The test consists of 80 random questions.
Total questions on this topic: 209
What corrections must be applied to the echo sounder reading to compare the depth of water with the depth printed on the chart?
Allowance for the ships speed.
The distance between the pulse Transmitter and Receiver.
Two mooring lines are pretensioned equally and have the same length, same breaking strength and same directional load. However, one is made of wire (with a full load elastic elongation of about 1,5 % of its length) and the other made of nylon (with a full load elongation of about 30 % of its length). If a gust of wind increases the load on the lines, how will it be shared?
The wire and rope will share the load equally.
Wire takes 45 % of the extra load. Rope takes 55 % of the extra load.
Wire takes 55 % of the extra load. Rope takes 45 % of the extra load.
Wire takes 95 % of the extra load. Rope takes 5 % of the extra load..
A ship normally turns (swings) around a point which is not the centre of gravity. What is this point normally called?
What is the probable cause of an error in position of the ship obtained from the GPS system?
A three dimensional instead of a two dimensional position output.
Incorrect height of the antenna.
All of the suggested answers.
Abnormal sun spot activity causing unusual radiation effects.
You are proceeding up a river, with berths on both banks. You see this flag hoist on a vessel moored on a berth ahead. What does it mean?
I am about to depart the berth.
Caution! I have an anchor down.
You should proceed at slow speed when passing me.
You are on a sailing vessel, underway in open water. This vessel is sighted on the starboard bow, on a steady bearing and the distance is closing. By the International Regulations for the Preventing Collisions at Sea, what action will you follow?
Risk of collision is deemed to exist and, as the other vessel is on a steady bearing on my starboard side, I am required to keep out of the way. I will make a broad alteration of course to starboard.
By Rule 18, a power-driven vessel underway shall keep out of the way of a sailing vessel. I will maintain my course and speed, but will continue to monitor situation to ensure the other vessel takes avoiding action.
Risk of collision is deemed to exist and, as the other vessel is on a steady bearing on my starboard side, I will maintain my course and speed.
This vessel is clearly a power-driven vessel and I anticipate that the bearing will therefore close and she will pass ahead at a safe distance.
What methods could be introduced into a passage plan for continuous monitoring of the ships position when navigating along a coastline?
Conspicuous headlands and navigational marks for taking positions.
The radar ranges of the coastline at all course alteration points.
All of the suggested answers.
Two ships travelling in opposite directions are to pass each other in a narrow river, as illustrated. Explain what is likely to happen as they pass each other?
Due to interaction, the bows will attract each other as they approach, then they will repel each other alongside and as they pass clear, the sterns will be attracted.
Due to interaction, the bows will repel each other, and then when alongside each other the two ships will be sucked together and finally the sterns will be repelled as they start to pass clear.
There will be very little effect between the two ships as they pass.
As they approach, rudder should be applied quickly to avoid sheering into the path of each other. Then as they are alongside they will be attracted and finally repel each other as they pass clear.
What corrections must be applied to the echo sounder reading to compare the depth of water with the depth printed on the chart?
The distance between the pulse Transmitter and Receiver.
Allowance for the ships speed.
When using the echo sounder in a river the soundings indicated may be incorrect, what would be the most probable cause of the error?
There should be no error with a properly working echo sounder.
The strength of the tide and current in the river.
The density of the water.
You are in an area of restricted visibility. You hear this sound signal. What does it mean?
That there is a vessel aground in the vicinity.
That there is a vessel at anchor in the vicinity.
That there is a vessel engaged in underwater operations in the vicinity. She has divers down.
That there is a vessel in distress nearby.
Where can a ship expect an act of piracy to take place?
At the south end of the Red Sea.
What is the correct understanding of the term “bank effect”? If a ship was approaching the bank at an angle, what would be the effect on the ship?
The whole vessel would continue straight towards the bank and would require a large helm order to avoid going aground.
The vessel’s bow is pushed away from the bank.
The vessel’s stern is pushed away from the bank.
The vessel’s bow is attracted by the bank.
What, by definition in the International Collision Regulations, is a “vessel restricted in her ability to manoeuvre”?
A vessel which because of her draught in relation to the available depth of navigable water is restricted in her ability to deviate from her course and keep out of the way of another vessel.
A vessel engaged in underwater work, such as the laying, picking up or servicing of a pipeline, or which is in support of diving operations, performing dredging and mine-clearance or is deploying or recovering a pilot.
