1.- MANOEUVRE AND HANDLE A SHIP
You are berthed with a steady offshore beam wind of 30 knots. This wind suddenly increases to 60 knots. When this happens, the force pushing the vessel off the berth will be…
Quadrupled
Your vessel is to turn to port in a narrow canal using one tug (turning the bow to port). In wich position and how will you use the tug? (Your vessel’s engine will also be used.)
Make the tug fast on the port shoulder and pull.
You are sailing in shallow water, with 15% underkeel clearance. Coming full astern from full ahead, how will your course change compared with deep water?
The heading will most likely change by a large amount.
You are sailing in shallow water, with 15% underkeel clearance. How will your stopping distance and turning circle change compared with deep water?
Stopping distance longer & turning circle larger.
When manoeuvring, when will you notice the effect of shallow water?
When your underkeel clearance is 50% or less
You are on a VLCC and are approaching shallow water with an underkeel clearance of 15%. What speed should you have when entering the shallow water and when should you slow down?
Reduce to slow or less in due time before entering.
What shape of hull does a course stable ship usually have?
A long, slim hull.
The rudder is hard over, engine full ahead in shallow water. How much rudder lift force remains when the engine is stopped?
About 10%
The rudder is hard over, engine full ahead in deep water. How much rudder lift force remains when the engine is stopped?
About 20%
The rudder is in the hard over position, propeller stopped. The ship is turning slowly. What can be done to make her turn faster without increasing forward speed?
Give a kick ahead.
A tug is connected by a line at your bow. Will the bollard pull be the same at any speed? Choose the most complete answer.
No when the speed exceeds 5 knots the tug will not be of much help.
Overshoot is an expression used when talking about a ship’s steering ability. How can overshoot be determined?
Do a 20/20 degree zigzag manouvre.
When a conventional rudder is put hard over it creates a lift force and a drag force. when the ship has to turn, how much lift force remains if the rudder-angle is decreased to 20 degrees from the hard over position?
About 80%
You are in a 360 degrees turn with engine full ahead. If you reduce speed while in the turn, how will the turning diameter change?
The turning diameter will increase.
What shape of hull would you say a course unstable ship would have?
A length to beam ratio less than 5.5.
You have made a turning test at full speed in deep water. You are now going to make one with initial speed, slow ahead. Do you think the diameter will differ from that of initial full ahead?
The diameter will be the same whatever initial speed we have when starting the turn.
At roughly what latitude does the warm air, that has risen from above the equator, start to descend forming a belt of high-pressure circulation?
30°
Tropical maritime air is usually:
Warm, moist and unstable.
What level of visibility does “Poor” indicate in a weather forecast?
Between 1,000 - 2,000 m.
What is “Ice blink”?
A glare on the horizon perhaps indicating ice ahead.
At what altitude do altostratus clouds generally form?
2,000 - 5,500 m
In the Northern Hemisphere, wich direction will the wind normally be from just before a cold front arrives?
SW
A depression is formed when:
Warm, damp air meets cold, dry air.
What does “soon” mean in a weather forecast?
Within 6-12 hours of the warning being given.
During which month do most tropical storms form in the Northern Hemosphere?
September
You observe a strong breeze of 25 knots accompanied by large waves with white foam crests and some spray. What force in the Beaufort scale would this be rated at?
6
What is the minimum sea water temperature necessary for hurricane to develop?
26°
In a weather forecast what wave height is indicated by the term “Moderate sea”?
1.25 - 2.5 m
What do tightly spaced isobars indicate?
Strong winds.
What wind speeds are likely when a weather forecast predicts an imminent Force 8 gale?
Over 34 knots.
If you are facing into the wind in the Southern Hemisphere, where would an area of low-pressure lie?
To your left.
What does it mean when the barometer shows air pressure to be falling rapidly?
Bad weather is on the way.
If vessels cut their speed by 50% how much does this reduce any damage caused by collision?
75%
In which direction does the coriolis force deflect winds in the southern Hemisphere?
To the left.
The passage of a cold front is often marked by Stratus or Stratocumulus cloud giving way to:
Cumulus
In certain latitudes icebergs present a considerable hazard to shipping. What proportion of their volume is normally visible?
10%
What is the most important way of using air pressure measurements to predict bad weather is coming?
Noticing a steady, fall in air pressure.
Artic air is usually:
Cold and dry.
What is normally the air pressure at sea level?
1013 mb.
What is isobar?
A contour line of constant air pressure.
Buys Ballot’s law says that if a seafarer faces the wind in the southern hemisphere then the area of low pressure will be:
To the left.
What is growler?
A small iceberg.
At what temperature can ice start to form on a vessel’s superstructure?
-2° C
What distance must visibility be reduced to before water vapor is classed fog?
1,000 m.
On synoptic weather chart, what level of air pressure would be represented by the figure 113?
1011.3 mb.
In the Northen Hemisphere, which is the most dangerous part of a storm in relation to the direction in which it is moving?
It’s right hand side.
What is the biggest cause of high waves forming?
Wind.
The frequency of slamming can be more than halved by reducing the ship speed by:
20 - 25 %
The breaking of long waves can be tiggered by their meeting the continental shelf. how deep is the continental shelf?
200 meters.
Which of these is not a meteorological classification of an air mass?
Equatorial maritime.
After allowing for latitude daytime variation, what sort of fall in air pressure might indicate an approaching storm?
3 mb in three hours.
In which direction do jet streams normally travel
West to East.
Most large tankers are moored using wire ropes on winches in order to remain safely moored alongside. If extra mooring lines are required, Would a mixture of wires and full-length synthetic fibre ropes be appropriate?
No, because the wires would take most of strain and the fibre ropes practically none.
A ship is being turned short round in a tidal stream that is running at three knots. If still waters this normally takes 12 minutes, what allowance, if any, should be made for the drift of the ship during the turn?
6 cables.
The graph shows the decrease of speed, against time, on a 100,000 deadweight tanker proceeding at full speed of 13.3 knots and at minute 0 the engine was stopped. What is the decrease in speed most likely to be?
Series 1.
The diagram shows the manoeuvring characteristics of a ship. What are the distance A1 and A2 called?
Transfer.