A number of ship owners and managers are now investigating the use of electronic charts as the primary form of navigation. However, the lack of "global" ENC coverage, confusion within the marketplace and the complexity of the current regulations hinder this move. This document aims to simplify regulatory issues governing the use of ECDIS and electronic charts.

To ensure conformance with International Maritime Organisation (IMO) requirements, ECDIS must pass type approval and test procedures developed by the International Electrotechnical Commission (IEC) based on IMO ECDIS Performance Standards and applying the IHO requirements S-52 and S57 in particular.

Type approval is normally conducted by recognised organisations or by marine classification societies nominated by Flag States.

All systems, which are not tested to show compliance with IMO ECDIS Performance Standards, can be generically designated as "Electronic Chart Systems" (ECS). An ECS may be able to use official ENCs, RNCs or other chart data produced privately and could have functionality similar to ECDIS.

When a vessel operates with ECS, the paper chart remains the official basis for navigation onboard, regardless of the type of electronic chart used.

The regulations governing the use of electronic charts state that the data must be issued by, or on the authority of, a government-authorised Hydrographic Office and kept up to date. Any vessels wishing to use ECDIS as the primary form of navigation i.e. a reduction or eradication of paper charts onboard, must use official data. Poly TGNS are a single source for official chart data as distributed by Primar Stavanger, United Kingdom Hydrographic Office (UKHO), Japanese Hydrographic Office (JHA) and other National suppliers from around the world.

There are two types of official electronic charts commonly available; Electronic Navigational Charts (ENC) and Raster Navigational Charts (RNC).

An ENC (Electronic Navigational Chart) is a database, standardised as to content, structure and format, issued for use with ECDIS on the authority of government authorised Hydrographic Offices (HO’s). It contains all chart information necessary for safe navigation and may contain supplementary information in addition to that contained in the paper chart (e.g. Sailing Directions), which may be considered necessary for safe navigation.

Only a type approved ECDIS operating with up to date official ENC’s and with appropriate back up arrangement may be used for primary navigation. Where official ENCs are not yet available, IMO regulations allow Flag States to authorise the use of official raster charts (ARCS) - (together with an appropriate folio of paper charts).

The IMO requires that when using a type-approved ECDIS:

• ENCs can be used for primary navigation in place of paper charts, provided there is a suitable backup (e.g. another ECDIS with a separate power supply, or an appropriate folio of up to date paper charts**).

• RNCs, when used in conjunction with ENCs (to fill the gaps in coverage) can be used for primary navigation together with an appropriate folio of up to date paper charts**.

** What is considered 'an appropriate folio of up to date paper charts' will vary between flag states, and may or may not represent a reduction in the number of paper charts required to be carried.

As there is no common interpretation of the term "appropriate" ship owners should consult their flag states and inform them of their intentions. Your Flag State Authority will then decide whether you meet their regulations.
 

IMO SOLAS Chapter V/2.
Nautical chart or nautical publication is a special-purpose map or book, or a specially compiled database from which such a map or book is derived, that is issued officially by, or on the authority of, a Government, authorised Hydrographic Office or other relevant government institution and is designed to meet the requirements of marine navigation.

IMO SOLAS V/19
2.1 All ships irrespective of size shall have:

2.1.4 Nautical charts and nautical publications to plan and display the ship’s route for the intended voyage and to plot and monitor positions throughout the voyage; an Electronic Chart Display and Information System (ECDIS) may be accepted as meeting the chart carriage requirements of this subparagraph;

2.1.5 Back-up arrangements to meet the functional requirements of subparagraph 2.1.4, if this function is partly or fully fulfilled by electronic means. Suitable back-up arrangements are defined in Appendix 6 to resolution A.817(19), as amended, and for example include an appropriate folio of paper nautical charts or a second ECDIS system.

IMO SOLAS V/27
Nautical charts and nautical publications, such as Sailing Directions, Lists of Lights, Notices to Mariners, Tide tables and all other nautical publications necessary for the intended voyage, shall be adequate and up to date.

Meeting carriage requirements with ECDIS
Only a type approved ECDIS operating with up to date official ENCs and with appropriate back up may be used to replace all paper charts on a vessel.

The two leading Regional ENC co-ordinating centres have joined forces to create a new guide aimed at demystifying the regulatory issues surrounding the use of ECDIS and electronic charts.

The document ‘Facts about Charts and Carriage Requirements’ is presented in a simple to follow manner and answers over twenty of the most commonly asked questions. It also comes with extensive annexes detailing regulations in force today for a number of Flag States including Greece, Norway and the UK and is set to provide a useful reference for anyone involved in the production, purchase or use of electronic charts. The new Guide will continue to be expanded and updated to ensure it remains accurate.