PHOTO CAPTION: The Los Angeles-class submarine Greenville carries the Advanced SEAL Delivery System (ASDS) off the coast of Pearl Harbor, Hawaii.

Battery Fire Damages US Navy Experimental Mini-Sub

The ASDS’s original silver-zinc batteries provided insufficient power for the craft’s missions, and more powerful lithium-ion batteries recently were substituted.

Published: 10-Dec-2008

The long-stalled future of the U.S. special warfare community’s troubled mini-submarine is even cloudier after a serious explosion and fire struck the craft last month, ironically on the cusp of a new mission and a new way ahead for the program.

The Advanced SEAL Delivery Vehicle 1 (ASDS-1) was having its lithium-ion batteries charged Nov. 9 when an explosion started a battery fire that burned for about six hours. No one was aboard the 60-ton craft, which was on shore at its base in Pearl Harbor, Hawaii.

Federal firefighters sealed the ASDS to put out the fire and continued to hose it down for several hours to cool hot spots. The mini-sub remained sealed for more than two weeks before the hatch was opened.

“The Navy has not yet determined the cause of the fire or the extent of the damage,” Lt. Clay Doss, a Navy spokesman at the Pentagon, said Dec. 5. Two investigations are underway to determine the fire’s cause and the extent of the damage, he added.

Sources familiar with the incident said that, in addition to fire damage, the craft likely would have significant water damage from having its interior flooded to fight the fire.

The incident came at a key time for the mini-sub program. The ASDS was to have deployed in November aboard the guided-missile submarine Michigan — the first SSGN deployment for the craft.

And, more than two years since U.S. Special Operations Command (SOCom) canceled further ASDS acquisitions, Pentagon officials reportedly were preparing to submit new program plans in the fiscal 2010 budget due to be sent to Congress on Feb. 2. No details of the new way ahead for the program have been revealed, although Pentagon sources said the submission would need to be reviewed in light of the pending investigations into the ASDS fire.

A primary question investigators will have is whether the craft’s new lithium-ion batteries caused or contributed to the explosion.

The ASDS’s original silver-zinc batteries provided insufficient power for the craft’s missions, and more powerful lithium-ion batteries recently were substituted. Built at Yardney Technical Products in Pawcatuck, Conn., the lithium-ion batteries are known to present hazards if not properly handled, particularly when the batteries are being recharged.

Although SOCom canceled the ASDS program in 2006, the Navy and the special warfare community remain eager to field the kind of capability embodied in the craft. Five or six people can ride inside the ASDS in a dry environment, unlike existing wet submersibles, in which riders sit astride their vehicles wearing diving gear. The wet environment is very debilitating and causes fatigue even before the SEAL reaches his destination — problems the ASDS eliminates. The 65-foot-long mini-sub is intended to be carried to operational areas aboard submerged submarines and has an operational range of more than 100 nautical miles.

The ASDS is intended to carry out a wide range of covert missions, including reconnaissance and surveillance, infiltration, sabotage and diversionary attacks, and counterterrorism and foreign internal defense missions. Navy officials routinely tout the ability to carry the craft as a key capability of existing and new nuclear attack subs and converted SSGNs.

The ASDS has had a long, checkered history. The first batch of six craft was to have been completed in the late 1990s, but technical problems led to long delays and a twelvefold cost overrun — the original $70 million contract for the first boat in 1994 ballooned to expenditures of at least $883 million by 2007, according to the Government Accountability Office. Only the first ASDS was completed and “conditionally” accepted by the Navy in August 2001, but the craft suffered from noise, vibration, power and a host of other technical and reliability problems. Although some of those problems have been solved, others have only been reduced in intensity or remain as challenges.

However, the ASDS has been used on several classified missions while improvements continue to be made.

The now-defunct Oceanic Division of Westinghouse Electric received the original design and construction contract. The division was bought by Northrop Grumman in 1996.

Sources at Northrop Grumman and rival General Dynamics Electric Boat said both companies remain eager to compete in a new ASDS program.

One submarine expert familiar with the program expected, before the fire, a new program for three boats at a cost of about $1.2 billion. Early, unofficial estimates of about $100 million to repair the damage to ASDS-1 are “very uninformed” and likely very low, the source said.

Several sources said they expected the explosion and fire would not end the use of lithium-ion batteries in the ASDS.

“Lithium-ion batteries can be quite dangerous but they’ve been safely used many times before, and these batteries have gone through many cycles,” a Pentagon official said.

“It almost certainly was a procedural issue,” the submarine expert said. “Like most things, it is very safe if you follow the procedures. But if you don’t follow the procedures, things can happen that you don’t expect.”

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