Oral Questions Flashcards

1
Q

Explain why azipod propulsion systems do not require rudders to steer the ship?

A

The Azipod rotates 360degrees allowing them to apply thrust in every direction.

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2
Q

What are two drawbacks of azipod propulsion?

A
  • Requires great initial cost.
  • Sits proud of the hull making it susceptible to damage.
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3
Q

What are the advantages of a Voith Schneider unit?

A

-Reliable.
-Energy-efficient.
- Environmentally friendly.
-Compact drive unit.
-Require no rudder.

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4
Q

What are the disadvantages of a Voith Schneider unit?

A
  • The hydro foils increase the draft of the vessel.
    -It can complicate procedures when drydocking.
    -Requires more regular maintenance.
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5
Q

What is the ‘bank effect’ on a vessel in narrow channels?

A

-The vessel will feel the bow being pushed away and the stern drawn towards the bank.
-If strong enough can generate roll towards the obstruction.

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6
Q

How does ‘squat’ effect vessels?

A

-Steering becomes sluggish.
-Stopping distance and turning circle increase.
-Increase of vibrations.
-Change in draft indicators.

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7
Q

What are the advantages of a Controllable pitched propeller?

A

-Good response at slow speed.
-Relatively easy to replace propellers.
-Often fitted with a shaft generator.

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8
Q

What are the disadvantages of a Controllable pitched propeller?

A

-3 times more expensive than FPP.
-Require ongoing maintenance.
-Propeller efficiency is lower than an FPP.

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9
Q

What are the operational principals of a CPP?

A

-Blades rotate round their own axis.
-Shaft turns in the same direction all the time regardless going ahead or astern.

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10
Q

How can squat be eliminated?

A

-Reduce ahead speed.

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11
Q

What are the advantage’s of inward turning propellors?

A
  • The best configuration for CPP.
  • Improve Vessels manoeuvrability going ahead.
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12
Q

What are the advantage’s of outward turning propellors?

A

-The best configuration for FPP.
-Decrease vessels turning circle.

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12
Q

What are the advantage’s of outward turning propellors?

A

-The best configuration for FPP.
-Decrease vessels turning circle.

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13
Q

What information would you find in a ships manoeuvring booklet?

A

-Comprehensive details of the ships manoeuvring characteristics.
-Should be displayed on the wheelhouse poster along with any other manoeuvring information.
-MGN 301

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14
Q

What specific information would you find in a ships manoeuvring booklet?

A

-Ships particulars.
-Characteristics of main engine.
-Course change performance.
-Turning circle in deep/shallow water.
-Stopping ability.
-Deceleration and acceleration performance.

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15
Q

Describe how you would turn a vessel short round in a river ?

A

-Start port side of river.
-Rudder hard to stbd on full ahead.
-Midship full astern.
-Stop engine.
-Wheel to stbd and engines ahead.

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16
Q

Describe how you would approach the berthing of a vessel with the wind blowing the vessel onto the berth.

A

-Approach at steep angel with bow aimed just off the centre of the berth.
-Stop engine when ships length away, let go offshore anchor.
-Use engines ahead and helm to control the stern. (pivot point will mean stern will set on the quay.
-Slack on anchor to bring bow alongside with aid of the wind.

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17
Q

Describe how you would approach the berthing of a vessel with the wind blowing the vessel off the berth.

A

-Approach at steep angle to reduce windage at minimum steerage way.
-Alter to course to swing stern towards quay.
-engines astern to stop the ship and use transverse thrust to stop rate of turn.
-Send over stern line as soon as practicable (request mooring boat if available).
-Stop engines
-Send over forward spring and move vessel into final position.

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18
Q

Demonstrate how you would carry out a running mooring?

A

-Drop windward anchor and proceed ahead.
-Alter rudder to windward to keep the stern away from the paying out anchor chain.
-Let go of leeward anchor.
-Gear up windward anchor and heave on at the same time as paying out leeward anchor to final position.

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19
Q

Demonstrate how you would carry out a standing mooring?

A

-Opposite to running mooring.
-Set leeward anchor and then windward anchor.
-Drop leeward anchor 4-5 shackles ahead of final position.

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20
Q

Demonstrate how you would carry out a Baltic mooring?

A

-Stern wire passed forward and shackled on between the d shackle and first joining shackle of the cable.
-Approach berth with wind on the beam parallel to the quay and with anchor walked out.
-Once near along side send out stern line and adjust placement to final position then send over remaining lines.
-(Aim to berth vessel just clear of the doc with a prevalent onshore wind).

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21
Q

Demonstrate how you would carry out a Mediterranean mooring?

