It's hard to surprise Atlanta drivers, who are used to seeing tires, ladders, auto parts and construction materials on and along metro interstates.

Motorists on I-20 in Fulton County, however, saw something Thursday morning they've likely never encountered: a submarine sitting by the side of the road.

Actually, it was a replica of a submarine, the Civil War-era H.L. Hunley, which was used by the Confederates to harass Union blockade ships -- sinking one of them -- in Charleston Harbor.

True to the original Hunley, which was rife with mechanical problems -- it sank a total of three times -- the replica's trailer broke down Thursday morning as it was being hauled to Shiloh, Tenn., where it is to be featured in the Battle of Shiloh Weekend.

Phil Lemieux, a volunteer for Friends of the Hunley, sat in a lawn chair with the sub while its owner, John Dangerfield, went to get parts to fix the trailer, which lost two wheels near the intersection of I-20 and I-285.

The replica is 98 percent accurate, 3 inches wider and 1 inch longer than the original, said Lemieux, who helped build it out of sheet metal and steel 10 years ago.

Based in Charleston, the vessel has been taken on the road for exhibits, educational purposes and events, he said.

The original Hunley was the first combat submarine to sink an enemy warship, the Housatonic, on Feb. 17, 1864. The Hunley sank after the attack and was not recovered until 1995. Nearly two dozen confederate soldiers, along with the sub's inventor, Horace Hunley, died in three different sinkings of the submarine.