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GMA OOW Deck practice questions

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Question 1Navigation

On a nautical chart the vertical distance between a charted depth (referred to Chart Datum) and the height of tide at that moment gives which quantity?

  1. The height of the tide above the charted sounding
  2. The charted depth corrected for the height of tide
  3. The drying height of the seabed
  4. The total water depth at that position Correct answer.

Explanation

Total water depth equals the charted depth plus the height of tide above Chart Datum at that position and time. Charted soundings already reference Chart Datum, so adding the predicted tide height yields the actual depth available. This is the basis of under-keel clearance calculations.

Question 2Navigation

A vessel's magnetic compass shows a deviation of 4°E and variation at the position is 7°W. What is the compass error?

  1. 11°W
  2. 11°E
  3. 3°E
  4. 3°W Correct answer.

Explanation

Compass error is the algebraic sum of deviation and variation, with east positive and west negative. Here +4° (E) plus −7° (W) gives −3°, i.e. 3°W. The compass therefore reads to the east of true and must be corrected westward when converting to true bearings.

Question 3Navigation

On an Admiralty chart, what does the magenta symbol of a sector of a light indicate?

  1. The arc in which the light is obscured by land
  2. The area covered by a traffic separation scheme
  3. The sector in which the light shows a distinctive colour Correct answer.
  4. The limits of the light's nominal range

Explanation

Coloured sectors on a chart show the arcs within which a light exhibits a particular colour or characteristic. They are drawn with the colour named and the arc limits, helping the navigator identify the light by its colour sequence. They are not range limits or obstruction arcs.

Question 4Navigation

A charted light is described as 'Fl(3)WRG 10s'. What does the '10s' refer to?

  1. The duration of each individual flash
  2. The period of one complete cycle Correct answer.
  3. The nominal range in nautical miles
  4. The height of the light above mean high water

Explanation

In a light characteristic, the number followed by 's' is the period, the time taken for one complete cycle of the characteristic. For Fl(3) the cycle contains three flashes followed by a longer eclipse, all within 10 seconds. Range and elevation are given separately.

Question 5Navigation

When plotting a position using a single position line and a depth contour, the resulting fix is best described as which type of fix?

  1. A position obtained from a line of position and a depth contour Correct answer.
  2. A running fix
  3. A transferred position line fix
  4. A three-point fix

Explanation

Combining a line of position such as a bearing with a depth contour gives a fix only where the two intersect. Because both are single lines, the intersection is a point but confidence is limited by sounding accuracy and tidal height error. This is a recognised but less precise method than a multi-bearing fix.

Question 6Navigation

What is the primary purpose of the echo sounder when navigating in coastal waters?

  1. To determine the vessel's heading
  2. To measure water depth beneath the vessel Correct answer.
  3. To detect other vessels ahead
  4. To measure the vessel's speed through the water

Explanation

An echo sounder measures the time for a pulse to travel to the seabed and back, giving depth under the transducer. This is compared with the charted depth and tide to confirm the vessel's position along the track. It does not detect other vessels or measure speed or heading.

Question 7Navigation

On a Mercator chart, what is the effect of increasing latitude on the chart scale?

  1. The scale decreases towards the poles
  2. The scale increases towards the poles Correct answer.
  3. The scale changes only along the equator
  4. The scale remains constant everywhere on the chart

Explanation

The Mercator projection stretches the meridians as latitude increases so that rhumb lines plot as straight lines. As a result the scale is not constant and grows larger towards the poles. The navigator must therefore measure distance at a latitude close to the position concerned.

Question 8Navigation

In the IALA Region A buoyage system, what does a red can buoy normally mark?

  1. The port side of a channel when entering from seaward Correct answer.
  2. A special area or spoil ground
  3. The starboard side of a channel when entering from seaward
  4. An isolated danger

Explanation

In Region A, red marks the port hand and green the starboard hand for a vessel entering from seaward. Red can buoys therefore indicate the port side of the navigable channel. Region B reverses this colour convention.

