The world’s largest cargo ship is leaving its shipyard this week to prepare for its July 15 maiden voyage, but much of its cargo space will be under-utilized as many ports don’t have the ability unload the 20-story-high container stacks the vessel can lug between Asia and Europe.

The ship, a $185-million, 1,300-foot long behemoth with a capacity of 18,000 containers, is a gamble for the vessel’s owner, Danish group A.P. Møller-Maersk A/S. Freight, which has been so battered by the recent global economic downturn that at one point it had hundreds of cargo ships sitting idle in Singapore. The ship is so big, it's essentially leap-frogged over many ports’ ability to off-load it when it's at full capacity.

“We will operate it as a smaller ship for the first few months while ports upgrade their cranes,” Lars Jensen, head of Maersk Line’s Asia-Europe operations, told Dow Jones Newswires.

The problem is that ports lack gantries -- those giant square-shaped cranes that slide over loaded cargo ships and pick up or drop off loaded containers -- that can accommodate a fully loaded Triple E. So before Maersk can utilize the ship’s full capacity at major ports, many of those ports have to invest in upgrading, a process that could take years.

Dow Jones says 16 ports on the ship’s route are certified to handle it, but “several” lack the adequate crane ability to handle it when it’s fully loaded. So for now, the ship will have to haul less, which eats into the company's potential profit. It will embark on its first journey on July 15 from Busan, South Korea, to Europe, after a stop at Singapore.