The largest ship ever to call at an American port will sail under the Golden Gate Bridge on Thursday headed for Oakland — and its arrival not only breaks shipping records, but also is a major test for the region’s maritime industry.

The ship is the CMA CGM Benjamin Franklin, which is nearly a quarter of a mile long and as tall as a 20-story building. This megaship can carry 18,000 20-foot-long shipping containers, about a third more than other large container ships.

It is due under the Golden Gate Bridge about 9 a.m. and will dock at the Oakland Outer Harbor about 10:30. The Benjamin Franklin is not only huge, but it also is brand new — this is the vessel’s maiden voyage, having set sail from China after being put into service earlier this month.

It is coming to San Francisco Bay from Los Angeles, where it arrived with great fanfare on the day after Christmas.

The voyage to America is a “test call, to see if ports in the United States are able to handle ships of this size,” said Blair Hennessy, who represents CMA CGM in the United States.

Megaships require special handling, including two ship pilots who have been specially trained to maneuver a ship 1,310 feet long and displacing 178,228 gross tons. The ship is larger than an aircraft carrier and three times the size of the biggest World War II battleship.

With some of the electronic antennas lowered, the ship will fit under the Golden Gate with about 20 feet to spare. The Bay Bridge is a little tighter, but not a problem.

The pilots have been training to navigate and dock megaships for several weeks on a simulator at the California Maritime Academy in Vallejo, said Capt. Peter McIsaac, president of the San Francisco Bar Pilots.

Big ships like this make economic sense because they can handle lots of cargo, are efficient to run and need only small crews — the Benjamin Franklin carries a crew of 28 mariners.

Special handling

However, they also need deeper channels, bigger cranes and better shoreside facilities to handle the larger volume of cargo. Not all ports are equipped to deal with these large vessels. Until now, most of these ships have sailed between Asia and northern Europe.

“Major shipping lines are gravitating to megaships,’’ said Mike Zampa, spokesman for the Port of Oakland. “Oakland is ready to handle these large ships, and we will get a chance to prove it.”

The ship loaded and unloaded about 11,000 shipping containers over its four-day call at Los Angeles, and will handle about 2,550 containers in Oakland. It will be in port during the New Year’s holiday and probably will sail for China on Sunday.

The CMA CGM Benjamin Franklin is not only a record breaker, but also a symbol of the globalization of maritime trade. Much of the electronic equipment and other goods produced in China and other Asian countries travels to the U.S. by sea on container ships. By some estimates, the maritime industry carries up to 90 percent of the world’s trade.

French ownership

Although the Benjamin Franklin carries an American name, its ownership is French and the ship flies the British flag. CMA CGM — the name stands for Compagnie Maritime d’Affretement and Compagnie Generale Maritime — is already the world’s third-largest container ship company, and it will soon become larger.

It is acquiring Singapore-based Neptune Orient Lines, which sails under the APL brand, once an old-line San Francisco company.

The old record for largest ship to enter San Francisco Bay was set by the MSC Fabiola, which could carry 12,500 containers and arrived in Oakland in March 2012. Before that, the mark was held by the 151,000-ton passenger liner Queen Mary 2, which docked in San Francisco on Super Bowl Sunday in 2007.

Carl Nolte is a San Francisco Chronicle staff writer. E-mail: cnolte@sfchronicle.com