Whitehorse | Bridge Equipment Flashcards
(179 cards)
1
Q
What does ECDIS Stand for?
A
Electronic chart display information system
2
Q
What is the primary purpose of ECDIS?
A
To enhance the safety of navigation
3
Q
How can OOWs avoid becoming over-reliant on ECDIS?
A
By regularly cross-checking the position given by the ECDIS and by thoroughly understanding the limitations of the system.
4
Q
What is datum shift?
A
Datum shift is when the datum used to derive the position doesn’t match the datum of the chart on which that the position is plotted.
5
Q
What is alarm fatigue?
A
Alarm fatigue is when users who are exposed to high-levels of spurious/false alarms begin to be desensitised and fail to respond to alarms appropriately
6
Q
Which vessels are required to be fitted with ECDIS?
A
All passenger ships of 500GRT or more, all tankers of 3000GRT or more and all cargo ships (other than tankers) of 10000GRT or more, on international voyages, are required to be fitted with ECDIS
7
Q
Must a vessel carry two, independent ECDIS systems to meet the carriage requirements of SOLAS V R19?
A
No, it is also acceptable to carry an appropriate folio of paper charts
8
Q
If a vessel does carry an additional ECDIS unit as a back-up, what are the additional requirements?
A
It must be an independent type-approved ECDIS unit with a separate (normal and emergency) power supply and GNSS input
9
Q
If an appropriate folio of paper charts is carried as a back-up, what are the additional requirements?
A
The paper charts must be corrected and kept up to date at all times, be readily available and the passage plan must be indicated on the charts.
10
Q
What are the training requirements for the use of ECDIS?
A
All officers using ECDIS must have attended a generic ECDIS course and have received type-specific ECDIS training
11
Q
Are officers required to complete a type-specific ECDIS training course?
A
No, but the company must ensure that their officers are appropriately trained and familiarised with the equipment. This may be through a course or a program of onboard training.
12
Q
Where is the vessels approval to use the ECDIS as primary means of navigation recorded?
A
On the vessels record of equipment, which is part of the Cargo Ship Safety Equipment Certificate (where is is known as Form E) or the passenger ship safety certificate (where it is known as Form P)
13
Q
What must the SMS contain regarding ECDIS?
A
It must include procedures for the carriage and safe operation with ECDIS
14
Q
What is the primary source of position input for ECDIS?
A
Global Navigation Satellite System (GNSS)
15
Q
Which input enables to generate a heading marker?
A
Gyrocompass
16
Q
Which input creates the small triangles on the ECDIS screen which represents other vessels?
A
Automatic Identification System (AIS)
17
Q
Which system input is used to display water depth and/or under keel clearance on the ECDIS?
A
Echosounder
18
Q
Which input provides the ECDIS with STW data?
A
Speed log
19
Q
Which system can be overlaid onto ECDIS and used for both position monitoring and assessing risk of collision?
A
Radar
20
Q
Which two mandatory alarms relate to the vessel’s GNSS units?
A
Change in geodetic datum and positioning system failure
21
Q
How many mandatory alarms are there?
A
5
22
Q
How many indications are there?
A
9
23
Q
What is the difference between an alarm and an indication?
A
An alarm is audible (and most likely visual), whereas a indication is solely visual
24
Q
Which electronic chart type is preferable when navigating with an ECDIS unit?
A
An Electronic Navigational Chart (ENC)
25
Does a small-scale chart represent more or less land/sea area?
More. A small-scale chart uses a smaller scale to represent more land/sea area on a single chart.
26
Which scale is an ENC at scale 6?
Berthing
27
What is an ECDIS called when it is being used to display RNC's?
A Raster Chart Display System (RCDS)
28
Which electronic chart type enables the interrogation of chart data?
ENCs
29
Which electronic chart type is a database of information which is then represented graphically to the user?
ENCs
30
Which electronic chart type makes it easier to find information on berth names/numbers?
RNCs, because this information is often harder to find on ENCs and can be laid out less clearly.
31
Which set of ECDIS symbols looks more like those found on paper charts?
Traditional
32
Which of the contours takes into account a 'Minimum UKC value'?