A vessel which from the nature of her work is restricted in her ability to manoeuvre as required by the Rules and is therefore unable to keep out of the way of another vessel.
A vessel which through some exceptional circumstance is unable to manoeuvre as required by the Rules and is therefore unable to keep out of the way of another vessel.
You are on a power-driven vessel underway in open water. You sight these lights on the port bow, on a steady bearing. The distance is closing. What are you looking at and what action will you take in compliance with the International Regulations for Preventing Collision at Sea?
This is a power-driven vessel, more than 50 metres in length or less than 50 metres in length and showing a second masthead light, restricted in her ability to manoeuvre. The sidelight of a second vessel can be seen beyond her. Under rule 18, I am obliged to keep clear of the first vessel and will therefore take appropriate avoiding action.
This is a power-driven vessel engaged in towing, less than 50 metres in length, length of tow under 200 metres and the tow, both being restricted in their ability to manoeuvre, seen from the starboard side. Under rule 18, I am required to keep clear and will take appropriate avoiding action.
What does this signal flag indicate when seen on a vessel in a port approach?
Keep clear. I have divers down.
I am in distress and require immediate assistance.
I require medical assistance.
The position of the ship is found by taking a series of bearings using a magnetic compass. How should an error of 5° WEST be applied to the compass bearings?
The error should be “High” or “Low” and therefore more information is required.
Add the 5° to the bearings.
Subtract 5° to the bearings.
The same error applies to all bearings and therefore it can be ignored.
When making a new pilot ladder onboard the ship, which of the following ropes would be best suited as the side ropes on which the steps are fastened?
Rule 12 of the International Collision Regulations prescribes the action to be taken by a sailing vessel when meeting another sailing vessel. This depends on the direction of the wind relative to each vessel. In the situation shown here, which sailing vessel (A or B) must keep out of the way of the other?
The upwind sailing vessel must keep out of the way of the downwind sailing vessel.
Sailing vessel B must keep out of the way of sailing vessel A.
Both sailing vessels are required to take avoiding action.
Sailing vessel A must keep out of the way of sailing vessel B.
What is the weather associated with being in the centre of an Anticyclone (a region of High Pressure)?
Strong winds and heavy rain.
Light winds and fair weather, sometimes fog.
Persistent rain and very humid weather.
Strong winds but with very little rain.
The rudder is hard over with the engine at full ahead. Will the turning effect of the rudder be changed if the engine is stopped?
Yes, the turning force will be dramatically reduced when the engine is stopped.
No, the turning force applied by the rudder will be maintained within about 90 % of the turning force when going full ahead.
Yes, the turning force will be reduced to about 50 % of the original force when the engine is stopped.
No, the turning force is unaffected by the speed of the propeller.
In the figure, which letter gives the correct understanding of the term “LENGTH OVERALL”?
Length Overall is indicated by D, in the figure.
Length Overall is indicated by C, in the figure.
Length Overall is indicated by B, in the figure.
Length Overall is indicated by A, in the figure.
The bridge Officer of the Watch (OOW) is plotting the ship’s position in the chartroom, when the ship is in collision with a fishing vessel. Why would the OOW be held responsible for the collision?
If the OOW is busy with the safe navigation of the ship he should have exhibited the “Not under Command” signals and made other ships keep clear.
If risk of Collision existed, the fishing boat should have contacted the larger ship over the VHF before the collision took place.
Under the Rules the fishing vessel should have kept clear of larger vessels and the OOW would not be responsible.
Under the Rules a proper lookout should be maintained at all times and by all available means.
What is the direction of wind associated with an anticyclone (area of high pressure) in the Northern Hemisphere?
Clockwise around the high pressure.
Anticlockwise around the high pressure.
Straight towards the centre of the anticyclone.
Directly away from the centre of the anticyclone towards the nearest low pressure.
Who is responsible for the number and the position of any tugs to be used during a mooring operation?
The Master, with consideration of the advice of the pilot.
The Pilot is fully responsible for the number and use of tugs within the port area.
It will be only the wind speed that will determine the required number of tugs and how they are used.
The Port Authority will dictate the tug requirements and their use within the port limits.
This vessel is sighted ahead and slightly to port. What is her situation? What will you do?
