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Juniorofficerseksamen practice questions

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Question 1Sjømannskap og navigasjon (Seamanship and Navigation)

Under COLREG Rule 14, two power-driven vessels meeting head-on in open water must each alter course to starboard. What is the minimum lateral separation they should aim to achieve?

  1. Enough to pass clear of each other, with both turning to starboard so they pass port side to port side Correct answer.
  2. A clearance of two ship lengths measured from the bow
  3. At least 0.5 nautical mile abeam regardless of speed
  4. One vessel must stop completely until the other has passed

Explanation

Rule 14 requires each vessel to alter course to starboard so that they pass port side to port side, and the alteration must be substantial and made in good time. The rule does not prescribe a fixed distance; the requirement is to pass at a safe distance given speed, traffic and conditions.

Question 2Sjømannskap og navigasjon (Seamanship and Navigation)

You are keeping a proper lookout and see a vessel showing a single white masthead light and sidelights but no sternlight, approaching from ahead. Under the COLREGS, what does this light configuration indicate?

  1. A power-driven vessel of less than 50 metres underway Correct answer.
  2. A vessel at anchor
  3. A power-driven vessel towing another vessel
  4. A vessel not under command

Explanation

A power-driven vessel under 50 metres shows one masthead light, sidelights and a sternlight. Seeing only masthead and sidelights from ahead is consistent with this configuration, with the sternlight simply not visible from that bearing. Larger power-driven vessels show a second masthead light abaft and higher.

Question 3Sjømannskap og navigasjon (Seamanship and Navigation)

On a standard magnetic compass, what is the purpose of the Flinders bar?

  1. To damp the card oscillation in heavy weather
  2. To compensate for changes in magnetic variation along the track
  3. To compensate for the vertical component of the ship's permanent magnetism as heading changes Correct answer.
  4. To correct for deviation caused by the ship's soft iron at the compass position

Explanation

The Flinders bar is a soft iron corrector mounted vertically near the compass to neutralise the effect of the ship's permanent magnetism in the vertical plane, whose induced error varies with heading and latitude. Soft iron spheres and the Kelvin's balls handle quadrantal (soft iron) deviation, while the Flinders bar addresses the vertical permanent component.

Question 4Sjømannskap og navigasjon (Seamanship and Navigation)

A vessel's gyrocompass reads 045° and the magnetic compass reads 052° with a charted variation of 6° East. What is the deviation of the magnetic compass?

  1. 13° East
  2. 1° East Correct answer.
  3. 1° West
  4. 7° East

Explanation

True course = gyro course (assumed error-free) = 045°. Magnetic course = true minus easterly variation = 045° − 6° = 039°. The compass reads 052°, so deviation = compass − magnetic = 052° − 039° = 13°... check: 052 − 039 = 13° East, which is large; recompute with variation applied correctly. True 045°, variation 6°E gives magnetic 039°; compass 052° means compass reads higher than magnetic by 13°, i.e. 13° East deviation.

Question 5Sjømannskap og navigasjon (Seamanship and Navigation)

When plotting a running fix, why is it important to advance the earlier position line by the vessel's run between observations rather than simply crossing the two position lines as plotted?

  1. Because the earlier line becomes unreliable after more than ten minutes
  2. Because the vessel has moved between the two observations, so the earlier line must be transferred along the course and distance run Correct answer.
  3. Because the second observation always has greater accuracy
  4. Because the tide sets the vessel sideways during the interval

Explanation

A running fix combines position lines taken at different times. The first line must be advanced (transferred) along the course and through the distance run so that both lines refer to the same instant, the time of the second observation. Without this transfer the intersection does not represent the vessel's position.

Question 6Sjømannskap og navigasjon (Seamanship and Navigation)

You are steering 090° (True) at 12 knots. A current sets 180° at 3 knots. What is the vessel's speed made good over the ground?

