ECDIS Explained: How It Works, SOLAS Requirements, Training & S-100 Update (2025-2026)
- Ravi Shankar FICS
- 2 hours ago
- 19 min read
Quick Answer: ECDIS (Electronic Chart Display and Information System) is a computer-based navigation system that displays Electronic Navigational Charts (ENCs) integrated with real-time vessel position data from GPS, radar, AIS, and other sensors. Under SOLAS Regulation V/19, ECDIS with adequate backup arrangements is accepted as an alternative to paper charts on most commercial vessels above 500 GT. It must be type-approved to IMO performance standards (currently Resolution MSC.232(82)), and deck officers must hold both generic ECDIS training under the 2010 STCW Manila amendments and equipment-specific familiarisation certificates.
A vessel ran aground because the officer on watch did not know that the safety contour alarm on the ECDIS had been switched off during a previous watch. The chart was up to date. The system was type-approved. The officer was trained. The alarm was off. This scenario repeated in various forms across PSC detention records and maritime casualty investigation reports, captures the central challenge of ECDIS: it is a powerful navigation system that becomes dangerous when its settings, alarms, and limitations are not understood by the people operating it.
This guide covers ECDIS the way an ExC Master Mariner explains it: how the system works, what SOLAS and STCW require, how alarm management prevents groundings, what PSC inspectors look for, and what the S-100 transition means for navigators and ship operators in 2025 and beyond.
What Is ECDIS?
ECDIS is a geographic information system for nautical navigation that complies with IMO and IHO regulations as the primary electronic navigation method on commercial vessels. It was developed to replace paper charts as the primary navigation tool, providing a real-time, continuously updated picture of the vessel's position relative to charted waters, hazards, and planned routes.
ECDIS displays information from Electronic Navigational Charts (ENCs) together with the vessel's position, heading, and speed obtained from connected sensors. Optionally, it also displays information from radar, AIS, Navtex, and depth sounders, creating a single integrated navigation picture for the officer on watch.
The system performs three core navigation functions. First, route planning: the officer plans the intended passage by setting waypoints, checking the route against chart data for hazards, shallow water, and traffic separation schemes, and calculating ETAs. Second, route monitoring: ECDIS continuously checks the vessel's actual track against the planned route and generates alarms for course deviations, cross-track distance exceedances, and approach to hazards. Third, continuous position plotting: the vessel's GPS position is plotted on the ENC in real time, replacing the manual chart plot that navigators previously made at regular intervals on paper.
ECDIS vs ECS: A Critical Distinction
Not every electronic chart system is an ECDIS. An ECDIS is specifically a system that has been type-approved to IMO performance standards (Resolution MSC.232(82)) and is capable of displaying official ENCs from authorised hydrographic offices. An Electronic Chart System (ECS) is any computer-based chart display system that does not meet these standards. Under SOLAS, only a type-approved ECDIS with adequate backup can replace paper charts. An ECS cannot. This distinction has direct PSC inspection implications: an ECS on a vessel that should be carrying ECDIS is a deficiency.
How ECDIS Works
ECDIS operates as an integration hub for multiple navigation data streams. Understanding each input helps navigators identify what happens when a sensor fails or provides corrupt data.
Position and Heading Inputs
The primary position input is a GPS or GNSS receiver, providing latitude and longitude updated at 1-second intervals or better. The gyrocompass provides heading data (true course). The speed log provides speed through the water (STW). Some ECDIS configurations also accept speed over ground (SOG) from the GPS for comparison. Dual-input configurations with independent position sources allow the system to flag discrepancies and provide redundancy.
Chart Database and SENC
ENC data is stored on the ECDIS in a format called the System Electronic Navigational Chart (SENC). The SENC is the ENC as processed by the specific ECDIS model for display, it may differ slightly from the raw ENC data due to system-specific rendering. ENC data is encrypted per IHO S-63 to prevent unauthorised copying and ensure only licensed users can access official charts. The officer accesses depth data, hazard information, and object attributes by querying the chart display, a function not available with paper charts or RNCs.