This is a vessel engaged in fishing vessel, with her nets fast on a obstruction. I will keep out of the way by rule 18 of the International Collision Regulations.
This vessel is aground. I will navigate with extreme caution given the nature of the hazard.
This is a vessel not under command at anchor.
This is a vessel aground. She appears to have been headed to starboard of my track and I will therefore alter course to port, passing under her stern.
The ship is to berth alongside a quay in calm conditions of no wind or current. The ship has a signle fixed pitch right handed propeller. Which angle of approach would be considered the most favourable?
The decision should be left to the pilot who is in charge of the manoeuvre.
You are in an area of restricted visibility, close to a port. You hear this signal. What vessel does it come from and what additional information does the signal provide?
A vessel at anchor, less than 100 metres in length. She is sounding the additional signal top give warning of her position.
A vessel at anchor, more than 100 metres in length. The additional signal indicates that her cable extends at least 25 metres from her bow.
A vessel at anchor, more than 100 metres in length. She is sounding the additional signal to give warning of her position.
A vessel aground, more than 100 metres in length. The additional signal indicates which side the clear water lies on.
What is the description for a sidelight, as shown in rule 21 of the International Regulations for Preventing Collisions at Sea?
A red, green or yellow lantern, showing an unbroken light over an arc of 112,5°.
A green light on the starboard side and red light on the port side, showing an unbroken light over an arc of 135°, from right ahead to 22,5° abaft the beam on the respective side.
A green light on the starboard side and red light on the port side, showing an unbroken light over an arc of 112,5°, from right ahead to 22,5° abaft the beam on the respective side.
A red light or a green light, with a minimum range, in a vessel of 50 metres or more, of 3 miles. In a vessel of 10 metres.
You are in an area of restricted visibility and hear this signal. It is repeated at 2 minutes intervals. What does it indicate?
That there is another vessel nearby, that she is underway, but stopped and making no way through the water.
That there is another vessel nearby, but that she is at anchor.
That there are two more vessels nearby.
That there is another vessel in the vicinity and that she has just altered course to port.
What does this signal hoist mean?
I require medical assistance.
Do you require assistance?
I require immediate assistance.
What is the correct understanding of the term “Block Coefficient” as applied to a ship?
The restriction of a valve in a pipe to the flow of fluid through that pipe.
The coefficient of a Block and Tackle.
The comparison of the underwater shape of the ship, to a rectangular block of the same extreme dimensions.
The ratio of the water plane shape of the ship to a rectangle of the same extreme dimensions.
Is the location of the Compass Binnacle critical?
Yes, it should be on the fore and aft centreline of the ship.
Yes, it should be sited on a non-metallic base if possible.
Yes, it should be away from all electrical power cables.
Yes, for the reasons stated in all of the suggested answers.
Which of the four calculations illustrated is the correct one to determine the latitude of the observer when the sun is on the meridian?
Calculation 3 is correct.
Calculation 2 is correct.
Calculation 1 is correct.
Calculation 4 is correct.
What could be the reason for the magnetic compass to swing through large angles when the ship is rolling in a seaway?
The error due to deviation is large for that ships heading.
The Coefficient B determined by the Compass Corrector at the last dry-dock was not correctly calculated.
The heeling error magnets are upside down and/or not in the correct position.
The induced magnetism from the earth’s magnetic field is very strong in that area.
In an extreme case, in addition to having your winch brakes as tight as can be, you can increase the brake holding capacity of the winch drum by putting it in gear and setting the power to the “heave” position. However this may cause:
All the listed alternatives.
The increased braking power of the winch to exceed the breaking strength of the wire and rope paid out from it which might cause the wire or rope to part.
Strain on the fairleads and rollers in use in excess of their Safe Working Load.
Damage to the winch by distorting the shaft.
What is the weather associated with being in the centre of an Anticyclone (a region of High Pressure)?
Strong winds and heavy rain.
Persistent rain and very humid weather.
Strong winds but with very little rain.
Light winds and fair weather, sometimes fog.
When should voyage planning be done?
Before the pilot is leaves the vessel at the departure port.
During the pilotage when leaving the berth.
Prior to leaving the berth.
Before the vessel completes the previous passage.
If a ship requires 2 nautical miles to stop in the water from a “crash stop” when proceeding at full ahead in deep water. What will the stopping distance be in shallow water?
