A 24-foot-long American flag believed to have been flown on shipboard during the Battle of Mobile Bay in Alabama by the USS Brooklyn is now on display at the former Grand Army of the Republic headquarters in the small town of Adams, Mass., in the northwestern part of the state. The headquarters, located on the second floor of the town library, has been maintained as it looked when the last of the members died in 1924.

The exhibit commemorates the 150th anniversary of the Aug. 5, 1864, naval battle when the Union fleet under Adm. David Farragut attacked the fortified entrance to Mobile Bay. One ship hit an underwater mine, also known as a torpedo, and blew up. When the nearby Brooklyn backed away from the area, Farragut demanded to know why. The Brooklyn signaled, “Torpedoes ahead.”

That led to Farragut’s famous order: “Damn the torpedoes! Full Steam ahead!” The fleet safely entered the bay and Union forces quickly knocked out two Confederate ships but fought a long, hard battle before disabling the CSS Tennessee.

The flag on display was given to the GAR by a resident of Adams, John Welch, who was aboard the Brooklyn at the Mobile Bay battle. Records indicate he asked for and received a flag from the Brooklyn when he retired from the service. He later presented it to the GAR. Since then, it has been assumed that it was a battle flag but the records aren’t clear on that point.

The exhibit closes Aug. 10.