Question 9Navigation

A vessel steams 090° true for 12 nautical miles. What is the approximate change of longitude?

  1. Zero, because the course is due east
  2. About 12 minutes divided by the cosine of the latitude Correct answer.
  3. 12 minutes of longitude
  4. About 12 minutes multiplied by the cosine of the latitude

Explanation

Departure equals change of longitude times the cosine of the latitude. For a due east course, departure equals the distance run, so change of longitude is 12 divided by cos(latitude) minutes. At higher latitudes the same distance spans more longitude.

Question 10Navigation

A vessel's true course is 045° and the gyrocompass reads 043°. What is the gyro error, expressed in the conventional form?

  1. 2° East Correct answer.
  2. 2° High
  3. 2° West
  4. 2° Low

Explanation

Gyro error is true heading minus gyro heading, with the result labelled east if the gyro reads low. Here 045° − 043° = +2°, so the gyro is 2° low, which is described as 2° East. The error is applied with the opposite sign to convert gyro to true.

Question 11Navigation

On a chart, a sounding is shown as a figure with a dotted circle around it. What does this convention indicate?

  1. A rock that is always submerged
  2. A depth obtained from a previous survey
  3. A drying height
  4. A depth reported but not confirmed by survey Correct answer.

Explanation

A sounding enclosed by a dotted circle, or a figure with a small circle, indicates a reported or doubtful depth that has not been confirmed by a systematic survey. The navigator should treat such soundings with caution. Confirmed soundings are shown as plain figures.

Question 12Navigation

A vessel is on course 000° true at 10 knots. At 1200 a light bears 090° true. At 1300 the same light bears 045° true. What is the vessel's distance from the light at 1300?

  1. 14 nautical miles
  2. 10 nautical miles Correct answer.
  3. 5 nautical miles
  4. 20 nautical miles

Explanation

The bearing changes by 45° over one hour while the vessel runs 10 miles. At 1300 the light lies 45° off the course, so the triangle formed is isosceles with the run of 10 miles equal to the distance off the beam at 1300. The distance from the light at 1300 is therefore 10 nautical miles.

Question 13Navigation

What is the purpose of the 'echo' reference in a compass deviation table?

  1. To list the dates of compass adjustments
  2. To note the variation at the vessel's home port
  3. To record the deviation on each cardinal and intercardinal heading Correct answer.
  4. To record the gyro error at each watch change

Explanation

A deviation table lists the deviation for each compass heading, usually at intervals of 15° or 30°, so the navigator can interpolate the error for any heading. It is produced during a compass swing. Variation is a separate quantity taken from the chart.

Question 14Navigation

A vessel's log reads 120.4 at 0800 and 132.9 at 1200. What is the average speed through the water for that period?

  1. 31.2 knots
  2. 12.5 knots
  3. 3.1 knots Correct answer.
  4. 6.2 knots

Explanation

The log difference is 12.5 nautical miles over four hours. Speed equals distance divided by time, so 12.5 ÷ 4 gives 3.125, approximately 3.1 knots. This is speed through the water, not speed over the ground.

Question 15Navigation

When using a position derived from a single bearing taken at a known time, what is the most appropriate description of the result?

  1. A line of position, which must be combined with another observation Correct answer.
  2. A fix, because a bearing always gives a position
  3. An estimated position corrected for leeway
  4. A dead reckoning position

Explanation

A single bearing defines a line of position along which the vessel lies somewhere. A fix requires the intersection of at least two position lines, or one position line combined with a depth contour or similar. Treating one bearing as a fix would overstate the accuracy of the position.

Question 16Navigation

A chart shows a tidal stream diamond with the figure '2.5' and the letter 'S'. What does this normally indicate?

  1. A neap rate of 2.5 knots in a southerly direction
  2. A depth of 2.5 metres over a shoal
  3. A spring rate of 2.5 knots in a south-easterly direction
  4. A spring rate of 2.5 knots in a southerly direction Correct answer.