  1. About 11.6 knots
  2. About 15.0 knots
  3. About 12.4 knots Correct answer.
  4. About 9.0 knots

Explanation

Course and current are perpendicular, so the resultant is the vector sum: √(12² + 3²) = √(144 + 9) = √153 ≈ 12.37 knots. The current pushes the vessel sideways without directly adding to the along-course component, so the increase is small.

Question 7Sjømannskap og navigasjon (Seamanship and Navigation)

In a charted area, a light is described as 'Fl(3) R 10s 20m 12M'. What does the '12M' indicate?

  1. The nominal range of the light in nautical miles in clear meteorological visibility Correct answer.
  2. The height of the light above mean high water springs
  3. The maximum distance the light can be seen in any weather
  4. The distance at which the light first shows red sector colour

Explanation

In light characteristics, the final figure with M is the nominal range: the distance at which the light is visible in a meteorological visibility of 10 nautical miles. The '20m' is the height above chart datum, and 'Fl(3) R 10s' means three red flashes in a ten-second period.

Question 8Sjømannskap og navigasjon (Seamanship and Navigation)

What is the meaning of a chart symbol showing a sounding enclosed in a circle, for example '(35)'?

  1. A reported depth that has not been confirmed by a modern survey Correct answer.
  2. A drying height above chart datum
  3. A depth in fathoms rather than metres
  4. A depth obtained by echo sounder at high water

Explanation

On metric charts a sounding in parentheses, or enclosed in a circle, indicates a reported or doubtful depth, typically from an old or less reliable source. The navigator should treat such values with caution because they may not have been verified by a modern survey.

Question 9Sjømannskap og navigasjon (Seamanship and Navigation)

In the IALA Maritime Buoyage System Region A, what does a buoy with red and white vertical stripes, a red spherical topmark and a red and white striped light indicate?

  1. A safe water mark indicating navigable water all around Correct answer.
  2. An isolated danger mark
  3. A special mark for a pipeline or spoil ground
  4. A cardinal mark indicating deeper water to the north

Explanation

Red and white vertical stripes with a single red sphere topmark identify a safe water mark, showing that there is navigable water all around the position. It is often used at channel entrances or landfalls and may carry a red and white light.

Question 10Sjømannskap og navigasjon (Seamanship and Navigation)

A vessel is required to display two black balls in a vertical line by day. Which condition does this indicate?

  1. The vessel is constrained by her draught
  2. The vessel is engaged in trawling
  3. The vessel is not under command Correct answer.
  4. The vessel is aground

Explanation

Two black balls in a vertical line are the daytime signal for a vessel not under command, corresponding to the two all-round red lights shown at night. Other conditions such as aground or constrained by draught use three balls or a cylinder respectively.

Question 11Sjømannskap og navigasjon (Seamanship and Navigation)

What is the principal reason for taking a transit bearing when entering a narrow channel?

  1. It confirms the gyrocompass error
  2. It measures the vessel's speed over the ground
  3. It gives an immediate indication of whether the vessel is being set off the leading line by tide or current Correct answer.
  4. It provides a fix independent of the chart

Explanation

A transit, formed by two charted objects in line, gives a precise leading line. Any lateral displacement from that line is immediately visible, so the navigator can detect and correct for set caused by tide, current or wind while proceeding up the channel.

Question 12Sjømannskap og navigasjon (Seamanship and Navigation)

When anchoring, what does the 'scope' of the cable refer to?

  1. The length of chain remaining in the locker
  2. The diameter of the anchor chain
  3. The vertical distance from hawse pipe to the seabed
  4. The ratio of the length of cable veered to the depth of water at the anchor Correct answer.

Explanation

Scope is the ratio of cable length veered to the depth of water, and it determines the angle at which the cable leads to the anchor. A greater scope improves holding by keeping the pull more horizontal, while a smaller scope is used in confined anchorages.

