Twistlocks are a necessary evil and a design overhaul is long overdue, as Stevie Knight explains
Twistlocks are, quite literally, the cornerstones of the container industry but to say they are ‘problematic’ is understating it; a tendency to jam from being bounced around under hundreds of tonnes of weight is compounded by the way they get treated. There’s a salutary video of one crane driver swinging his spreader wildly to get a failed twistlock mechanism to release, which is worth looking up if you are in any doubt that there is ‘terminal craziness’ out there.
Larry Nye of Moffatt & Nichol sums it up nicely when he says: “Although you can think about the terminal of the future and all the advances made by sophisticated machinery, pretty soon you’ve got to answer the question, what are we going to do about the damn twistlocks?”
Peter Walker of StaffaIPI points out there are issues with both automatic and semi-automatic varieties: “The semi-automatic kind rely on stevedores working between the stacks or at height to unlock them while the automatic variety only solves a small part of the problem.” Neither do automatic twistlocks address the issues faced by rail and road transport, he adds, which are stuck with the manual version since neither can handle the forces required to spring the automatic action. Other sources highlight a different concern: unlocking could occasionally be triggered by a ship’s rolling motion.
Mr Nye says that there have been many attempts to get the better of the existing systems with little luck. “People look at it and say ‘sure we can do something with this’ but the environment in which they must work and the forces the twistlocks have to stand up to make it almost impossible to automate.”
Mr Nye has seen innovations that attempted to help: “Radio controlled twistlocks have been proposed and tested, but the environment is just too harsh for sophisticated equipment.” He adds that the issue of consistency makes this kind of technology awkward “and not one exception or the crane will try to pick up a box locked to the one below and then there will be trouble”.
However, Mr Walker says “the real problem comes placing and removing these cones at every step of the supply chain. They say if the crane isn’t moving you are losing money, but stopping for twistlock fitting or removal can add between 15% and 20% to a cranes cycle period.” Further, the handling typically takes place in areas of dense traffic or close to moving containers such as the apron of a container terminal.
Injury prone
Injuries arise in all sorts of ways: stevedores fall from stacks, limbs are crushed and twistlocks can suddenly drop on an unlucky worker from a height. Lars Meurling of Bromma says: “We do hear about fatalities, but I am fairly certain that there are many more than we actually find out about.
“Getting people out from underneath a dangling container where they can’t even be seen by the crane driver would alone justify a change.”
With all this in mind Bromma and RAM have both come up with a platform which automatically fits and/or removes the twistlocks: Bromma’s stores the twistlock in an automatic magazine for reuse while the RAM platform relies on manual reloading.
But these machines are expensive, so operators are looking for cost and time savings as well as safety from the investment.
Mr Meurling admits that how much is shaved off a crane’s cycle time depends on the yard configuration. “A straddle carrier operation will probably be the most effective,” he explains; the crane doesn’t have to wait for the deconing process to finish as the strad can simply take the box away, allowing a decoupled operation. “It’s only theoretical, but a typical calculation for a high productivity berth is around 30 moves per hour, so if you can cut 15 seconds from every cycle you could process 7.5 more containers per hour.”
Labour cost is the final argument, says Mr Meurling: “In Europe typically there are two pin men to a crane, but with this system this could drop to one man to every four or six cranes. That’s the ball park figure we are looking at.” So he reckons that payback time, counted on an average European or US terminal, comes down to two and a half years “and if you add in the extra productivity then it could be as little as a year”, he claims.
Solid performance
But all this has to rest squarely on solid consistency: reliability issues mixed with the sheer variety of twistlock and box combinations has the potential of slowing everything down and putting the emphasis back on the dock workers.
As Mr Nye explains, interventions are often still needed either during the setting-up process which can mean physically preloading the machine with the right twistlocks, or because one gets jammed – not an uncommon issue. “Exception management means a delay and someone with a hammer to hit the cones,” he says: “Overall it seems you could end up by using a number of stevedores to manage the cone bins, the machine and tackle the jams.”
Despite this, Mr Meurling says that recently development has come on apace and reliability has improved enormously. “Now we can say that if a terminal ordered a twistlock handling machine today, we will deliver a machine that will do the job.”
However Mr Meurling admits “realistically you may still have to take some containers away to an exception handling area and occasionally be prepared to go back to manual operation”.
Simplicity itself
The Universal Container Locking System (UCLS) is really a very simple idea: the twistlocks are mechanically linked so as a hoisting spreader locks to the container, the UCLS at the bottom rotates to the unlocked position, when the spreader releases, the UCLS returns to its locked position. Further they can still be mixed with other conventional twistlocks and lashings in the maritime sector. For rail and road there’s straightforward, economical, one time upgrades which allow conventional and UCLS containers to be transported together.
The gains could be large; for a terminal of 1m teu with six quay cranes, Mr Walker estimates an annual saving of approximately 50,000 to 55,000 man hours; this is quite apart from time saved by no longer pausing a lift midway for twistlock handling and the safety benefits.
However, finding the right lever for the market is as important as the one on the container. Although converting a container to a UCLS is approximately an hour’s work, even a single ship’s worth equals a substantial investment - although new container manufacture would be a fraction of this.
The question is who does the work, who pays for it and who benefits? Mr Walker admits that one stumbling block is that lines tend to see the gains from the UCLS as being all on the terminal operators’ side but the operators, even if they pay out for the change, won’t necessarily see the converted boxes come back again without some kind of buy-in from the lines.
Despite the buck being passed around, Mr Walker thinks an open, constructive dialogue across the logistics sector would help as automating the twistlock handling process with something as simple as the ULCS could create significant financial benefits for road and rail too. As he points out, everyone has so much to gain.
A twistlock handling station can offer gains beyond the elimination of the human factor, as long as the positioning in the port is right.
At present these platforms are repositioned with every crane move but they could be shifted on to the crane leg to great benefit.
This would reduce crane travel distance and could be combined with a backreach trolley to lift off the box. However this will add to the overall weight of the crane and put pressure on the gantry rail with considerations needed for stress and crane capacity.
Other issues surrounding twistlock platforms are on the way to being resolved. “While the machine can deal with 95% of the twistlocks around today, there are still the other 5% that we are working on tools for, but actually in getting a machine in place we’d talk to everyone and find out what kind of twistlocks were handled and adapt to those conditions,” says Lars Meurling of Bromma.
perhaps the only answer is to employ humans , Good old stevedores, Job for life and protect the environment by preventing containers falling of vessels and polluting the oceans
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