ECDIS FUNCTION 1 ORAL QUESTIONS

SECOND MATE OF A FOREIGN GOING SHIP

Oral-Navigation (FUNCTION –1)

The following questions came from a WhatsApp group where candidates posted the question right after they had finished their oral exam.

ECDIS

1. What is ECDIS?

ELECTRONIC CHART DISPLAY AND INFORMATION SYSTEM

It is a navigation system accepted by SOLAS as a replacement for paper charts.
It is for safe navigation and should not be used for collision avoidance.
In 2009, IMO adopted the amendment to SOLAS CH-V Reg 19 to make mandatory the carriage of ECDIS.
The amendment entered into force on 1 January 2011.

2. What are the performance standards of ECDIS?

The main ECDIS must have its own workstation. The backup ECDIS can be on the chart table.
If you are not carrying a paper chart, the backup ECDIS must have its own completely different system.
The effective size of the chart presentation screen for route monitoring should be at least 270 mm x 270 mm.
If you don’t feed your safety contour, the default setting contour will be set to 30 m (automatically). It will also give a visual alert then.
The display should be capable of meeting the color and resolution recommendations of the IHO (International Hydrographic Organization).
One should come to the center of the display, i.e., own ship position, on a single click.
ECDIS should be connected to GPS, Gyro Compass & Doppler log.
It should not be possible to alter the contents of ENC.
It should be possible to plan an alternate route in addition to the selected route.
In case of power failure, the ECDIS should remain on for at least 45 seconds & once power comes back, the screen must come up with the ship in the center.

3. What are the errors or limitations of ECDIS?

Lack of global coverage
Over reliance
Too much information may cause clutter and can be distracting
Complacency due to the automatic plotting of the position
Wrong settings and wrong input may lead to an accident
Alarm fatigue: If alarms start going off too frequently,the navigator could end up acknowledging the alarm even without checking it
Being electrical equipment, if the power supply fails, ECDIS is useless
Failure of the GPS & Gyro compass will make ECDIS useless
Repeated cost of ENC
Different vessels have different types of equipment. Even if essential features are the same but it still takes some time until one gets comfortable

4. Characteristics of charts in ECDIS?

There are two types of electronic charts that ECDIS can display:

-> Raster Navigational Chart (RNC)

-> Electronic Navigational Chart (ENC)

✱ Raster Navigational Chart (RNC)

Scanned copy of paper chart
RNC data will not trigger an automatic alarm
Interrogation of information will not be available
Information appears cluttered
Zooming may cause distortion

✱ Electronic Navigational Chart (ENC)

Information is saved in many layers
Various settings and alarms are provided
By clicking on any object, pick-up reports are available, i.e, all details of that object will be displayed
Cluttering can be avoided
Information can be added as well as removed
There is no distortion while changing scale/zooming in

5. Difference between ENC & SENC?

ENC is produced by IHO & is in a standardized format, whereas

SENC is a system ENC, which is converted from S-57 ENC format into an internal format by ECDIS itself. SENC format is different in different ECDIS manufacturers. It is optimized for chart image-creating routines.

The ENC, when fed into a particular system (ECDIS), the format changes based on the equipment & then it becomes SENC.

6. What are the various settings on ECDIS?

The most important setting in ECDIS is the safety setting, which is as follows:-

→ Safety depth: Draft + Squat + Heeling effect + UKC + CATZOC – Height of tide

→ Safety contour: same as safety depth

→ Shallow contour: same as the draft

→ Deep contour: twice the draft

7. What is the use of safety depth & safety contour? (AND) Difference between safety depth & safety contour?

Safety depth setting:

It portrays the sounding in grey for deeper depth and in black for shallower depth with respect to the safety depth value set by an officer.
It highlights the safe & unsafe areas for navigation.

Safety contour setting:

It marks the boundary between safe water and shallow water with an extra wide iso-line and is used to give an alarm if the ship is going to cross the safety contour within the time specified by the mariner.

8. What is XTD & its use?

Cross-track distance (XTD) is set at some meters on both the port & starboard side of the track line.
This corridor can then be automatically checked for under-keel clearance w.r.t the safety setting set by the mariner.
It will also trigger an XTE (cross-track error) alarm when the ship crosses this line.

9. What is AIO in ECDIS?

Admiralty Information Overlay

It is additional information (such as ADMIRALTY Temporary and Preliminary Notices to Mariners) designed to display over ENC in ECDIS to provide information that makes passage planning & navigation efficient.
It is issued by UKHO & covers the whole world except for areas where there is no Admiralty Chart.
It is a separate service of AVCS & needs to be subscribed to & obtained independently.
If the producer nation does not include T & P notices in ENC & UKHO has issued the T & Ps of that area on a paper chart, it is then issued as AIO.
If UKHO is not able to seek coverage and add additional information. In those areas, AIO shows a grey hatched polygon labeled “NO OVERLAY”.

