ECDIS as the primary means
ECDIS is used as the primary means of navigation, and the Chief Mate ensures it is set up correctly for every passage: official ENCs installed and updated, the safety contour and safety depth set for the ship, sensible alarms and a check-ahead time, and the route checked against the charts with every warning resolved. Source-data quality (CATZOC) is checked, and the electronic position is cross-checked against radar, visual marks and the depth. An ECDIS run on default settings, or blindly trusted, is a known cause of grounding.
Radar, ARPA and the rules
- Set radar up for the conditions — gain, sea and rain clutter — and use it to fix position and to detect and track targets.
- Use ARPA to obtain each target's CPA, TCPA, true course and speed, remembering its delay after a manoeuvre and its limits.
- Apply the IRPCS: a steady bearing with closing range is risk of collision; take early, substantial, obvious action, to starboard in a crossing or head-on meeting.
- In restricted visibility apply Rule 19 — no stand-on vessel, safe speed, avoid close-quarters — and fuse radar, ARPA, AIS and ECDIS into one picture.
WARNING — Aids inform; the rules and the lookout decide ARPA and AIS build the picture but do not make the decision. Rule 7 warns against assumptions on scanty information; confirm with radar and eyes, then act under the collision regulations.
NOTE — Set ECDIS up for the ship, every passage The safety contour and alarms only protect the ship if set for her draught and the waters. Setting ECDIS up correctly for each passage, and checking the route, is a management-level habit, not a formality.