Scientists pumped about Hunley clues

Part could help reveal how crew died

Pulling answers out of the H.L. Hunley has never been easy, but on Thursday it took a crane.

Scientists, however, may have just snagged the answer to one of the Confederate submarine's most perplexing mysteries: whether the crew drowned or ran out of air.

After weeks of work and years of planning, conservators and archaeologists on Thursday removed the sub's heavy aft pump, one of two such devices that emptied its ballast tanks.

Encased in a rock-hard casing of sand and shell, the pump might not look like much, but it might soon answer a lot of questions.

"The whole reason it was taken out was for conservation," archaeologist James Hunter said, "but now that it's out, we'll be trying to figure some things out."

The settings of the pump's valves will tell whether the crew was trying to pump water out of the ballast tanks or the sub's floor when they died. If they were pumping, it would mean they were trying to surface or the sub was filling with water.

If they weren't, it could suggest the Hunley's crew simply ran out of air. The Hunley disappeared shortly after it sank the USS Housatonic four miles off Sullivan's Island on Feb. 17, 1864.

"Once we know the pump's setting, it will help us close in on discovering what prevented the Hunley and her crew from returning home," said Sen. Glenn McConnell, R-Charleston, chairman of the state Hunley Commission. "It will help us eliminate some of the existing possibilities."

The answer has always been there, but the pump sat in a place that made it just about impossible to X-ray its valves. Now that it's out, conservators say they hope to get a better look to the internal workings of the pump in a couple of weeks.

Philippe de Vivies, a Hunley conservator, said the pump was heavier than they thought — the estimate is between 120 and 180 pounds — and they had to drop one of the sub's keel ballast blocks to get it out.

Hunter said some of the primary things archaeologists want to know — beyond the obvious — is how the pump system worked and whether it was built from the ground up special for the Hunley.

"For the submarine, it's a fairly complex piece of machinery," Hunter said.

Right now, it looks like the pumping system was fairly intricate. There was one pump for the each of the two ballast tanks on the sub, but the piping system on the sub suggests that either the forward or aft pump could drain either ballast tank, like a fail-safe, Hunter said.

One or both of the pumps also might have been able to pump water from the floor of the sub's crew compartment.

The aft pump is famous in Hunley lore for nearly killing the crew in January 1864. It became clogged with seaweed during an underwater test, forcing William Alexander, who helped build the sub and crewed it for a while — to take the pump apart in the dark, unclog it and reassemble it before the crew suffocated.

Now, the pump might serve another purpose: revealing what happened to the Hunley's last crew.

Reach Brian Hicks at 937-5561 or bhicks@postandcourier.com.