ABOARD THE RESEARCH VESSEL MANTA, Gulf of Mexico -- The world will soon get its first good look at the wreckage of the only U.S. Navy ship sunk in combat in the Gulf of Mexico during the Civil War, thanks to sophisticated 3-D sonar images that divers have been collecting this week in the Gulf's murky depths.

The USS Hatteras, an iron-hulled 210-foot ship that sank about 20 miles off the coast of Galveston, Texas, in January 1863, has sat mostly undisturbed and unnoticed since its wreckage was found in the early 1970s. But recent storm-caused shifts in the seabed where the Hatteras rests 57 feet below the surface have exposed more of it to inspection, and researchers are rushing to get as complete an image of the ship as possible before the sand and silt shifts back.

"You can mark Gettysburg or Manassas, (but) how do you mark a battlefield in the sea?" said Jim Delgado, the director of maritime heritage for the National Oceanic and Atmospheric Administration's Office of National Marine Sanctuaries, and the person overseeing the project.

On Monday, a team of archaeologists and technicians began two days of scanning the wreckage using a sonar imaging technology that hadn't been used yet at sea, Delgado said.

On Monday aboard the research vessel, Manta, researcher Christopher Horrell gleefully pored over computer images of the Hatteras' stern and paddlewheels that had just been transmitted from the seafloor.

"This is what I got into archaeology for. It's fantastic," said Horrell, a senior marine archaeologist for the Department of the Interior.

The images, taken by a roughly 2-foot-long cylindrical device deposited near the wreckage, were used to position divers who then used 3-D scanning devices to map the site. The sand and silt-filled water near the seafloor limited the divers' visibility to 3 to 10 feet, and it makes filming or photographing the wreckage difficult. But it doesn't affect the sonar technology, which produces images by analyzing sound waves bouncing off of objects, allowing scientists to capture a more complete look at the wreckage.

Delgado said he's hoping to post the images online for the public by January, in time for the 150th anniversary of the battle. He said he also hopes researchers review them to look for ways to preserve the wreckage.

"Whatever we can do to make it accessible," Delgado said. "We want to share this with folks and show people history is real."

The wreckage site was discovered in the early 1970s by a Rice University professor, according to Amy Borgens, the Texas state marine archaeologist.

"We knew it was here but didn't know exactly," she said. "One of the problems with shipwrecks is you can't take people down there to show them.

"And there's all this drama with shipwrecks, which are almost always the result of a tragedy."

The Hatteras wreck is in waters administered by the federal Bureau of Ocean Energy Management and the ship itself still remains property of the U.S. Navy.

According to the Navy Historical Center, the 1,126-ton Hatteras was built in 1861 in Wilmington, Del., as a civilian steamship. Later that year, it was purchased by the Navy, commissioned at the Philadelphia Navy Yard and assigned to join the blockade of the Florida coast to keep vessels from delivering supplies and munitions to the Confederacy. It had an active tour, in Florida, raiding Cedar Keys, destroying at least seven schooners and facilities before being transferred to the Gulf.

On Jan. 6, 1863, it joined the fleet commanded by David Farragut, of "Damn the torpedoes" fame, for similar assignments off of Galveston, which was then the most prominent city and port in Texas, which had joined the Confederacy. Five days later, it pursued and tracked down a three-masted ship that identified itself as British, but later opened fire on the Hatteras from 25 to 200 yards away and revealed it was actually the CSS Alabama, a notorious Confederate raider.

Forty-three minutes later, with the Hatteras was burning and taking on water, Cmdr. Homer Blake surrendered, and he and his crew were taken aboard the Alabama as prisoners, eventually winding up in Jamaica. Of the 126-man crew, two were lost and are believed entombed in the wreck, which became the only Union warship sunk by a Confederate raider in the Gulf.

"It's hard to believe we're in the middle of a battlefield," said Ed Cotham, the project historian, who carried with him Monday an original photograph of Blake, a formal portrait showing the officer in his uniform. "It's the first time he's returned since January 1863."

Before the work began, a wreath was placed in the Gulf, red and white rose petals were scattered on the water's surface and a priest, the Rev. Stephen Duncan, conducted a brief memorial service for the two crewmen, William Healy, 32, a coal heaver, and John Cleary, 24, a stoker, in what was likely the first religious service for them ever at the site. Both men, from Ireland, probably were Catholic, he said. No relatives are known to be in the U.S. and it likely took years for their relatives back in the Civil War times to learn of their fate, he said.

