Lessons learnt: Avoid over- reliance on ECDIS for route monitoring

Lessons from UK MAIB’s Marine Accident Reports

The UK MAIB has recently issued the first Safety Digest for this year which includes lessons learnt from maritime accidents.One case draws the attention on checking the passage plan without rely only on ECDIS and ensuring that navigational equipment is effective

The Accident

On a calm and clear night a modern, well equipped tanker was heading through a busy coastal traffic separation scheme. To the OOW and lookout, everything on the bridge seemed normal. The OOW was sitting in the bridge chair, where he could see the radar display and the ship’s ECDIS. He was following the route shown on the ECDIS display and he adjusted the ship’s heading whenever necessary to keep on track.

Unexpectedly, the ship’s speed reduced to zero and soon afterwards an engineering alarm sounded. Assessing that there was a problem with propulsion, the OOW phoned the second engineer and asked him to check the engines.

The second engineer called the bridge back and confirmed that power was available on the starboard engine, so the OOW applied power using the starboard control lever. But the ship still did not move. The OOW also called the captain to explain that propulsion had failed in the traffic separation scheme.

Ashore in the local coastguard station, a watchkeeper noticed that the ships position was directly over a well charted sandbank, and called the ship on VHF radio to ask about the situation. Only when prompted by the coastguard did the OOW realise that the ship was hard aground on the sandbank.

Lessons Learnt

1. Checking the passage plan is vital. ECDIS was the ships primary means of navigation and the deck officers had all been trained and certified in its use. However, the passage plan, which passed directly over the sandbank, had not been properly checked using the ECDIS check route function. The master was also unable to use the ECDIS system and had not properly checked the plan before departure.
2. Avoid over-reliance on ECDIS for monitoring the route. Correlation of visual, radar, echo sounder and electronic navigation information is critical to maintaining good situational awareness, especially on a coastal passage in a traffic separation scheme.
3. Good bridge team management means making sure the lookout is encouraged to contribute to the safe navigation of the ship. In this case, despite the lookout seeing flashing lights from the buoys marking the sandbank ahead of the ship, this information was not reported to the OOW or acted upon.
4. There was no ECDIS alarm because the safety settings in the system were inappropriate; the safety contour value was wrong and the audible alarm was not working. If ECDIS is the primary method of navigating the ship, it is crucial that the system is properly set up for the passage. Alarm management is also important to ensure the bridge team are warned of navigational hazards or system failures.
5. If navigational equipment is defective, dont ignore or try to live with the problem. Get it fixed!

Source: UK MAIB