Explanation

Tidal diamonds give the direction and rate of the tidal stream, with the letter indicating the direction and the figure normally the spring rate. The neap rate is derived using the appropriate factor. The diamond does not show depths.

Question 17Navigation

A vessel is proceeding along a course of 270° true. A conspicuous headland bears 315° true. What is the bearing of the headland relative to the vessel's head?

  1. 45° on the starboard bow Correct answer.
  2. 45° on the port bow
  3. 45° on the port quarter
  4. 45° on the starboard quarter

Explanation

Relative bearing is the true bearing minus the course, measured clockwise. Here 315° − 270° = 45°, which places the object 45° to starboard of the bow. A relative bearing between 0° and 90° is on the starboard bow.

Question 18Navigation

What is the principal limitation of a dead reckoning position after several hours without a fix?

  1. It accumulates errors in course, speed, and steering Correct answer.
  2. It requires a sight of a celestial body
  3. It ignores the effect of wind and current
  4. It cannot be plotted on a Mercator chart

Explanation

Dead reckoning advances a position using course steered and speed through the water, so errors in either accumulate with time. Set and drift from current and leeway are not included unless an estimated position is plotted. The longer the interval since the last fix, the larger the probable error.

Question 19Navigation

On a chart, a magenta line with the abbreviation 'TSS' and arrows indicates what?

  1. A cable area to be avoided
  2. A prohibited anchoring area
  3. A recommended route for deep-draught vessels
  4. A traffic separation scheme with established directions of traffic flow Correct answer.

Explanation

Traffic separation schemes are charted with magenta lines and arrows showing the direction of traffic flow in each lane. The scheme is intended to reduce head-on encounters in congested waters. Anchoring and cable areas use different charting conventions.

Question 20Navigation

A vessel is steering 090° true at 12 knots. A current sets 180° true at 3 knots. What is the approximate course made good?

  1. About 076° true Correct answer.
  2. About 104° true
  3. About 090° true
  4. About 180° true

Explanation

The current sets the vessel to the south while it steams east, so the resultant track lies south of east. Using the vector triangle, the drift angle is arctan(3/12), roughly 14°, giving a course made good of about 076° true. The speed made good is slightly greater than 12 knots.

Question 21Navigation

A vessel's position is fixed by radar ranges to two charted features. Which factor most affects the accuracy of the resulting fix?

  1. The colour of the charted features
  2. The angle of intersection between the two range arcs Correct answer.
  3. The height of the vessel's antenna above the water
  4. The vessel's speed through the water

Explanation

The geometry of the intersection governs fix accuracy; arcs crossing at a wide angle, ideally near 90°, give a well-defined point. Shallow crossings produce a long error ellipse. Antenna height affects detection range rather than the geometry of the fix.

Question 22Navigation

A vessel's echo sounder indicates a depth of 20 metres. The charted depth at the position is 14 metres and the height of tide is 5 metres. What is the most likely explanation for the discrepancy?

  1. The charted depth is referred to a different datum
  2. The echo sounder is measuring speed
  3. The echo sounder is reading the height of tide
  4. The vessel is not at the assumed position Correct answer.

Explanation

The expected depth from the chart and tide is 14 + 5 = 19 metres, close to but not matching the 20 metres shown. A discrepancy of this kind most commonly indicates that the vessel is not exactly at the assumed position, perhaps offset along the track. Datum differences would normally be stated on the chart.

Question 23Navigation

A vessel on a course of 000° true observes a light bearing 030° true at 2000 and 060° true at 2100. If speed is 8 knots, what is the distance off the light at 2100?

  1. 4 nautical miles
  2. 13.9 nautical miles
  3. 16 nautical miles
  4. 8 nautical miles Correct answer.

Explanation

The bearing changes by 30° over one hour while the vessel runs 8 miles. At 2100 the light is 60° off the course, and the geometry of the triangle gives a distance off equal to the distance run, 8 nautical miles. This follows from the relationship between bearing change and distance run.