The Alabama, which was credited with some 60 kills, was eventually sunk thousands of miles away, when a Union ship attacked it in the English Channel in June 1864 after it underwent repairs in a French port.

Earlier on HuffPost:

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  • A group of seven Civil War battlefield photos of unidentified persons is seen at he Museum of the Confederacy in Richmond, Va., in a Friday, May 25, 2012 photo. Officials at the the Museum of the Confederacy are publicly releasing the images in the admittedly remote chance a descendant might recognize a facial resemblance or make a connection the battlefields where they were found. (AP Photo/Steve Helber)

  • Ann Drury Wellford, manager of Photographic Services for The Museum of the Confederacy, a Civil War battlefield photos at the museum in Richmond, Va., Friday, May 25, 2012. Private Thomas W. Timberlake of Co. G, 2nd Virginia Infantry found this child's portrait on the battlefield of Port Republic, Virginia, between the bodies of a Confederate soldier and a Federal soldier. Eight photographs are publicly releasing the images in the admittedly remote chance a descendant might recognize a facial resemblance or make a connection the battlefields where they were found. (AP Photo/Steve Helber)

  • Ann Drury Wellford, manager of Photographic Services for The Museum of the Confederacy, holds a Civil War battlefield photo at the museum in Richmond, Va., Friday, May 25, 2012. This Gem daguerreotype locket was found by a soldier in Hampton's cavalry brigade on a battlefield in 1863. Eight photographs are publicly releasing the images in the admittedly remote chance a descendant might recognize a facial resemblance or make a connection the battlefields where they were found. (AP Photo/Steve Helber)

  • This image provided by the Museum of the Confederacy shows an Ambrotype photo of an unidentified soldier, who left this image of himself with Mrs. L.M.C. Lee of Corinth, Mississippi, on the eve of the battle of Shiloh. The soldier never reclaimed his image and was presumed to have been killed in battle. The Museum of the Confederacy is publicly releasing eight images recovered on battlefields of unidentified persons in the admittedly remote chance a descendant might recognize a facial resemblance or make a connection the battlefields where they were found. (AP Photo/The Museum of the Confederacy)

  • This image provided by the Museum of the Confederacy shows an Ambrotype photo of an unidentified young militia lieutenant, that was found on a battlefield near Richmond, Virginia, and donated to the Museum of the Confederacy in 1936. The Museum of the Confederacy is publicly releasing eight images recovered on battlefields of unidentified persons in the admittedly remote chance a descendant might recognize a facial resemblance or make a connection the battlefields where they were found. (AP Photo/The Museum of the Confederacy)

  • This photo provided by the Museum of the Confederacy shows a tin-type photograph of an unidentified man. The tintype and a bible with the name of John Brice in it were found in a tent somewhere in North Carolina during the Civil War. The Museum of the Confederacy is publicly releasing eight images recovered on battlefields of unidentified persons in the admittedly remote chance a descendant might recognize a facial resemblance or make a connection the battlefields where they were found. (AP Photo/The Museum of the Confederacy)

  • This ambrotype image provided by the Museum of the Confederacy shows an unidentified woman that was found in the effects of a soldier identified as Joseph Warren during the Civil War. The Museum of the Confederacy is publicly releasing eight images recovered on battlefields of unidentified persons in the admittedly remote chance a descendant might recognize a facial resemblance or make a connection the battlefields where they were found. (AP Photo/The Museum of the Confederacy)

  • This image provided by the Museum of the Confederacy shows an Ambrotype photo of an unidentified soldier, who left this image of himself with Mrs. L.M.C. Lee of Corinth, Mississippi, on the eve of the battle of Shiloh. The soldier never reclaimed his image and was presumed to have been killed in battle. The Museum of the Confederacy is publicly releasing eight images recovered on battlefields of unidentified persons in the admittedly remote chance a descendant might recognize a facial resemblance or make a connection the battlefields where they were found. (AP Photo/The Museum of the Confederacy)

  • This image provided by the Museum of the Confederacy shows a Daguerreotype, of a women and two children found in the effects of a soldier identified as Joseph Warren during the Civil War.The Museum of the Confederacy is publicly releasing eight images recovered on battlefields of unidentified persons in the admittedly remote chance a descendant might recognize a facial resemblance or make a connection the battlefields where they were found. (AP Photo/The Museum of the Confederacy)