Similar distance to deep water.
About 1,5 nautical miles.
A balanced rudder has some of the rudder area forward of the rudder axis. About how much area should this be to call it a balanced rudder?
When splicing an eye on a mooring wire (using the recommended 5 full tucks and 2 half tucks) the effective breaking strength of the wire may be affected by the splice. What would be the anticipated change in the breaking strength of the wire?
A reduction in strength of 1 % to 5 %.
A reduction in strength of 10 % to 15 %.
A reduction in strength of 30 % to 40 %.
No reduction in strength.
Is the location of a vessel’s standard compass binnacle critical?
Yes, it should be on the fore and aft centreline of the ship.
Yes, for the reasons stated in all of the suggested answers.
Yes, it should be sited on a non-metallic base if possible.
Yes, it should be away from major electrical power cables.
The position of the ship provided by the GPS should always be confirmed by other means, when possible. Which of the following suggested methods would be the most accurate?
The ranges of three distinctive shore objects on the radar.
Bearing and distance from a navigational Buoy.
Compass bearings of three shore objects.
Bearing using the Radio Direction Finding of three radio beacons.
The Master arrives on the bridge obviously under the influence of alcohol and states he is taking over the “con” of the ship. What actions should the Officer of the Watch (OOW) take in this situation?
Watch the actions made by the Master and if not dangerous, wait until the Master becomes more capable to take control or leaves the bridge.
Attempt to diplomatically avoid taking any actions that would put the ship or crew into danger and call the Chief Officer for assistance.
Tell the Master you do not think this is a good idea and retain control of the watch.
Tell the Master you consider him incapable of taking over the responsibility of the watch and that he should retire to his cabin and sleep it off.
A man is reported to have fallen overboard and the Officer of the Watch releases the lifebuoy and starts a man overboard manoeuvre, who are the first persons onboard he should inform?
The crew quarters for extra lookouts.
Chief Officer and lifeboat party.
The ship’s engine is going astern and the ship is piking up sternway. The rudder is amidships and the ship has a single, right-handed, fixed pitch propeller. What would be expected to happen?
The ship will probably start to change heading to starboard and stern speed will increase.
The ship will probably start to change heading to port and stern speed will increase.
The ship will move astern at an increasing speed and the stern start to swing off to starboard.
The ship will probably go straight astern without a change in heading and the stern speed will increase.
What special equipment can often provide assistance in locating a survival craft or man overboard and in the water?
A sectored search pattern.
After passage planning with ECDIS, how should the route be checked for safety?
Using the ECDIS route and geometry checker only.
Using the ECDIS route checker and by visually sighting all along it.
Transfer the ECDIS plan onto paper charts.
Investigate the displayed waypoint list after it is printed out.
Visual signals are used by aircraft in search and rescue operations to direct ships towards a casualty. The signals shown here are part of a sequence. What does it indicate?
The assistance of your vessel is no longer required.
The casualty is sighted and will require medical assistance.
The aircraft is short on fuel and is returning to base.
The aircraft is directing a vessel towards the casualty.
The IMO Standard Marine Communication Phrases are recommended to be used when the ship’s Officer is verbally talking to whom?
When talking between ship and shore personnel.
In circumstances described in all of the answers provided.
When giving orders on board with other seafarers.
When talking on the VHF between ships.
How can an ARPA assist the ship to steer a suitable course to make good the entrance to a channel?
Select Relative motion display and make Own Ship vector pass through the middle of the entrance to the channel.
Acquire the buoy at the entrance to the channel and on relative vector display alter course to make the vector of the buoy pass directly through the centre of the screen.
Select True ground stabilised vectors and make the vectors from both buoys at the entrance to the channel pass either side of the centre of the screen.
Select ground stabilised true motion display and alter course so that own ships true vector passes through the middle of the entrance to the channel.
The lights here show those that must be exhibited by a vessel engaged in towing, as per rule 24 of the International Collision Regulations. But how long is the tow behind this vessel?
It is less than 200 metres.
It is more than 50 metres but less than 200 metres.
The tug has been released and is all clear. As officer in charge of that operation, should this be reported and to whom?
Reported all clear to the Bridge.
Report all clear to the tug.
No need for reporting as the order was given from the bridge.
Report all clear to the Engine Room.
Two ships travelling in opposite directions are to pass each other in a narrow river, as illustrated. Explain what is likely to happen as they pass each other?