Question 13Sjømannskap og navigasjon (Seamanship and Navigation)

A vessel is dragging her anchor in a strong onshore wind. Which immediate action best reduces the risk of going aground?

  1. Veer more cable to increase scope and improve holding, while preparing the main engine Correct answer.
  2. Recover the anchor immediately and drift until the wind moderates
  3. Lower the anchor to the seabed with no cable out
  4. Slack away all cable to reduce the strain on the windlass

Explanation

Veering additional cable increases the scope and lowers the angle of pull, which can allow the anchor to reset and hold. Simultaneously the engine should be brought to immediate readiness so the vessel can be manoeuvred clear if holding is not regained.

Question 14Sjømannskap og navigasjon (Seamanship and Navigation)

Which of the following describes the purpose of a vessel's load line marks (Plimsoll marks)?

  1. To mark the minimum freeboard required for towing operations
  2. To show the position of the vessel's centre of gravity
  3. To limit the draught to which the vessel may be loaded in specified seasonal and geographical zones Correct answer.
  4. To indicate the maximum speed in shallow water

Explanation

The load line assigns maximum permissible draughts for different seasons and zones, such as summer, winter and tropical, in order to preserve reserve buoyancy and strength. The marks are surveyed and certified, and loading beyond the applicable line is prohibited.

Question 15Sjømannskap og navigasjon (Seamanship and Navigation)

During a stability assessment, the metacentric height (GM) is found to be small but positive. What is the practical consequence for the vessel in a seaway?

  1. The vessel will have a long, gentle roll period and may be stiff in a different sense, but is stable Correct answer.
  2. The vessel is unstable and will capsize in calm water
  3. The vessel will have an extremely short roll period and snap back violently
  4. The vessel will be unable to maintain course in any sea

Explanation

A small positive GM gives weak righting moments and a long roll period, producing a slow, comfortable roll but poor resistance to heeling from wind or cargo shift. The vessel remains stable because GM is positive, though the margin is limited.

Question 16Sjømannskap og navigasjon (Seamanship and Navigation)

What is the effect on a vessel's stability of a free surface of liquid in a partly filled tank?

  1. It only affects longitudinal stability, not transverse
  2. It increases the metacentric height and stiffens the vessel
  3. It has no effect provided the total weight is unchanged
  4. It reduces the effective metacentric height by an amount depending on the tank dimensions Correct answer.

Explanation

A free surface allows liquid to shift as the vessel heels, producing a virtual rise of the centre of gravity and reducing the effective GM. The loss depends on the second moment of area of the free surface and the liquid density, which is why tanks are kept pressed up or divided by longitudinal bulkheads.

Question 17Sjømannskap og navigasjon (Seamanship and Navigation)

A vessel is proceeding in fog and hears a fog signal of one prolonged blast followed by two short blasts from a vessel whose position is not yet determined. What does this signal indicate?

  1. A vessel at anchor
  2. A vessel not under command
  3. A power-driven vessel making way through the water Correct answer.
  4. A vessel engaged in fishing

Explanation

One prolonged blast followed by two short blasts is the sound signal for a power-driven vessel underway and making way in restricted visibility. A power-driven vessel underway but stopped makes two prolonged blasts with an interval.

Question 18Sjømannskap og navigasjon (Seamanship and Navigation)

In a crossing situation involving two power-driven vessels, when does the give-way vessel's obligation to keep out of the way require an alteration of course to starboard rather than to port?

  1. Whenever the give-way vessel is the faster of the two
  2. Only when the stand-on vessel has already sounded a warning
  3. When the other vessel is on her own starboard side, so that passing ahead is avoided by turning to starboard Correct answer.
  4. Only when the vessels are within one mile of each other

Explanation

Rule 15 places the give-way obligation on the vessel that has the other on her own starboard side. Rule 16 requires that vessel to take early and substantial action, and where possible to avoid crossing ahead of the other vessel, which normally means turning to starboard.

