A longstanding American ally, South Korea is also the world’s second-largest shipbuilder after China. This prowess, officials from Seoul will argue, can help Mr. Trump with his goal of reviving America’s maritime industry. In exchange, they hope to mitigate the punishing 25 percent tariff Mr. Trump plans to impose on South Korean exports like Hyundai and Kia cars, steel and aluminum, and LG dishwashers.

Both sides have said that Mr. Trump wants shipbuilding to be part of a new trade deal between the two countries. A new agreement ​is also likely to include large purchases of American liquefied natural gas by South Korea to help lower its trade surplus with the United States.

But “since President Trump and his administration have expressed big interest in cooperation in shipbuilding, it will become a very important negotiating card for us,” South Korea’s trade and industry minister, Ahn Duk-geun, told Parliament last week.