NAV II JULY A

1. This layer of our atmosphere extend upwards to 10 mi. in the tropics, 7 mi. in the temperate latitudes and about 5 mi. at

the poles:

A. Stratosphere

B. Troposphere

C. Ionosphere

D. Exosphere

THE ATMOSPHERE

TROPOSPHERE

STRATOSPHERE

MESOSPHERE

THERMOSPHERE

EXOSPHERE

5 MI.7 MI.10 MI.

TROPOPAUSE

STRATOPAUSE

MESOPAUSE

THERMOPAUSE

IONOSPHER

E

OZONE LAYER

TROPSTRAMESTHEREX

1. COEFF. A- CONSTANT IN ALL HEADINGS.2. “ B- SEMI CIRCULAR DEV.,SINE OF

COMPASS HEADING.3. “ C - SEMI CIRCULAR DEV.,COS OF

COMPASS HEADING.4. “ D- QUADRANTAL DEV., SINE OF TWICE

THE COMPASS HEADING.5. “ E- QUADRANTAL DEV.,COS OF TWICE

THE COMPASS HEADING.6. “ J- DEV. FOR HEEL OF 1 DEG.

2. It is the change of deviation for a 2. It is the change of deviation for a heel of 1ºheel of 1º while the vessel is on compass heading 000º.while the vessel is on compass heading 000º.A. Coefficient BA. Coefficient BB. Coefficient DB. Coefficient DC. Coefficient JC. Coefficient JD. Coefficient ED. Coefficient E

3.You are planning a voyage to San Francisco 3.You are planning a voyage to San Francisco from Japan. Which publications contain from Japan. Which publications contain information on the ocean’s routes?information on the ocean’s routes?A. Sailing Directions (Planning Guide)A. Sailing Directions (Planning Guide)B. Sailing Directions (Enroute)B. Sailing Directions (Enroute)C. Coast PilotC. Coast PilotD. World Port IndexD. World Port Index

• 4. Magnets are placed in horizontal trays in the compass binnacle to compensate for the:

• A. permanent magnetism of the ship• B. magnetic fields caused by electric

currents in the vicinity• C. change in the magnetic field when the

vessel inclines from the vertical• D. induced magnetism in the vessel’s

horizontal soft iron

5. It is a semi-circular which is proportional to the sine of the compass heading. It is the maximum on compass heading east or west, and zero on compass heading north or south:

• A. Coefficient A

• B. Coefficient C

• C. Coefficient D

• D. Coefficient B

6. On Sept. 23, 1997 about 7 a.m. the ship time (approximate L.M.T.D.R. Long.45ºW. the ship’s chronometer reads 10h-00m-00s. what is the Greenwich Time and Date?

• A. GMT 10h-00m-00s Date: Sept. 24

• B. GMT 22h-00m-00s Date: Sept. 23

• C. GMT 10h-00m-00s Date: Sept. 23

• D. GMT 22h-00m-00s Date: Sept. 24

LZT = 07 – 00 SEPT.23,1997

ZD = 3 (+) (W)

GMT =10 – 00 SEPT.23,1997

• 7. Time element is often of vital importance in piloting a vessel in inter-island waters. Which of the following is correct watchkeeping procedure for an officer to perform for the safety of the ship?

• A. Assign a steersman who does not have a keen ability to steer, and have tolerance in his straying from the prescribed course

• B. Organization and training of watch keeping crew who will assist in any way during his watch

• C. A thorough knowledge of the methods and techniques of piloting

• D. Study the chart of the area to familiarize with channels, shoals, tides, currents, aids to navigation inside the chartroom when on watch

• 8. Which magnetic compass corrector(s) can be set while the vessel is on a heading magnetic North or magnetic South?

• A. Quadrantal spheres

• B. Heeling magnets

• C. Fore-and-aft magnets

• D. Flinder bar

NE,SE,NW,SW

E / W

E /W

HANSOR

FEW

• 9. What is the cause of variation which affects the directive force of a magnetic compass of a ship?

