Trace Elements: The Beginners Guide To Maritime Container Tracking

05 Aug 2019 - Matthew Kenney

Trace Elements: The Beginners Guide To Maritime Container Tracking

When a cargo owner sends containerised goods by sea, chances are they will not know where their payload is for some time and delays will be unforeseen because most ocean freight disappears into ‘Davy Jones’ locker’, only to resurface at some vague point in the future - hopefully at the right terminal and, especially in the case of reefer cargo, still in useable condition.

It is a testament to faith that shippers have been content with this regime for so long, but things are now changing.  Soon, very few containers will be carried through this shroud of radio silence, as if transiting the dark side of the moon.  Instead, technology is converging to bring the humble container into the light, where its progress (and delays) can be seen and acted upon by all those concerned with its carriage.  Here, we take a brief look at both sensorless and ‘IOT’ container tracking solutions and ask: Can a container really be tracked from end to end if there is an ocean in between?

I recently bought a keyring from an online retailer of unprecedented scale and with a jungle-esque persuasion (no prizes for guessing which!) and once again, I was impressed by the ability to track my purchase from end to end.  The item cost me less than a skinny latte from a Richmond coffee house (as many things do), but I was able to know at each stage where my keyring was and watched it wend its way to my house, where I was ready to catch it as it fell from the letter box.

Domestically at least, this kind of visibility in the supply chain is easy to achieve.  So easy, evidently, that it comes as standard, even if you only purchase a keyring for a few pounds.  The technology is simple in principle; using a mixture of sensorless ‘checkpointing’, where the item is scanned into and out of known locations, and sensor-equipped location tracking where the item is traced using satellite positioning.  By connecting this data with a communications network, a customer can be kept informed at each stage. In the case of my keyring, I was informed when the item was dispatched, I could see when it passing into and out of two freight forwarding depots and finally I was presented with a map to show the location of the courier’s van as s/he closed with my purchase. 

As we know, carrying sea freight, whilst prima facie appearing to be a simple affair, is riddled with challenges: For containerised cargo to arrive when it is expected, the container must be stuffed and transported in time to be loaded onto the intended ship during a specified port call.  The ship must then depart when anticipated, make passage without deviation from the scheduled route and without incident to vessel or cargo. It must then arrive at the destination port on time and with minimal delay waiting for an available berth; being efficiently offloaded for domestic forwarding as planned, incurring minimal idle time in the process.  

Adding to the uncertainty, sea freight relies on a large, multinational team of customs officials, terminal operators, harbour authorities, maritime service providers, insurance brokers etc. and of course the ship’s crew.  The process is also vulnerable to a myriad of other factors such as the weather, sea state, political and industrial unrest and, in extremis, piracy or negligence.  It is easy to see then, how no two ocean freight deliveries will be the same.

The best remedy for this uncertainty is visibility.  Many of the factors above are out of the BCOs control, so perhaps it is best to be able to see deviations and delays and mitigate for them, rather than hoping to eliminate them altogether.  But the case for container tracking goes beyond being of benefit to the cargo owner alone. In such an interconnected ecosystem, visibility to the supply chain itself can reap major benefits.  Speaking about increasing supply chain visibility at the annual Transport Practitioners Meeting this year, Maersk CEO Søren Skou said “Both we and our customers will get value of our increased visibility.  Customers will get better insight in to their supply chains and Maersk will save costs.” Because these cost savings will be gleaned from efficiency gained through greater visibility, the result will be an overall improvement in the performance of sea freighting for the benefit of all. 

Tracking containers

There are two principal technology options for tracking shipping containers - ‘Internet of Things’ or ‘IOT’ systems, and sensorless, process-based container tracking. The former uses a device affixed to the container itself. Measurements can be made automatically on a number of things like location, temperature and physical dynamics, which is then transmitted to the cloud. By contrast, the latter harnesses human input to update the status and characteristics of the container as it progresses through the supply chain - similar to the checkpointing system.


