Horses for courses
Kalmar 1
Maximum stacking heights depend on the type of operation, says Jari Pirhonen, general manager, terminal development, at Kalmar.
"For operations where high selectivity is required - import loads with random arrival of road trucks, for example - it is lower than for export or transhipment operations," he says. "However, high selectivity is also required for transhipment containers sometimes, due to fast changes in feeder operations.
"Empty containers can be stacked higher than loaded containers as usually containers are grouped based on owner and type, so high selectivity is not required."ASC (automatic stacking crane) systems help in increasing the container stacking density and the efficiency of the system by lower operational costs, he says.
"Naturally, the operational costs are heavily dependent on local conditions and especially the labour and energy costs. Automation naturally makes more commercial sense in high labour cost markets, where labour costs can be clearly more than half of the overall costs. ASC and RTG crane-based operations give similar overall storage capacity - but optimising must be done case-by-case for every terminal."
Marko Hopeaharju, Kalmar's product manager, yard cranes, says the proportion of one-over-three straddle carrier deliveries is increasing compared with one-over-two models, although one-over-two still make the clear majority.
Meanwhile, the majority of ordered reachstackers are for five-high stacking.
"The average stacking height of loaded containers is lower, due to selectivity issues. Empty container handlers are delivered for up to eight-high stacking of empties but in many ports winds limit the stacking height to lower."
RTG sizes are increasing; the majority of Kalmar delivered RTGs are one-over-five, and there is increasing demand for one-over-six. "It is possible to go up to one-over-six high, 9+1 wide in order to get maximum storage capacity," he says.
In cases of terminal expansions when delivering automated systems, Kalmar says customers are looking for a highly efficient yard system for maximising the throughput of the container yard, and a supplier with a strong system integration capability and responsibility for the overall system.
A major project in which Kalmar is involved is the ASC project at CTB Hamburg (HHLA), in which existing yard capacity of 2.6m teu will be doubled to 5.2m teu by 2014.
"This is being done by converting the straddle carrier operated yard to ASC operations with ten-wide, five-high cranes."
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