Weights Questioned after Containers Lost Overboard
The Danish Maritime Accident Investigation Board has released its report into the incident involving containers lost overboard by Svendborg Maersk on 13 February 2014 in the northern part of the Bay of Biscay. The Danish container ship departed from Rotterdam, bound for the Suez Canal, and subsequently the Far East. The master expected to encounter adverse weather conditions on the route. However, the forecast did not give rise to concern.
The following day, as the ship had left the English Channel, the weather conditions started deteriorating. In the afternoon, the ship suddenly and without warning rolled to extreme angles and a large number of containers fell overboard.
In the early evening, the ship again suddenly rolled violently, reaching an extreme angle of roll of 41° to port. Again a large number of containers were lost over board and, now, the master considered the situation to threaten the safety of the ship. The master sounded the general alarm to muster the crew members. Later in the evening he assessed that the weather no longer posed an immediate danger to the ship.
The weather conditions encountered were more severe than the forecast had predicted.
Svendbord Maersk proceeded towards Malaga, Spain, for repairs of the ship and removal of damaged containers on board. The ship arrived alongside at 1715 on 17 February 2014.
Lashing gear for 600-700 containers was found to have been damaged during the incident. The counting of the containers showed that 517 units had been lost over board. From the cargo documentation it was established that of these, 75 units contained cargo and the additional 442 units were empty. Another 250 units were found to be damaged.
The majority of the containers lost overboard were from positions where the containers were stacked up to tier 98. The high stacking of containers may have contributed to the severity of the consequences. However, the lashings had never been calculated or designed to withstand the roll angles encountered.
Some uncertainty about the properties of the securing of the cargo can be expected, as it is difficult for the crew members to effectively assure the proper securing and settings of all lashing equipment under the constraints imposed by a busy sailing schedule and environmental factors such as rain and darkness.
Calculating the correct dynamic forces acting on the containers would require the container weight encountered in the cargo software to be accurate. All the parameters of the software were satisfied prior to departure from Rotterdam, although the calculated draught and the observed draught differed. It has not been possible to establish whether the discrepancy was the result of discrepancies in container weights on deck. However, discrepancies can affect the actual forces acting on the container stacks, adding to the uncertainty about the properties of the ship and the cargo capability in adverse weather conditions.
A number of factors coincided and caused the incidents and subsequent consequences. In the analysis the DMAIB has addressed topics such as the master’s decision making and the information available to him, as well as optimization processes and the ship’s capability to withstand adverse weather conditions.
The report contains information received from Maersk Line about preventive actions taken.
The Danish Maritime Accident Investigation Board has prepared a marine accident report in English, which is available here.