North Irvine, Calif.—In 1864, the H.L. Hunley, a Civil War submarine and the first ship capable of maneuvering completely underwater, sank off the coast of South Carolina while returning from its first mission. Now, after over 135 years at the bottom of the Atlantic, one of the most sought-after artifacts in the history of naval warfare has been raised and is being restored.

Rosemount Analytical, a division of Emerson Process Management (Austin. Tex.), has been assisting this monumental undertaking. The ruggedness and reliability of the firm's products, combined with Rosemount's analytical expertise, resulted in its being selected to provide sensors and analyzers for restoring and preserving the Hunley. Phase one of the restoration project was recently completed, and phase two is expected to begin in January 2002.

After the delicate wooden submersible was raised 15 months ago, and moved from the sea to a large tank of water, Rosemount Analytical devices were used during the preservation process to monitor the Hunley's conductivity, pH/ORP (oxidation reduction potential), and dissolved oxygen levels. Rosemount's sensors for the Hunley project are housed in ruggedized cowlings to prevent damage to the electrodes.

The first phase of the restoration project included raising the sub, excavating artifacts, and removing the crewmen's remains. In phase two, the chloride-removal process will begin, which will prevent the sub from corroding, rusting or deteriorating. One step in that process involves immersing the sub in a large tank filled with an electrolyte solution of water and sodium hydroxide, which will draw the chlorides out of the metal.

For more information, visit www.rosemountanalytical.com, www.hunley.org, or www.controleng.com/freeinfo.