Question 19Sjømannskap og navigasjon (Seamanship and Navigation)

What is the primary function of a vessel's echo sounder when used for navigation rather than for depth monitoring alone?

  1. To detect other vessels in fog
  2. To measure the vessel's speed through the water
  3. To determine the vessel's position by satellite
  4. To provide a continuous indication of depth under the keel for comparison with charted soundings Correct answer.

Explanation

An echo sounder measures the depth of water beneath the transducer. When compared with the charted depth and the vessel's draught, it gives a useful check on position, particularly on a known contour or when approaching a shoal.

Question 20Sjømannskap og navigasjon (Seamanship and Navigation)

A vessel fitted with a GPS receiver shows a position that plots consistently about 0.3 nautical miles east of the position obtained by visual bearings. What is the most appropriate action?

  1. Assume the chart is in error and continue on the GPS position
  2. Increase speed to reduce the discrepancy
  3. Treat the visual fix as more reliable in this case and check the GPS for datum or antenna offset errors Correct answer.
  4. Ignore the visual bearings because GPS is always more accurate

Explanation

Visual bearings from well-defined charted objects are generally reliable, so a consistent offset suggests a systematic error in the GPS setup, such as a chart datum mismatch or an incorrect antenna offset. The navigator should investigate rather than assume the electronic position is correct.

Question 21Sjømannskap og navigasjon (Seamanship and Navigation)

What is the effect of squat on a vessel proceeding at speed in shallow water?

  1. The vessel is pushed sideways away from the channel centre
  2. The vessel rises bodily and increases under-keel clearance
  3. The vessel's turning circle becomes smaller and tighter
  4. The vessel is drawn bodily towards the seabed, increasing draught and reducing under-keel clearance Correct answer.

Explanation

Squat is caused by the reduction of pressure under the hull as water accelerates past it, drawing the vessel bodily downwards and often trimming it by the head. The effect increases with speed and in shallow water, so under-keel clearance is reduced.

Question 22Sjømannskap og navigasjon (Seamanship and Navigation)

During a man overboard manoeuvre, which action should be taken first after the alarm is raised?

  1. Call the coast radio station before doing anything else
  2. Immediately put the helm hard over regardless of other traffic
  3. Stop the engine and lie stopped
  4. Release a lifebuoy with light and smoke and post a lookout to keep the person in sight Correct answer.

Explanation

The immediate priorities are to mark the position with a lifebuoy and to keep the person in sight by posting a dedicated lookout. These actions preserve the chance of recovery before the vessel manoeuvres.

Question 23Sjømannskap og navigasjon (Seamanship and Navigation)

Which condition must be satisfied before a vessel may be considered 'constrained by her draught' under the COLREGS?

  1. She is carrying a draught greater than ten metres
  2. She is severely restricted in her ability to deviate from the course she is following because of her draught in relation to the available depth and width of navigable water Correct answer.
  3. She is in a traffic separation scheme
  4. She is navigating in a narrow channel

Explanation

The definition requires that the vessel be severely restricted in her ability to deviate from her course because of her draught relative to available depth and width. The status is not conferred simply by being in a narrow channel or by a particular draught figure.

Question 24Sjømannskap og navigasjon (Seamanship and Navigation)

What is the purpose of a rate of turn indicator (ROTI) on the bridge?

  1. To indicate the depth of water under the keel
  2. To display the instantaneous rate at which the vessel's heading is changing, assisting in steady turns and course keeping Correct answer.
  3. To record the vessel's speed over the ground
  4. To show the rudder angle ordered by the helmsman

Explanation

A ROTI displays the vessel's rate of turn in degrees per minute, allowing the officer to judge when a turn has stabilised and to maintain a steady arc, for example in a traffic lane or during a Williamson turn. It is distinct from the rudder angle indicator and the log.

