Pass Benchmark: 70% (21/30) • Standard: USCG NMC / 46 CFR
USCG Navigation Problems (Set 9)
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Question 1 of 30
On 8 August at 0545 ZT, morning stars were observed, and the vessel's position was determined to be LAT 26°16.0' S, LONG 94°16.0'E. Your vessel is steaming at 20.0 knots on a course of 346°T. A sextant observation of the Sun's lower limb is made at 0905 ZT. The chronometer reads 03h 02m 52s, and the sextant altitude (hs) is 38°07.5'. The index error is 5.2' off the arc, and the chronometer error is 2m 17s slow. Your height of eye on the bridge is 72 feet (22.0 meters). What is the observed altitude (Ho) and azimuth (Zn) of this sight using the assumed position?
Browse Questions in Set 9
30 MCQs #1 On 8 August at 0545 ZT, morning stars were observed, and the vessel's position was determined to be LAT 26°16.0' S, LONG 94°16.0'E. Your vessel is steaming at 20.0 knots on a course of 346°T. A sextant observation of the Sun's lower limb is made at 0905 ZT. The chronometer reads 03h 02m 52s, and the sextant altitude (hs) is 38°07.5'. The index error is 5.2' off the arc, and the chronometer error is 2m 17s slow. Your height of eye on the bridge is 72 feet (22.0 meters). What is the observed altitude (Ho) and azimuth (Zn) of this sight using the assumed position? #2 On 11 October at 0516 ZT, morning stars were observed, and the vessel's position was determined to be LAT 23°21.0'N, LONG 139°27.0'W. Your vessel is steaming at 14.0 knots on a course of 293°T. A sextant observation of the Sun's lower limb is made at 0927 ZT. The chronometer reads 06h 30m 21s, and the sextant altitude (hs) is 39°48.7'. The index error is 2.0' on the arc, and the chronometer error is 02m 56s fast. Your height of eye on the bridge is 63.0 feet. What is the azimuth (Zn) of this sight using the assumed position? #3 On 18 October at 0518 ZT, morning stars were observed and the vessel's position was determined to be LAT 25°31.0'N, LONG 146°29.2'E. Your vessel is steaming at 19.0 knots on a course of 308°T. A sextant observation of the Sun's lower limb is made at 0915 ZT. The chronometer reads 11h 17m 11s, and the sextant altitude (hs) is 34°51.4'. The index error is 2.0' off the arc, and the chronometer error is 01m 57s fast. Your height of eye on the bridge is 54.0 feet. What is the azimuth (Zn) of this sight using the assumed position? #4 On 21 November at 0430 ZT, morning stars were observed, and the vessel's position was LAT 22°14.0'S, LONG 79°23.0'E. Your vessel is steaming at 14.5 knots on a course of 246°T. A sextant observation of the Sun's lower limb is made at 0816 ZT. The chronometer reads 03h 14m 16s, and the sextant altitude (hs) is 44°29.2'. The index error is 1.0' on the arc, and the chronometer error is 01m 47s slow. Your height of eye is 61.0 feet (18.6 meters). What is the azimuth (Zn) and intercept (a) of this sight using the assumed position method? #5 On 22 June at 0906 EDT (ZD +4), your position is LAT 24°36'N, LONG 69°30'W. You are on course 165°pgc at a speed of 14.8 knots. A sextant observation of the Sun's lower limb is made, and the sextant altitude (hs) is 42°44.0' with an index error of 0.8' off the arc. At this time the chronometer reads 01h 10m 12s, and is 2m 42s slow. If your height of eye is 70 feet, what is the azimuth (Zn) of the sight using the assumed position? #6 On 30 June at 0630 zone time, morning stars were observed, and the vessel's position was determined to be LAT 25°15.0'S, LONG 175°36.0'E. Your vessel is steaming at 16.0 knots on a course of 302°T. A sextant observation of the Sun's lower limb is made at 1015 zone time. The chronometer reads 10h 14m 38s, and the sextant altitude is 32°07.9'. The index error is 4.5' on the arc, and the chronometer error is 01m 25s slow. Your height of eye on the bridge is 58.0 feet. What is the azimuth (Zn) of this sight using the assumed position? #7 On 18 August at 0600 ZT, morning stars were observed, and the vessel's position was determined to be LAT 19°48'N, LONG 108° 34'W. Your vessel is steaming on course 166°T at a speed of 16 knots. An observation of the Sun's lower limb is made at 1036 ZT. The chronometer reads 05h 34m 48s and is slow 01m 24s. What is the computed altitude (Hc) and azimuth (Zn) for this 1036 ZT observation using the assumed position method? #8 You observe the planet Saturn at a sextant altitude (hs) of 63°05.1' on 25 May. The index error is 4.5' off the arc. The height