Route Planning on ECDIS
Route planning on ECDIS involves setting a series of waypoints defining the intended track, with leg distances, bearings, and ETA calculations generated automatically. Before activating a route, the system performs an anti-grounding check: scanning the planned track and a configurable corridor around it against the chart's safety contour. Any charted feature shallower than the safety contour within the corridor triggers an alarm before departure. This pre-departure route check, mandatory under MSC.1/Circ.1503/Rev.2 guidance, replaces the navigator's manual chart check on paper.
Radar Overlay
The radar overlay function superimposes a radar image onto the ENC display, allowing the navigator to correlate radar targets with charted features. This is a powerful tool for visual fix confirmation and hazard identification. However, it introduces a risk: navigators must understand that the radar image and ENC may not align perfectly due to GPS errors, gyro error, or scale differences. Treating the radar overlay as precise when it is not has contributed to incidents where navigators misidentified charted shoals as radar artefacts.
ENC vs RNC: Chart Types in ECDIS
ECDIS can display two types of electronic charts, but only one fully satisfies SOLAS requirements for paper chart replacement.
Feature | ENC (Electronic Navigational Chart) | RNC (Raster Navigational Chart) |
Format | Vector database — IHO S-57 or S-101 standard | Scanned raster image of paper chart |
Interactivity | Fully interactive: click on object to query attributes, depth, hazard data | No interactivity — image only |
Display layers | Multiple selectable layers (base, standard, all) | Single fixed image |
Alarm capability | Full alarm functionality against chart data | Limited — no object querying for alarms |
SOLAS compliance | Fully compliant for paper chart replacement | Only permitted with paper chart backup (dual fuel mode) |
Official authority | Published by government hydrographic offices | Scanned from official paper charts — not vector data |
Update mechanism | Cell-based updates via licensed service | Full chart replacement required |
Standard | IHO S-57 (current), S-101 (next-generation under S-100) | IHO S-61 |
IHO Standards Explained
S-57 is the current IHO standard for ENC data structure, used for virtually all ENCs distributed today. S-101 is the next-generation ENC standard under the broader S-100 Universal Hydrographic Data Model framework, offering richer data and improved capabilities. S-52 defines how ENC data must be displayed to ensure consistency across different ECDIS systems. S-63 defines the data protection and encryption scheme that prevents unauthorised chart use. All official ENCs for ECDIS are distributed through Regional ENC Coordinating Centres (RENCs) — primarily PRIMAR (based in Norway, serving most of Europe and international waters) and IC-ENC (UK Hydrographic Office service for British and international charts).
SOLAS Carriage Requirements
SOLAS Chapter V (Safety of Navigation) establishes the legal framework for ECDIS carriage. Regulation V/19 lists the navigational equipment ships must carry. Regulation V/27 requires charts to be adequate and up to date for the intended voyage. ECDIS with adequate backup arrangements satisfies both regulations, provided the ECDIS is type-approved and the ENCs cover the intended voyage area.
Phased Implementation Schedule
Vessel Type | GT Threshold | New Build Compliance Date | Existing Ship Compliance Date |
Passenger ships | >500 GT | 1 July 2012 | 1 July 2014 |
Tankers | >3,000 GT | 1 July 2012 | 1 July 2015 |
Cargo ships | 3,000 - 10,000 GT | 1 July 2013 | 1 July 2017 |
Cargo ships | 10,000 - 50,000 GT | 1 July 2013 | 1 July 2016 |
Cargo ships | >50,000 GT | 1 July 2013 | 1 July 2016 (survey after 30 June 2016) |
Backup Arrangement Requirements
ECDIS alone is not sufficient. SOLAS requires that adequate backup arrangements be provided. An adequate backup is typically one of: a second independent ECDIS unit, or a folio of up-to-date paper charts covering the intended voyage. Many vessels carry two ECDIS units as the primary and backup, with paper charts for emergency use only. When operating in areas where ENCs are not available, an ECDIS in RNC mode must be backed up by paper charts for the area concerned.
Type Approval
ECDIS must be type-approved against the IMO performance standards in Resolution MSC.232(82) to satisfy SOLAS requirements. Type approval is issued by flag state administrations or recognised organisations (classification societies). The USCG maintains a verified list of type-approved ECDIS systems for US-flagged vessels and vessels calling US ports. A PSC inspector can check type approval by verifying the certificate carried on board and cross-referencing with the flag state type approval register.