Safety contour
33
Which Chart presentation mode contains the least information?
Base
34
What is the safety depth value normally set to?
Same value as Safety Contour
35
Which contour is intended to indicate to the OOW that the vessel is entering an area where they may start to experience squat?
Deep contour
36
What does a spot sounding which is deeper than a safety depth look like?
A light grey number
37
What happens when the look-ahead sector touches the safety contour?
An alarm will sound on the ECDIS. This is one of the mandatory alarms.
38
In the context of ECDIS, what does 'interrogating' mean?
Clicking on an ENC object to see more information about it.
39
What is SCAMIN?
SCAMIN is a filter, based on scale, which is used to manage the amount of information displayed on the ECDIS screen
40
Which scale chart should we navigate on?
In general, we should always navigate on the largest-scale chart available
41
How should the position be monitored when using ECDIS?
The GNSS feed into the ECDIS will provide it with continuous position updates but the OOW must also cross-check this position at appropriate intervals using other means, such as visual and radar fixes
42
Which ENC standard ensures the consistency of presentation across ECDIS systems?
S-52
43
Which is the current version of presentation library?
Version 4.0 - 2017
44
What are the four ENCs standards?
S-52, S-57, S-63, & S-100
45
What are VDRs used for?
To record data from various systems during a voyage so that this information can be accessed in case of an accident, much like the black box on a plane.
46
How many metres are there in a shackle?
27.5m
47
How many GPS satellites must be in sight of a receiver unit in order to provide a 3D fix?
Four
48
Under SOLAS, which vessels are required to carry a GNSS unit?
All vessels on international voyages, regardless of size.
49
Which was the original GNSS system?
The American NAVSTAR Global Positioning System (GPS)
50
What is an advantage of GLONASS over GPS?
GLONASS's constellation provides better accuracy at high latitudes.
51
What type of course data will be provided by a GNSS?
COG (course over ground)
52
How does a GNSS present position data?
In latitude and longitude
53
What does a GNSS give speed in reference to?
GNSS speed is always Speed Over Ground
54
Is a more accurate fix indicated by a smaller or larger DOP value?
Smaller
55
How does RAIM work?
For receivers using the NAVSTAR GPS constellation, it uses additional satellites that are within range to cross-check the integrity of the position data.
56
Which source of interference is the deliberate substitution of a genuine position signal with a fake one?
Spoofing
57
Which error can occur when the GNSS signal bounces off of a vessels funnel before being received by the antenna?
Multipath error
58
How does the radar understand the bearing of detected objects?
By reference to the vessels heading.
59
What size vessels are required to carry an X band radar?
Over 300GRT
60
Why must the first radar carried by a vessel be an X band?
Because only X band radars are able to detect SARTs.
61
What size vessels are required to carry an additional X band or S band radar?
Vessels over 3000GRT are required to carry either two X band radars or one of each.
62
Why do most large vessels carry an X band and an S band radar?
Because each has its advantages, so it's best to have one of each.
63
What is the wavelength and frequency of S Band?
W = 10cm, frequency = 3GHZ
64
What is the wavelength and frequency of an X Band radar?
W = 3cm, frequency = 9GHZ
65
What are the advantages of S Band radar?
Detects longer range, able to penetrate clouds, better tracking in poor weather
66
What are the advantages of X Band radar?
More detailed image, better at detecting small targets, it can detect SART
67
A radar must ensure that targets can be detected while the vessel encounters a roll of up to how many degrees?
10 degrees
68
What is the required radar bearing accuracy for detected objects?
Within 1 degree
69
Which error causes multiple targets at the same bearing but different ranges?
Multipath error
70
How much sea and rain clutter should be applied on our radar?
The minimum necessary to achieve a usable image. We should not attempt to have a 'clean' radar screen.
71
Which error results from additional, weaker radiation emanating from the radar scanner?
Side-lobe error
72
What causes indirect echo error?
When the radar pulse returns to the scanner having bounced off part of the ships structure, such as the funnel.
73
What is likely to occur in a vessels blind sector?
Targets will not be detected and acquired targets are likely to be lost
74
When should you conduct a performance monitor on your radar?
