11-1
11. Chart Alerts
11.1 General
The ECDIS can detect areas where the depth is less than the safety contour or detect an area where a specified
condition exists. If you plan a route or if prediction of your ship's movement goes across a safety contour or an area
where a specified condition exists, the system will display a visual alert or sound an audio alarm to alert you to
impending danger. For this function, the ECDIS utilises the chart database (S57 charts) stored on the hard disk in
SENC format. Note that the ECDIS calculates dangerous areas using the largest scale chart available, which
may not be the visualised chart.
You can select objects that are included for calculation of danger area (for example, restricted areas). A window lists
the various areas that activate danger warnings.
You can also define your own safe area by creating a user chart area. The system can utilise these areas when
calculating chart alerts. This is very useful with raster chart material such as ARCS.
The ECDIS can check the following for you:
• Predicted movement area of your ship
• Planned route with an easy to use locator function to find dangerous areas
The ECDIS will highlight the following for you:
• Dangerous areas inside predicted movement area of your ship
• Dangerous areas inside your monitored route
• Dangerous areas inside your planned route
Note: If any of the selected danger area alerts are in pending state, an alert for the same category of danger area will
not cause a new alert. For example, there is a safety contour alert acknowledged but the condition currently exists. In
this case, that safety contour alert will not generate a new visual or audio alert.
11.2 Chart Alert
Official S57 chart material contains depth contours that can be used for calculation of chart alerts. A chart database
also includes different types of objects that the operator can use for chart alerts. The procedure for setting chart
alerts is outlined below.
1. Select suitable safety contour for your ship. See section 11.2.1 "How to select safety contour".
2. Check that "Chart Alerts" is set for display. See section 11.2.3 "How to highlight chart alert areas". If you want
chart alerts to be included in some other objects or areas, select them for indication or alert. See section 11.2.2
"How to select objects used in chart alerts".
3. In the route planning mode, define a new route or select an existing one. Make a chart alert calculation of the
route if there are indications of danger areas in the route. See section 11.5 "Route Planning". Modify your route
if necessary and do the chart alert calculation again.
4. Select route as monitored route.
5. Set watch sector for your ship. See section 11.4 "How to Activate Own Ship Check".
The system is now ready for chart alert calculation of monitored route.
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