Although IOT appears to offer a more advanced solution, there are some major drawbacks. The idea of remotely tracking containers in the same way a transport company might track its trucks, is an appealing one. What better way to confirm the location of a container than by viewing a live ‘ping’ on a map? In reality, however, that is not what IOT tracking delivers - at least, not always.

GPS-enabled trackers, whilst having the ability to pinpoint a container to within a few feet, have three major drawbacks in the maritime environment. Firstly, GPS antennae require a clear view of a number of satellites in order to gain a fix. Once the container is stacked in a yard or lowered into a ship’s hold, or obscured by an obstruction, this signal is lost and the container effectively falls, once more, in to radio silence.

Secondly, communicating with satellites consumes enough power to make battery life problematic. This is being tackled by tracker manufacturers who are fitting their devices with solar panels, programming-in passive modes and harnessing improvements in battery technology. But none of these fixes offers an entirely satisfying solution - you either have to keep your container bathed in sunlight, accept planned breaks in communication or pay more for the hardware.

Lastly, the cost. Not only because the cost of streaming data via satellite networks is still relatively high, but the capital expenditure required to deploy sensors to thousands of containers is a major consideration; and that is after it is decided who should pay - the shipper, the carrier, or logistics company? Satellite service providers have been talking of reduced data exchange rates in response to the change that IOT is hailing, but according to some, data rates for tracked containers can still be as high as $10 USD per container / per month.

Sensorless Container Tracking

Without the ad-hoc nature of GPS tracking, sensorless tracking represents an efficient, reliable and cost-effective method of tracing cargo through the supply chain.

Simply by recording the arrival and departure of cargo at certain key points and transmitting this data to the cloud, it is possible to harness many of the same benefits that sensor-enabled tracking provides, i.e - knowing the physical location of the cargo and even what condition its in.

One major benefit to sensorless tracking is the human interface. Although there are algorithms and computing power behind much of a sensorless system, the human is integrated and able to check the logic at each stage. Seafarers have never been more highly trained and as competent as they are today and digitalisation does not need to shun or supercede this talent just yet. Smart digital technology can work with seafarers, not only for the benefit of the cargo owners that drive the shipping industry, but for the benefit of the industry itself.

Resolution is no barrier to sensorless tracking either. GPS can resolve to only a few meters, anywhere on the globe. But, if a cell location is known, then a unit of cargo can be assigned to it - no need for GPS to grapple for a fix.

The downside to sensorless tracking is that it requires some method of unification with other supply chain partners to get the best from it. Standardisation is key here and the work of the Digital Container Shipping Association (DCSA), talked about in my last article, will be instrumental in propelling forward all types of container tracking in this regard.


Tracking containers is here and will continue to be the future for the container shipping industry. The benefits of visibility to both the customer and the supply chain at large are now well understood and carriers are already investing in the technology to bring these benefits to the fore.

The two principal types of tracking technology, while each having their individualities, essentially deliver the same outcomes. Sensor-equipped tracking has the benefit of being a self-contained end-to-end solution, but has drawbacks in terms of cost and technological limitations - especially when it comes to satellite positioning and global connectivity.

Sensorless tracking voids these concerns, but does require effective integration across the supply chain. As standards in message formats and technology standards emerge, sensorless tracking will become a robust end-to-end solution.

Of course, there is no reason whatsoever, that sensor-equipped and sensorless tracking cannot work together. Indeed, each would complement the other well. The capital expenditure of each could also be more evenly spread throughout the supply chain; with sensors being implemented by cargo owners or logistics companies, and sensorless infrastructure falling to the carrier and terminal operators.

There is no doubt that the majority of boxes shipped globally, will benefit from enhanced tracking and visibility within the next decade - many already are. For that reason, it is vital that both types of solution are developed cohesively and standards are agreed upon which will allow for a fully integrated, comprehensive and democratised end-to-end solution.

©Intelligent Cargo Systems 2019