He kept his sub underwater during the daylight hours that followed. At nightfall, aided by tourist guidebooks to New York he had brought along, he surfaced and followed the southern shore of Long Island and Queens, glimpsing the lights of homes and cars in the Rockaways and the illuminated Ferris wheel at Coney Island.

After getting to the outer reaches of New York Harbor, he returned to deeper waters off Long Island, where he sank the British oil tanker Coimbra about 100 miles from New York.

The sinkings of the Norness and the Coimbra, a day apart, made for front-page headlines. Captain Hardegen then headed to Cape Hatteras, N.C., where his submarine sank three more ships before he returned to his base at Lorient, France.

On his second war patrol to America, between March and May 1942, his toll including the American oil tanker Gulfamerica off Jacksonville, Fla. But his boat was nearly sunk off St. Augustine, Fla., by a destroyer’s depth charges before he managed to get away.

After leaving the submarine service in May 1942, he held a naval training position and worked on the development of advanced submarine torpedoes. In the winter of 1945, with German forces reeling, he was transferred to land warfare and became a battalion commander.

Soon after Germany surrendered, he was arrested by the British, who mistook him for a someone with the same last name who had been a member of the Nazi SS forces. He was held for 16 months before he convinced them that he was a career Navy officer.

“I was not a Nazi,” he told The Atlanta Journal-Constitution in a 1999 interview. “I did my duty for my country, not for Hitler.”