Dec 082011
 

Pilot applied port helm too late

CMA CGM Platon made hard contact with a quay because the well-experience pilot ordered port helm too late to prevent the vessel being taken to starboard by the tidal stream says a report from the UK’s Marine Accident Investigation Branch.

The tug used during the unberthing operation was released shortly after the
vessel’s departure from the berth and, once control of the vessel had been
lost, there was little the pilot and bridge team could do, in the time available, to
prevent collision with the quay on the opposite riverbank.

The quay sustained superficial damage but the vessel suffered significant damage to her bow, and her forepeak tank was punctured. Fortunately there was no pollution and no-one was hurt.

An MAIB analysis concludes: “Although CMA CGM Platon’s speed through the water was about 8.5 knots, the flood tide acting on her port bow, coupled with the downdrain and wind acting on her starboard quarter, was sufficient to overcome the turning effect of the applied port helm. This resulted in the vessel unexpectedly turning to starboard.

“Although the engine was then set to ‘full astern’, the vessel’s stopping distance of 4 cables exceeded the available space ahead and she consequently made contact with the quay”.

Simulator studies conducted after the accident indicated that the complex tidal flow in the area during flood tides meant that there was little margin for error.

In 2007, a tanker was outbound from Grays Terminal on an ebb tide. As the pilot manoeuvred the vessel around Tilburyness, he lost control of the vessel and she contacted the quay at Northfleet Terminal. This resulted in damage to the vessel’s shell plating. A contributing factor was the vessel’s bow entering an area of counter-flow while her stern remained in the main ebb flow, causing her bow to unintentionally pay off to starboard.

In 2009, an outbound container vessel left Northfleet Hope Container Terminal on a flood tide. Shortly afterwards, the pilot lost control as he manoeuvred the vessel around Tilburyness and she contacted the quay at Bevans Wharf. The vessel sustained superficial damage but the quay and its supporting structures were severely damaged. The visibility was poor and caused the pilot to lose situational awareness. The vessel’s bow had entered the strong flood tidal stream while her stern remained in the downdrain, which caused the vessel’s bow to unintentionally pay off to starboard.

The PLA investigations revealed that, in both accidents, tugs had been used for unberthing the vessels and had then been released and were unavailable to provide assistance in time to prevent the vessels from contacting the quay. However, There was no system to check that the information circulated to pilots by the PLA had been received and read. The PLA therefore had no means for ensuring that the lessons identified in its accident investigations had been effectively promulgated to its pilots.

1.         As CMA CGM Platon’s bow entered the main  flood tidal stream, her stern remained in  the downdrain. This, together with the wind   acting on her starboard quarter, caused a   coupling effect, which resulted in the vessel  unexpectedly turning to starboard.

2.         The near-reciprocal nature of CMA CGM Platon’s heading and the direction of the flood tidal stream meant that a small change in the lateral position of the vessel and/or the edge of the tidal stream could make a significant difference to the point at which the vessel’s bow entered the tidal stream. The margin for error in achieving the intended manoeuvre was small and the pilot had unintentionally not applied port helm until after the vessel’s bow had entered the flood tidal stream.

3.         This accident might have been prevented had the pilot retained the option of using the tug for longer, as he could have used it to assist the vessel to turn into the flood tidal stream. Alternatively, he could have used the tug to pull the vessel off the berth while applying starboard bow thrust until the vessel had laterally entered the flood tidal stream.

4.         Although the master and pilot’s aborting manoeuvre was insufficient to prevent the accident, their primary aims were to avoid contacting the vessel moored ahead and limit damage to their own vessel.

5.         The master and pilot did not conduct a detailed exchange of information. Had they discussed areas of the river transit that may have posed a risk, they might have decided to retain the use of the tug until CMA CGM Platon was clear of the complex tidal flows that exist around Tilburyness.

6.         The PLA had no means for ensuring that the lessons identified in its accident investigations had been effectively promulgated to its pilots.

Read the full report

See also

Amok DP Scores HAT Trick

MV Antonis contact: A Bridge Too Far

Djurgården 4 Contact: Disconnected Cable Led To Crush

Villum Clausen – A Berth Too Bumpy

A Quay Of Silves

 

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