ECDIS Flashcards
What does ECDIS stand for?
Electronic Chart Display & Information System
What is the difference between ECDIS & ECS?
ECDIS complies with the IMO’s SOLAS class vessels requirements, while the ECS does not.
What is the main purpose of the ECDIS?
Improve Safety of Navigation.
What are some limitations of the ECDIS?
- Over-Reliance
- Alarm Fatigue
- Lack of Whole World Coverage
- Datum Shift
- Different Scales on Adjacent Charts
- Vulnerable to Single- Point Failure
How do you avoid over-reliance on the ECDIS?
By cross checking position regularly, using range-baring or any other means.
What is Alarm Fatigue?
Exposed to alarms daily until the officer becomes desensitized to them and doesn’t respond accordingly.
What is Datum Shift?
Datum used to derive position does not match the datum of chart used to plot position.
What are the carriage requirements of the ECDIS? State the regulation.
As per SOLAS Ch.V (Safety of Navigation), Reg.19.
- Passenger Ships 500gt or more
- Cargo Ships 3000gt or more
In international voyages must be fitted with ECDIS and a back up in case of ECDIS failure.
What is the back up in case of ECDIS failure?
Could be:
- Another second independent type-approved ECDIS with a separate power supply and GNSS input.
- Carriage of up-to-date paper charts.
What are some requirements for the ECDIS in order to be used a a primary means of navigation?
- Type-Approved
- Appropriate Back-Up Arrangements
- Official ENCs & RNCs are used
- Officers a Qualified & Competent
- Annotated in the vessel’s record of equipment as a primary means of navigation
- SMS includes carriage procedures & safe operation.
- It is capable of displaying current version of IHO library
What are the training requirements for officers in terms ECDIS?
- Generic ECDIS Certificate
- Type-Specific ECDIS Training (NOT Mandatory but companies must ensure officers are familiarized with it)
What are the inputs of the ECDIS?
- GNSS (Pos.-Time-COG-SOG)
- Gyro Compass: Heading
- Speed Log: STW
- AIS (Works VFH)
- RADAR
- ARPA
- Anemometer: Wind Speed & Direction
- Echo Sounder: UKC
What is an Alert and an Indication? What’s the difference between them?
Alert - Audible and/or visual announcement of a condition requiring immediate attention. Priorities are alarm, warning, and caution.
Indication - Visual indication giving information on the condition of a system or equipment.
What are the five mandatory ECDIS alarms?
- Deviation from Route
- Reaching a Critical Point
- Different Geodetic Datum
- Positioning System Failure
- Look-Ahead Sector Making Contact with Safety Contour
What three situations where it can either give off an alarm or indication?
- Pass closer then set distance from an area with special conditions.
- Pass closer then set distance from a danger in route monitoring mode.
- Malfunction of ECDIS
What are some cases where an indication is shown on the ECDIS?
- Default Safety Contour
- Larger Scale ENC Available
- Information Over-scale
- Information not displayed due to Scale Minimum
- Different Reference System
- No ENC available
- Customized Display
- Route Planning closer than set distance from safety contour
- Route Planning closer than set distance to a specified area
- Monitored route closer than set distance from safety contour
- monitored route closer than set distance to a specified area
- System Test Failure
What are some areas with special conditions that show either an alarm or indication on the ECDIS?
- TSS
- ITZ
- Restricted Area
- Caution Area
- Offshore Production Area
- Areas to be avoided
- User Defined Areas to be Avoided
- Military Practice Area
- Seaplane Landing Areas
- Submarine Transit Lane
- Anchorage Area
- Marine Farm/Aquaculture
- Particularly Sensitive Sea Area (PSSA)
What does ENC stand for, and what are they?
Electronic Navigational Chart, AKA Vector Chart. They are a digital representation of geographic and navigational information.
What are some features of an ENC?
- The user can interrogate elements on the chart for more information.
- Allows full use of ECDIS functions due to it being intractable with ECDIS.
- Can add, remove and edit layers.
- Seamless transition between charts
Difference between large and small scale charts? And when to use them?
- Larger Scale gives more details and is used for navigation in more constrained waters
- Smaller Scale gives off less details and is used more commonly in more open waters as it covers a larger geographical area.
What is a compilation scale on the ECDIS?
It is the best scale at which the ENC is intended to be used for navigation.
What are the different scales for different chart types?
6 - Berthing - <1:4,000
5 - Harbor - 1:4,000 to 1:12,000
4 - Approaches - 1:22,000 to 1:45,000
3 - Coastal - 1:90,000 to 1:180,000
2 - General - 1:350,000 to 1:700,000
1 - Overview - 1:1,500,000 to 1:3,000,000
What is SCAMIN?
A filter used to control the amount of information displayed on an ECDIS screen to avoid cluttered display.
What does a higher/lower SCAMIN value for a feature mean?
Higher - The feature displays at a smaller scale setting (More Zoomed Out)
Lower - The feature displayed at a larger scale setting (More Zoomed In)
What does RNC stand for and what are they?
Raster Navigational Chart. They are digitally scanned and geo-referenced image of a paper chart.
What is the difference between ENCs and RNCs?
- ENCs are electronic charts whereas RNCs are digital scans of paper charts.
- Objects on ENCs can be interrogated for more information. RNCs can not.
- ENCs are not covered worldwide whereas RNCs cover the whole world.
- ENCs allow for the full functionality of the ECDIS by allowing alarms and route checking.
What are the two types of symbology used in ENCs? And what’s the difference between them?
Simplified and Traditional. Traditional symbols are the same symbols used in paper charts whereas the simplified have been created after for easier identification.
What are the four main groups of ENC symbols?
- General: Chart layouts, distances & directions
- Nav Aids & Services: Lights, Buoys, fog signals, radio services.
- Topographical: Natural features of land
- Hydrographical: depths, tides, currents, seabed nature, underwater obstructions.
Which publication gives detailed explanations of all ENC symbols on the ECDIS?
NP5012 - Guide to ENC Symbols
What are the chart presentation modes (layers)?
- Base: not enough data for safe navigation.
- Standard
- Full: Should be used for passage planning. Could clutter the screen if used during navigation.
- User-Defined
What are the four contours on an ECDIS?
- Shallow Contour: Indicates areas were the vessel will run aground
- Safety Contour: Difference between safe and unsafe waters
- Safety Depth: Soundings less than safety contour
- Deep Contour: It is where the vessel is expected to experience squat.
What is the calculation for the safety contour?
Draft + Squat + Min UCK - Height of Tide
How do you calculate the deep contour?
2 x Ship’s Draft
What are the two orientations of an ENC? And which is more commonly used?
North-Up and Course-Up. North-Up is more commonly used.
What is the safety depth value usually set to?
The same value as the safety contour.
How do spot soundings appear in relation to the value of the safety depth?
Depths Shallower than value appear in bold. Depths safer appear in light grey.
Which four performance standards has the IHO set for how ENCs are made for the ECDIS?
S-52: Colors and Symbols of ENCs
S-57: Format and Specifications of ENCs
S-63: Protection of Integrity of ENCs Data
S-100: Digital Hydrographic Products
How do you calculate an anchor watch swing circle?
Swing Circle = Length Overall of Vessel + (N. of Shackles x 27.5 meters)
Swing Circle/1852 meters = Number of Cables