• A. Magnetic force from the earth’s magnetic field

• B. Magnetism within the vessel

• C. Lack of oil in the compass bearings and point

• D. Worn gears within the compass housing

• 10. According to Buys Ballot’s Law, when an observer in the Northern Hemisphere experiences a northwest wind, the center of low pressure is located to the:

• A. Northeast

• B. West- Southeast

• C. Northwest

• D. South- Southeast

• 11. A planet referred to as the morning star will:

• A. appear in the eastern sky and western sky

• B. appear in the western sky

• C. appear in the eastern sky

• D. none of these

• 12. What may occur when strong currents set over an irregular bottom or meets an opposing current?

• A. Wave

• B. Tsunami

• C. Ebb current

• D. Tide rips

• 13. Your ship is steering 173º true, running 12 knots. At 0522 Hours you see dead ahead a light of a lighthouse 16.7 miles away. You change course to pass the lighthouse 3.5 miles on your port side. Assuming that there is no current, what is your ETA when the lighthouse is abeam?

• A. 0653 Hours• B. 0644 Hours• C. 0648 Hours• D. 0655 Hours

+

16.7 mica

b A

B

C

3.5 mi.

SOHCAHTOA

SIN B = OPP / HYPO = 3.5 /16.7 = 12˚

PYTHAGORIAN c2 = a2 + b2

a2 = c2 – b2

a = √c2 – b2

a = √ (16.7)2 - (3.5)2

= √278.89 – 12.25 = 16.33 mi.

?

TAN B = OPP / ADJADJ = OPP / TAN B = 3.5 / TAN 12˚ = 16.33 mi.

TIME = DIST / SPEED = 16.33 / 12 = OI h 22 m = 5 22 = 06 44

0522

• 14. From a vessel steering East, a lighthouse was sighted dead ahead 10 miles distant. After steaming 5 miles, it bore 078º, distance 6 miles. What is the set and drift of the current ?

• A. S 33º,22’W 1.83 miles

• B. S 30º,45’W 2.00 miles

• C. S 32º,18’W 2.43 miles

• D. S 34º,51’W 1.52 miles

+A B

C

ab

c

6 mi.

5 mi.

?

SINE LAW a = b = c . SIN A SIN B SIN C

COS LAWa2 = b2 + c2 – 2bc cos A = √(6)2 + (5)2 – 2(6)(5) cos 12˚ = 1.52 mi.

a = c sin A sin CSin C = c sin A a = 5 sin 12˚ 1.52 = 43˚09”

12˚

258˚ 00”- 43˚ 09” 214˚ 51”- 180˚ 00” S 34˚ 51” W

43˚ 09”+ 12˚ 00” 55˚ 09”-180˚ 00” 124˚ 51”

+

+

• 15. Where would you find information about the time of high tide at a specific location on a particular day of the year?

• A. Tide Tables

• B. Tidal Current Tables

• C. Coast pilot

• D. Nautical Almanac

• 16. Deviation which is maximum on inter-cardinal headings may be removed by:

• A. fore-and aft magnets

• B. transverse magnets

• C. flinders bar

• D. soft iron spheres on the sides of the compass

• 17. The correction determined by a line drawn from the center of the earth to the center of the moon and a line drawn from the surface of the earth to the center of the moon is:

• A. Parallax

• B. Augmentation

• C. Refraction

• D. Semi-diameter

• 18. When do Neap Tides occur?

• A. when the sun, moon, and the earth are nearly in the line regardless of alignment order

• B. at the start of spring, when the sun is nearly over the equator

• C. when the sun and the moon are at approximately 90º to each other

• D. the moon is on the first quarter and third phases

• 19. What will be the Gyro compass heading of the ship to place it on a magnetic heading North if the variation is 23º E, and the gyro error is 1º W?

• A. Magnetic compass heading 023º, Gyro compass heading 022º

• B. Magnetic compass heading 337º, Gyro compass heading 024º

• C. Magnetic compass heading 337º, Gyro compass heading 022º

• D. Magnetic compass heading 023º, Gyro compass heading 024º

• 20. For navigational purposes, each great circle on earth has a length of:

• A. 3,600 miles

• B. 12,500 miles

• C. 5,400 miles

• D. 21,600 miles

360° x 60 = 21,600

• 21. In Asian continent during Northern winter, when it is cooled and no intense high pressure area form over Eastern Siberia, what do you call the wind circulating in the area?

