant reads 29°07.2'. Your chronometer reads 11h 51m 45s, and your chronometer error is 01m 36s slow. Your height of eye is 56 feet, and the index error for your sextant is 1.5' on the arc. What is the latitude of your vessel from your observation of Polaris? #18 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 chronometer time of the sight is 09h 38m 12s, and the chronometer error is 03m 12s slow. The index error is 4.3' off the arc, and the height of eye is 52 feet (15.9 meters). What is your latitude by Polaris? #19 On 2 January your 1759 zone time DR longitude is 45°17.6' W. At that time you observe Polaris with a sextant altitude (hs) of 24°16.5'. The chronometer time of the sight is 08h 57m 10s, and the chronometer error is 02m 16s slow. The index error is 3.5' on the arc, and the height of eye is 42.5 feet. What is your latitude by Polaris? #20 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 chronometer time of the sight is 03h 44m 10s, and the chronometer error is 01m 55s slow. The index error is 2.2' off the arc, and the height of eye is 59.8 feet (18.2 m). What is your latitude by Polaris? #21 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? #22 On 7 November your 0830 zone time position was LAT 27°36.0'N, LONG 162°19.0'W. Your vessel was steaming on course 289°T at a speed of 19.0 knots. An observation of the Sun's lower limb was made at 0945 ZT. The chronometer read 08h 43m 11s and was slow 01m 51s. The observed altitude (Ho) was 38°21.1'. Local Apparent Noon (LAN) occurred at 1138 zone time. The observed altitude (Ho) was 45°35.0'. What was the longitude of your 1200 zone time running fix? #23 On 16 February your 0640 zone time (ZT) position was LAT 23°46.0'N, LONG 156°24.0'W. Your vessel was steaming on course 222°T at a speed of 18.0 knots. An observation of the Sun's lower limb was made at 0910 ZT. The chronometer read 07h 08m 06s and was slow 01m 56s. The observed altitude (Ho) was 27°15.8'. LAN occurred at 1245 ZT (ZD +10). The observed altitude (Ho) was 55°25.3'. What was the longitude of your 1245 ZT running fix? #24 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 Sun's lower limb is made at 0915 zone time. The chronometer reads 01h 14m 11s, and the chronometer error is 00m 53s slow. The observed altitude (Ho) is 45°10.7'. LAN occurs at 1150 zone time, and a meridian altitude of the Sun's lower limb is made. The observed altitude (Ho) is 65°32.8'. Determine the vessel's 1200 zone time position. #25 On 22 February your 0800 zone time position is LAT 24°16'S, LONG 95°37'E. Your vessel is on course 126°T at a speed of 14 knots. An observation of the Sun's lower limb is made at 0945 zone time. The chronometer reads 03h 47m 22s, and the chronometer error is 02m 37s fast. The observed altitude (Ho) is 57°02.1'. LAN occurs at 1148 zone time, and a meridian altitude of the Sun's lower limb is made. The observed meridian altitude (Ho) is 75°22.3'. Determine the vessel's 1200 zone time position. #26 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°39.3 E. The chronometer reading at the time of the sight is 11h 21m 18s and the chronometer is 48s slow. The height of eye is 59 feet and the index error is 2.5' on the arc. What are the azimuth (Zn) and intercept (a) of this sight using the assumed position? #27 On 22 July at 0720 ZT, in DR position LAT 20°38.2'N, LONG 87°16.0'W, you observe the Moon's lower limb. The sextant altitude (hs) is 38°32.6, and the chronometer reads 01h 18m 14s. The chronometer is 01m 28s slow. The index error is 3.1' off the arc, and the height of eye is 68 feet. What is the azimuth (Zn) and intercept (a) of this sight from the assumed position? #28 On 26 July your 1901 ZT position is LAT 28°28'N, LONG 157°16'E when you take an observation of Jupiter. The chronometer at the time of the sight reads 08h 54m 34s and is 06m 24s slow. The sextant altitude (hs) is 33°51.5'. The index error is 2.8' off the arc, and the height of eye is 48 feet. What are the azimuth (Zn) and intercept (a) for this sight using the assumed position? #29 On 28 April your vessel's 0515 zone time position is LAT 23°26'S, LONG 95°30'E. At this time, the observed altitude (Ho) of the star Rigil Kentaurus is 24°51.4'. Your chronometer reads 11h 16m 36s and is 01m 18s fast. What is the intercept (a) based on the assumed position method? #30 On 17 April your vessel's 1856 zone time DR position is LAT 22°35.0'N, LONG 63°15.0'W. At that time, a sextant observation of the star Sirius is made. The sextant altitude is 42°45.0' and the chronometer reads 10h 59m 27s. The index error is 2.6' off the arc, and the chronometer error is 03m 01s fast. Your height of eye is determined to be 45 feet. What is the computed altitude (Hc) and azimuth (Zn) for this sight using the assumed position?
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