A

-Approach parallel to the berth with the berth on port side.
-Let go offshore anchor whilst maintaining headway.
-Pay out anchor as vessel moves ahead.
-Rudder hard over away from the berth.
-Engines astern.
-Let go second anchor.
- Pay out second anchor and heave on offshore anchor.
-(Aim to berth vessel just clear of the doc with a prevalent onshore wind).

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22
Q

Demonstrate how you would carry out an open mooring?

A

-Bow into the strongest element.
-Let go stbd anchor.
-Alter course to port 20-30 degrees and crab vessel.
-Pay-out anchor until half a cable of planed scope and drop port anchor.
-Rudder amidships.
-pay out on both anchors evenly and then test them for holding.

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23
Q

What are the effects of squat?

A

-Vessel takes longer to answer her helm (sluggish).
-Erratic steering at normal speed.
-Bow and stern wave increases in height.
-

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24
Q

You are the OOW on the anchor watch and the anchor starts to drag how would you go about arresting the dragging?

A

-Use vessel engines if available.
-Drop anchor if possible without fouling the 1st anchor.
-Let out more chain to see if the additional length helps the anchor to hold.

25
Q

How would you turn in heavy weather?

A

-Without use of excessive speed.
-Without undue delay.
-Crew members should be informed prior to turning especially ER and galley encase of excessive rolling.

26
Q

Describe the phenomenon of synchronised rolling.

A

-When the vessels rolling period is in sync with the wave period.
-Vessel rolling heavily.
-Rolling angle is the same or increases every roll.

27
Q

How would would you break the effect of synchronised rolling.

A

-Alter course.
-Alter speed.
-Change GM by ballasting/deballasting or shifting ballast fwd or aft.

28
Q

How would would you break the effect of synchronised pitching.

A

-Same as in synchronized rolling.
-Reduce speed if possible.

29
Q

What are 5 factors that affect a vessels turning circle?

A

-Reduced resistance to forward motion at the bow.
-Vessel with increased draught carry their way longer due to the greatly increased momentum.
-A vessel with a right handed propeller will have a smaller turning to port.
-Vessel trimmed by the head will have a lesser turning circle than a vessel trimmed by the stern.
-Vessel with heel or list to the opposite side of turn will have a smaller turning circle.
-Shallower water will have a dramatic effect on the vessels turning circle (interaction)

30
Q

Explain the movement of a vessel pivot point from stopped to full ahead and full astern.

A

-Going ahead the pivotal point will move approximately 1/4 of the waterline length from the forward.
-Going astern the pivotal point will move approximately 1/4 of the waterline length from the aft.

31
Q

How would you conduct a Williamson turn?

A

-Hard over to the side from which the person fell.
-Steady ship when altered 60 degrees from course.
-Hard over to the opposite side.
-Once 20 degrees off reciprocal course rudder midships.
-Vessel steadied and engine controlled for manoeuvring.

32
Q

How would you carry out an Scharnow Turn?

A

-Rudder hard over.
-After deviation from original course by 240 degrees rudder hard over to the opposite side.
-Once heading 20 degrees short of reciprocal, rudder to midships.

33
Q

Explain the operational principals of a Voith Schneider unit.

A

-(moving ahead) top blade curved surface has been increased causing a large amount of lift.
-Side blades are also angled to generate lift but also cancel each other. out.
-Bottom blade opposite to the top which generates drag to aid forward motion.

34
Q

What are the advantages of controllable pitch propellers?

A

-High propulsion efficiency.
-Good manoeuvrability.
-Going ahead to astern is smooth without any ‘dead time’.

35
Q

What are the disadvantages of controllable pitch propellers?

A

-Greater initial costs.
-More complex maintenance requirements.
-Increased stern tube loading due to weight of assembly.

36
Q

What are the advantages of Voith units?

A

-Highly manoeuvrable.
-Can be placed anywhere under the hull as no rudders required.
-Provide more control for vessels such as tugs or mine clearance.

37
Q

What are the disadvantages of Voith units?

A

-Very complex design meaning blades are difficult to replace.
-Increases UKC
-Reduced max speed compared to traditional propulsion.

38
Q

What factors would be taken into account in assessing how much anchor cable to put out?

A

-Water depth.
-Nature of the sea bed.
-Weather.
-Weather fore cast.
-Current/tidal strength.
-Swinging room.
-Length of stay.

39
Q

How would you carry out a low frequency rudder cycle stop?

A

-Hard to port.
-20 degrees off course half ahead.
-40 degrees off course hard to stbd.
-At the maximum overswing slow ahead.
-Once initial course hard to port.
-Dead slow ahead.
-Once almost original course hard to stbd and engines full astern.
-Original course stop engines.

40
Q

How would you carry out a high frequency rudder cycle stop?