On start up & once per watch
75
Which type of clutter control reduces the amplification of the returning pulse in the vicinity of the vessel?
Sea clutter
76
What is the correct order in which to set-up a radar?
B-G-T, rain then sea
77
How should the gain be set for optimum performance?
It should be increase slowly until a light speckling appears across the entire screen and then decreased ever so slightly until the speckling disappears.
78
What should the performance monitor result be checked against?
The image in the manufacturers instructions.
79
Which may be more accurate, especially on smaller vessels; radar ranges or bearings?
Radar ranges, due to the beam width causing poor bearing discrimination
80
How many lines of position must be used for all position fixes?
A minimum of three
81
How should charted objects/features be selected for use in position fixing using radar?
Objects/features must be radar conspicuous and easily identifiable so that there isn't any inaccuracy or confusion when applying the range/bearing to the chart/ECDIS.
82
Which MGN gives guidance on the use of navigation aids?
MGN 379
83
Your PI is set off a headland to starboard of your track, at 3.6nm. If the PI is to seaward of the headland (i.e. over the water, not land), are you to port or to starboard of your track?
To port
84
Why is parallel indexing referred to as a 'real-time' method?
Because it enables continuous monitoring of the vessel's position, as opposed to fixes which are always historic.
85
Which technique is used to help the OOW monitor the cross-track distance?
Clearing ranges.
86
Which technique is used to help ensure that the vessel stops at the required point?
Dead ranges.
87
When should PIs be identified and marked on the chart?
During the passage planning process.
88
How does a SART indicate its position on an X band radar at a range of approximately 6nm?
Arcs
89
What is the battery life of a SART in passive mode?
96 hours.
90
Where is a SART located in relation to the twelve dots?
At the first dot, closest to the your vessel on the radar.
91
Which type of radar can detect SARTs?
X band
92
What pattern does a RACON form on the radar screen?
A series of dots and dashes to create a morse code letter
93
How long does the OOW need to wait before taking decisions based on ARPA data?
Three minutes.
94
What size vessels are required to carry an ARPA?
Vessels over 10,000GRT.
95
What does ARPA stand for?
Automatic Radar Plotting Aid
96
How many targets should an ARPA be capable of tracking simultaneously?
20
97
Which system is used to assist the OOW with manual plotting of targets?
Electronic plotting aid (EPA)
98
Which system enables automatic tracking of targets but isn't required to acquire them automatically?
Automatic tracking aid (ATA)
99
Which system must be capable of carrying out a trial manoeuvre?
Automatic radar plotting aid (ARPA)
100
Which radar ARPA data remains reliable even with a gyro error or failure?
CPA & TCPA
101
What must the OOW do when target swap occurs?
Ensure that both targets are reacquired (if necessary) and ensure that three minutes elapses before the target data is used for collision avoidance again.
102
Why is there a delay between a vessel altering course and this being reflected by the ARPA data?
Because ARPA tracks a vessels past motion in order for it to predict its future motion - it is inherently retrospective. If a vessel alters course, the ARPA will provide inaccurate information until the old course is no longer incorporated into its tracking window, which is why we must wait for three minutes.
103
Which mode gives us a prediction of the future movement of another vessel in relation to our vessel?
Relative vectors
104
Which mode gives us a historic representation of a vessels actual motion?
True trails
105
What information can relative vectors provide at a glance?
An indication of whether a target could have risk of collision (when the vector is pointing towards our own vessel).
106
How often does Class A AIS transmit dynamic information for a vessel alongside?
Every 3 minutes
107
Under the Work Boat Code, which vessels are required to carry an AIS unit?
Those operating more than 20nm from land.
108
Passenger vessel on international voyages are required to be fitted with which class of AIS?
Class A
109
What is voyage information in regard to AIS?
Information relating to the current voyage of the vessel such as; destination, ETA and draft.
110
What is dynamic AIS information?
Information about the vessel which is constantly changing, including the speed, course, position and heading.
111
What is AIS static information?
Information that is not subject to change, such as the vessel's IMO number, call sign, name, dimensions and type.
112
Over which band do AIS units transmit?
Very High Frequency (VHF)
113
Which MGN outlines the procedures for the appropriate use of AIS?