• A. NE moonsoon

• B. SE moonsoon

• C. Anabatic wind

• D. Katabatic wind

• 22. Which of the following in relation to the “geographic position” of a celestial body is not correct?

• A. To an observer at the geographic position, the celestial body would be at the Zenith and the altitude will be 90

• B. It is possible to draw the whole circle of equal altitude in the navigational charts currently in use

• C. The geographic position of celestial body will be along the arc of a circle of position or circle of equal altitude

• D. The altitude of the body to an observer 300 miles away from observer where the body is on the Zenith, will be 85

• 23. The dew point temperature is:

• A. always lower than the air temperature

• B. always higher than the air temperature

• C. equal to the difference between the water and dry bulbs

• D. the temperature at which the air is saturated with water

• 24. A publication listing the location, characteristics known facilities and available services of many ports, shipping facilities and oil terminals throughout the world:

• A. Sailing direction

• B. World port index

• C. Guide to port entry

• D. Almanac

• 25. Aids to navigation that emits audible signal use to indicate the location where cannot be seen due to reduce visibility:

• A. Radio signal

• B. Fog signal

• C. Loud speaker

• D. Gong

• 26. This is the raising phenomena when the upper limb of the sun is just on the observer’s visible horizon:

• A. Theoretical

• B. Hypothetical

• C. True sun

• D. Visible sun

• 27. It is the variation change that occurs twice daily due to lunar and solar tide in the earth’s atmosphere:

• A. Local attraction

• B. Diurnal change

• C. Atmospheric variation

• D. Celestial variation

• 28. Which of the following is not a problem of navigation?

• A. Determining the direction to go

• B. Fixing the position of the ship

• C. Distance run over the water

• D. Depth of the water

• 29. The magnets in the binnacle of a magnetic compass is intended to reduce the effect of:

• A. local attraction

• B. deviation

• C. repel magnetic field influences

• D. variation

• 30. How many points are there in a compass card?

• A. 4

• B. 32

• C. 8

• D. 24

• 31. What is the geographic longitude of a body whose GHA is 215 15”?

• A. 144 45’ E

• B. 35 15’ E

• C. 35 15’ W

• D. 144 45’ W IF GHA < 180 / GP = GHA NAMED WIF GHA > 180 / 360 – GHA = GP NAMED E

GW E

☼

GPGHA

• 32. Which of the following are the only magnetic compass correctors that correct for both permanent and induced effects of magnetism?

• A. Heeling magnets

• B. Quadrantal spheres

• C. Fore-and-aft magnets

• D. Atwarthship magnets

• 33. What do you call the layer of the atmosphere separating the troposphere and the stratosphere ?

• A. Mesopause

• B. Exopause

• C. Stratopause

• D. Tropopause

• 34. A resultant force of the layer pressure gradient which is always directed from high to low pressure:

• A. Low pressure

• B. High pressure

• C. Coriolis force

• D. Pressure gradient force

• 35. Under the IALA-B Buoyage System, when entering from seaward, a buoy that should be left to port will be:

• A. Black

• B. Green

• C. yellow

• D. red

• 36. The observed sextant altitude (Ho) is the altitude of a navigational body measured from:

• A. the surface of the earth to the center of the body from the sensible horizon

• B. the center of the earth to the center of the body from the celestial horizon.

• C. the center of the earth to the center of the body from the visible horizon

• D. the surface of the earth to the center (or limb if the moon or sun) the body from the rational horizon

• 37. Which of the following is not correct in relation to the meridians?

• A. They are great circles that pass through the poles of the earth

• B. All are of equal length

• C. Every point of the circumference of longitudes are equidistant and parallel to the prime meridian

• D. One is called Prime meridian and one is called the International dateline

• 38. What is the correct term for a change in the average wind direction of 45 or more that takes place less than 15 min. with wind speed greater than 10 kts?

