Nuclear U-Boat: `Original Stealth'

THE B-2 bomber isn't the only Pentagon weapon that is black, oddly shaped, and designed to escape detection. Navy officers say the United States arsenal already includes the first true stealth platform - the submarine. Attack subs such as the Los Angeles class are intended to run so quietly they cannot be detected by sonar as they sneak up on targets. Ballistic-missile subs such as the Trident class carry a large portion of the US nuclear deterrent beneath the waves, and are much less vulnerable to attack than land-based missiles or bombers.

Ballistic-missile subs ``are the most important part of the nuclear triad,'' claims Vice-Adm. Daniel Cooper, assistant chief of naval operations for undersea warfare.

In recent years submarines have been spared the level of controversy that has enveloped the B-1B and B-2 bombers. But the Navy isn't necessarily watching the problems of the Air Force with indifference. Subs could run into their own troubled waters.

Congress is increasingly restive about what it feels to be too-conservative submarine research and development. A recent congressional report on the subject charged that the Navy's technical experts focused too much on tinkering with existing subs ``at the expense of research and development for the fleet of the future.''

For the last two years Congress has taken away some of the Navy's R&D money and given it to the Defense Advanced Research Projects Agency (DARPA), a small arm of the Pentagon that specializes in cutting-edge work. Among technologies DARPA is looking at are advanced propulsion systems and a composite hull that would be tougher to penetrate than steel.

The focus of concern by some members of Congress is the Navy's next-generation attack submarine, the SSN-21 Seawolf. The Seawolf is supposed to keep the US subs one step ahead of Soviet subs from the late 1990s into the early decades of the 21st century, at a sail-away cost of $1 billion-plus apiece.

When designing the Seawolf the Navy opted for increased size. Seawolf will be 326 feet long and 40 feet wide, displacing more than 9,000 tons as opposed to the 7,000-ton displacement of the current SSN-688 Los Angeles-class attack subs.

More size will enable the Seawolf to have eight torpedo tubes, as opposed to the four of the SSN-688. It will carry 170 to 180 percent more torpedoes and cruise missiles than its predecessor class.

Bulk will also enable the Seawolf to run quieter, because it will provide more space to change ``how you mount equipment, and the things you can do internally and externally to the hull,'' according to Admiral Cooper.

Quietness is still the primary virtue of submarine warfare, says the Navy's top submarine officer. The Navy claims the Seawolf will be three times more combat effective than Los Angeles-class boats.

Critics in Congress doubt that assessment. They claim that Soviet subs, particularly the new Akula model, are far more advanced than the US expected only a few years ago and will be able to dive deeper and run faster than the Seawolf.

With the SSN-21 ``there has been marginal quality improvement but there certainly haven't been any breakthroughs,'' according to one congressional staff member who works on military issues.

Last fall, a Defense Department inspector general report said that Navy assessments of the Seawolf's capabilities hadn't used the latest intelligence estimates of next-generation Soviet subs. The Navy disputed that finding, claiming Soviet subs of the first decade of the 21st century won't be much different from those of the 1990s.

Congress authorized purchase of the first Seawolf last year. Navy plans call for eventual purchase of 29.

US ballistic-missile submarines, meanwhile, are rolling off the slips. The first big Trident missile sub was delivered in 1981. Eight Tridents are now in operation, with eight more in various stages of construction.

The new longer-range, more accurate Trident 2 nuclear missile for these subs should be fielded in 1990, says Cooper, despite a recent spectacular failure in which a test Trident 2 spun over the ocean like a Roman candle.

The relative ease with which Navy nuclear weapons modernization has proceeded contrasts sharply with the experience of the Air Force, whose bombers and MX and Midgetman missiles have been the subject of intense criticism for cost and/or technical problems.

Some of the Navy's good fortune was a matter of timing. The Trident program coincided with military spending increase of the Reagan era, while the B-2 has come along in an era of zero growth or declining budgets. ``The other legs [of the nuclear triad] now need improvement and that is a financial burden,'' Cooper says.

While the admiral maintains that the Navy's missile subs are the most important part of the US nuclear arsenal, and attack subs the ``linchpin'' of the Navy's maritime strategy, he doesn't foresee a near future when all Navy ships travel under the seas.

If nothing else, aircraft carriers are necessary for big-stick diplomacy. ``If I sail up to the 12-mile limit and raise my periscope, it doesn't strike fear in the heart of terrorists,'' he says.