U.S. NAVY VIA ASSOCIATED PRESS An E-2C Hawkeye from the "Black Eagles" of Airborne Early Warning Squadron (VAW) 113 launches off the deck of USS Ronald Reagan near Honolulu. The carrier group was on a four-day anti-submarine warfare exercise in the Pacific.

USS Ronald Reagan trains to find silent threat

The carrier group is part of a larger effort to detect submarines

ABOARD THE USS RONALD REAGAN » Two Navy destroyers and a cruiser dangle sonar machines into the ocean to listen for enemy submarines lurking about 50 miles south of Honolulu. Naval aviators in P-3 surveillance planes and helicopters drop sonar buoys into the sea to give the sailors more ears below the surface.

The "enemy" submarines are not about to attack Hawaii. They're U.S. Navy submarines participating in anti-submarine warfare training against the USS Ronald Reagan aircraft carrier strike group.

The exercises, held Jan. 9-12 near the Hawaiian Islands, are something Navy sailors will be doing more of in coming years. The U.S. Pacific Fleet has made training to track and fight submarines its top combat priority amid concerns its sailors' skills haven't been keeping up with the advanced diesel submarines China and other Pacific Rim countries have been buying.

"There is a real threat out there -- over 140 diesel submarines in the Pacific, and the technology on them is getting better every day," said Capt. David F. Steindl, who directed the Reagan strike group's ships and aircraft during the exercises. "We need to train constantly to be ready if we ever have to face that threat."

Steindl, commander of Destroyer Squadron 7 since April, said he's been spending twice as much time on anti-submarine warfare exercises compared to the last time he served at sea four years ago.

Now, he said, his team is training "almost constantly" for anti-submarine warfare.

Starting last summer, sailors aboard the Reagan spent months off San Diego matching their wits against the Gotland, a Swedish submarine that is among the world's quietest and hardest to detect diesel submarines.

The Gotland uses advanced technology to muffle the sound it emits. It also uses equipment allowing it to stay underwater for weeks at a time. Most diesel submarines have to surface every day to run their diesel and recharge their batteries, making them vulnerable to attack.

Steindl said his sailors found ways to track the Gotland during their exercises, though he declined to say how. He said the training prepared his crew well.

"If we can go against her, we can go against anyone," he said.

Other Navy ships will get to train against the Gotland until June when the Swedish sub is due to go home.

The Navy also has been training with other nations that have diesel subs in their fleets. Last fall, U.S. ships held separate exercises with the Australian, Indian, and Japanese navies.

The Navy plans for all 11 of its other aircraft carrier strike groups and all of its expeditionary strike groups -- vessels centered around amphibious assault ships -- to undergo similar training as the Reagan.

Tracking submarines fell down the Navy's list of priorities after the Cold War ended and the former Soviet Union began retiring some of its undersea vessels. The Pentagon more urgently needed the Navy for its ability to deliver fighter jets for air strikes in places like Iraq, Kosovo and Afghanistan.

The emergence of increasingly quiet diesel submarines, once too loud to present much of a threat to the Navy, however, has given anti-submarine warfare new prominence.

These diesel submarines aren't challenging the U.S. Navy's undisputed supremacy at sea. They can't go fast enough for long enough distances for that.

But they are quieter and thus harder to find, especially closer to shore where they have the greatest advantage.

Ten nations lining the Eastern Pacific own 212 diesel submarines, including 132 that fall in the SSK, or "hunter-killer" category, according to "The Military Balance 2005-2006," a book put out by The International Institute for Strategic Studies. China alone owns 64.

Just over half of China's diesel submarines are outdated Romeo-class subs, but Beijing moved to upgrade its fleet by acquiring four advanced Russian-made Kilo-class submarines in the 1990s and ordering eight more in 2002.

Owen Cote, associate director of the security studies program at the Massachusetts Institute of Technology, said when it comes to submarines, the United States is most concerned about the possibility China would use its diesel subs to block commercial ship access to Taiwan.

He said Beijing could use the tactic to try to force Taiwan to capitulate if Taipei and Beijing ever faced off militarily.

China considers the self-governing island a renegade province and has vowed to invade it if Taiwan declares independence. While the United States does not have official ties with Taiwan, it has committed to defending the island if it is attacked by China.

Cote said the Navy might have some concerns about countering North Korean submarines if war broke out on the Korean peninsula or about fighting Iranian submarines in the Persian Gulf if conflict developed between Washington and Tehran. But he said such worries were not as significant.

Adm. Gary Roughead, the commander of the Pacific Fleet, said he was concerned that a country with capable submarines would try to disrupt the significant volume of trade that crosses the Pacific and contributes to the region's prosperity.

He said the nationality of the opposing submarine didn't concern him.

"I don't go chasing after flags," Roughead said. "If I can train our Navy, particularly the Pacific Fleet, to counter a particular capability, that is the most important thing. The flag is not important to me -- it's the capability. And I want to be able to dominate that capability."