• A. Squall

• B. Wind shift

• C. wind movement

• D. coriolis force

• 39. How often is equation of time given in the Nautical Almanac?

• A. Every hour of the day, monthly

• B. Every 15 minutes of the day of the year

• C. Every 30 minutes of the day, monthly

• D. Every 6 hours of the day of a year

• 40. This force diverts the wind towards the right in the Northern Hemisphere and to the left is the Southern Hemisphere and is most noticeable in higher latitudes:

• A. Squall

• B. Wind shift

• C. Wind movement

• D. Coriolis force

• 41. Course over the ground is the direction of the path actually followed usually a somewhat irregular line. What is the correct term for the direction to which the vessel is pointed at that moment?

• A. Track

• B. Heading

• C. Relative course

• D. Directed path

• 42. The quadrantal spheres are used to:

• A. compensate for induced magnetism in vertical soft iron

• B. removed deviation on the inter-cardinal headings

• C. removed heeling error

• D. removed deviation on the cardinal compass headings

• 43. These are charts intended for coastwise navigation outside outlaying reef and shoals (1:150,000 to 1:600,000 scale):

• A. General charts

• B. Sailing charts

• C. Coast charts

• D. Harbour charts

CHART CLASSIFICATION• 1.HARBOUR CHART- (1:50,000 & LARGER SCALE)

USE IN HARBOUR AND SMALLER WATERWAYS.• 2.COASTAL CHART- (1:50,000 – 150,000) USE FOR

INSHORE NAVIGATION, ENTERING/LEAVING HARBOURS.

• 3.GENERAL CHART- (1:150,000 – 600,000) OUTSIDE OF OUTLYING REEF AND SHOALS.

• 4.SAILING CHART- (1:600,000 & SMALLER SCALE) USE FOR VOYAGE PLANNING,FOR SAILING BETWEEN DISTANT COASTWISE PORT.

• 44. The sailing directions (enroute) contain information on all of the following EXCEPT:

• A. tidal currents

• B. other dangers to navigation

• C. ocean currents

• D. major port anchorages

• 45. Which of the following statements in relation to the “theory of celestial navigation” is NOT correct?

• A. if an observer moves 4 miles away from the direction of a celestial body, its altitude will change 1 minute

• B. an observer on the earth’s surface sees the altitude of a celestial body rise or set with a change in time

• C. the altitude of a celestial body also changes with a change in the observers position

• D. distance on the earth’s surface is measured in degrees as well as in miles

• 46. To process the gyrocompass to the approximate heading of the ship, we press on the :

• A. mercury ballistics

• B. vertical ring

• C. compensating weights

• D. rotor housing

• 47. Isobars connect lines of equal pressure. What do you call those concentric circles centered on the position of lowest pressure in a weather map?

• A. Isobath

• B. Isobrout

• C. Isobars

• D. Isoclinal

• 48. The velocity of the current in a large coastal harbor is:

• A. predicted in tide and current tables

• B. generally constant

• C. generally weak to be concerned about

• D. unpredictable

• 49. This is inversely proportional to the frequency being greatest VLF. It enables the reception of radio waves at a considerable distance away from an obstacle:

• A. Diffraction

• B. Refraction

• C. Absorption

• D. Scaterring

• 50. This scale of chart represents a small area, usually anchorages, harbors and small waterways:

• A. Small scale chart

• B. General chart

• C. Large scale chart

• D. Pilot chart

• 51. On a mercator chart, how would a great circle appear?

• A. convex towards the equator

• B. loxodromic

• C. straight line

• D. concave towards the equator

• 52. This layer of the ionosphere is characterized by, during the day maximum ionization occurs but at night becomes weaker by 2 orders of magnitude and in a constant height:

• A. F layer

• B. C layer

• C. E layer

• D. D layer

• 53. The sun is the principal cause of ionization in what ionosphere layer are signals particularly erratic because of the rapidly fluctuating conditions within layer itself?

• A. E layer

• B. D layer

• C. F layer

• D. C layer

• 54. You are sailing in navigable water of the United States. You must have a currently corrected copy (or extract) of the following per CFR 164.33.Which is not included?

