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.

• 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 sec & once power come back, the screen must come as ship in center.

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

There are two types of electronic charts 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 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 setting and alarms are provided
• By clicking on any object, pick-up report are available i.e. all details of that object will be dispalyed 
• Cluttering can be avoided
• Information can be added as well as removed
• There is no distortion while changing scale/zooming in

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

SENC is 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.

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

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.

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

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 & get 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”.

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

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 week

→ Online:

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

The procedure for loading updates in ECDIS:

• Insert the CD or 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”

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

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

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 on 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 hazard

(III) Marking

• Mark the parallel index from the fixed object on the route
• Mark the NO-GO areas along the route
• Mark 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

• 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 terrestrial object

=> If GPS fails, how to use ECDIS

        Change the position sensor input in DR mode

• Inform MASTER
• Plot the position on a paper chart (if available)
• Use the back-up ECDIS for navigation
• Master to inform technical superintendent and contact manufacture 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

• 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 last minute
• Various safety setting
• 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

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

IHO – S 52: Presentation Library

• How presentation of 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 hydro-graphic data (from UKHO to on-board ship)

IHO – S 61: RNC product specification

IHO – S 63: Data protection

• 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.

• 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