/ SEARCH
/ DEUTSCH/ ENGLISH

Two-box-taxis

Tollerort has managed to shift considerably more containers with the same number of straddle-carriers since these have been capable of shifting two 20-ft boxes simultaneously. This boost to efficiency is proving very welcome to customers.

 

“Twin” pioneer Thomas Ritscher drives straddle-carrier No. 93 under container gantry crane 9, where two 20-ft containers just unloaded from the “Cosco Hope” stand ready end-to-end. Ritscher positions his vehicle – with a height of 14 metres – over the two boxes. He lowers the spreader precisely to meet the eight locking points, lifts the cargo and confirms by tapping the monitor that he is moving two containers on one run. Two minutes and eleven seconds later, he lowers the pair in Block Y7. This marked the first successful transport of two boxes on just one run at HHLA’s Container Terminal Tollerort (CTT).

Saving of 574 straddle-carrier runs

The straddle-carrier drivers use the touch screen to select twin-operation functions

Whereas it is quite normal at many terminals for container gantry cranes to function in what is known as twin operation, i.e., to discharge or load two 20-ft containers simultaneously, straddle-carriers as a rule transport boxes individually. That these vehicles should also work in twin operation is something that so far only happens at a handful of terminals worldwide. Along with various software adjustments and vehicles sufficiently large for twin operation, this considerably more efficient process requires especially careful planning of both slot allocation in the yard and order distribution for the separate container transport runs, as well as even more precise work from the straddle-carrier drivers.

 

“At CTT the container gantry cranes and straddle-carriers are equipped with twin-spreaders, and the planning/control software is theoretically capable of handling twin operation. Yet considerable preparatory steps are needed to put this into practice.   We launched the twin project in summer 2011 to lift the potential,” explains project manager Thomas John. The effort has paid off. After almost a year’s preparation, twin operation at CTT immediately ran very well. “The team really put their backs into achieving results that could be applied rapidly,” sums up Ulf Zielsdorf, Commercial Manager and Head of Projects.

 

One month before the launch of twin operation, with the handling of the “Cosco Taicang”, CTT’s team already performed outstandingly: 68 percent of the 20-ft boxes for loading were brought to the 10,000-TEU vessel in pairs by straddle-carriers, and no less than 87 percent of those 20-ft containers were moved from the edge of the quay into the yard in pairs. This extremely high “twin” proportion represented a saving of 574 straddle-carrier runs on handling just the one ship, and a considerable rise in crane productivity.

 

“We had originally planned a run-up time of six weeks and a learning phase of a few months,” recollects Rene Eisenberg of CTT’s Project Department. Yet it was then decided at short notice that all the straddle-carriers working on the ULCS should operate with the twin software introduced. And it worked. “Thanks to our excellent experience on Whit Monday we had a run-up time of three days and a learning phase of three weeks,” reports John.

 

Doubly efficient - That goes down well

Doubly efficient: the driver deposits two 20-ft boxes in the yard simultaneously

Twin discharge functioned perfectly more or less right from the start. Since the spreaders on the container gantry cranes are adjustable to the same measurements as those used on the straddle carriers, the pair of 20-ft containers can be lowered under the crane so that the straddle-carrier can easily lift them, with the two boxes standing end-to-end and with the correct gap between them. That makes it easy for experienced straddle-carrier drivers like Ritscher to pick them up together. The control center then needs to ensure that he has no problems depositing the two boxes in the yard.

 

“When we see that a ship with a large quantity of 20-ft containers is coming, then we are obliged to clear out the container yard particularly thoroughly. We then arrange the import rows, for example, so that the 20-ft pairs can be deposited. Of course these can only be placed on top of other 20-ft containers,” explains Jan Ladendorf from the terminal control centre. Just as the ship’s planners ensure by prudent stowage planning that as many twin moves as possible are feasible, Ladendorf and his team at Yard Planning need to create the conditions required for twin operation and to react rapidly, should the straddle-carrier drivers hit problems. “If I am to be bringing two containers to the ship, which are standing slightly at an angle in the yard or a few centimetres too far apart, then I cannot shift them as a pair,” explains Ritscher. He then notifies staff at the terminal control centre by radio-telephone so that they can immediately adapt the work sequence laid down by the ship’s planners to enable another straddle-carrier to bring the container abandoned by Ritscher to the ship.

 

Yet the Twin returns show that such problems are occurring increasingly rarely, and most 20-ft containers that can theoretically be shifted in a pair are actually being moved that way. Only a few container pairings are being abandoned, e.g. when reefers or boxes containing hazardous goods are involved, or two boxes differ too much in weight. “Around 80 percent of possible ‘twin containers’ are being discharged that way, and at least half of all those loaded,” says Eisenberg. Ritscher, who also works as a container gantry crane operator, explains that when loading containers on to a vessel, he really has to step on the gas if three straddle-carrier drivers under the crane are presenting him with pairs of boxes. “Our shipowner customers have also noticed that since the beginning of June, individual crane output has shot up,” reports Zielsdorf. “That naturally goes down well.”