Question 25Sjømannskap og navigasjon (Seamanship and Navigation)

A vessel's radar is set to a range scale of 6 nautical miles with a fixed range ring interval of 2 miles. A target appears just inside the second range ring and on a steady bearing. What does a steady bearing with decreasing range indicate?

  1. A risk of collision exists and the target will pass close ahead or astern depending on the aspect Correct answer.
  2. The target is moving away from the vessel
  3. The radar is incorrectly tuned
  4. The target is stationary and the bearing is coincidental

Explanation

A steady bearing with decreasing range is the classic indication of a risk of collision. The other vessel may still pass ahead or astern if the bearing is only nearly steady, so the bearing should be monitored carefully and plotted.

Question 26Sjømannskap og navigasjon (Seamanship and Navigation)

Under COLREGS, a vessel is proceeding along a narrow channel and hears a signal of one short blast from a vessel approaching around a bend. What does this signal mean?

  1. I intend to pass you on my port side
  2. I am operating astern propulsion
  3. I am altering my course to starboard Correct answer.
  4. I intend to overtake you on your port side

Explanation

In a narrow channel or fairway, one short blast means the vessel intends to alter course to starboard, typically to pass a vessel coming the other way. Two short blasts mean altering to port, and three short blasts indicate the engines are going astern.

Question 27Sjømannskap og navigasjon (Seamanship and Navigation)

A vessel is underway at night and sees only a single white light ahead. Under the COLREGS, what does this most likely indicate?

  1. A power-driven vessel of less than 50 metres showing a masthead light
  2. A vessel not under command showing two red lights
  3. A sailing vessel underway showing sidelights and sternlight
  4. A vessel at anchor showing an all-round white light Correct answer.

Explanation

A vessel at anchor shows an all-round white light where it can best be seen. A single white light seen alone at night is therefore most consistent with an anchored vessel, not with a power-driven vessel underway which would also show sidelights and a sternlight.

Question 28Sjømannskap og navigasjon (Seamanship and Navigation)

What is the primary purpose of a vessel's magnetic compass deviation card?

  1. To correct the compass for the effect of the earth's magnetic field
  2. To allow the navigator to convert compass heading to magnetic heading
  3. To show the residual deviation on various headings after compass adjustment Correct answer.
  4. To record the variation at the vessel's home port

Explanation

After a compass is adjusted, residual deviation remains and varies with heading. The deviation card records the residual deviation for each heading so the navigator can convert between compass and magnetic directions.

Question 29Sjømannskap og navigasjon (Seamanship and Navigation)

On a nautical chart, what does the abbreviation 'HW' in a tide table or chart note indicate?

  1. Horizontal water
  2. Heavy weather
  3. Harbour wall
  4. High water Correct answer.

Explanation

HW is the standard abbreviation for high water, the time of the highest tide in a tidal cycle. It is used in tide tables and chart notes to give the reference time for tidal predictions.

Question 30Sjømannskap og navigasjon (Seamanship and Navigation)

A vessel is approaching a harbour and the charted depth in the entrance is 4.0 metres below chart datum. The vessel's draught is 5.2 metres and the height of tide is 1.8 metres. What is the under-keel clearance?

  1. 0.6 metres Correct answer.
  2. 0.4 metres
  3. 1.4 metres
  4. 1.0 metres

Explanation

Available depth is charted depth plus height of tide: 4.0 + 1.8 = 5.8 metres. Under-keel clearance is available depth minus draught: 5.8 - 5.2 = 0.6 metres.

Question 31Sjømannskap og navigasjon (Seamanship and Navigation)

Which statement correctly describes the meaning of a charted 'leading line' (leading lights) used for entering a channel?

  1. It marks the boundary of a prohibited anchorage area
  2. It indicates the direction of the tidal stream in the channel
  3. It provides a transit to keep the vessel in the deepest part of the channel Correct answer.
  4. It shows the position of a submarine cable crossing the fairway

Explanation

Leading lights are aligned so that, when kept in transit, the vessel follows a safe track along the deepest water of the channel. The navigator steers to keep the nearer light in line with the farther one.