• A. sailing directors

• B. tide tables

• C. list of lights

• D. Pollution Prevention Regulations

• 55. When steering a course of 159 true, you wish to observe a body for a latitude check, what would be the azimuth have to be?

• A. 090• B. 000• C. 260• D. 060

+

Zn = 000

LOPLAT

LONG

159˚

AZIMUTH:LATITUDE – 000 / 180LONG. - 090 / 270SPEED - PARALLELSET - PERPENDICULAR

• 56. When the light of a lighthouse is not of sufficient power, the______ range is given in the light lists.

• A. Luminous

• B. Charted

• C. geographic

• D. minimum

- EXISTING VIS. OR VIS. AT THE MOMENT

- CURVATURE OF THE EARTH

NOMINAL RANGE- VIS OF 10 N.M. ON CLEAR WEATHER

• 57. If the wind speed exceed two knots more stable_______ waves gradually form and progress with the wind.

• A. Oscillatory

• B. Gravity

• C. attenuated

• D. seismic

• 58. You are attempting to locate your position with reference to hurricane center in the Northern Hemisphere. If the wind direction remains steady but velocity diminishes with time, you are most likely:

• A. on the storm track ahead the center

• B. on the storm track behind the center

• C. on the right hand semi-circle

• D. on the left hand semi-circle

• 59. The risk of a vessel dragging her anchor is caused by:

• A. bad holding ground

• B. strong tidal current

• C. strong winds

• D. short scope of the cable

• 60. Your ship is at long. 179°59’ W. The mean time is 23h 56m 56s on March 8,1997. Six minutes later your ships position is long.179 59.8’ E. Your local mean time and date is:

• A. 24h 50 m March 9• B. 00h 50m March 9• C. 00h 02m March 8• D. 00h 02m March 10

LMT - 23h 56m 56s mar. 8 (+) 6m 00h 02m 56s mar. 9 (+) 1 dayLMT –00h 02m 56s mar.10 180

LONG. E LONG. W

W’LY CO.

EASTING = ADV.1HR./RET. 1 DAY(E’LY CO.)

WESTING= RET.1 HR./ADV. 1 DAY(W’LY CO.)

• 61. Which of the following statements in relation to the “Horizon System” of the celestial sphere is NOT correct?

• A. The primary circle of the Horizon System is the rational horizon

• B. Verticals are secondary to the rational horizon and intersect the circles of altitude at right angles

• C. The plane of the primary circle of the Horizon System passes through the center of the earth

• D. The zenith and nadir are the poles of the Horizon System

• 62. What is the angle between a line in the direction of gravity and the plane of the equator called?

• A. Geodetic angle

• B. Geographical angle

• C. Deflection of the vertical

• D. Astronomical latitude

• 63. Equation of time is the angle at the pole between the meridian of the true sun and the meridian of:

• A. the observer

• B. Greenwich

• C. the apparent sun

• D. the mean sun

• 64. While observing the moon it is noted that the sun west of the moon. The moon is more than half. Which of the following is correct in describing the state of the moon?

• A. Crescent-waxing

• B. Crescent-waning

• C. Gibbous-waxing

• D. Gibbous-waning

• 65. The probability of a sudden wind may be foretold by:

• A. a partly clouded sky

• B. an overcast sky

• C. a fast approaching line of dark clouds

• D. the information of cumulus clouds in the sky

• 66. The phantom element of a gyrocompass is kept in alignment with the sensitive element by the:

• A. azimuth motor

• B. transmitter

• C. mercury ballistics

• D. master alternator

• 67. “The air is Saturated” is an expression which means:

• A. the relative humidity is 100%

• B. cloud cover is 100%

• C. the vapor pressure is at minimum for the prevailing temperature

• D. precipitation has commenced

• 68. What instrument is set on a gyro compass repeater fitted with a prism for observing the direction of the sun?