MGN 324
114
Why should AIS voyage data not be relied upon?
Because the OOW on the other vessel may not have updated the voyage data before departure, after anchoring, following a change of ETA etc.
115
Which data should always be given priority on the radar for collision avoidance; AIS or ARPA?
ARPA data must always be given priority for collision avoidance.
116
What is an MKD?
A minimum keyboard display
117
What are some advantages of AIS data over ARPA?
AIS enables us to see targets which are behind obstructions or in heavy rain and AIS data is current whereas ARPA data is historical.
118
How often does an AIS SART transmit each of its eight distress messages?
Once per minute.
119
Which type of AIS ATON is a physical object but has its AIS message transmitted from ashore?
Synthetic AIS ATON
120
Which type of AIS ATON does not physically exist?
A virtual AIS ATON.
121
Which pole does a magnetic compass point towards?
It points towards magnetic north pole.
122
Which vessels are required to carry a magnetic compass onboard?
All vessels.
123
At which pole does the magnetic field exit the Earth's surface?
At the magnetic south pole.
124
What keeps the compass level in rough seas?
The gimbal.
125
Which vessels are required to carry a spare magnetic compass?
Vessels over 150GRT, if they aren't fitted with an approved gyro compass.
126
What are cardinal points?
North, East, West, South
127
Which pole moves slowly over time?
The magnetic poles. True north is a fixed geographical point.
128
Calculate compass error if the variation is 7 W and the deviation is 3 E.
4 W
129
Which type of magnetism changes with the vessel's latitude and heading?
Induced magnetism.
130
What is the metal which acquires permanent magnetism also referred to as?
Hard iron.
131
How can the OOW check the deviation that they should expect on a particular heading?
By reference to the vessel's deviation card.
132
Which changes slowly due to the movement of the Earth's magnetic poles; deviation or variation?
Variation.
133
On a paper chart, how is the variation in a location quantified?
The centre of the compass rose gives the variation for the year of publication, as well as an annual correction which should be applied in subsequent years.
134
Which type of compass corrector corrects for induced magnetism in the ships funnel?
Flinders bar
135
Who is qualified to swing a magnetic compass?
In the UK, only a compass Adjuster holding the appropriate Compass Adjusters Certificate of Competency may adjust a compass.
136
How often must a compass be corrected?
Once every two years, unless a Compass Record Book is being maintained and regular compass checks are being carried out.
137
Which magnets correct for permanent magnetism in a longitudinal direction?
Fore & aft correcting magnets.
138
Which body is typically used to take an amplitude for the purpose of checking the compass error?
The sun.
139
How can the Line of Berth be used to conduct a compass error?
If a large vessel is firmly alongside a straight berth, the vessels heading can be compared to the Line of Berth from the chart.
140
How often should the compass error be checked?
Ideally, the compass error should be checked once per watch and after each major course alteration.
141
Which method of controlling a gyro changes the gyro's path from circle to an ellipse?
Gravity control
142
What size vessels should carry a gyrocompass?
Vessels over 500GT on international voyages.
143
What is the difference between a gyroscope and a gyrocompass?
A gyroscope is a heavy, free spinning wheel which points at a fixed location in space but it can't be used for navigation (i.e. as a gyrocompass) until is has been controlled through precession and damping to make it point in the same direction.
144
Aside from the Bridge, where else must a gyro repeater be fitted?
In the Steering Flat, for use when emergency steering.
145
Calculate the true bearings: Gyro = 095 deg (G) - Gyro error = 1.5 deg low.
096.5 deg (T)
146
Which factors will increase speed error?
A higher vessel speed, a higher latitude and a more northerly/southerly course.
147
Calculate the gyro bearing: True bearing = 311 deg (T) - Gyro error = 0.5 deg high
311.5 deg (G)
148
What is lubber line?
The error is caused when the gyrocompass isn't perfectly aligned with the vessel's centreline.
149
How are modern gyro errors corrected?
Modern gyrocompasses typically have an input from the GNSS so that the gyrocompass knows the speed, latitude and course and can automatically make corrections. Older models may have manual inputs for key values.
150
How many rings of optical fibre are used to make a fibre-optic compass?
