Digital Imaging of The Hunley


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Vulcan : Applications : As-built

H.L. Hunley Conservation Project

The wreck of the Confederate submarine H.L. Hunley was discovered early in May, 1995, off Sullivan's Island, South Carolina. The 40-foot Hunley sank in the aftermath of her maiden attack on February 17, 1864, after ramming the Union warship USS Housatonic with a harpoon torpedo mounted on an iron shaft extending from the bow. All nine men aboard the Hunley were lost. The wreck of the Hunley is considered priceless because of its historic significance--it was one of the first submarines, and the first to be used successfully in warfare.On August 8, 2000, the H.L. Hunley was raised from the floor of Charleston Harbor in front of tens of thousands of observers. It is currently undergoing conservation at the Warren Lasch Conservation Facility located on the grounds of the Old Naval Shipyard, Charleston, South Carolina.

Arc Second @ Work

Arc Second was asked to help determine the exact dimensions and locations of critical elements on the Hunley. Before they raised the submarine, they only had old sketches and drawings to go by --- no original plans existed. Consequently, there had been a lot of speculation about various aspects of the submarine --- from its overall size, to what condition it was in upon sinking (i.e., were there penetrations in the hull). Interestingly, many of the older drawings showed a "bull-nose" (i.e., flat) front and the spar attached to the top side of the sub. In reality, the front was a more hydrodynamic (curved) profile and the spar attached at the bottom. Basically, the archaeological team wanted an accurate survey of the "as-built" and "as-found" condition of the submarine. Clearly, this was a very difficult work environment with water and grime everywhere, and obstructions at every turn.

In a little over 6 hours of measuring time, we measured 2,000 discrete points on the submarine. We used the Vulcan (Pole configuration) with a full 6-feet of length --- and  mounted the transmitters on their sides and strapped them to the steel support structure for some of the measurements. These points were taken to capture critical information --- like where the conning towers were located, where the snorkel tube was located, the location and size of the spar (basically a long "stinger" that carried a bomb), and where various hull weld seams were located. We also mapped the propeller and ballast tank. The submarine was completely ensconced in a steel support structure that looked like a girder for a highway bridge. This made the measurements very challenging to obtain. We tied our four data sets together in Rhino, then used this information to create the surface models seen below. It took about 3 days to complete the model. 

For more information about this project, please send email to


The Vulcan (pole configuration) receiver is placed on the point to be measured. The trigger is pressed to instantly record the point's 3D coordinates.


Arc Second’s technology is changing the current 3D data capture and processing model — from the existing "stand-alone instrument" model, to a new "networked environment " model allowing multiple users to collect, process and disseminate 3D information simultaneously and seamlessly.

Our technology, with more than 30 U.S. and international patents and patents pending, has won national awards for excellence and innovation, including the Business Week Industrial Design Award, and is being used in high profile applications in film making ("Titanic" and "Dinosaur"), NASCAR racing, and crime and accident scene reconstruction.


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