• A. Bearing circle

• B. Alidade

• C. Azimuth circle

• D. Stadimeter

• 69. The rise and fall of ocean’s surface due to a distant storm is known as:

• A. Sea

• B. Fetch

• C. Swell

• D. Waves

• 70. A violent, intensely cold wind laden with snow mostly or entirely picked up from the ground or any heavy snowfall accompanied by strong wind;

• A. Tornado

• B. Gust

• C. Blizzard

• D. Dust whirl

• 71. In plotting three bearings taken by compass with constant error, the position will not meet in a common point. The position is normally called:

• A. triangular error

• B. dead reckoning

• C. estimated position

• D. running fix

• 72. Which of the following is the cause of winds blowing from high pressure area to a low pressure area deflects to the right in the Northern Hemisphere?

• A. Difference in air temperatures

• B. Rotation of the earth on its axis

• C. Movement of the earth on its orbit around the sun

• D. Magnetic attraction from the earth’s magnetic fields

• 73. The prevailing winds in the band of latitude from approximately 15 north to 30 north are called the:

• A. Doldrums

• B. Horse latitudes

• C. Northeast trade wind

• D. Southeast trade wind

• 74. The error introduced in a gyro compass by the motion of a vessel along its track is:

• A. speed error

• B. heeling error

• C. latitude error

• D. lateral error

• 75. The spherical triangle being solved in computing altitude and azimuth of a celestial body and in solving Great Circle Sailing is:

• A. navigational triangle

• B. celestial triangle

• C. terrestial triangle

• D. astronomical triangle

• 76. The fog most commonly encountered at sea is called:

• A. radiation fog

• B. smog

• C. frost smoke

• D. advection fog

• 77. What causes the waves on the surface of the sea?

• A. Tides

• B. Submarine earthquakes

• C. Volcanic eruptions

• D. Wind

• 78. After passage of a cold front the visibility:

• A. improves rapidly

• B. does not change

• C. becomes poor

• D. improves only slightly

• 79. In a fine normal day, the highest reading of a barometer occurs 2 times a day. This occurs at what time?

• A. 0400 Hours and 1600 Hours

• B. 0800 Hours and 2000 Hours

• C. 0000 Hours and 1200 Hours

• D. 1000 Hours and 2200 Hours

- LOWEST

• 80. SHA of star is 214, GHA of Aries is 277 longitude of the observer is 159W. Find the LHA of the star:

• A. 028• B. 290• C. 330• D. 332

GHA٧ = 277˚ (-)Λw = 159˚ LHA٧ = 118˚(+)SHA* = 214˚ LHA* = 332˚

• 81. The arc drawn from the geographic position of a celestial body equal to the radius of the circle of altitude is which of the following?

• A. Altitude

• B. Co – declination

• C. Zenith distance

• D. Declination

• 82. What is added to the vertical ring of a gyrocompass to affect symmetrical distribution of correction on the vertical axis of a gyrocompass?

• A. Compensator weight

• B. Mercury ballistics

• C. Dashpot dampers

• D. Modulator

• 83. When getting a position by bearing lines, why is nearer objects preferable than those at considerable distance?

• A. Constant error decrease with distance

• B. Linear error increase with distance

• C. Constant error increase with distance

• D. Linear error decrease with distance

• 84. When navigating a ship of piloting, which of the following is true/

• A. There is no immediate danger of grounding• B. The proximity of other vessels increases the

possibility of collision• C. Courses and speed are maintained for long

periods of time• D. You have to take star sights to check the

ship position and take an amplitude during twilight

• 85. A local wind which occurs during the daytime and is caused by the different rates of warming of land is called:

• A. Land breeze

• B. Anabatic breeze

• C. Sea breeze

• D. Katabatic breeze

• 86. During a lunar eclipse, the moon is about:

• A. full moon

• B. last quarter

• C. first quarter

• D. new moon

• 87. The height of the tide is the:

• A. depth of water at a specific time due to tidal effect

• B. difference between the depth of the water at high and at low tide

• C. difference between the depth of the water and the high water tidal level

• D. vertical distance from the tidal datum to the level of the water at any time

• 88. An apparent force causing a deflection of ocean currents to the left in the southern hemisphere is:

• A. gravitational pull

• B. difference in air pressure over the ocean

• C. trade winds

• D. coriolis force

• 89. A correction for refraction is applied to observed altitudes taken of:

• A. Venus and Mars only

• B. The sun only

• C. The moon only

• D. All celestial bodies

• 90. The primary wind build which has the greatest effect on the set, drift and depth of the equatorial currents is the:

• A. Doldrums

• B. Horse

• C. Northeast trade wind

• D. Southeast trade wind

• 91. What causes the wind to deflect to the left in the Southern Hemisphere instead of blowing directly from a high pressure area to a low pressure area?