ECDIS Alarm Management: The Critical Section
Most serious ECDIS-related maritime incidents do not involve equipment failure. They involve incorrect alarm configuration, alarm fatigue, or a navigator's failure to understand the meaning of an alarm. IMO Circular MSC.1/Circ.1503/Rev.2 (ECDIS — Guidance for Good Practice) dedicates significant attention to alarm management for this reason.
Safety Contour
The safety contour is the depth value the navigator sets in ECDIS below which the system shades water areas in a distinctive colour (typically blue or grey) and triggers alarms when the vessel approaches or enters. It must be set to a depth that provides adequate under-keel clearance (UKC) for the vessel, typically the vessel's maximum draught plus a UKC margin appropriate for the area. Setting the safety contour to zero or to an inappropriate value is one of the most common ECDIS configuration errors. If set too shallow, the display becomes cluttered with false alarms. If set at zero or below the vessel's draught, the anti-grounding function is effectively disabled.
Safety Depth
The safety depth is the depth value below which individual soundings are highlighted on the display. Soundings shallower than the safety depth appear in a contrasting colour, drawing the navigator's attention to specific areas of concern. It is related to but distinct from the safety contour — the contour defines shaded areas, while the safety depth highlights individual depth values within those areas.
Anti-Grounding Alarm
The anti-grounding function checks the vessel's predicted track — the area ahead of the vessel that it will traverse based on current course and speed — against the chart data and the safety contour. If the predicted track enters an area shallower than the safety contour, an alarm is generated. The look-ahead time (how far ahead the system checks) must be configured appropriately for the vessel's speed and the complexity of the passage. In open ocean conditions, a long look-ahead time is appropriate. In confined waters, a shorter look-ahead prevents nuisance alarms from unavoidable proximity to shoals in narrow channels.
Alarm Categories
ECDIS alarms are classified as either Alarms or Indications. An Alarm must be both audible and may be visual; it requires acknowledgement. An Indication may be visual only and does not necessarily require an audible signal. The distinction matters operationally: navigators must not configure Alarm-category events as Indication-only, as this removes the audible alert that would wake a watchkeeper whose attention has drifted.
Common Alarm Misconfiguration Errors
Safety contour set to 0 metres: disables shallow water warnings
Alarms acknowledged without being reset or actioned: alarm acknowledged, no corrective action, vessel continues toward hazard
Display scale too small to resolve individual hazards: charted shoals appear as a dot or not at all at coarse scale
Look-ahead time set inappropriately for passage type: either too long (nuisance alarms) or too short (insufficient warning time)
Anti-grounding alarm disabled for passage through a busy port: not re-enabled after the passage
Safety depth not updated when vessel changes draught between ports
STCW Training Requirements
The 2010 Manila amendments to the STCW Convention introduced mandatory ECDIS training for all deck officers on vessels fitted with ECDIS. The requirement has two separate components that are frequently confused.
Generic ECDIS Training
Generic ECDIS training is an approved course covering ECDIS operation independent of any specific make or model. It typically runs for five days and covers system architecture, chart types, route planning and monitoring, alarm management, maintenance, and failure modes. Successful completion results in a training certificate confirming competency to operate ECDIS generally, as required by Table A-II/1 of the STCW Code. This certificate is issued by the training institute and is not vessel or system specific.
Type-Specific Familiarisation
Type-specific familiarisation covers the specific make and model of ECDIS installed on the vessel the officer is joining. It is required under STCW Regulation I/14 and ISM Code Sections 6.3 and 6.5. It is not a formal course but a structured familiarisation, typically conducted by the vessel's Chief Officer or a manufacturer's representative, and must be documented. The MPA Singapore guidance (May 2025) following MSC.1/Circ.1503/Rev.2 clarifies that this familiarisation record must appear in the officer's training documentation. Officers cannot demonstrate operational competency with a specific ECDIS model based on generic training alone.
