1 As a result of investigations concerning a recent maritime incident, the United Kingdom Hydrographic
Office (UKHO) has informed the Directing Committee of a limitation in some ECDIS equipment software. It
seems likely that some ECDIS software does not properly recognise and take into account isolated land areas that
have been encoded in small-scale ENCs. This is particularly the case for ENCs depicting land areas in poorly or
sparsely surveyed areas that contain little, if any surrounding bathymetric information. Notwithstanding the fact
that IHO publication S52 section 8.5.1 Safety Depth Contour identifies a requirement to consider the
circumstances described above, it appears that some ECDIS equipment does not do so.
2 As a result of its finding, the UKHO has informed the UK Maritime Administration that has, in turn,
issued the following NAVAREA warning:
- As previously notified by NAVAREA warning, mariners using ECDIS are advised not to rely
solely on automated voyage planning and monitoring checks and alarms. It is recommended that
mariners undertake careful visual inspection of the entire planned route to confirm that it, and any
deviations from it, is clear of dangers. The ECDIS display should be configured to display all
soundings during this inspection.
- Particular care should be taken when planned routes cross areas where only small scale ENCs
(Usage Bands 1 and 2) are available. In some display configurations, such as when no names are
shown, small islands and other point features may be difficult to identify or could be obscured by
surrounding depth contours. Some ECDIS systems appear only to undertake route check functions
on larger scale ENCs and therefore alarms might not activate. This may not be clearly indicated on
the ECDIS display.
- The International Hydrographic Organization (IHO) is leading technical action to investigate these
matters in consultation with ECDIS equipment manufacturers. Further information will be made
available through Notices to Mariners.