Due to interaction, the bows will repel each other, and then when alongside each other the two ships will be sucked together and finally the sterns will be repelled as they start to pass clear.
There will be very little effect between the two ships as they pass.
Due to interaction, the bows will attract each other as they approach, then they will repel each other alongside and as they pass clear, the sterns will be attracted.
As they approach, rudder should be applied quickly to avoid sheering into the path of each other. Then as they are alongside they will be attracted and finally repel each other as they pass clear.
The ship is to berth alongside a quay in calm conditions of no wind or current. The ship has a single fixed pitch right handed propeller. Which angle of approach would be considered the most favourable?
The decision should be left to the pilot who is in charge of the manoeuvre.
What is the depth of an iceberg below the surface of the sea?
The draught of an iceberg is normally about 3/4 of its total depth.
The draught of an iceberg varies with the type of berg and its age.
The depth of an iceberg below the surface is always about one sixth of its total depth.
The draught of an iceberg is about the same as the visible part of the iceberg above the water.
Which method is used to make a physical connection between a rescue vessel and a wreck?
What would be the effects of a ship passing into shallow water?
The vessel has a tendency to swing to port with a single fixed-pitch right-hand turning propeller.
There is no noticeable difference in performance of the ship.
The speed is not affected, but more rudder is required to steer the ship.
The ship is less responsive to both rudder and propeller.
When navigating along a coastline what should be considered the most accurate method of navigating?
Use of radar ranges and bearings.
Passing close to navigational buoys.
Bearings of navigational shore marks such as lighthouses.
What are the additional duties required by the Officer of the Watch when navigating in fog?
Sound fog signal, effective radar watch reporting ship movements to Master and keep a good lookout for ships and fog signals.
All of the suggested answers.
Sound fog signal, plot positions and keep a good lookout.
When navigating in fog the Master will take over the watch and the Officer of the Watch should follow all of his instructions.
The ship’s rudder is full over when the ship’s engines are full ahead. Will the turning effect (lift force) of the rudder be changed when the engine is stopped?
Yes, the lift or turning force will be reduced to about 50 % of the original lift force when the engines are stopped.
Yes, the lift force will be dramatically reduced when the engines are stopped.
No, the lift force is unaffected by the speed of the propeller.
No, the turning force applied by the rudder will be maintained within about 90 % of the lift force when going full ahead.
The rudder is in the hard over position with the propeller stopped and the ship turning slowly. On a ship with a single fixed pitch right handed propeller and no thrusters, what can be done to make the ship increase the speed of turn without significantly increasing the forward speed of the ship?
Give dead slow ahead on the engines and leave the rudder in the hard over position.
Give the engines a short kick ahead.
Give half astern on the engines as this will increase the rate of turn.
Give full astern on the engines until ship has stopped and then full ahead on the engines with rudder hard over.
What can be simply rigged to assist a survival craft in keeping alongside own vessel?
The accommodation ladder deployed to the water surface.
The survival craft painter made fast on the vessel’s deck.
A single weighted line hanging over the side from the deck.
A painter rigged fore and aft against the vessel’s side.
Where can the size of the Magnetic Compass Error be found?
By taking the error from the Deviation Table on the bridge.
By taking a transit bearing of two fixed geographical positions and comparing it with the bearing of the same points on the chart.
On the chart in the centre of the compass rose or by reference to the Variation chart, taking into account the annual changes.
By reference to the last entry in the Compass Error Log Book.
Where would the “pivot point” be considered to be located when the ship is proceeding at full speed ahead and there is no wind or current?
At a position near the stern of the ship.
At about 1/6 of the ship’s length from the stern.
At about 1/6 of the ship’s length from the bow.
What is the colour and characteristic of a “towing light”, as defined in the International Regulations for Preventing Collisions at Sea?
Yellow, fixed, seen over an arc of 135° and so arranged as to display 67,5° from right aft on each side of the vessel.
Amber, all-round, flashing, where it can best be seen.
One of two all-round amber, alternate flashing lights, displayed where they can best be seen.
White, fixed, displayed as an additional light on the foremast over an arc of 225°, from right ahead to 22,5° abaft the beam on each side of the vessel.
What is the two letter signal, to be used by flags, radiotelephony or radiotelegraphy, meaning “Calling All Ships”?