What PSC Inspectors Check for STCW ECDIS Compliance
Valid generic ECDIS training certificate with course content confirming Manila 2010 amendment compliance
Type-specific familiarisation record for the ECDIS make and model on board
Ability to demonstrate route planning, alarm configuration, and position monitoring on the ship's ECDIS
Documentation of familiarisation in the officer's training file or shipboard training record
ECDIS and PSC Inspections
Port State Control inspections under the Paris MOU, Tokyo MOU, and USCG scrutinise ECDIS compliance as a priority area. Common ECDIS-related deficiencies include ENCs that are not current, safety contour misconfiguration, absence of documented backup arrangements, and deck officers who cannot demonstrate operational competency.
9-Point PSC Preparation Checklist for Masters
Confirm ECDIS type approval certificate is on board and valid for the flag state
Verify ENC update date: all cells covering the intended voyage must be current (weekly AVCS updates)
Confirm backup arrangement: second ECDIS operational, or paper chart folio current and covering the voyage
Check safety contour setting against the vessel's maximum draught and UKC policy
Confirm anti-grounding alarm is enabled and correctly configured for the current passage
Verify that all deck officers hold generic ECDIS training certificates compliant with Manila 2010
Confirm type-specific familiarisation records are documented for each officer for the ECDIS on board
Test backup arrangement: switch to backup ECDIS or confirm paper charts are accessible and usable
Ensure ECDIS software version is current per manufacturer guidance and type approval conditions
ECDIS Cybersecurity Risks
ECDIS is a computer-based system connected to navigation sensors, often to the ship's LAN, and sometimes to internet-connected update services. These connections create cybersecurity vulnerabilities that have grown in significance as maritime cyber incidents have increased.
GPS Spoofing
GPS spoofing is the broadcast of counterfeit GPS signals that override authentic satellite signals, causing the vessel's GPS receiver — and therefore the ECDIS position display — to show a false position. Spoofing incidents have been recorded in the Black Sea, the Persian Gulf, and near conflict zones. A spoofed position can displace the vessel's displayed position by miles without any obvious indication of failure. The ECDIS will not alarm on position accuracy alone unless the navigator has configured a consistency check against an independent position source. Mitigation requires cross-checking the GPS position against radar fixes on charted features, celestial observations, and AIS-derived relative positions.
Network Vulnerabilities
The 2017 NotPetya malware attack affected navigation systems and IT infrastructure across major shipping companies. ECDIS units connected to ship LANs are potential entry points for malware, particularly when ENC updates are downloaded from internet connections without adequate network segregation. IMO Resolution MSC.428(98) requires maritime cyber risk management to be incorporated into the ISM Code safety management system from January 2021. Ship operators must document identified cyber risks and mitigation measures as part of their safety management system.
AIS Manipulation
AIS data is displayed on ECDIS as vessel identification targets overlaid on the chart. AIS signals are unauthenticated and can be spoofed or manipulated to create phantom vessels, alter transmitted positions, or remove real vessels from the AIS display. Navigators must treat AIS targets as supplementary information, not as primary collision avoidance data, and maintain radar watch independently of the AIS overlay on ECDIS.
S-100 and the Next Generation of ECDIS
The IHO S-100 Universal Hydrographic Data Model is the framework for the next generation of maritime data standards, replacing the S-57 standard on which current ENCs are based. S-100 enables richer, more interoperable data products, real-time information overlays, and machine-readable chart information that supports e-Navigation and eventually autonomous navigation.
S-101: Next-Generation ENC
S-101 is the ENC product specification under S-100. It uses an upgraded object catalogue, improved display rules, and supports a richer set of navigational data. S-101 ENCs will eventually replace S-57 ENCs as the standard for ECDIS, although the transition will span multiple years with both standards in circulation during the changeover.
NCSR 12 (May 2025) — New ECDIS Performance Standards
The IMO's Sub-Committee on Navigation, Communications, Search and Rescue (NCSR 12), meeting in May 2025, finalised new ECDIS performance standards that will apply to equipment installed on or after 1 January 2029. During the transitional period from 1 January 2026 to 1 January 2029, ECDIS equipment may comply with either the current standards (Resolution MSC.232(82)) or the new standards. NCSR 12 also agreed on guidance for an IP-based S-100 data distribution framework, enabling shore-to-ship digital data delivery over internet protocol — replacing the current cell-based satellite broadcast update model.
