For example, the amount of detail shown on different scales may be specified.Moreover, ENCs are seamless and there are no boundaries between charts.
It is recommended that BNWAS is also used at anchor, if appropriate.“All ships, irrespective of size, shall have 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) is also accepted as meeting the chart carriage requirements of this subparagraph.If a ship uses ECDIS for navigation, the “Record of Equipment” must clearly state that it is used, and the back-up arrangements in place.Declaring ECDIS in the ship’s “Record of Equipment” makes ECDIS a surveyable item under SOLAS regulations.It will display the same data as on the paper chart and also has the same perimeter.
Alarms and warnings cannot be set in the same manner as an ENC.
Depending on the Flag State’s agreement, such arrangements may include: ECDIS systems use ENCs which have been published by an authorised hydrographic office.
An ENC, often referred to as a vector chart, is a database of information permitting chart data to be displayed according to the user’s requirements.
However, Resolution MSC.232(82), Appendix 6 “Back-up Requirements” does not specify acceptable alternatives.
Consequently approval by the vessel’s Flag State will be necessary if alternative back-up arrangements are to be used.
However, depending on the system it may be possible for the user to set boundary alarms, such as for danger areas.