• A. Doppler effect

• B. Magnetic attraction from the earth’s magnetic fields

• C. Coriolis force

• D. Inversion

• 92. The impact to a locality hit by the wind of Public Storm Signal number 2 is:

• A. Banana plants may be stripped of leaves

• B. Some coconut trees may be tilted and others broken

• C. Nipa houses and cogon roof are totally blown down

• D. Inter-island vessels can still sail but stay close to shore

• 93. Which month will the equatorial counter current be strongest?

• A. January

• B. August

• C. May

• D. December

• 94. Which of the following in relation to lines of position is correct?

• A. A vessel may be presumed to be located on such a line accurately as a result of measurement or observation

• B. Lines of position are great value but can be error because of imperfection instruments used for obtaining them

• C. A line of position may be considered of unquestionable accuracy inspite of human limitations in the use of navigational instruments

• D. It may considered that every line of position is very accurate and highly reliable

• 95. You want to make a good course of 040 True, and a speed of 12 knots. A current is setting east with a drift of 3 knots. Total compass correction is 8 W. What is the course to steer ?

• A. 029• B. 031• C. 026• D. 036 +e

r

12 KTS.er – CMG/SMGem – SET/DRIFTmr – CTS/SPD

3 KTS.mA

a=?

B

b C

C=

50

COS LAW:a2 = b2 + c2 – 2bc cos A = √(3)2 + (12)2 – 2(3)(12)cos 50 = 10.33

SINE LAW: a = bSin A Sin BSin B = b Sin A a = 3 Sin 50 10.33 = 12.8

A = 50B = 13 (+) 63 180 (-)C = 117 90 (-) 27

?

• 96. To measure a distance of 30 miles on a mercator chart between a point in lat. 43 30’ N and a point in lat. 40 30’ N, the divider is set at;

• A. 42 00’ and 42 30’

• B. 41 45’ and 42 15’

• C. 42 15’ and 42 45’

• D. 41 30’ and 42 00’

• 97. What American Agency publish the “Light Lists”?

• A. Oceanographic Office

• B. Army Corp of Engineers

• C. United States Coastguard

• D. National Ocean Service

• 98. The greatest depth where there is free horizontal communication between a large depression or more or less oval form is called:

• A. sill depth

• B. gulley

• C. deep

• D. detritus

• 99. What is the diurnal type of tide? There is/are ______ each tidal day.

• A. one low and no high tides

• B. one high and one low tides

• C. one high and no low tides

• D. no tide occurs

• 100. Your ship is sailing in area where a current sets NW with a drift of 3 knots. Your speed by engine is 10 knots. You want to make good course of 240. The total compass error is 4E. Find the compass course to steer:

• A. 219• B. 225• C. 210• D. 224

er = CMG / SMG

em = SET / DRIFT

mr = CTS / SPD.

+ e

m

r

3 KNOTS

10 K

NOTS

A

B

C

b

ac

SET = 315CMG = - 240ANGLE A= 75

75?

SINE LAW a = cSIN A SIN CSIN C = c SIN A a = 3 SIN 75 10 = 16.84

ANGLE A = 75.00ANGLE C = 16.84 (+) 91.84 180.00 (-)ANGLE B = 88.16 135.00(+) 223.16

““The air is Saturated” is an expression which means:The air is Saturated” is an expression which means:--the relative humidity is 100%--the relative humidity is 100%““The dew point temperature is:The dew point temperature is:--the temperature at which the air is saturated with water--the temperature at which the air is saturated with water“The ratio of the amount of water vapor actually in the air to the amount that would be in the air if the air were saturated is known as:--relative humidity