What S-100 Means for Ship Operators
Ship operators buying new ECDIS from 2026 onwards should clarify whether the system is designed to support S-100/S-101 data. Systems installed before 2029 may comply with either the current or new performance standards, but operators should plan for the hardware replacement cycle that the new 2029 type approval requirements will eventually necessitate. ENC update services will migrate from S-57 to S-101 on a chart-by-chart basis over the coming decade, with both standards available simultaneously during transition.
ECDIS vs Other Navigation Systems
System | Primary Function | Integration with ECDIS | Key Distinction |
ARPA | Collision avoidance: tracks radar targets, calculates CPA/TCPA | Radar overlay on ECDIS; ARPA targets displayed | ARPA cannot display chart data; ECDIS cannot track targets as ARPA does |
AIS | Vessel identification and traffic awareness | AIS targets overlaid on ECDIS chart | AIS requires authentication — do not use as sole collision avoidance tool |
GPS/GNSS | Position fixing | Primary position input to ECDIS | GPS alone cannot display chart data or generate safety alarms |
Radar | Traffic and obstacle detection in poor visibility | Radar overlay on ECDIS | Radar detects objects; ECDIS interprets them relative to charted features |
Echo Sounder | Under-keel depth measurement | UKC data fed to ECDIS for display | Measures actual depth; ECDIS uses charted depth for alarm generation |
VDR (Voyage Data Recorder) | Record bridge data for investigation | ECDIS data (track, alarms) recorded by VDR | Retrospective tool — not real-time navigation aid |
Paper Charts | Traditional navigation chart | No integration possible | Backup for ECDIS failure; required when ENCs unavailable for an area |
ECDIS Update and Maintenance
ECDIS maintenance encompasses both software and chart currency. Failure to maintain either can result in PSC deficiency notices, SOLAS non-compliance, and potentially invalidated type approval.
ENC Currency
ENCs are issued and updated by national hydrographic offices and distributed through licensed services such as the UK Hydrographic Office's Admiralty Vector Chart Service (AVCS) and PRIMAR. Updates are issued weekly and cover new Notices to Mariners, corrected chart data, and new or amended hazard information. A PSC inspector will check the date of the most recent ENC update for the cells covering the vessel's trading area. Cells not updated within the expected update cycle are a direct deficiency.
Software Maintenance
ECDIS software must be maintained per the manufacturer's guidance as a condition of type approval. Outdated software may introduce display bugs, security vulnerabilities, or non-compliance with the terms of the type approval certificate. NCSR 12 (May 2025) finalised guidelines for software maintenance of shipboard computer-based navigation equipment, establishing a standardised approach to ensure software updates do not compromise type approval compliance.
Hardware Lifecycle
ECDIS display units must meet IEC 60945 (marine environment) and IACS E10 standards for durability and reliability in the shipboard environment. As ENCs advance toward S-101 and the S-100 framework requires greater processing capability, older hardware may not support the rendering requirements of next-generation chart data. Operators should plan hardware review cycles aligned with the 2029 performance standard transition.
Frequently Asked Questions
What does ECDIS stand for?
ECDIS stands for Electronic Chart Display and Information System. It is a computer-based navigation system that displays official Electronic Navigational Charts (ENCs) integrated with real-time position, heading, speed, and sensor data. It was developed to replace paper charts as the primary navigation tool on commercial vessels and is mandatory under SOLAS on most cargo ships, tankers, and passenger vessels above certain gross tonnage thresholds.
Is ECDIS mandatory on all ships?
ECDIS is mandatory on most commercial vessels engaged in international voyages above specified gross tonnage thresholds, under SOLAS Regulation V/19. The phased implementation programme completed for all vessel classes by 2017. Passenger ships above 500 GT, tankers above 3,000 GT, and cargo ships above 3,000 GT must carry ECDIS. Vessels below 3,000 GT, non-SOLAS vessels, and vessels on non-international voyages may be exempt, subject to flag state requirements.
What is the difference between ECDIS and ECS?
An ECDIS is a navigation system that has been type-approved to IMO performance standards (currently Resolution MSC.232(82)) and can legally replace paper charts under SOLAS. An Electronic Chart System (ECS) is any other computer-based chart display system that does not meet these performance standards and cannot replace paper charts regardless of its capability. The distinction is the type approval certificate — if the system is not type-approved to the relevant IMO resolution, it is an ECS, not an ECDIS.
