On Jan. 11, 1863, a Union warship was sunk in a skirmish with a Confederate vessel in the Gulf of Mexico.
Exactly 150 years later, a new 3-D map of the USS Hatteras has been released that shows what the remains of the warship look like. The Hatteras rests on the ocean floor about 20 miles (32 kilometers) off Galveston, Texas, according to a release from the National Oceanographic and Atmospheric Administration, which helped to sponsor the expedition to map the shipwreck.
The Hatteras was sunk in a battle with the Confederate raider CSS Alabama, and was the only Union warship sunk in combat in the Gulf of Mexico during the Civil War.
"Most shipwreck survey maps are two-dimensional and based on observations made by sight, photographs or by feeling around in murky water while stretching a measuring tape," said James Delgado, with NOAA's Office of National Marine Sanctuaries, in the statement. "Thanks to the high-resolution sonar, we have a three-dimensional map that not only provides measurements and observations, but the ability for researchers and the public to virtually swim through the wreck's exposed remains and even look below the surface at structure buried in loose silt."
Recent storms have dislodged some of the sediment that covered the ship, 57 feet (17 meters) beneath the surface, so researchers took advantage of the opportunity to map the vessel with state-of-the-art sonar in the fall of 2012, according to the statement.
The map has revealed previously unknown features of the shipwreck, including a largely intact paddlewheel that once propelled the vessel forward. It also shows damage to the wheel's steering column and the engine room.
The Hatteras rests in federal waters, and is protected under the Sunken Military Craft Act as a war grave, according to the release.
The ship was part of a blockade to prevent goods from traveling to and from Galveston, which remained one of the last bastions of the Confederacy late into the Civil War, the NOAA noted.