Megavessels—ships longer than the 1,063-foot-high Eiffel Tower—are in demand again. … Shipping lines are preparing for the completion of the $5.25 billion expansion of the Panama Canal and the recovery of global trade. In the 10 months through October, orders valued at $6.3 billion were placed for ships that can carry a total of 516,600 containers. That’s more than a sixfold jump from a year earlier, says London-based Clarkson, the world’s largest ship broker. Most orders were for big, big ships: Vessels that can each move more than 8,000 containers made up a record 80 percent of the volume, surpassing 2007’s previous peak of 66 percent. That was the year that work on the canal’s expansion began.