One bridge team member should be tasked with overall situational awareness at all times, but especially when in congested waters and under close manoeuvring. The Nautical Institute gives this advice after a tanker crew lost sight of a buoy causing the ship’s propeller and rudder to become entangled with its chain.

The Nautical Institute gathers reports of maritime accidents and near-misses. It then publishes these so-called Mars Reports (anonymously) to prevent other accidents from happening. A summary of this incident:

A tanker was approaching a crowded anchorage area where a ship-to-ship transfer (STS) was to take place. Visibility and weather conditions were good and the bridge team was fully mobilised with the master, two officers, a helmsman and a lookout on duty.

As the vessel approached the pick-up position of the mooring master, a small police boat was moving somewhat erratically ahead. There were other vessels anchored to starboard, so the tanker’s bridge team altered course to port and slowed to about 3 knots.

Speed was further reduced and soon the STS mooring master arrived along with two tugs. The tanker, now almost stopped, was affected by the northwest current. Shortly after the STS mooring master had boarded, the tanker’s port side lightly made contact with an anchorage buoy.

The buoy slid aft along the hull and its chain became entangled with the vessel’s propeller and rudder. The mooring and STS operation was aborted and the tanker anchored with tug assistance. The chain was cleared with the help of divers. Some minor damage to the propeller was recorded.

Advice from The Nautical Institute

In addition to the advice given above, The Nautical Institute remarks the following with respect to this incident:

  • Even in perfect weather conditions and full daylight, a bridge team can lose situational awareness. It is possible that the boarding of the STS mooring master combined with the erratic movements of the police boat and other congestion preoccupied the bridge team and caused the tanker’s movement towards the buoy to go unnoticed until it was too late.

Mars Reports

This accident was covered in the Mars Reports, originally published as Mars 202071, that are part of Report Number 338. A selection of this Report has also been published in SWZ|Maritime’s January 2021 issue. The Nautical Institute compiles these reports to help prevent maritime accidents. That is why they are also published on SWZ|Maritime’s website.

More reports are needed to keep the scheme interesting and informative. All reports are read only by the Mars coordinator and are treated in the strictest confidence. To submit a report, please use the Mars report form.