When a vessel is navigating in an area where ENC coverage is not available, the ECDIS will switch to using RNC data.
An RNC is a facsimile copy of a paper navigation chart.
Moreover, ENCs are seamless and there are no boundaries between charts.
Once fitted, BNWAS must be used whenever the vessel is underway.
It is recommended that BNWAS is also used at anchor, if appropriate.
Regulation 19 has been revised to include Electronic Chart Display and Information Systems (ECDIS) and Bridge Navigation Watch Alarm Systems (BNWAS).
New and existing vessels must be fitted with these systems according to rolling timetables as detailed below.