Question 24Navigation

A chart is stated to be on a scale of 1:75,000. What does this mean for the navigator?

  1. The chart is suitable only for harbour approaches
  2. One unit on the chart represents 75,000 of the same units on the earth Correct answer.
  3. The chart covers 75,000 square nautical miles
  4. Depths are shown in units of 75,000 metres

Explanation

A natural scale expresses the ratio of chart distance to earth distance in the same units. At 1:75,000, one centimetre on the chart represents 75,000 centimetres, or 750 metres, on the earth. The scale says nothing about the area covered or the depths.

Question 25Navigation

A vessel's gyrocompass is checked by azimuth of the sun. The true bearing of the sun is 120° and the gyro bearing is 118°. What is the gyro error and how is it applied?

  1. 2° East, applied by subtracting from gyro bearings
  2. 2° West, applied by adding to gyro bearings Correct answer.
  3. 2° East, applied by adding to gyro bearings
  4. 2° West, applied by subtracting from gyro bearings

Explanation

Gyro error is true minus gyro, so 120° − 118° = +2°. Because the gyro reads less than true, the error is westerly and is added to gyro bearings to obtain true bearings. The label describes the direction the gyro is displaced, not the correction sign.

Question 26Navigation

Under the IALA Maritime Buoyage System, a vessel approaching a harbour with the flood tide setting into the harbour keeps which side of the channel marked by port-hand buoys?

  1. Centre of the channel, passing between the marks
  2. Either side, since the marks are safe-water marks
  3. Port side, leaving starboard-hand marks to starboard Correct answer.
  4. Starboard side, leaving port-hand marks to port

Explanation

Region A port-hand marks are red cans and are left to port when entering a harbour with the flood stream; starboard-hand marks are green cones left to starboard. The rule is defined by the direction of the buoyed channel relative to the set of the tidal stream, not by compass heading. Keeping to the correct side of the lateral marks is what keeps the vessel in the dredged channel.

Question 27Navigation

A vessel's magnetic compass reads 087° while the true course is 094°. Variation at the position is 5°E. What is the deviation of the compass?

  1. 2°W Correct answer.
  2. 2°E
  3. 12°W
  4. 12°E

Explanation

Compass to true: apply deviation to get magnetic, then variation to get true. Here 087° compass plus 5°E variation gives 092° magnetic, which is 2° short of the 094° true course, so the deviation is 2°W. Deviation is found by comparing compass heading with magnetic heading, not with true heading.

Question 28Navigation

A vessel is making good a course of 000° at 12 knots. A current sets 090° at 4 knots. What course must be steered to make good 000°?

  1. About 108° true
  2. About 342° true Correct answer.
  3. About 018° true
  4. About 072° true

Explanation

The current pushes the vessel to the east, so the steered course must be angled to the west of the desired track. The drift angle is arcsin(4/12) ≈ 19.5°, giving a course of about 340°–342° true. Steering 018° would double the easterly set and carry the vessel off track.

Question 29Navigation

A position line obtained from a single visual bearing should be regarded as what?

  1. A position fixed only if the object is a lighthouse
  2. A line of position on which the vessel lies somewhere Correct answer.
  3. The vessel's position at the bearing line's midpoint
  4. A definite position along the whole bearing line

Explanation

A single bearing gives a line of position: the vessel is somewhere along that line but its distance along it is unknown. A fix requires at least two position lines crossing at a good angle, or one position line combined with a range or sounding. Treating the bearing alone as a fix overstates the accuracy available.

Question 30Navigation

A vessel's echo sounder reads 18 metres. The charted depth at the position is 11 metres and the charted drying height of the nearest rock is 2 metres above chart datum. What does the reading indicate about the sounder's reference?

