Drewry has suggested larger ships do not strictly result in faster loading times.

From its own research, it states the current trend towards larger vessels does not automatically offer similar improvements in handling times at ports.

According to the consultants: "For shipping lines, what matters is turnaround time from vessel arrival to vessel departure - and essentially this means berth moves per hour across the ship."

It further argues that cranes are also important, as the number of gantry cranes available across the ship will help with loading and unloading. As a result, longer ships are preferred over height and width.

For example, it states that the average 15,000 twenty-foot, equivalent unit (teu) ship is 400 m in length. The typical 18,000 teu ship is also 400 m long. At the same length, the cargo is more packed and, as a result, the 18,000 teu transport would only have access to the same number of cranes as a 15,000 teu ship.

It also referenced the maiden voyage of Maersk Mc-Kinney Moller - the 18,000 teu vessel that offers record container productivity, despite its size.

Drewry predicts when ships get to the range of 22,000 to 24,000 teu, the overall length will become "a key factor in port performance".