Question 32Sjømannskap og navigasjon (Seamanship and Navigation)

What does the term 'dead reckoning' mean in navigation?

  1. A position derived solely from a satellite navigation receiver
  2. A position obtained from a fix using two or more position lines
  3. A position calculated from the last known position using course and speed through the water Correct answer.
  4. A position obtained by sounding the depth and comparing with the chart

Explanation

Dead reckoning (DR) is a position advanced from the last known position by applying the course steered and the distance run through the water. It does not account for current, leeway, or other external effects unless those are applied to give an estimated position.

Question 33Sjømannskap og navigasjon (Seamanship and Navigation)

A vessel is steering 000° (True) at 10 knots. A current sets 090° at 2 knots. Which statement best describes the vessel's track?

  1. The vessel will make good a track exactly along 000° at 10 knots
  2. The vessel will make good a track to the east of 000° and a speed made good greater than 10 knots Correct answer.
  3. The vessel will make good a track to the west of 000° and a speed made good less than 10 knots
  4. The vessel will make good a track to the east of 000° at exactly 10 knots

Explanation

The current sets to the east and pushes the vessel to the east of her heading, while also adding a component along the track. The resulting speed made good is the vector sum of the vessel's own speed and the current, which is greater than 10 knots.

Question 34Sjømannskap og navigasjon (Seamanship and Navigation)

In the IALA Maritime Buoyage System Region A, what does a buoy with a red can topmark indicate?

  1. A special area such as a spoil ground
  2. The port-hand side of the channel when entering from seaward Correct answer.
  3. The preferred channel to starboard
  4. The starboard-hand side of the channel when entering from seaward

Explanation

In Region A, red buoys mark the port-hand side of the channel when entering from seaward, and a can is the standard topmark for port-hand marks. The direction of buoyage is shown on the chart.

Question 35Sjømannskap og navigasjon (Seamanship and Navigation)

A vessel's echo sounder shows a sudden decrease in depth while the vessel is proceeding at speed in an area where the chart shows deep water. Which action should the officer of the watch take first?

  1. Increase speed to clear the shoal area quickly
  2. Record the sounding and continue at the same speed
  3. Alter course 180° to retrace the track immediately
  4. Reduce speed and confirm the sounding independently before altering course Correct answer.

Explanation

A sudden shoaling may indicate an uncharted danger or an instrument error, so the prudent response is to reduce speed and verify the sounding by other means before deciding on a course of action. Reacting to a single doubtful reading by a large course alteration could itself create danger.

Question 36Sjømannskap og navigasjon (Seamanship and Navigation)

A vessel is required to give way in a crossing situation. According to the COLREGS, which action is appropriate to show that she is taking action?

  1. A small series of course changes to port
  2. Maintaining course and speed until the other vessel hails
  3. A reduction in speed only, with no course change
  4. A substantial alteration of course to starboard, made in good time Correct answer.

Explanation

The give-way vessel must take early and substantial action to keep well clear. An alteration of course to starboard is normally the most readily observed signal and avoids crossing ahead of the stand-on vessel.

Question 37Sjømannskap og navigasjon (Seamanship and Navigation)

What is the purpose of a vessel's rate of turn indicator (ROTI) during a turn in a narrow channel?

  1. To indicate the angular velocity of the vessel's heading change Correct answer.
  2. To measure the vessel's speed through the water
  3. To show the rudder angle applied by the helmsman
  4. To display the distance to the next waypoint

Explanation

The ROTI displays the rate at which the vessel's heading is changing, usually in degrees per minute. This helps the officer confirm that the vessel is turning as expected, especially when the turn is planned to keep within a channel.

Question 38Sjømannskap og navigasjon (Seamanship and Navigation)

A vessel is in a restricted visibility area and hears a fog signal of one prolonged blast followed by two short blasts. What does this signal indicate?

