WITH a slight shudder that belies its awesome bulk, one of the most intricate and lethal pieces of engineering ever conceived noses silently beneath the fog-cloaked waters off Long Island.
Inside the cramped command center of the USS Philadelphia, a nuclear-powered attack submarine, eyes lock on consoles. Talk is subdued. Air blowers whirl unceasingly. ''Passing course zero-nine-zero,'' intones a sailor. ''Rudder is right 5 degrees.''
As the USS Philadelphia glides out into the tranquil Atlantic Ocean depths on another cruise, a political battle rages on the surface over America's nuclear-powered attack submarine program. The outcome will not only determine the shape of the fleet well into the 21st century, but the future of the US submarine industry, its specialized work force, and the communities it sustains as well.
It's a classic post-cold-war problem: Do some weapon-production lines need to be kept humming and ready, even in times of peace? The United States nuclear sub production capacity has been assembled at great expense and effort over many years, and many in the Navy are loath to see it broken up for want of contracts. Yet how can the Pentagon justify billions for new weapons intended to counter an adversary who no longer exists?
''There are no post-cold-war threats that justify these kinds of weapons systems,'' argues Sen. John McCain (R) of Arizona.
The Navy operates two basic submarine types: attack submarines and Trident nuclear missile-armed ships. With the threat of atomic war diminished by the Soviet Union's collapse, the Navy plans to cut back its Trident fleet to 14 by the year 2003.
As for attack submarines, the Clinton administration acknowledges that the US has more than it needs and wants to reduce the 87-strong fleet to between 45 and 55 vessels. Even so, new vessels will still have to be built to replace those the Navy plans to retire at the end of their 30-year life spans.
When, where, and at what rates the new ships should be produced -- or not produced -- are the issues now being disputed in Congress as it considers the future of the submarine program. The Navy wants to begin deploying early in the next century what it calls the New Attack Submarine (NAS), which is now under design at the Electric Boat Company in Groton, Conn. While the first NAS is forecast to cost about $3.4 billion, the Navy says the price will drop to $1.5 billion with the fifth ship.
The problem is that Electric Boat, a subsidiary of General Dynamics Corporation, says it doesn't have enough business to sustain itself until construction of the first NAS. After building an average of 4.5 submarines a year in the 1980s, the firm will run out of work by 1999, when it finishes the second of two Seawolf-class attack subs. Successor to the now top-of-the-line Los Angeles class, the Seawolf will be the quietest sub in the world until the NAS's debut. The first Seawolf is being built for about $2.3 billion. Its sister ship will cost about $1.8 billion.
But the Seawolf is a product of the cold war, and its deep-sea design is unsuited to shallow coastal regions, such as the Persian Gulf, in which US forces now operate more frequently. Even so, the Clinton administration wants Congress this year to approve a third Seawolf to keep Electric Boat's production lines engaged until NAS construction begins.
Without the third Seawolf, Electric Boat says $900 million already invested will be wasted and its yard will have to close all but its design operations. That would leave Virginia's Newport News Shipbuilding Company as the last US facility building nuclear-powered ships. There were once seven such yards.
Electric Boat says it is already planning to reduce its highly skilled work force of 14,300 to 6,000 in 1997. Without the third Seawolf, those remaining workers will follow the others in taking their talents elsewhere, it contends. Furthermore, the firm's dwindling number of specialized subcontractors, like nuclear-component manufacturers, will have to close or move into other fields.
''We will not be able to maintain our edge in technology and construction unless we have the third Seawolf as a bridge to maintain not only the plants and equipment, but the skilled people who build these submarines,'' says Rep. Jack Reed (D) of Rhode Island. Electric Boat makes submarine hull sections at a plant in Quonset Point, R.I.
Proponents warn that restarting Electric Boat's production lines and reconstituting its work force to build the NAS will add as much as $1 billion to the project, far more than Congress may be willing to accept. But critics contend that, because the nation's finances are so tight and it no longer faces a rival superpower, now is not the time to be plowing billions of dollars into new submarines.
Senator McCain's legislation that would have killed the third Seawolf fell three votes shy of winning Senate approval in 1993. He says he believes he will succeed this year in persuading the GOP-run Congress to deny the administration the $1.7 billion it wants in fiscal 1996 for building the third Seawolf and $1.2 billion it is seeking in NAS funds.
McCain and other opponents argue that as a money-saving alternative, the Navy should extend the 30-year life span of its Los Angeles-class submarines and delay the NAS program until after the turn of the century. These experts argue that the Los Angeles-class boats, such as the USS Philadelphia, will remain unrivaled for years to come. They reject the Navy's contentions that delaying the NAS will allow Russia to deploy new submarines far quieter than any US vessel. Some experts also contend that Electric Boat can be kept afloat with work other than the third Seawolf, such as modernizing Los Angeles-class vessels.
As for Electric Boat's closure, Newport News President W.P. Fricks told a congressional committee last week that his yard could build the NAS $2 billion cheaper. He wants his firm to be given a chance to bid for the project.
A number of experts, however, also question the military wisdom of building new nuclear-powered attack submarines. During the cold war, US attack submarines' main task was to silently track Soviet subs carrying nuclear missiles targeted at the United States. A secondary mission was intelligence-gathering. Even though the first mission has now all but disappeared, the Navy says the second is still important.
Furthermore, the Navy contends that the attack subs' ability to fire cruise missiles and antiship missiles makes them the kind of stealth weapons system that gives the US enormous advantages in an increasingly unstable world.
But other experts say that nuclear-powered submarines are unsuited to the new era of regional conflicts and shallow-water patrolling. ''We did not operate nuclear subs in the Persian Gulf during the Gulf War,'' observes James Bush of Washington's Center for Defense Information.
To sailors on board the USS Philadelphia, all the talk of submarine types and roles isn't as important as the quality of the crew.
''It doesn't matter who the bad guy is. I can deploy a weapon against anybody,'' says Kenneth Shreve of Jacksonville, Fla., who cares for the sub's 26 torpedoes and Tomahawk cruise missiles.
''For years we've concentrated on training and preparing to go up against the Soviets. But the same training skills that we have developed are applicable to any adversary,'' adds the ship's skipper, Cmdr. Richard Luke, a 20-year submarine veteran.
In the soft, deliberate manner with which he gives orders, Commander Luke tells his staff to bring the ship up in an emergency surface. An officer yanks two chrome handles that activate high-speed pumps. Air blasts into the ballast tanks, expelling water back into the sea. Freed from the weight that kept it down, the sub pitches up bronco-like. Within seconds, its blunt nose breaks into the frosty Atlantic air.