In reefer logistics, secure power supply and handling of cables has been a well known challenge for many years on board vessels and ashore at the terminals. Often there have not been enough power outlets, so several reefer containers must be connected to the same outlet. Further, when they are stacked – sometimes up to four containers on top of each other – it requires a long cable to reach down to the nearest power source.
With cable pickers, it is not difficult to reach the cable from the top container in the stack and pick the cable up. The cable is retrieved, and then gravity takes care of the rest. But when the container is handled, the cable has to be rolled up again, and then suddenly there is an exceedingly long way up to the cable tray on the container. As a rule, the cable is rolled up ’best possible’, but this is far from an optimal situation.
”For Maersk, it is always Safety First, and we have identified this work situation as time-consuming, impractical, and a potential safety risk both on board and ashore,” says Morten Rene Baerentz, Reefer Tech and Engineering Manager, Reefer Innovation at Maersk, and he continues: ”We continuously monitor all types of security risks and act purposefully to solve the problem. This is a workflow with several risk factors, but there are also many circumstances in the unloading of reefers that make it a challenge to change the state of things.”
Risky reefer cable business
With highly stacked reefer containers, the crew on the vessel can only roll up the bottom meters of each cable and tie it together. This means that a long, free-swinging cable can hang freely in the air when unloading the container. The terminal crew then has to coil up the rest of the cable, but often this is not done or not done well enough due to time pressure.
”The free-swinging power cable can cause damage to the crew, or it can get stuck, complicate the unloading and lead to dangerous situations,” explains Morten Rene
Baerentz from Maersk. ”If the cable gets stuck, it will eventually be cut off and fall to the ground, but this poses a host of other challenges.”
If it often happens that cables get stuck and are cut off during unloading, new cables must be fitted, which costs time, money, and manpower. In short, this is an unsustainable situation, and therefore Maersk contacted its technical partner Følsgaard in 2018 and asked them to contribute to a technical solution to the
The first ideas, the final solution
Maersk and Følsgaard have previously developed innovative products together for the shipping industry. This includes the CEE 3H/6H reefer plug that can be adapted to both receptacles used on vessels and trucks, a fast splice kit which can ensure high speed and a good splice quality, plus other projects.
With the reefer cable problem, Maersk presented a new challenge. Both parties chipped in, and several options were discussed in the initial phase. Technical Manager Lei Zhang was part of the team at Følsgaard, and he explains that one of the first ideas to solve the cable issue was to look at how a vacuum
cleaner rolls in its cord after use:
”It seemed like an obvious idea to develop a device in the cable tray on each reefer container that would be able to roll the cable in – just like an ordinary vacuum cleaner. But the idea was rejected as the containers on deck are exposed to extremely harsh and changing conditions which soon would endanger reliability.”
It was also tested whether it was possible to coil the cable from the bottom up, but this was made impossible by the transverse lashing bars. In the end, a similar solution was the winner, but it would be necessary to coil the cable with a unit that was able to reach the cable tray of each container.
Prototype and a pandemic delay
In 2019, Følsgaard and Maersk developed the prototype of their cable coiler. It consisted of a telescopic pole that can be extended to a total length of 9.5 meters so that it can reach the cable tray of a reefer in the ’fourth tier’, even if the operator is standing on a lowered catwalk between the bays. At the top, a sensorcontrolled motor was mounted to active two wheels for winding the cable – these two wheels slide apart and disengage the cable when it is completely coiled up in the cable tray.
Technical Manager Lei Zhang explains: ”On July 11, 2019, we were able to test the prototype under realistic conditions, and the test went well. It turned out that it was not an optimal solution to have two motors built into the unit, and there were also angles to adjust, but the most important result of the test was: The concept proved its worth. We left with the certainty that we had found the right solution. And then everything came to a standstill.”
The pandemic hit and everything shut down. Partners, subcontractors, component suppliers... For the initiators, the delay was frustrating, but further work was done behind the scenes, and important decisions were made regarding the construction and the choice of materials.
”We decided that the telescopic pole should be made of carbon fibre, as it will be long and difficult to operate when fully extended and must be used under challenging conditions such as strong winds. For the same reason, the battery is located at the bottom of the pole to ensure stability. The speed was adjusted so that the coiling does not take too long during a hectic port call, and the battery capacity was upped to three hours to make it sufficient for unloading four bays, ”explains Lei Zhang.
The innovative HF Cable Coiler
Getting ready for production
After further tests, optimization of the electronics in the unit and choice of materials, the innovative reefer cable coiler has moved closer to production.
”We wanted a solution that ensures safety in our operation, and the solution has now been made available,” states Morten Rene Baerentz, Reefer Tech and Engineering Manager, Reefer Innovation at Maersk. Følsgaard has made an invaluable contribution to the development work, and therefore it is only natural that they carry the solution further, introduce it on the market and help distribute this considerable advancement for safety in reefer stacks.”
Neither Morten Rene Baerentz from Maersk nor Lei Zhang from Følsgaard will at present put figures on how many units are to be produced or state an exact delivery date for the first devices. Initially, selected key ports will be designated as receivers so that the various vessels in the fleet can be equipped with the cable coiler. Next, an obvious target group will be the workforce in the terminals, who in some terminals today use lifts to reach the upper cable trays on the reefer containers if and when reefer racks are not available e.g. during peak season.
There are obvious benefits to be gained for all parties in the form of time savings, reduced repair costs, fewer damaged loads in the containers and more smooth unloading without interruptions. But both parties behind the invention are first and foremost happy to eliminate a risk factor for the crew at vessels and in ports around the world. A much welcomed step forward for a good working environment