MSC Zoe project

 

Deep performed a complete survey scope and salvage support during the recovery operation of the MSC ZOE

 

On the second of January 2019 container vessel MSC Zoe lost containers in severe weather conditions. The vessel continued her voyage to Bremerhaven. The containers were lost in the Dutch and German territorial waters, north of the Wadden Islands.

Ardent Maritime Netherlands BV was contracted for the recovery works of the containers and debris and subcontracted Deep BV for the survey content of the recovery scope.

Deep BV was responsible for the coordinating, combining and interpreting of the survey data. Results from the survey were then passed on to the recovery vessels.

 

In the week after the incident happened, Deep set up a survey center in the office of Ardent in Ijmuiden, from where all operations could be coordinated. At a very early stage in the search operation, the first survey results indicated numerous objects present on the seabed. At this stage the contacts could not (unquestionably) be related to the MSC Zoe, as no visual images were available yet. The size and shape of the contacts indicated that many of the lost containers load had disintegrated and their content had been scattered over the seafloor. Multibeam echosounder and side scan sonar data displayed the presence of objects (and scour) that had sunken onto the seabed at a depth of about 25 meters very clearly.

 

Initial response

At that time the scope of the project was not yet determined and together with Ardent we had to make a fast assessment defining clients and authorities priorities:

 

  • Establish safe navigation for all vessel traffic, with main focus on the traffic lane itself.  By surveying this route, Deep quickly could establish the minimum depth requirements for vessel traffic not to be obstructed.
  • Clearing vulnerable areas/structures
  • Gaining information about the status of the lost containers (Integrity). It soon became clear that the containers did not contain their cargo and that this was scattered across the seabed. This was important input for Ardent to determine the removal methods
  • Determining size of incident area.

 

The survey area covered over 3000km2 covering both Dutch and German waters and there were several critical aspects that determined the operational approach. The fact that the area contains a busy traffic lane, several windfarms and offshore structures like Gas/Oil platforms, existing wracks and a depth ranging from -4  to -25 meter LAT made it a dynamic working environment.

 

Survey techniques

In order to conduct the search and recovery operations Side scan sonar was used for object detection and vessels were equipped with a towed sensor. Multibeam Echo Sounder provided an accurate bathymetric chart of the site extension and positional accuracy of targets. As many vessels were acquiring data simultaneously, which were processed by one processing team, it was very important that all parties involved used the same equipment settings and parameters.

 

All the acquired data of the surveys were interpreted in a shore-based site office and detected contacts were verified against a national database of known seabed objects, wrecks, pipelines and subsea cables, which was made available by the authorities for this operation. After correlation, a total amount of 5984 possible incident related objects (pIRO’s) were listed as field-investigation targets.

As if not challenging enough the incident had occurred in one of the most heavily fought-over parts of the North Sea, which is believed (based on historical research) to contain numerous remaining unexploded ordnance’s dating back to World War 2. So, for safety of personnel and equipment, precaution measures were taken, such as approaching every target as a pUXO by means of visual inspection by ROV.

Initially 6 survey vessels were engaged to ensure most sensitive areas were mapped, safeguarding seagoing traffic. Soon the operation evolved to a much larger scale and at the peak of it 14 survey vessels were managed simultaneously, 60 FTE were engaged offshore and 5984 targets were investigated (whereof 1836 were assessed to be MSC ZOE related). The above mentioned, in combination of the close cooperation and engagement with our clients, the authorities and our several subcontractors made it a successful and memorable project.

 

After 144 days, on the 26th of May 2019 the area was declared cleared of IRO’s by the Client, completing the search and recovery operation.