What is the situation of this vessel?
This vessel is not under command, but is making way through the water.
This vessel is not under command and stopped in the water.
This is a vessel constrained by her draft.
What does this flag mean?
My vessel is stopped and making no way through the water.
I have a diver down; keep well clear at slow speed.
I wish to communicate with you.
What is “AIR DRAUGHT”, in the figure?
Air draught is indicated by A, in the figure.
Air draught is indicated by D, in the figure.
Air draught is indicated by C, in the figure.
Air draught is indicated by B, in the figure.
What radar device assists in the detection and location of a survival craft?
A personal locator beacon.
Why should Ground Stabilised True Motion display mode be avoided when using the ARPA for anti-collision purposes?
The Relative Motion display and relative vectors is the only display to use for anti-collision purposes.
True motion does not provide the collision risk of other ships.
The true vector can never give an indication of collision risk with another ship.
The collision regulations are based on ship courses through the water.
You are proceeding along a coastal route when you hear this signal. The visibility is severely restricted. What does the signal mean?
There is a vessel at anchor in the vicinity. She is more than 100 metres in length. She is sounding an additional warning signal to approaching vessels, directing them to “keep clear”.
There is a vessel aground in the vicinity. She is less than 100 metres in length. She is sounding an additional warning to approaching vessels to “navigate with extreme caution”.
There is a vessel at anchor in the vicinity. She is less than 100 metres in length. She is sounding an additional warning to approaching vessels that they are “running into danger”.
There is a vessel aground in the vicinity. She is more than 100 metres in length. She is sounding an additional warning to approaching vessels that they are “running into danger”.
What actions should the Officer of the Watch take when the ship’s steering gear fails?
Call the Master and advise him of the situation.
Display the NUC signal and consider stopping the engines.
All of the suggested answers.
Request the engine room to check the steering gear.
The Master arrives on the bridge obviously under the influence of alcohol and states he is taking over the “con” of the ship. What actions should the Officer of the Watch (OOW) take in this situation?
Attempt to diplomatically avoid taking any actions that would put the ship or crew into danger and call the Chief Officer for assistance.
Tell the Master you do not think this is a good idea and retain control of the watch.
Tell the Master you consider him incapable of taking over the responsibility of the watch and that he should retire to his cabin and sleep it off.
Watch the actions made by the Master and if not dangerous, wait until the Master becomes more capable to take control or leaves the bridge.
A ship is navigating in the Caribbean in August when it receives the warning of a Hurricane. To determine the centre of the storm the Master uses “Buys Ballot’s Law” and faces the wind. On what side of the Master would the low pressure area be located?
This is not a suitable method to use with a Hurricane.
What is important to check when transferring a position from the GPS output to a paper chart?
Any necessary corrections are applied to convert between the GPS datum and the chart datum.
Ensure that the chart has been corrected up to date.
Ensure that the GPS is setup on the same datum as the chart.
It is important to ensure that the GPS is setup on 2 dimensional and not 3 dimensional position fixes.
The ship is drifting in the open sea with a temporary engine breakdown. The ship is equipped with GPS navigation equipment. What should the bridge Officer of the Watch do in this situation?
All of the possible answers.
Keep a good lookout for other ships.
Display the “Not under Command” signal and switch off the normal steaming lights.
Plot the direction and rate of drift and predict the ships position for the period while the ship is “Not Under Command”.
You are proceeding along a narrow channel in front of another vessel, both heading for port. You hear this signal from the vessel behind you. What does it mean?
I intend to overtake you on your port side.
I am faster than you. Get out of the way.
I intend to overtake you on your starboard side.
I am operating astern propulsion.
You are proceeding along a coastal route when you hear this signal. The visibility is severely restricted. What does the signal mean?
There is a vessel aground in the vicinity. She is more than 100 metres in length. She is sounding an additional warning to approaching vessels, directing them to “keep clear”.
There is a vessel aground in the vicinity. She is less than 100 metres in length. She is sounding an additional warning to approaching vessels to “navigate with extreme caution”.
There is a vessel aground in the vicinity. She is more than 100 metres in length. She is sounding an additional warning to approaching vessels that they are “running into danger”.
There is a vessel at anchor in the vicinity. She is less than 100 metres in length. She is sounding an additional warning to approaching vessels that they are “running into danger”.