Electronic Navigational Chart
The vector chart database that feeds ECDIS, the S-57 and S-101 standards, and the carriage requirements under SOLAS Chapter V.
An electronic navigational chart is the vector chart database, issued by or on the authority of a government hydrographic office, that an electronic chart display and information system uses. It is defined by content and by standard rather than by appearance: a raster scan of a paper chart is not an electronic navigational chart, and a system displaying one is not operating in the mode that satisfies the carriage requirement.
The long-standing product specification is IHO S-57, which is being succeeded by the S-100 framework and its S-101 chart specification. SOLAS Chapter V regulation 19 carries the ECDIS fitting requirements, and an ECDIS meets the chart carriage requirement only when operating on official electronic navigational chart data, with an appropriate folio and current updates.
Chart currency is an operational rather than an administrative matter in constrained water. The seventh edition covering the Strait of Malacca and Singapore Strait incorporates joint hydrographic survey data and adds one-metre depth contour intervals in areas where under-keel clearance is critical, which is what allows a deep draught vessel to determine its margin against the 3.5 m requirement. The full article will cover the standards, the update and licensing regime, safety contour and safety depth settings, the transition to S-101, and the common ECDIS configuration errors found in casualty investigations.