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Visual navigation in fog is a sure accident risk

Gillberg
Visual navigation in fog is a sure accident risk

The Nautical Institute reports on an incident in which a loaded cargo ship set out under pilotage in daylight and with moderate visibility.

A A tug was present but was released after the vessel had passed the harbour jetties. About seven minutes after the tug had left the vessel, visibility unexpectedly decreased to about 200 m. The vessel was travelling at six knots and over the next two minutes the pilot ordered the helmsman to make a 44-degree turn to port out to sea (see diagram).

The ship turned further to port than desired. When the pilot noticed this, he gave starboard orders, but it was too late. About four minutes after the first port order, the ship ran aground outside the channel marked with buoys. Attempts to return to the channel using the ship’s power were unsuccessful and salvage tugs had to be used.

The investigation found, among other things, that the vessel lacked a complete voyage plan for exiting the port (i.e. courses, safety distances, bearings, rate of turn, etc.) and that the pilot navigated primarily visually. When visibility unexpectedly decreased, the bridge crew was at a disadvantage. No one on the bridge could control the course of the 44-degree port turn using electronic means such as ECDIS or radar.

Lessons learned: Visual navigation in fog is a sure accident risk

Photo credit: The Nautical Institute

Lessons learned

  • A shared plan is a safe plan. In this case, the plan was in the pilot’s head, as we saw in MARS 202153.
  • Even when a pilot is on board, a master should ensure that courses are plotted on the chart or ECDIS and that the OOWs closely follow the vessel’s progress.
  • Visual navigation in fog is a sure risk of accidents.
  • When in doubt, reduce speed if possible. In this case, the ship was doing six knots, which is not that fast – except that they were not able to assess the situation well. At four knots, they would have had 50% more time to assess the situation.

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