The contest for undersea supremacy. US subs hold technological edge, but the Soviets are closing the gap

Inside the Soviet Navy, it is called ``Zolotaya Ryba,'' Golden Fish -- the most expensive submarine in the world. It is the Alfa-class attack sub, the dragster of the seas. With a hull made of costly titanium, it can dive deeper and run faster than its United States counterparts.

But it is a dragster without a muffler. When an Alfa went on a Norwegian Sea run in 1980, it was reportedly tracked by US underwater listening devices in Bermuda.

Like the Alfa, Soviet subs as a whole are a mixture of power and relative crudeness. The USSR still lags behind the US in the technological race for supremacy of the deep, US experts claim.

But ``we've witnessed them gaining on us, closing a differential that was significant 10 years ago,'' says Chief of Naval Operations James D. Watkins.

The Walker spy case has shone a spotlight on the shadowy world of submarines and antisubmarine warfare. Navy officers are concerned that spies may have passed US secrets that have helped the Soviets increase the capabilities of their undersea fleet.

That fleet is the largest in the world. It ranges from ballistic-missile subs longer than World War II aircraft carriers to tiny submersibles that skitter across the ocean floor like bugs.

The USSR currently has 371 operational submarines, according to the International Institute for Strategic Studies (IISS). The US, by way of contrast, has about 130.

Seventy-nine of the Soviet subs carry nuclear-tipped ballistic missiles. One of the most modern of these subs, the Typhoon, is the largest underwater vessel in the world, claims the Pentagon publication Soviet Military Power.

Three Typhoons, each carrying up to 180 warheads on 20 missiles, are already in service, with three or four more under construction.

The Soviets also field 211 attack submarines, according to the IISS. In the event of war, these subs would be used to protect Soviet surface ships and to hunt down US Navy ships. While the Alfa class may still be the speediest of these subs, it has already been superseded by four new types, including the rakish-looking Akula.

Overall, the Soviets produce new types of subs far faster than does the US. Nine new classes of Soviet subs are being developed, including a speedy attack boat with a projected top speed of 50 knots, according to the authoritative Defense Week. Miscellaneous Soviet subs, now operational, include ones armed with cruise missiles and tiny reconnaissance submersibles widely thought to be crawling around the Swedish and Norwegian coasts.

In numbers and variety, Soviet submarines are undeniably impressive. Measuring their quality, however, is more difficult.

The Soviets think about submarine warfare in a different way than the US does, experts say. US subs are designed to be effective lone wolves, silent stalkers that appear from nowhere to attack concentrations of enemy force. USSR subs, on the other hand, seem better suited to work with other subs or surface ships. Their missions range from coastal protection to operation under Arctic ice.

``The Soviet are far more thoughtful about the roles of submarines than we are,'' says Michael MccGwire, a senior fellow at the Brookings Institution.

USSR subs emphasize speed and diving ability. But the Soviets have so far not made their subs nearly as quiet as US counterparts. And subs that can be heard can be destroyed. US P-3 antisubmarine planes, packed with sophisticated listening gear, routinely find Soviet subs on patrol -- and can even identify the individual sub they are listening to, US government sources claim.

Soviet subs evince other signs of relative technological crudeness. About half are nuclear powered, with the rest running on diesel engines and batteries. The US has not built a diesel sub for 20 years.

Many of the Soviet submarine missiles are liquid fueled -- dangerously unstable things to be carrying in a closed tube hundreds of feet underwater.

Soviet subs use some inefficient construction techniques, such as wrapping pressurized tubes with unpressurized hulls, that the US has long abandoned.

And the Soviet sub fleet doesn't cruise around as much as its US counterpart. Most of the Soviet ballistic-missile subs sit in port, while half of the US subs with nuclear weapons are always on patrol, notes defense analyst Andrew Cockburn in a book on Soviet military force.

The relative immobility of Soviet missile subs may be the result of unreliability. It may also be a conscious decision.

At any one time, there are several Soviet ballistic-missile subs patrolling off both US coasts, says retired Navy Comdr. Richard Ackley, now head of the national-security program at California State University at San Bernardino.

Usually these subs are relatively old Yankee-class models. To reach station, they have to travel through narrow ``choke points'' where they would be easy to catch and destroy, in time of war. If they are coming from the Soviet Northern Fleet, they must pass the narrow points between Greenland, Iceland, and the United Kingdom; if they are coming from the Pacific Fleet in Vladivostok, they pass close to Japan.

But missiles on the Soviet's newest subs, such as the Typhoon, could hit the US even if fired from port. US analysts believe that the Soviets may therefore be planning a ``bastion'' strategy. In case of hostilities, Typhoons would sail north, surface at a weak spot in the Arctic ice pack, and become well hidden, mobile missile bases.

Thus, the US Navy is again interested in something it pioneered -- under-ice submarine operations.

Next: US antisubmarine warfare efforts.