What is the difference between an ENC and an RNC?
An ENC (Electronic Navigational Chart) is a vector database created by a national hydrographic office to IHO S-57 or S-101 standards. It is interactive, allowing navigators to query objects for attribute data, and it supports full ECDIS alarm functionality. An RNC (Raster Navigational Chart) is a scanned digital copy of a paper chart — an image file with no interactivity and no queryable data. Only ENCs fully satisfy SOLAS carriage requirements for paper chart replacement. ECDIS operating with RNCs (dual fuel mode) must carry paper chart backup for the area concerned.
What STCW training is required to operate ECDIS?
Two separate training requirements apply under the 2010 STCW Manila amendments. First, generic ECDIS training: an approved five-day course covering ECDIS operation independent of any specific make or model, resulting in a training certificate per Table A-II/1 of the STCW Code. Second, type-specific familiarisation: a documented briefing on the specific make and model of ECDIS fitted on board, required under STCW Regulation I/14 and ISM Code Sections 6.3 and 6.5. Both are required before an officer operates ECDIS independently on watch.
What is a safety contour in ECDIS?
The safety contour is a depth value the navigator sets in ECDIS below which shallow water areas are shaded in a distinctive colour and safety alarms are generated. It must be set to a depth that provides adequate under-keel clearance for the vessel's draught and the waters being navigated. If set to zero or below the vessel's draught, the anti-grounding function is effectively disabled. Setting the safety contour correctly for each passage is one of the most important ECDIS configuration tasks for the navigating officer.
Can ECDIS replace paper charts?
Yes, under SOLAS Regulation V/27, a type-approved ECDIS with adequate backup arrangements and current ENCs covering the intended voyage is accepted as an equivalent to paper charts. The backup arrangement must be documented and operational — typically a second independent ECDIS unit or a current paper chart folio. ECDIS in RNC mode (raster charts) must always be backed up by paper charts. The ENCs must be current — updated per the most recent Notice to Mariners for the area.
What is S-100 and how does it affect ECDIS?
S-100 is the IHO Universal Hydrographic Data Model — the framework for the next generation of maritime data standards, replacing S-57. S-101 is the next-generation ENC product specification under S-100. The IMO's NCSR 12 (May 2025) agreed new ECDIS performance standards applying to equipment installed from 1 January 2029, supporting S-100 data products and an IP-based shore-to-ship data distribution framework. For operators, S-100 means richer chart data, eventually real-time overlay information (tidal prediction, weather, port services), and a hardware replacement cycle aligned with the 2029 type approval requirements.
What do PSC inspectors check regarding ECDIS?
Port State Control inspectors typically check: the ECDIS type approval certificate and its validity for the flag state; the date of the most recent ENC update for cells covering the intended voyage; the backup arrangement documentation and operational status; the safety contour configuration against the vessel's draught; deck officers' generic ECDIS training certificates; type-specific familiarisation documentation for the ECDIS on board; and the officer's ability to demonstrate route planning, alarm configuration, and position monitoring on the system.
What is GPS spoofing and how does it affect ECDIS?
GPS spoofing is the broadcast of counterfeit satellite signals that override genuine GPS signals, causing the ECDIS to display a false vessel position. The displayed position may be displaced by hundreds of metres to several miles without any alarm from the ECDIS, which cannot distinguish genuine from spoofed signals autonomously. Spoofing incidents have been documented in the Black Sea, the Persian Gulf, and near conflict zones. Mitigation requires independent position verification: radar fixes on charted features, celestial observations, or consistency checks with a second independent GPS receiver.
What is a SENC?
SENC stands for System Electronic Navigational Chart. It is the ENC as processed by a specific ECDIS model for display — essentially the ENC data after the ECDIS has applied its rendering rules (per IHO S-52) and any system-specific processing. The SENC is what the navigator actually sees on screen. It may differ slightly from the raw ENC data due to system-specific rendering, but must comply with S-52 display standards. The SENC is created by the ECDIS from the ENC data and cannot be transferred between different ECDIS makes/models.
How often must ECDIS charts be updated?