Three, one for each axis, X, Y and Z
151
What are the carriage requirements for fibre-optic compasses?
There is no carriage requirement for fibre-optic compasses but SOLAS V R19 does permit them to be carried in lieu of gyro compasses.
152
When is the voltage induced into the two sensing coils, of the Fluxgate compass, the same?
When the fluxgate compass is aligned with the Earth's magnetic field
153
How are fluxgate compasses used on large vessels?
To provide Rate of Turn (RoT) data
154
Before using a Pelorus to take a relative bearing, what two things must the OOW align?
The bearing plate with the ships head
155
What is the Azimuth mirror used for?
To take bearings of the sun or other objects that are above the horizon.
156
What must an azimuth ring be fitted to before it can be used?
It must be fitted to the magnetic compass bowl or gyrocompass repeater.
157
Which speed log works by detecting the change in frequency of the returning signal?
A doppler log
158
Which speed log works by measuring the voltage induced as seawater passes through an electromagnetic field?
An electromagnetic log.
159
Which type of speed log is commonly fitted to smaller vessels?
An impeller.
160
Do echo sounders transmit acoustic or electromagnetic pulses?
Echo sounders transmit an acoustic (sound) pulse.
161
How is the depth calculated by an echo sounder?
The echo sounder transmits a pulse and listens for the echo which returns. The time between transmission and return is divided by two and multiplied by the speed of sound in water to give the distance.
162
What is the speed of sound in water?
It varies due to a range of different factors but, for the depth sounding purposes, we assume that it travels at 1500 metres per second.
163
What is a double Janus configuration?
When a speed log transmits pulses fore/aft and athwartships.
164
When an echo sounder is exhibiting second trace echoes, which trace should the OOW rely on?
The OOW should search for the seabed from the 'top down' to make sure that the weaker, true echo is not missed.
165
What can affect the accuracy of a doppler log?
Anything which interferes with the pulse (attenuation by air bubbles or marine growth on the transponder) or which affects its velocity (salinity, particle content and temperature of the water). Non-Janus doppler logs can also be affected by rolling, yawing and pitching errors.
166
What is Pythagoras error, relating to an echo sounder?
An error caused by the transmitting and receiving components of an echo sounder being in different places on the hull, although this should be corrected for on installation.
167
How can trim affect the accuracy of an echo sounder?
If a vessel with an echo sounder mounted near the bow is trimmed by the stern, the UKC given by the echo sounder will be less than the actual UKC because the stern is deeper in the water.
168
Which autopilot mode does not rely on a GNSS input?
Autopilot, heading mode
169
Which vessels should be fitted with an autopilot systems?
Vessels over 10,000GRT
170
What are the risks of operating a Track Pilot in course mode?
Lose of situational awareness, and complacency if they are not monitoring the drift angle, etc.
171
What is the difference between course mode and track mode?
Course mode uses a GNSS input to maintain a given course over ground. Track mode takes this one step further and uses an ECDIS input to ensure that the vessel is proceeding along the planned track.
172
What is drift angle?
The difference between the heading and the course over the ground, expressed in degrees.
173
If the OOW encounters a gyrocompass failure whilst using the autopilot, what is their first action?
Engage hand steering.
174
How do weather-related settings affect how an autopilot performs in adverse weather conditions?
They tell the autopilot to accept a certain degree of yawing without reacting, which minimises steering inputs in bad weather. This can result in better heading-keeping, prevent unnecessary wear and tear, and decrease fuel consumption.
175
How will GNSS failure affect a track pilot?
Track pilots use GNSS inputs to maintain a given course over the ground or to keep to a given track on the ECDIS. Without a GNSS input, it will not be able to perform these functions and is likely to revert to heading control.
176
What should the OOW do if the speed log input fails?
The OOW should engage in hand-steering and then ensure the correct manual speed input before engaging it again.
177
Before engaging hand steering, in which position should the helm be?
Amidships
178
What is yawing?
An oscillation in direction or heading, either side of the desired value
179
What should happen immediately after hand-steering is engaged?
The crew member should apply a couple of degrees of helm each side to ensure that they have control and that the rudder is responding appropriately