  1. The reading shows the tide height is 7 metres above chart datum
  2. The reading proves the sounder is calibrated to chart datum
  3. The reading is consistent with depth below the transducer plus transducer draught Correct answer.
  4. The sounder reads depth below the keel and needs no correction

Explanation

Echo sounders normally measure depth below the transducer, so the depth below the keel equals the reading plus any offset set, or minus the transducer's depth below waterline. The charted depth plus height of tide should match the sounding if the datum and offsets are correct. A reading of 18 m against 11 m charted suggests a tide and/or offset that must be reconciled before the sounding is used.

Question 31Navigation

On a nautical chart, what does a light described as 'Fl(3) R 10s 20m 12M' indicate?

  1. A group of three red flashes every 10 seconds, 20 m high, visible 12 M Correct answer.
  2. Three red lights at 10-second intervals, 20 m apart, range 12 M
  3. A flashing red light every 10 seconds, elevation 12 m, range 20 M
  4. A fixed red light of 10 seconds' duration, 20 m high, visible 12 M

Explanation

The abbreviation gives the light's character, colour, period, elevation and nominal range in that order. Fl(3) means a group of three flashes, R is red, 10s is the period, 20m is the height above high water and 12M is the nominal range in nautical miles. Reading the sequence correctly is essential when timing a light for a position fix.

Question 32Navigation

A vessel steering 045° true at 10 knots observes a lighthouse bearing 090° true. After 30 minutes the same lighthouse bears 135° true. What is the vessel's distance off the lighthouse at the second observation?

  1. 7 nautical miles
  2. 10 nautical miles
  3. 5 nautical miles Correct answer.
  4. 2.5 nautical miles

Explanation

The bearing changes by 45° over 30 minutes, during which the vessel runs 5 nautical miles. When the bearing change equals the angle on the bow at the second observation (45°), the distance run equals the distance off, so the vessel is 5 M from the lighthouse. This is the classic doubling-of-angle or four-point bearing technique.

Question 33Navigation

What is the primary reason for plotting a vessel's position using three position lines rather than two?

  1. A cocked hat reveals systematic error in the observations Correct answer.
  2. Three lines remove the need for a chronometer
  3. Three lines are required by the COLREGs in restricted visibility
  4. Three lines always cross at a single point

Explanation

With three position lines the small triangle, or cocked hat, formed when they fail to meet at one point indicates the magnitude and likely direction of observational error. Two lines give a fix with no internal check on accuracy. The size of the cocked hat is used to judge the reliability of the fix.

Question 34Navigation

A vessel's dead reckoning position after six hours without a fix is most unreliable because of which accumulation?

  1. The magnetic variation changes continuously with longitude
  2. The chart scale changes as the vessel moves
  3. The echo sounder drifts out of calibration
  4. Errors in course steered, speed and leeway all accumulate over time Correct answer.

Explanation

Dead reckoning extrapolates from the last fix using course, speed and estimated leeway and current. Any error in these inputs grows with the time elapsed, so the position uncertainty expands as a cone from the last fix. Regular fixes are needed to reset the DR and confine the error.

Question 35Navigation

A chart is stated to be on a scale of 1:150,000. What does this mean?

  1. One unit on the chart represents 150,000 of the same units on the earth Correct answer.
  2. One nautical mile on the chart equals 150,000 metres
  3. The chart covers a coastline 150,000 metres long
  4. The chart's accuracy is 150,000 times that of a small-scale chart

Explanation

A representative fraction of 1:150,000 means one unit measured on the chart corresponds to 150,000 of the same unit on the earth's surface. The larger the denominator, the smaller the scale and the less detail shown. It is a ratio, independent of the units used.

Question 36Navigation

In passage planning, what is the purpose of marking a 'no-go' area on the chart?

  1. To mark the limits of a traffic separation scheme
  2. To show where anchoring is prohibited by harbour bye-laws
  3. To indicate where the magnetic variation is unreliable
  4. To identify water too shallow or hazardous for the planned draught Correct answer.

