PHILADELPHIA — President Donald Trump and some members of Congress want to revive a depleted American shipbuilding industry to compete with China, the world’s biggest maker of ships by far.

It is such a daunting goal that some shipping experts say it is destined to fail. More hopeful analysts and industry executives say the Trump administration and Congress could succeed but only if they are willing to spend billions of dollars over many years.

One of the places where Washington’s maritime dreams might take shape or fall apart is a shipyard on the southern edge of Philadelphia that was bought last year by one of the world’s largest shipbuilding companies, a South Korean conglomerate known as Hanwha.

“The shipbuilding industry in America is ready to step up,” David Kim, the CEO of Hanwha Philly Shipyard, said in an interview.

But to do that, he said, the yard must have a steady stream of orders for new vessels. And the federal government will need policies that subsidize American-built ships and penalize the use of foreign vessels by shipping companies that call on U.S. ports.

Last month, Trump issued an executive order aimed at revitalizing American shipbuilding. “We’re going to be spending a lot of money on shipbuilding,” he said when announcing the order. “We’re way, way, way behind.”

The Office of the United States Trade Representative set new rules in April that penalize Chinese ships and require that certain commercial vessels be built in the United States. In Congress, lawmakers from both parties are pushing a sprawling bill that contains significant subsidies to bolster American shipbuilding.

But there is much to overcome.

The Philadelphia yard won’t have space for new orders until 2027, and other U.S. shipyards are so tied up with filling orders for the Navy that they don’t have the capacity to produce commercial vessels.

It takes far longer to build ships in the United States than in Asia, and costs nearly five times as much. The Philadelphia yard makes roughly a ship and a half a year, compared with around a ship a week at Hanwha’s larger facilities in its home country, Kim said.

But the company would bring methods, like automated welding, he added, to speed up production at the roughly 115-acre yard in Philadelphia. Kim declined to say how much the company intended to invest in its U.S. shipyard, which it bought for $100 million.Colin Grabow, an associate director at the Cato Institute, a research organization that favors fewer government regulations of business and the economy, said the shipbuilding push gave him an uneasy sense of déjà vu.

Previous government efforts to encourage domestic shipbuilding largely failed, including an effort to produce more commercial vessels in Philadelphia after the closing of the naval base in the city in 1995. “We’ve been down this road before,” Grabow said.

In addition to China, ships that transport goods to or from the United States are built in Japan, South Korea and other friendly countries. These vessels are typically owned and operated by global shipping companies, many of them based in Europe and Asia.

But as Chinese commercial vessel production soared in recent years, lawmakers in Washington became concerned that China was gaining a nearly unassailable strategic advantage.

“It’s just become a stampede,” said Michael Roberts, a senior fellow at the Hudson Institute, a conservative research group that favors government backing for American shipbuilding.

In the past 10 years, Chinese shipbuilders delivered 6,765 commercial ships, nearly half of global deliveries, according to data from BRS Shipbrokers. Japan delivered 3,130, South Korea 2,405 and the United States just 37.

The few American-made vessels that shipping lines do buy usually transport cargo solely between U.S. ports. Under the Jones Act, a more-than-100-year-old law, such voyages can be served only by U.S.-built vessels. An order for three Jones Act-compliant container ships, struck by the previous owner of the Philadelphia yard, cost about $330 million a vessel.

A similar size ship built in Asia would cost about $70 million, said James Lightbourn, founder of Cavalier Shipping, a ship financing advisory firm.

In their shipbuilding bill, Democratic and Republican lawmakers seek to address the cost difference by subsidizing shipping companies to put 250 American-made vessels operated with U.S. crews into a “strategic commercial fleet.” The secretary of defense could call on the vessels for supply missions.

Lawmakers hope that assembling such a fleet and other incentives will not only provide a steady stream of orders for U.S. shipbuilders, but also help them grow and become more efficient.

Sen. Mark Kelly, D-Ariz., a sponsor of the legislation, described it as “the most ambitious effort in a generation to revitalize the U.S. shipbuilding and commercial maritime industries, and counter China’s dominance over the ocean.”

Critics of the bill contend that it would provide endless subsidies to high-cost shipbuilders. A better approach to countering China’s dominance, they say, would be to make up the strategic fleet with vessels made in Japan and South Korea, both U.S. allies and proven shipbuilders.

But Kim, said many products, not just ships, cost more to make in the United States, and he added that outsourcing shipbuilding to other countries had contributed to the withering of American production.

“It’s not just about business,” he said. “It’s about the country, it’s about labor, and it’s about priorities and strategic decisions.”

Washington’s grand designs for shipping include the tankers that carry liquefied natural gas, which are much more complex to manufacture than ships that carry containers. The Trump administration’s new shipping rules require that an increasing portion of these ships be built in the United States within several years.

Hanwha has produced 200 such vessels in South Korea, and Kim said the dry docks at the Philadelphia yard were big enough to accommodate certain LNG carriers.

But even if Hanwha successfully transfers its manufacturing expertise to the United States, it may struggle to find skilled workers. It is planning to double the size of its workforce from 1,500 employees in less than 10 years, said Kelly Whitaker, a spokesperson for Hanwha Philly.

Next year it wants to double the size of its apprentice class to 240 trainees. Niecey Zlomek, who moved to Philadelphia from Baltimore eight years ago, joined Hanwha Philly as an apprentice in January and is earning $22 an hour.

“This is probably the best job I’ve had since I’ve lived here,” she said. Zlomek has worked on three vessels, helping to install a bow thruster, a type of propulsion system, and a conveyance system for large rocks.

Even when shipbuilders do manage to recruit workers, they have often struggled to keep them.