What is the fuel usage per trip? This ships are huge and so are the engines. They are also pretty much Pacific Ocean going as they will not fit into any of the world's canals. The Pacific is huge. What is the cost in fuel one way to make the trip from China to the U.S. West Coast. At what point will the transport cost overwhelm the labor saving?

Here is one engine specification

Even at its most efficient power setting, the big 14 consumes 1,660 gallons of heavy fuel oil per hour.

A Panamax II (open 2014) can take container ships 2 m narrower than Emma Maersk, but 10 m longer (exact dimensions from memory). Draft depends upon the density of the containers. Worst case, unload 500 containers, rail them across Panama and reload on other side (little oil required).

The Emma Maersk class can pass through the Suez Canal today, even before increasing the draft (as planned for oil supertankers).

Alan