It is not just the shipping lines, searching for the best deal in a kind of port arbitrage, that are putting pressure on New York to become more efficient. In the past half-dozen years, four of the region’s six container terminals, which used to be privately held businesses, have been bought by pension funds and investment firms, including financial giants like A.I.G. and Deutsche Bank. Looking for returns in the short term, they have focused much of their attention on labor costs.

The union, Mr. Curto said, perceives a threat in these developments, and “its natural reaction is to hunker down and protect what it has.”

While longshoremen at other ports have traditionally worked in shifts, those in New York have always been organized into clannish gangs that work around the clock until a job is done. Imagine a ship that takes a full day to unload. At ports in Los Angeles or Seattle, the work is divided into segments, and the gangs are rotated in and out. In New York, however, the gang that starts the job works continuously until it is finished. This requires extra workers in relief in each gang, all of whom receive full pay, even when they are resting.

“The way we work,” Mr. Curto said, “we’re paying people for 24 hours each, even if they’re only really working seven or eight.”

This spring, the Waterfront Commission of New York Harbor, a state agency meant to combat corruption, published a report saying that up to 40 percent of all workers at the port were there to accommodate breaks and relief. The report also described a core of union supervisors who were paid, in an idiosyncrasy unique to the waterfront, for every hour that workers under their care were on the clock, even if they themselves were at home barbecuing or mowing their grass.

There was, for instance, Paul Buglioli, a union timekeeper responsible for overseeing work hours, who earned $474,947 last year because of this contractual quirk — and despite his testimony to the commission that he didn’t “physically check to see that someone who is signed in is actually present on the pier.” There was also Ralph Gigante, a union shop steward, who earned $406,659 in 2011 because he was allowed to bill for hours that other people worked. Even though Mr. Gigante — a nephew of Vincent Gigante, the former boss of the Genovese crime family — was a union representative, he admitted under oath that he didn’t know that the letters C.B.A. stood for collective bargaining agreement.

Mr. Curto recalled that when he began working at the port in 1970, as a junior terminal manager, straddle carriers hauling containers to the storage yard would pass beneath a tower and a man would shout down directions, telling the driver where to place the box. Now, it is done electronically. Technology has changed, he said, and so must “certain work practices that make the port noncompetitive.”