of eye is 62 feet. What is the observed altitude (Ho)? #9 You observe the planet Jupiter at a sextant altitude (hs) of 66°27.6' on 26 May. The index error is 5.2' on the arc. The height of eye is 52 feet. What is the observed altitude (Ho)? #10 During twilight on 28 December around 1800 GMT, in DR position LAT 4°00'N, LONG 0°06'W, the sextant altitude (hs) of Venus was 30°46.8'. The height of eye was 36 feet, and the index error was 2.0' on the arc. The temperature was 68°F. The barometer read 1030 mb. Calculate the observed altitude (Ho). #11 You observe the star Deneb at a sextant altitude (hs) of 48°34.8' on 16 December. The index error is 4.0' off the arc. The height of eye is 58 feet. What is the observed altitude (Ho)? #12 On 29 June you observe the star Achernar at a sextant altitude (Hs) of 54°18.9'. The index error is 4.7' off the arc. The height of eye is 58 feet. What is the observed altitude (Ho)? #13 You observe the star Antares at a sextant altitude (hs) of 38°18.7' on 28 February. The index error is 2.4' on the arc. The height of eye is 40 feet (12.2 meters). What is the observed altitude (Ho)? #14 You observe the lower limb of the Sun at a sextant altitude (hs) of 24°00.7' on 10 January. The index error is 2.6' off the arc. The height of eye is 55 feet. What is the observed altitude (Ho)? #15 You observe the lower limb of the Sun at a sextant altitude (hs) of 75°12.3' on 6 August. The index error is 1.5' off the arc. The height of eye is 32 feet (9.8 meters). What is the observed altitude (Ho)? #16 You observe the lower limb of the Sun at a sextant altitude (hs) of 54°28.2' on 22 July. The index error is 1.5' off the arc. The height of eye is 56 feet (17.1 meters). What is the observed altitude (Ho)? #17 On 4 July you observe the lower limb of the Sun at a sextant altitude (hs) of 25°29.8'. The index error is 3.1' off the arc. The height of eye is 48 feet (14.6 meters). What is the observed altitude (Ho)? #18 You observe the lower limb of the Sun at a sextant altitude (hs) of 37°47.2' 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)? #19 You observe the lower limb of the Sun at a sextant altitude (hs) of 31°31.5' on 6 March. The index error is 2.5' on the arc. The height of eye is 76 feet. What is the observed altitude (Ho)? #20 You observe the lower limb of the Sun at a sextant altitude (hs) of 58°06.6' on 5 April. The index error is 1.0' off the arc. The height of eye is 55 feet (16.8 meters). What is the observed altitude (Ho)? #21 You observe the lower limb of the Sun at a sextant altitude (hs) of 35°26.3' on 25 June. The index error is 1.5' on the arc. The height of eye is 58 feet (17.6 meters). What is the observed altitude (Ho)? #22 On 25 June your 0900 zone time DR position is LAT 24°10.0'S, LONG 148°30.0'W. Your vessel is on a course of 230°T at a speed of 18.0 knots. What is the zone time of local apparent noon (LAN)? #23 On 12 February your 0900 zone time DR position is LAT 16°43.0'N, LONG 51°42.0'W. Your vessel is on course 093°T at a speed of 18.5 knots. What is the zone time of local apparent noon (LAN)? #24 On 31 January your 0920 zone time DR position is LAT 24°16.0'S, LONG 151°33.0'E. Your vessel is on course 258°T at a speed of 18.5 knots. What is the zone time of local apparent noon (LAN)? #25 On 10 July your 0930 zone time DR position is LAT 26°31.0'S, LONG 4°41.0'E. Your vessel is on course 308°T at a speed of 22.0 knots. What is the zone time of local apparent noon (LAN)? #26 On 16 November your 0800 zone time DR position is LAT 25°11.0'N, LONG 117°41.0'W. Your vessel is on course 252°T at a speed of 14.5 knots. What is the zone time of local apparent noon (LAN)? #27 On 17 March your 0800 zone time DR position is LAT 21°27.0'N, LONG 65°25.0'W. Your vessel is on course 105°T at a speed of 17.5 knots. What is the zone time of local apparent noon (LAN)? #28 On 7 February your 0800 zone time DR position is LAT 22°16.0'N, LONG 92°26.0'W. Your vessel is on course 270°T at a speed of 20.0 knots. What is the zone time of local apparent noon (LAN)? #29 On 14 October your 0800 ZT DR position is LAT 28°22.0'N, LONG 161°17.0'E. Your vessel is on course 116°T at a speed of 17.5 knots. What is the ZT of local apparent noon (LAN)? #30 On 2 April your 0900 zone time DR position is LAT 28°04.0'S, LONG 94°14.0'E. Your vessel is on course 316°T at a speed of 18.5 knots. What is the zone time of local apparent noon (LAN)?
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