Containerships of 20,000-TEU plus are coming, the Container Supply Chain conference at this week's TOC Europe in Rotterdam was told.

Speaking at the Container Supply Chain conference, Ocean Shipping Consultants project director Andrew Penfold said designs for such ships had become quite advanced.

"We have been working closely with Lloyd's Register and can confirm that there is no technical reason why ships cannot go above 20,000 TEU - and we have had very serious discussions about vessels of 22,000 TEU," said Mr Penfold.

"After that, there may be a pause in ordering greater vessel sizes, although I would imagine it will resume," he said.

Maersk Line north Europe procurement chief Hans Augusteijn said the dimensions of the recent Maersk order were due to the carrier's assessment of where demand and supply on Asia-Europe trades was heading.

"The reason Maersk is ordering vessels of 19,630 TEU is to keep up with market growth," he said. "But we didn't want to go beyond that because we wanted to grow in line with how we expect the trade to grow."

Berth productivity was another factor, he said. Although average berth productivity had increased in terms of crane moves per hour, this had not kept up with rising ship size.

Mr Penfold said an increase in vessel sizes inevitably led to more containers being exchanged in a single vessel call, and that larger vessels would place even further pressure on terminals.

The conference then moved on to how carriers treated shippers. Stanley Black & Decker transport chief Filip Degroote unveiled a wish list to help his company's supply chain.

"We always seems to discuss port-to-port transits, but never door-to-door," he said. "Too much time is lost at origin and destination," he said.

"Carriers need to create value at origin and destination in the supply chain, particularly with support logistics at origin, such as consolidation," he said.

Ports, too, could find ways to speed the handling of mega ships at berth and smooth inland logistics, he said.