Decades later, Mr. Lightfoot changed the lyrics slightly after investigations into the accident revealed that waves, not crew error, had led to the shipwreck. In the new lyrics, he sang that it got dark at 7 that November night on Lake Superior — not that a main hatchway caved in.

“That’s the kind of meticulous, looking-for-the-truth kind of guy that he was,” Mr. Greenberg said.

“The Wreck of the Edmund Fitzgerald,” like its creator, endured as a Canadian classic long after slipping off the Top 40 charts. The bluegrass guitarist Tony Rice (who also released an entire album of Lightfoot cover songs) and the rock bands Rheostatics and the Dandy Warhols were among those who sang covers over the years.

“The melodies are so powerful and he’s such a good storyteller and such a beautiful lyricist,” the Canadian singer-songwriter Sarah McLachlan said in the 2020 documentary. “And the combination of those things just really makes for a great song.”

Mr. Lightfoot remained proud of it for decades, and he kept newspaper clippings and items given to him by the crew members’ surviving families in his home, Mr. Greenberg said.

The song’s success had one downside: It turned the wreck, which lies in Canadian territory at a depth of about 500 feet, into a trophy for divers, upsetting the lost sailors’ families. In 2006, the government of Ontario adopted a law protecting the site.