Explanation

A no-go area is drawn to enclose water that the vessel cannot safely enter given its draught, squat and under-keel clearance, allowing for tide and swell. It provides a visual boundary that keeps the planned track clear of hazards. It is a planning aid, not a legal designation.

Question 37Navigation

A vessel is steering 270° true. A light bears 315° true. What is the bearing of the light relative to the vessel's head?

  1. 135° on the port quarter
  2. 90° on the starboard beam
  3. 45° on the starboard bow Correct answer.
  4. 45° on the port bow

Explanation

Relative bearing is true bearing minus heading: 315° − 270° = 45°. A positive result is measured to starboard, so the light lies 45° on the starboard bow. Converting between true and relative bearings is fundamental when reporting contacts and plotting.

Question 38Navigation

A vessel's gyrocompass reads 043° while the true course is 045°. What is the gyro error, expressed conventionally?

  1. 2° west
  2. 2° low
  3. 2° high Correct answer.
  4. 2° east

Explanation

Gyro error is conventionally stated as high or low, meaning the compass reads more or less than the true heading. Here the gyro reads 043° against a true 045°, so it reads 2° low. High and low replace the east/west convention used for magnetic compasses.

Question 39Navigation

A vessel's echo sounder shows a trace with a second, fainter echo at roughly twice the indicated depth. What is the most likely explanation?

  1. The sounder is picking up a double reflection off the seabed Correct answer.
  2. The transducer is faulty and reading half depth
  3. The tide is rising rapidly beneath the vessel
  4. The depth is actually twice the displayed figure

Explanation

A secondary echo at about double the depth is a multiple reflection, where the pulse bounces between the seabed and the hull before returning. The true depth is the first, stronger return. Multiples are common in shallow water over hard ground and should not be mistaken for the bottom.

Question 40Navigation

On a Mercator chart, how is a great-circle track normally represented?

  1. As a rhumb line of constant bearing
  2. As a straight line between the two positions
  3. As a series of parallel latitude lines
  4. As a curve concave to the equator Correct answer.

Explanation

On a Mercator projection a great circle plots as a curve that is concave towards the nearer pole, while a rhumb line is straight. For long ocean passages the great-circle track is shorter, so waypoints are plotted along the curve. This is why ocean passages are planned on a great-circle or gnomonic chart.

Question 41Meteorology

On a standard synoptic chart, a station model shows a wind arrow with the shaft coming from the northwest. In the Southern Hemisphere, how is this wind reported and what is the surface wind direction?

  1. Northwest wind, blowing toward the northeast
  2. Northwest wind, blowing toward the southeast Correct answer.
  3. Southeast wind, blowing toward the southwest
  4. Southeast wind, blowing toward the northwest

Explanation

Wind direction is always named by the direction from which the wind blows, so a shaft originating in the northwest indicates a northwest wind. The air moves toward the opposite point of the compass, that is toward the southeast.

Question 42Meteorology

A vessel's barometer reads 1013 hPa and the reading is falling steadily at about 1.5 hPa per hour. Which interpretation is most appropriate for the officer of the watch?

  1. Pressure is normal and the trend is insignificant
  2. A rapid fall indicates an approaching or deepening low with worsening weather likely Correct answer.
  3. The fall shows the vessel is steaming toward the equator
  4. A falling barometer always means a ridge of high pressure is building

Explanation

A steady, rapid fall of pressure is a classic warning of an approaching or deepening depression, with deteriorating weather and increasing wind expected. The absolute value of 1013 hPa is near average, but the rate of change matters more than the level.

Question 43Meteorology

In the International Code of Signals and in meteorological reports, what does the term 'veering' describe about the wind?

  1. An increase in wind speed without change of direction
  2. A change of direction in a clockwise sense Correct answer.
  3. A change of direction in an anticlockwise sense
  4. A decrease in wind speed without change of direction

Explanation

Veering means the wind changes direction clockwise, for example from southwest to west to northwest. Backing is the opposite, an anticlockwise change, and speed changes are described separately as strengthening or moderating.