10. What is CATZOC?

CATEGORY ZONE OF CONFIDENCE

It is the values used to highlight the accuracy of the position of an object in ENC and the accuracy of the depth survey.

There are six zones of confidence:-

A1 – have 6 stars

A2 – have 5 stars

B – have 4 stars

C – have 3 stars

D – have 2 stars

U – written as ‘U’ means unaccessed area

11. How to update ENC?

Updates to the ENC reach the ship in various ways, which are

→ via Data distribution media (DVD)

→ As an email attachment (SATCOM)

→ As an internet download

There are three methods followed on board to update ENCs:

→ Sequential:

As it name suggests, this method is to be done in sequence
It should be done every week
If we miss one week, the ECDIS will not load the update for next week

→ Cumulative:

In this method, we do not need to put the previous updates compulsorily
When we put the current CD, it will automatically take all the previous updates to date
It should be done once in 3-4 weeks

→ Online:

In this function, our ECDIS is connected online & it keeps getting all the updates automatically
But due to cybersecurity reasons, it is not preferable

The procedure for loading updates in ECDIS:

Insert the CD or the Pendrive
Select “CHART” → “CHART PORTFOLIO.”
Choose “Load & update chart.”
Choose a destination – “From CD-ROM” or “From Pendrive.”
Define the location inside the CD-ROM or Pendrive and select the file “AVCS UPDATE.”
Click on the load button. Your ENC is now corrected up to the current week.
Do check it by checking the “ENC UPDATE REPORT.”

12. How to check whether ENC is updated to the current week?

Go to Menu → Chart Menu → ENC status report → ENC update status report

There you can see week up to when the ENC is updated

13. How will you prepare a passage plan on ECDIS?

It is somehow similar to what we do on paper charts.

(I) Route planning

Gather all the information from the required publications
Ensure appropriate ENCs are available & up to date
Go to the route planning menu
Take the cursor to the starting point and keep on clicking wherever you wish to create a waypoint
One can keep zooming in and out as and when required while creating the route
Once the route is created, save the route

(II) Route check

Before that, set the safety setting according to your draft of the next voyage
Also, set the cross-track distance (XTD) as per the company or as the master allows
Now, to check the route, each ECDIS has a function called “Route check” or “Safety check.”
The ECDIS will check the route and show all the dangers within the route
Then, we can check those errors individually & edit the route accordingly
One should also manually scroll along the entire route to visually check for any hazards

(III) Marking

Mark the parallel index from the fixed object on the route
Mark the NO-GO areas along the route
Mark the wheel over position on each waypoint
Mark abort point
Mark position plotting interval
Mark other information such as Bridge watch level, Call master, Contingency anchorage, Reporting point, E/R notice

14. How do you know if GPS fails on ECDIS?

It will give an audible & red color visual alarm
In the event of GPS loss, the SPD is shown as “✱✱.✱ kn.”
SOG changes to STW
When navigating near the coast, fix the position by putting the range & bearing of a terrestrial object

=> If GPS fails, how to use ECDIS

Change the position sensor input in DR mode

15. What are the actions in case of ECDIS failure?

Inform MASTER
Plot the position on a paper chart (if available)
Use the backup ECDIS for navigation
Master to inform the technical superintendent and contact manufacturer for fault finding & troubleshooting
In case of failure of both ECDIS, the Main engine is to be put on notice. Vessel to proceed at safe speed.
Carry out defect rectification as soon as possible

16. What are the advantages of ECDIS over a paper chart?

All chart information is available at a single click of a mouse
Simple & fast updating of charts
It triggers an automatic alarm
Availability of the chart – especially when voyage orders are received at the last minute
Various safety settings
It is convenient & less time-consuming for Route planning, Route monitoring, route and waypoint management, and real-time position plotting
Various equipment can be integrated
Easy log keeping
Voyage playback is possible

17. What is Radar Overlay?

This technology includes the digital integration of radar data over an ECDIS

18. International Hydrographic Office (IHO) standard

IHO – S 52: Presentation Library

How the presentation of the screen should look
Presentation library 4.0 is currently in force
Detection & notification of navigation hazard
Detecting of safety contour

IHO – S 52 Appendix 2: Presentation Library

Color & symbol specification

IHO – S 57: Transfer standard for digital hydrographic data (from UKHO to on-board ship)

IHO – S 61: RNC product specification

IHO – S 63: Data protection

19. What is compilation scale?

It is the best display scale of ENC data.
At this scale, the maximum level of detail is revealed as specified by IHO.
At this scale, the ENCs are made.

20. What is SCAMIN scale?

It is the minimum scale below which the object is no longer visible.
The purpose is to: (i) de-clutter the screen, (ii) prioritize the object to display

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