A

-Hard to port stop engines.
-As vessel starts to answer to port helm hard to stbd.
-Swing to port arrested.
-Vessel crossing original heading hard to port.
-Vessel still swinging to stbd under port helm will require short burst of ahead power.
-As vessel answers port helm hard to stbd.
-Procedure repeated until vessel stopped in the water.

41
Q

How do kicks ahead on the engines affect the diameter of the turning circle?

A

As long as vessel speed does not pick up pivot point will remain as far forward as possible giving the largest turning lever when using rudders reducing diameter of turning circle.

42
Q

What are the two forces used in bringing two ships together for a lightering operation?

A

-Larger vessel steams at steerage way into the strongest element.
-Smaller vessel approaches slightly quicker that steerage way of larger vessel on a steady bearing.
-Small vessel draws parallel along side.
- The positive pressure at the smalls bow prevents her from moving too rapidly whilst the negative pressure draws the two vessels together.
-When close lines are sent.
-Smaller vessel slows down first and then larger vessel to a stop before commencing operations.
-Display RAM on both vessels.

43
Q

How would you spring a vessel off a berth from the shoulder?

A

-Single up headline and forward spring.
-Helm hard to port, heave on the headline and slow ahead on the engines.
-Swing vessel through 70-90 degrees from the berth.
-Stop engines and helm amidships.
-Slack away forward and engines astern.
-Let go forward.
-Use transverse thrust to cant bow clear of berth and proceed on passage.

44
Q

How would you spring a vessel off a berth from the quarter?

A

-Single up to headline and aft spring.
-Slack away on the headline and helm away from berth.
-As bow falls away rudder amidships (water flow wedge).
-Slack slowly on both lines and vessel will move sideways.
-Engines slow ahead.
-Once clear of berth proceed on passage.

45
Q

What information would you find in on a ships manoeuvring poster/plan?

A

-Steering particulars.
-Anchor chain (shackles)
-Ballast
-Propulsion particulars.
Thruster effect (trial conditions).
-MOB rescue manoeuvre.
-Draught increase (loaded).
-Turning circles at max rudder angel.

46
Q

What is Drift angle?

A

The angle between the vessel’s fore and aft line and the tangent to the turning circle.

47
Q

What is Advance?

A

Distance gained towards the direction of the original course after the rudder is put over.

48
Q

What is Transfer?

A

Distance gained perpendicularly to the original course after the rudder is put over.

49
Q

What is Tactical Diameter?

A

The transfer after turning 180 degrees.

50
Q

On recovering the anchor you find a large boulder trapped between the flukes, what two methods would you try to dislodge the boulder?

A

-Lower anchor gear to just above the sea bed, hold on brake and take out of gear, let go of break and drop the anchor to try and dislodge it.

51
Q

How would you attempt to free a semi-recovered anchor that has fouled an underwater cable?

A

-Position anchor where you can pass a wire underneath the fouled cable.
-Secure wire on deck.
-Lower anchor clear of cable.

52
Q

What are the disadvantages of inward turning propellers?

A

-Poor ship handling ability as transverse thrust acts against the direction of turn.

53
Q

Describe the forces affecting two vessels with one overtaking the other in a narrow river.

A

-Vessel B is going faster causing greater bow pressure than A causing A’s stern to be pushed away and the bow drawn to the negative pressure near B’s quarter.

54
Q

How does girting occur between a tug and a large ship?

A

-Typically conventional tugs with propulsion at the stern and towing hook amidships.
-Pivot point moves forward under the hook whilst in strain.
- with the pivot point forward of propulsion this can result in capsize when the ship turns independently and too quickly away from the tug or ships excessive straight line speed.

55
Q

What are the onboard preparations made prior to a helicopter transfer.

A

-Risk assessment/checklist verification.
-Vessel speed and relative wind direction.
-Met forecast.
-RAM signals tested.
-Communications tested.
-Bridge team briefing.
-Documentation prepared.
-D.P. wind sensors.
-Notice to E.R.
-LSA and FFA equipment prepared.

56
Q

Describe and expanding square search.

A

-Most effective when the location of the search abject is known within relatively close limits.
-Commence search point from the datum.
-Would use if only one vessel was carrying out the search.

57
Q

Describe a sector search.

A

-Most effective when the position of the object is accurately known and the search area is small.
-Used in a circular area on the datum point.
-Would use if only one vessel was carrying out the search.
-Vessel and aircraft can conduct this at the same time, independent of one another.
-Aircraft radius 5-20nm and vessel 2-5nm turning 120 degrees to stbd.

58
Q

Describe a parallel track search.

A

-Used to search a large area when survivor location is uncertain.
-Most effective over water or flat terrain.
-Search legs are parallel to one another.
-Can be used by multiple vessels

59
Q

Demonstrate and emergency towing arrangement for towing and towed vessel?

A

-Chafing chain (3 meters outboard of fairlead)