Question 44Meteorology

A vessel is in the Northern Hemisphere with a low-pressure centre bearing due south of the ship. Applying Buys Ballot's law, where should the officer expect the wind to come from?

  1. From the north, with the low astern
  2. From the east, with the low on the left hand Correct answer.
  3. From the south, blowing directly out of the low
  4. From the west, with the low on the right hand

Explanation

In the Northern Hemisphere, standing with your back to the wind puts low pressure on your left. With the low to the south, the wind must come from the east so that the low lies on the left hand.

Question 45Meteorology

Which cloud type is most characteristic of an approaching warm front and typically produces the first continuous steady rain?

  1. Altostratus
  2. Cumulonimbus
  3. Cirrocumulus
  4. Nimbostratus Correct answer.

Explanation

A warm front produces a sequence from cirrus through cirrostratus and altostratus to nimbostratus, and nimbostratus is the thick layer cloud that gives continuous steady precipitation. Cumulonimbus belongs to unstable, showery conditions rather than the warm-front sequence.

Question 46Meteorology

A ship's anemometer records a true wind of 30 knots from the north while the vessel steams due north at 12 knots. What apparent wind will the officer of the watch experience on deck?

  1. 18 knots from the north
  2. 12 knots from the south
  3. 30 knots from the north
  4. 42 knots from the north Correct answer.

Explanation

When the vessel steams directly into the wind, the apparent wind speed equals the true wind plus the ship's speed, so 30 plus 12 gives 42 knots from ahead. The apparent direction remains from the north because the ship is heading into the wind.

Question 47Meteorology

In the tropics, a vessel encounters a small-diameter circulation with a calm centre, violent winds close to the centre, and a rapid fall then rise of pressure. Which system is being described?

  1. An extratropical frontal depression
  2. A polar low
  3. A tropical revolving storm Correct answer.
  4. A thermal low over land

Explanation

A tropical revolving storm has a compact circulation, an eye of relative calm, very strong winds close to the centre and a sharp pressure minimum. Extratropical depressions are much larger with frontal structure and a gentler pressure profile.

Question 48Meteorology

A vessel in the Northern Hemisphere is in the dangerous semicircle of a tropical revolving storm. To increase distance from the storm centre, which manoeuvre is generally recommended?

  1. Steam with the wind on the port bow and hold that heading
  2. Stop engines and ride out the storm head to wind
  3. Steam with the wind on the starboard bow, altering to put the wind on the starboard quarter Correct answer.
  4. Steam directly toward the storm centre to pass through the eye

Explanation

In the Northern Hemisphere dangerous semicircle, the recommended tactic is to put the wind on the starboard bow and then alter to bring it onto the starboard quarter, so the vessel runs away from the advancing track. This uses the wind to open distance from the centre.

Question 49Meteorology

Which statement correctly describes the relationship between isobar spacing and wind speed on a surface synoptic chart?

  1. Isobar spacing has no relation to wind speed
  2. Closely spaced isobars indicate a steep pressure gradient and strong winds Correct answer.
  3. Widely spaced isobars indicate strong winds
  4. Wind speed depends only on the absolute pressure value at the centre

Explanation

The pressure gradient is represented by the spacing of isobars, and a steep gradient with closely spaced isobars drives stronger winds. Widely spaced isobars indicate a slack gradient and light winds.

Question 50Meteorology

A vessel is approaching a coastline at night and the officer notices a lowering, thickening cloud base and a freshening onshore wind. Which weather change is most likely imminent?

  1. Deteriorating conditions with rain and stronger wind Correct answer.
  2. A steady improvement with veering wind and rising pressure
  3. Immediate onset of fog with calm air
  4. Clear skies with a building ridge

Explanation

Lowering cloud, thickening cloud and a freshening onshore wind are signs of an approaching frontal system with deteriorating weather. Rain and stronger winds are consistent with this pattern, and the officer should prepare accordingly.