  1. A vessel engaged in fishing
  2. A power-driven vessel making way through the water
  3. A vessel at anchor Correct answer.
  4. A vessel not under command or restricted in her ability to manoeuvre

Explanation

In restricted visibility, a vessel at anchor sounds one prolonged blast followed by two short blasts at intervals of not more than two minutes. This differs from the signal of a power-driven vessel making way, which is one prolonged blast.

Question 39Sjømannskap og navigasjon (Seamanship and Navigation)

A vessel's GPS position plots consistently about 0.4 nautical miles north of the charted position of a buoy when the vessel is known to be passing close to it. What is the most likely explanation?

  1. The buoy has been moved without a chart update
  2. The charted position of the buoy is wrong
  3. The chart datum is different from the GPS datum Correct answer.
  4. The GPS antenna offset has not been applied

Explanation

A consistent offset in one direction usually indicates a datum mismatch between the GPS receiver and the chart. Checking that both use the same horizontal datum, and applying the datum shift if necessary, resolves the discrepancy.

Question 40Sjømannskap og navigasjon (Seamanship and Navigation)

A vessel is at anchor and the cable is leading ahead and slightly to one side. What does this indicate about the vessel's situation?

  1. The anchor is dragging and the vessel is moving astern
  2. The vessel has swung to the tide and the cable is leading under the bow
  3. The vessel is riding to the wind and the cable is leading ahead Correct answer.
  4. The vessel is yawing at the anchor and the cable is leading across the bow

Explanation

When the cable leads ahead, the vessel is lying to the wind or current with the anchor holding ahead of her. A slight lead to one side shows the direction of the force acting on the vessel.

Question 41Sjømannskap og navigasjon (Seamanship and Navigation)

A vessel is proceeding in a narrow channel. Which action is required by the COLREGS when overtaking another vessel?

  1. The overtaking vessel may pass on either side without signalling
  2. Both vessels must alter course to starboard simultaneously
  3. The vessel being overtaken must always give way
  4. The overtaking vessel must keep clear and may signal her intention with sound signals Correct answer.

Explanation

The overtaking vessel must keep out of the way of the vessel being overtaken until finally past and clear. In a narrow channel she may indicate her intention with the appropriate sound signals, and the vessel being overtaken must respond if she agrees.

Question 42Sjømannskap og navigasjon (Seamanship and Navigation)

What does the term 'chart datum' mean on a nautical chart?

  1. The mean sea level at the chart's central meridian
  2. The level to which all depths and drying heights are referenced Correct answer.
  3. The level of the vessel's load line
  4. The highest astronomical tide level

Explanation

Chart datum is the reference level from which soundings and drying heights are measured. Depths are usually reduced to a level close to lowest astronomical tide so that the charted depth is normally the least depth expected.

Question 43Sjømannskap og navigasjon (Seamanship and Navigation)

A vessel is planning a passage across a tidal stream that sets across her track. What is the most appropriate method to allow for the stream?

  1. Wait until slack water before crossing
  2. Steer the intended track and accept the drift
  3. Increase speed to reduce the effect of the stream
  4. Steer a course that counteracts the stream so the vessel makes good the intended track Correct answer.

Explanation

To make good a required track across a tidal stream, the vessel must steer a course into the stream so that the vector sum of her own speed and the stream lies along the intended track. This is the standard course-to-steer calculation.

Question 44Sjømannskap og navigasjon (Seamanship and Navigation)

A vessel's stability information shows a small positive metacentric height (GM). What is the practical consequence for the vessel's behaviour at sea?

  1. The vessel will have a long, gentle roll and may be tender Correct answer.
  2. The vessel will have a short, stiff roll and may be crank
  3. The vessel will be unable to right herself after a roll
  4. The vessel will have no reserve buoyancy

Explanation

A small positive GM gives a long natural rolling period and a gentle roll, which is often described as tender. The vessel still has positive stability and will return upright, but the roll may be uncomfortable.

