Shoal Areas on ENCs

16 May 2010 Resource

Problem with some shoal areas not properly shown on ECDIS

Two or three months ago I heard that the data on some (many?) ENCs had been incorrectly compiled and that some shoal areas would not be properly shown when ECDIS is in Standard or Base display mode. Has this problem now been sorted out or do we still have to be careful? Is there a list of ENCs affected? 


(June 2010)

Earlier this year it was discovered that one of the methods used by Hydrographic Offices to encode isolated shoal depths in ENCs could result in some of them not being displayed adequately on ECDIS.  The matter was complicated by the fact that different ECDIS systems treated these encoded depths in different ways and in some cases alarms were not activated by them.  As a precautionary measure the following NAVAREA warning was issued to alert mariners using ECDIS to the issue. 

Mariners are advised that ECDIS may not display some isolated shoal depths when operating in "base or standard display" mode. Route planning and monitoring alarms for these shoal depths may not always be activated. To ensure safe navigation and to confirm that a planned route is clear of such dangers, mariners should visually inspect the planned route and any deviations from it using ECDIS configured to display "all data". The automated voyage planning check function should not be solely relied upon. The International Hydrographic Organization (IHO) is leading technical action to resolve this matter. Further information will be made available through Notices to Mariners.
The secretariat of the International Hydrographic Organization (IHO) immediately informed all Hydrographic Offices producing ENC and requested feedback on the extent of this form of encoding and, where it was used, the plans to amend any affected ENCs.   Investigation showed that whilst the encoding was common, only in a very small percentage of cases was this of navigational significance.   Most hydrographic offices have reacted very quickly to the issue and the majority have, as of mid- June 2010 completed any necessary amendment to their ENCs and these have been issued as ENC updates.    The following countries have yet to confirm completion of any necessary remedial action, Canada, Malaysia, Mexico, Pakistan, Peru, Russian Federation, Ukraine, USA, and Venezuela.


Additional response

(July 2010)

Supplied by the International Hydrographic Organization

All of the world's 42 ENC producing countries except Canada, Peru, Ukraine, USA and Venezuela have now declared through Notices to Mariners or similar action that any necessary updating action to affected ENCs has been carried out and the updates issued.