Investigations into a series of incidents of collapsed containers and containers lost overboard have led to calls for every container to be weighed at the port before loading – and also highlighted lashing issues.

The correct stacking and lashing of boxes to avoid such incidents at sea obviously places heavy responsibilities on ports but there are also critical safety implications for the ports’ employees, too.

At the recent “Learning from Annabella” conference, held to address issues affecting the safe operation of shortsea containerships, port operators were particularly vocal, says David Cheslin, managing director of Dunelm PR, which staged the conference.

“One was quite critical of containership design, particularly feeder vessels, which are very compact – and that is being polite,” he says. “It is a case of trying to cram as many containers on the ships as possible, while keeping the ships as small as possible. When you are lashing vessels, some of the spaces between stacks are very tight and do not really leave enough working space to do the lashing properly.”

But of more concern was the diversity, weight and stacking capacities of the actual containers, he says. Many tank containers are not designed to stack high. The stacking weight that other containers can withstand varies tremendously.

“Ports feel this is a major issue. It has become extremely difficult for ports to know just how high they can stack these things. They are not necessarily clearly labelled – just a tiny tag to see the stacking weight,” says Mr Cheslin.

The possibility of weighing all containers was the really big issue to come out of the conference. “People told a lot of horror stories about overweight containers – for example, timber left outside to get wet and put into a container, and the shipper would still automatically regard that as being the standard weight for the quantity when dry. But the difference could increase the weight from 18 to 25 tonnes.”

Ports also highlighted the increasing number of mis-declared empties. “Containers are coming back to the port declared as empties but when the ports get to lift them, they are anything but empty,” says Mr Cheslin. “The record was 16 tonnes – a box full of plastic waste, but declared as empty. The implications from a safety point of view if the port tried to lift this with an empty container forklift truck are clear.”

What isn’t clear is whether shippers are using “empty” containers as an excuse to dump old packaging, for example, thinking no-one will notice, or if shipping lines are mis-declaring, he adds.

A lot of containers now in circulation are not ISO and handlers have to look closely at the plate – often corroded and barely legible after sustained use – to establish a container’s stack weight capability. In the case of the Annabella, a container only capable of supporting a 100 tonnes stack load was at the bottom of a 200 tonnes stack.

“But the big recommendation was that all containers should be weighed before being loaded on board a vessel,” says Mr Cheslin. “It is possible that within the next six to 12 months there will be moves to make container weighing possible – voluntarily in the beginning, with a view to becoming mandatory eventually.

The technology has been available as an option on container handling equipment for some years; if a discrepancy of more than, say 5%, was identified in the weight, this revised weight would be automatically feed an alert into the system for planning the loading of the ship. The first priority of such a message would be the safety implications, but clearly further action could be taken. Mr Cheslin believes that faced with this reality, “shipping lines would clean up their act”.