24/7 emergency response: Predicting the drift of lost shipping containers from YM Efficiency

On 1st June 2018, 81 containers were lost overboard from container ship YM Efficiency, 30 km east southeast of Newcastle, Australia, when it rolled heavily during strong gale force winds and very rough seas. Shipping containers can create a dangerous maritime hazard in coastal waters, and can also be a major pollution risk.

To support the emergency response operations, Australian Maritime Safety Authority (AMSA) activated RPS through its 24/7 emergency response service contract requesting drift modelling to help locate and recover the containers where possible, and determine the search areas for the underwater side-scan and Remote Operated Underwater Vehicle (ROUV) surveys.

RPS’ predictions were delivered within 2 hours of the initial request, as per the callout procedures. The results assisted AMSA to locate many of the containers, and were also consistent with debris that ultimately washed up along the nearby shorelines.

Timely response is critical

As a timely response is vital during an incident, when AMSA undertook coordination of the underwater search for the missing containers, the most important question was raised: where are the containers and where do we start looking? The potential safety and environmental risks are high and acting early is critical.

This is where RPS’ expertise in rapidly predicting the drift of objects in the chaotic ocean comes to the fore. Ocean currents, wind, tide and water depth are all factors, along with object drift characteristics and degree of submergence. RPS maintains models, data and personnel at all times ready to respond to these incidents quickly and reliably.

The drift modelling was carried out using our leading search and rescue/recovery drift model SARMAP for the 40 ft containers. The modelling was based on containers both fully and partially submerged, since winds and currents affect the drift characteristics in different ways. The tides, winds and currents were drawn from high resolution forecast predictions considered accurate for the location.

Running a variety of cases, reflecting the diversity of the local conditions and the disposition of the containers, allowed RPS to provide clear advice on initial drift character and search areas, and to evolve this over the following week. As with all modelling of this type, results are only half the task. RPS to be able validate and evolve the work as containers were located.

Accurate predictions

Our predictions indicated that the containers would likely drift north to north-northeast along the coast towards Nelson Bay, consistent with real time data obtained from a surface buoy deployed during the incident. Sightings of 4 containers the day after the incident confirmed this drift, with the locations consistent with predictions made assuming fully submerged containers.

During the following months our SARMAP drift predictions, guided bathymetric and sonar surveys which successfully located and confirmed many submerged container and debris locations. Debris from other containers found washed ashore also agreed with initial predictions, further reinforcing the reliability and accuracy of our drift predictions.

Preventing container loss, AMSA

According to AMSA, around 1,500 shipping containers are lost at sea around the world every year. They can be lost for a number of reasons, but what's important is implementing strategies to prevent, or at least minimise, this potential. And when accidents do occur, act fast to minimise environmental pollution and safety risk. 

For more information in the AMSA strategies to prevent container loss please follow these links, here.