* Company to investigate problem with air-making system
* Alternate system burns chemicals to make oxygen
* 2 UK sailors died after fire linked to similar system
By Andrea Shalal-Esa
ABOARD USS NEW HAMPSHIRE, Arctic Ocean, March 21 (Reuters) - The machine that produces fresh air aboard the USS New Hampshire submarine failed during a mission under the vast ice cap of the Arctic Ocean last week, prompting the submarine to use an alternate oxygen candle system instead.
Hamilton Sundstrand, a unit of United Technologies Corp (UTX.N), is sending a representative to a temporary ice camp to investigate the problem with the oxygen generator, said Navy Commander John McGunnigle, captain of the nuclear-powered Virginia-class submarine.
Daniel Coulom, a spokesman for Hamilton Sundstrand, confirmed late Monday that company staff would travel to the ship to help repair the oxygen generator, but said it was too early to speculate on what caused the problem.
McGunnigle told Reuters he had spoken with the company shortly after the submarine surfaced on Sunday afternoon in a small area of open water surrounded by ice sheets. The ship is in the Arctic to participate in a month of military exercises with another submarine, the USS Connecticut.
The emergency system that is now producing oxygen for the submarine’s 130-plus crew burns chemical candles in a closed metal cylinder that vents to an air-circulating system.
McGunnigle said the system was safe and crew members carefully monitored its use, but he acknowledged that it was the same kind of equipment that caused a fire and explosion on board the British submarine Tireless during a similar Arctic exercise in 2007, killing two sailors.
Lieutenant Jason Revitzer, the ship’s supply officer, said the ship had well over 600 oxygen candles on board, which would allow it to continue using the alternate system until it got back to its home port in Groton, Connecticut.
“Good thing we packed that many,” Revitzer said.
McGunnigle said there were several other issues with the ship during the Arctic operations, including condensation caused by the temperature difference between the frigid water outside and warmer temperatures inside. For now, the crew has rigged sheets of plastic to catch any condensation drips and route them away from sensitive electronic equipment.
The ship’s air conditioning system, which keeps the sophisticated electronic equipment on board from overheating, also failed after its ascent to the surface, but the ship’s crew was able to reset that system later.
The USS New Hampshire, built by General Dynamics Corp (GD.N), is the fifth Virginia-class U.S. submarine, weighs 7,800 tons and measures 377 feet long, about the length of a football field. It entered service in October 2008.
The ship cost about $2.4 billion to build, McGunnigle said, calling it one of the most complex machines ever built.
Powered by small nuclear reactors, Virginia-class submarines can carry 38 different weapons, including Mark 48 Advanced Capability torpedoes, advanced mobile mines, unmanned underwater vehicles and Tomahawk land-attack missiles like those fired on Libya this past week.
Virginia-class submarines were designed to have a minimal Arctic capability, including a strengthened sail that allows the ship to surface through thin ice without damage.
On Saturday the ship had surfaced through nearly a foot of ice to evacuate a sailor stricken with appendicitis, but no damage was reported.
Before any Arctic deployment, ships like the New Hampshire, are outfitted with special upward-facing sonar sensors that provide data on the ice sheets and keels above, as well as a special camera that provides video images of the ice overhead.
The ships also have an acoustic top sounder system that measures ice draft and ice thickness.
(Reporting by Andrea Shalal-Esa; Editing by Richard Chang)
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