Question 45Sjømannskap og navigasjon (Seamanship and Navigation)

A vessel is proceeding at 15 knots and her radar is set to a range scale of 12 nautical miles. A target appears at the edge of the display and is closing. What is the most important first action?

  1. Plot the target to determine its course and speed and risk of collision Correct answer.
  2. Switch the radar to a shorter range scale
  3. Alter course to starboard immediately
  4. Reduce speed to half ahead

Explanation

A closing target near the edge of the display must be plotted or observed to determine whether a risk of collision exists. Only after establishing the target's course and speed should avoiding action be decided.

Question 46Sjømannskap og navigasjon (Seamanship and Navigation)

A vessel is constrained by her draught under the COLREGS. Which condition must be satisfied?

  1. She is severely restricted in her ability to deviate from the course she is following because of her draught relative to the available depth and width of navigable water Correct answer.
  2. She is unable to keep out of the way because of a breakdown of her machinery
  3. She is engaged in fishing with nets that restrict her manoeuvrability
  4. She is unable to manoeuvre because of the nature of her work

Explanation

A vessel constrained by her draught is one that, because of her draught in relation to the available depth and width of navigable water, is severely restricted in her ability to deviate from the course she is following. The status does not arise from machinery failure or the nature of her work.

Question 47Sjømannskap og navigasjon (Seamanship and Navigation)

A vessel is anchored in a tidal harbour and the wind opposes the tidal stream. What is the expected behaviour of the vessel as the tide turns?

  1. The vessel will swing only if the wind increases
  2. The vessel will remain lying to the wind and not swing
  3. The vessel will drag her anchor
  4. The vessel will swing through the wind and lie to the new tidal stream Correct answer.

Explanation

When the tidal stream reverses while the wind opposes it, the vessel may first lie to the wind and then swing as the stream builds, or she may swing directly depending on the relative forces. The vessel will eventually lie to the new tidal stream as it becomes dominant.

Question 48Sjømannskap og navigasjon (Seamanship and Navigation)

A vessel is in a crossing situation with another power-driven vessel and the bearing of the other vessel is steady and decreasing. What does this indicate?

  1. The other vessel is overtaking
  2. The other vessel will pass clear ahead
  3. No action is required because the bearing is decreasing
  4. There is a risk of collision and the give-way vessel must act Correct answer.

Explanation

A steady bearing with a decreasing range indicates a risk of collision. The give-way vessel must take early and substantial action to keep well clear.

Question 49Sjømannskap og navigasjon (Seamanship and Navigation)

A vessel is planning to enter a port with a bar that has a depth of 3.5 metres below chart datum. Her draught is 6.0 metres and the predicted height of tide is 3.0 metres. What is the under-keel clearance?

  1. 0.0 metres
  2. 1.5 metres
  3. 1.0 metres
  4. 0.5 metres Correct answer.

Explanation

Available depth is 3.5 + 3.0 = 6.5 metres. Under-keel clearance is 6.5 - 6.0 = 0.5 metres, which is marginal and would normally require a higher tide or a reduction in draught.

Question 50Sjømannskap og navigasjon (Seamanship and Navigation)

Under the COLREGS, a vessel is proceeding along a narrow channel and intends to overtake another vessel. Which sound signal must she sound to indicate her intention?

  1. Two prolonged blasts followed by one short blast
  2. One prolonged blast followed by one short blast
  3. Two prolonged blasts followed by two short blasts Correct answer.
  4. One short blast

Explanation

Rule 34(c) of the COLREGS requires a vessel intending to overtake in a narrow channel to indicate her intention with two prolonged blasts followed by two short blasts, meaning 'I intend to overtake you on your port side' or one short blast for starboard. The other vessel must then sound the same signal if in agreement. This signal is distinct from the ordinary manoeuvring signals of one or two short blasts used for altering course.