Environmental Protection

Thompson Pump Makes History by Helping

A major supplier to the water and wastewater industry does not often get a chance to become a part of history. But that is what occurred when Thompson Pump & Manufacturing Co. helped retrieve a sunken Confederate submarine off the coast of South Carolina in 2000.

The submarine recovery is just one example of a unique project this $54.5 million company has been involved in. Others have included cleaning up an oil spill in Alaska, moving an East Coast lighthouse, fighting western fires, controlling Midwest floodwaters, pumping floodwaters in New Orleans, and assisting with the Sept. 11 terrorist attack recovery effort in New York City.

The H.L. Hunley, the world’s first successful combat submarine, sank the USS Housatonic on Feb. 17, 1864, and then sank shortly after. Lost at sea for more than a century, the Hunley was located in 1995 by author Clive Cussler’s National Underwater and Marine Agency.

In a plan to raise the vessel, the recovery team of private and government organizations called upon Thompson Pump of Port Orange, Fla., to supply pumps and personnel for the job. On Aug. 8, 2000, the team retrieved the Hunley and transported it to the Warren Lasch Conservation Center in North Charleston, S.C., where it is still undergoing conservation and can be seen in a special saltwater tank that aids in preservation.

Bill Thompson, president of Thompson Pump, learned about the Hunley excavation and wanted his company to become involved because he is a history buff. Employees Majid Tavokoli, vice president of applied products, Don Polzon, South Carolina sales representative, Tim Creech, regional manager, and Jack Frost, field demonstrator, all played key roles in the recovery effort, along with former Thompson Pump employee Ben Mann, sales engineer at the time.

“It was very interesting because of the engineering part of the recovery effort, and actually seeing a part of history come alive is very uplifting. Some things you don’t forget,” said Tavokoli, who was on scene during the recovery.

The project required significant study and care given the sub’s delicate condition. The team lowered two 18-by-12-foot custom-engineered suction piles 35 feet to the ocean bottom to be used as platforms, then placed a truss onto the submarine. Nylon slings with inflated foam pillows and sensors wrapped underneath the Hunley, and then a crane lifted the truss to the surface. The Hunley and truss then were taken by barge to the Charleston Navy base and eventually to the Warren Lasch Conservation Center.

Used in this process were three Thompson pumps: a 4-inch, 32-horsepower unit and hydraulic pump head and two 6-inch high-pressure jet pumps. Once the suction piles were placed, the hydraulic submersible pump head was coupled to the top of the suction pile. The 32-horsepower pump on the deck of the support vessel powered this pump head. Pumping from inside the pile created a differential pressure that pushed the suction pile into the ocean floor. Careful control of the pump flow rate was critical to sink the suction pile level at a steady state. Once the Hunley was retrieved, water was pumped back into the suction piles to lift them off the ocean floor and onto a barge.

"They used two high-pressure jet pumps that supplied divers with high-pressure water in an attempt to, as delicately as possible, remove the ocean silt off of the submerged submarine,” added Polzin, describing the recovery process.

Besides damage to the equipment from the salt water, another challenge was weather. Retrieving the Hunley from the ocean took about four months, due in part to the painstaking and slow task of divers carefully removing sediment from around the sub and to allow time for excavation of other ocean sediment for artifacts. The Hunley was buried under 3 feet of sediment.

“They were three miles offshore, so the ocean swells were a problem. They were working on a floating vessel to start with called a mud boat. When you’re trying to do something with cranes, and a vessel is in 30 feet of water, and the boat is rocking, it’s hard to be very precise,” Polzin added.

So what did the Hunley look like when it finally surfaced out of the water? Not much, according to Polzin, who took pictures of the effort from a nearby boat.

“It looked like a very long, rusty piece of pipe,” he said. “But it was a part of history and exciting.”

Along with artifacts that included a gold coin and Union ID tag, the recovery team found the remains of eight crewmembers inside the submarine. The crew members were honored with a formal service and burial on April 17, 2004 in the tradition of the 1860s. Period-style horse-drawn carriages transported the remains to Magnolia Cemetery in Charleston.

For Thompson Pump, the Hunley recovery marked an important milestone for the company founded in 1970 by George A. Thompson and his sons, Bill and George Jr. The company serves the pumping and dewatering needs of more than 6,000 clients nationally and internationally. Thompson’s product line includes various types of pumps ranging in size from 2 to 18 inches.

Another important milestone for the company was adaptation in 1973 of a rotary pump for dewatering. In 1977, Thompson introduced its own version of vacuum-assisted pumps, and in the 1980s launched hydraulic power units with submersible pump heads for high head applications, such as mines or quarries. Other innovations included dry prime pumps with compressor-assisted priming systems suited to sewer bypass applications and sound-attenuated pumps that reduce noise.

This article originally appeared in the 07/01/2007 issue of Environmental Protection.

About the Author

Debbie Bolles is managing editor of Water & Wastewater News.

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