ENCs should be updated weekly using the licensed update service — typically the Admiralty Vector Chart Service (AVCS), PRIMAR, or equivalent. Each update incorporates the most recent Notices to Mariners affecting the chart cells in the vessel's trading area. Some vessels receive updates via SATCOM broadcast or email. Cells that have not received their expected weekly update cycle should be flagged and resolved before the vessel transits the relevant area. PSC inspectors check ENC update dates and will raise a deficiency for outdated chart cells.
Glossary of Key ECDIS Terms
Term | Definition |
ECDIS | Electronic Chart Display and Information System — type-approved navigation system displaying ENCs with real-time position and sensor data, accepted as paper chart equivalent under SOLAS |
ENC | Electronic Navigational Chart — official vector chart database created by a national hydrographic office to IHO S-57 or S-101 standards |
RNC | Raster Navigational Chart — scanned digital image of a paper chart; not interactive; requires paper chart backup when used in ECDIS |
SENC | System Electronic Navigational Chart — the ENC as processed and displayed by a specific ECDIS model using its own rendering rules |
ECS | Electronic Chart System — any chart display system not type-approved to IMO performance standards; cannot replace paper charts under SOLAS |
IHO | International Hydrographic Organization — international body establishing hydrographic data and chart standards (S-57, S-100, S-52, S-63) |
S-57 | Current IHO standard for ENC data structure, used for virtually all ENCs distributed today |
S-101 | Next-generation ENC product specification under the IHO S-100 framework; richer data, improved display |
S-100 | IHO Universal Hydrographic Data Model — framework replacing S-57 for next-generation maritime data products |
S-52 | IHO display standard specifying how ENC data must be rendered by ECDIS to ensure cross-system consistency |
S-63 | IHO data protection scheme for encrypting and digitally signing ENC data to prevent unauthorised copying |
SOLAS V/19 | SOLAS regulation listing mandatory navigational equipment, including ECDIS (with backup) as paper chart equivalent |
STCW | International Convention on Standards of Training, Certification and Watchkeeping for Seafarers; 2010 Manila amendments added ECDIS training requirements |
Safety Contour | Depth value set by navigator in ECDIS below which shallow water is shaded and alarms generated; must reflect vessel's UKC requirement |
Safety Depth | Depth value in ECDIS below which individual soundings are highlighted on the display |
Anti-Grounding Alarm | ECDIS function checking the vessel's predicted track against the safety contour ahead of the vessel |
ARPA | Automatic Radar Plotting Aid — tracks radar targets and calculates collision risk (CPA/TCPA); often displayed on ECDIS via radar overlay |
AIS | Automatic Identification System — transmits vessel identity, position, and voyage data; targets displayed on ECDIS |
AVCS | Admiralty Vector Chart Service — UK Hydrographic Office ENC distribution and update service |
RENC | Regional ENC Coordinating Centre — PRIMAR (Norway) and IC-ENC (UKHO) distribute and coordinate official ENCs worldwide |
PRIMAR | Nordic Regional ENC Coordinating Centre based in Stavanger, Norway; primary ENC wholesaler for most global chart coverage |
IC-ENC | International Centre for ENCs — UK Hydrographic Office RENC service covering British and associated international charts |
UKC | Under-Keel Clearance — vertical distance between the vessel's keel and the seabed; ECDIS safety contour and safety depth settings must reflect UKC requirements |
PSC | Port State Control — inspection regime by port authorities verifying compliance with SOLAS, STCW, MARPOL, and other conventions; ECDIS compliance is a priority check area |
MSC.232(82) | IMO Resolution setting current ECDIS performance standards for type approval; transitional period 2026-2029 as new standards apply to equipment installed from 1 January 2029 |
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Ravi Shanker
Co-Founder & CCO, Shipfinex
Ravi Shankar FICS is Co-Founder and Chief Commercial Officer of Shipfinex, and General Secretary of the ICS Middle East Branch. A Fellow of the Institute of Chartered Shipbrokers with extensive experience in ship sale and purchase, chartering, and maritime consultancy, he has previously held senior roles at Maersk Broker and Eastgate Shipping DMCC. His day-to-day commercial work spans dry bulk and tanker market analysis, SnP transactions, and shipbroking advisory.
