Submarine: A Guided Tour Inside a Nuclear Warship

^{Notional view of a BSY-1 fire control console analyzing the velocity of sound in the water at various depths. The data is generated through launching of a bathythermograph from the 3-inch ejector tube. JACK RYAN ENTERPRISES, LTD.}

The radio equipment covers a broad spectrum of frequency ranges from ultra-high frequency (UHF), high frequency (HF), very low frequency (VLF), and extremely low frequency (ELF). In addition, there is equipment designed to allow the Miami to contact communications satellites, as well as underwater telephone equipment commonly known as Gertrude. Most of the radio equipment is tied to sophisticated encryption gear (called crypto) designed to make it impossible for anyone but an American to read the message traffic.

This particular point has not always been so secure, as the discovery of the Walker family spy ring showed in 1985. For over fifteen years, a Navy petty officer, along with his family members and a friend, helped the Soviet Union acquire the keys to the various crypto systems used by the United States. This meant that the Soviets had access to virtually all our major crypto systems from 1969 to 1985, when the ring was finally apprehended. Since that time the National Security Agency, which is charged with the design and security of crypto systems, has apparently rebuilt the U.S. family of encryption systems and allegedly changed the procedures that allowed John Walker and his family to put so much of our national security at risk.

The most interesting of these systems are the ELF and VLF systems, which are mainly used as command and control systems for submarines. Their special property is that the signals from ELF and VLF systems can penetrate the water to be picked up by the antenna trailed from the port side of the fairwater. More often than not, because of their relatively low rate of transmission (ELF works at about one letter character every fifteen to thirty seconds; VLF is fast enough for teletype communications), they are used to cue submerged submarines to come to periscope depth, and poke one of their communications masts up to get a signal from a satellite or UHF channel.

It is standard on submarines to minimize any actual transmission from their radio systems. Always looming over the submarine force are the memories of what the Allied ASW forces were able to do to the U-boats in World War II, because of their knowledge of the German Enigma cipher system. The penetrations of U.S. systems by the Walker spy ring have only reinforced the belief that transmitting with a radio is an invitation to a funeral. Thus it is only occasionally when they are close to a potential enemy that they will send messages. To a submariner, only silence is a friend. Any noise, acoustic or electronic, is an enemy.

Another method of communicating with the outside world is for the boat to eject a SLOT (Submarine- Launched One-Way Transmitter) buoy from its forward 3-inch signal ejector launcher. Located in a small compartment forward that doubles as the ship's pharmacy, it resembles a tiny torpedo tube. The first step is to record a message, such as a contact report, on the buoy's recorder. The buoy is then fired into the water, where it waits a period of time, say thirty minutes to a couple of hours, then sends out a high-speed burst transmission that can be picked up on a special satellite communications channel.

In addition to launching SLOT buoys, the 3-inch ejector can be used to launch bathythermographs to monitor thermal layers in the water, as well as several types of decoys such as noisemakers and bubble generators. A second 3-inch ejector is aft in the engineering spaces, and both units can be controlled and fired from a panel in the control room.

Keeping track of the electronic noises an SSN encounters is the job of Miami's Electronic Support Measures (ESM) suite. Technically the suite is made up of a radar and electronic signal receiver known as WLR-8 (V). This is used to monitor the radar and radio emissions in operational areas. In addition, the Miami is equipped with a BPS-15 surface search radar to assist in ship handling and navigation. All these systems have their antennas mounted on retractable masts, which can be raised while the boat is at periscope depth.

^{The placement of the Miami's forward sonar arrays. JACK RYAN ENTERPRISES, LTD.}

AN/BSY-1 Combat System

At the very heart of the Miami's combat power is the new BSY-1 (pronounced 'busy one') submarine combat system. All the sensor, fire control, and weapons systems of the Flight I and II Los Angeles-class boats, as well as a few new items, are tied together into a single system controlled by a battery of UYK-series computers running almost 1.1 million lines of Ada (the defense department's systems programming language) computer code. Developed by IBM, with Hughes, Raytheon, and Rockwell as subcontractors, BSY-1 represents the first use of what is known as distributed processor architecture. All of it is tied together by a data highway known as a data bus, which is becoming something of a standard on weapons systems such as the F-18 Hornet fighter/ bomber and the Patriot surface-to-missile system.

This means that instead of having one large computer running all the sensor and combat functions, a central computer hands out processing assignments to other computers running code designed to handle a specific job like acoustic processing or cruise missile mission planning. In this way the distributed system actually runs faster than a larger single computer would. It also makes the BSY-1 system easier to upgrade and better able to operate in a degraded or damaged condition.

^{Mounting of the Miami's towed sonar arrays. JACK RYAN ENTERPRISES, LTD.}

Other than the racks of UYK-7, UYK-43, and UYK-44 computers buried in the computer compartments, the most visible signs of the BSY-1 system are the consoles in the sonar room, forward of the control room, along the starboard passageway. Here four manned sonar consoles provide the Miami with her ears to the underwater world. Into these consoles the BSY-1 system feeds information from the various sonar systems. The Miami's main sonar system, almost identical to the BQQ-5D system on earlier Los Angeles-class boats, is actually a collection of many different sonar systems, including:* The spherical sonar array, located in the bow. The large sphere (15-foot diameter) has both active (echo ranging) and passive (listening) modes, and is currently one of the most powerful active sonars (over 75,000 watts of radiated power) afloat anywhere in the world.* The conformal array is a low-frequency passive sonar array mounted around the bow.* The high-frequency array is an upgrade to the spherical array, allowing it to generate the advanced waveforms that make the active modes of the BSY-1 so effective. It also incorporates an under-ice and mine detection capability from an array in the fairwater.* The TB-16D is the basic towed array, which is fed from the tubular shroud on the starboard side of the hull. It is a passive system, designed to provide medium-range detection of low-frequency noise. It is fed from a large reel in the forward part of the boat and played out from a tube in the starboard horizontal stabilizer. It has a 2,600-foot cable that is 3.5 inches/89mm thick, with the receiving hydrophones in a 240-foot-long array at the end of the cable.* The TB-23 is the new passive 'thin line' towed array associated with the BSY-1 system. Its smaller diameter (1.1 inches/28mm) means that the hydrophone array can be longer (approximately 960 feet), and it can be farther away from the noise of the towing submarine. The TB-23 is specifically designed to detect very low frequency noise at very long ranges. It is stowed on a reel in the aft and fed from a receiver in the port horizontal stabilizer.* The WLR-9 is the acoustic intercept receiver designed to alert the crew that an active sonar is being used, such as large active sonar arrays or sonar on incoming weapons.

Associated with all these systems is a series of signal processors and other equipment, which translate the sounds emitted and collected by the various sonar systems into the data displayed on the sonar consoles. The four BSY-1 sonar consoles are usually configured to have three of them looking at particular elements of the BQQ-5D sonar sensors while the fourth is used by the sonar watch supervisor. There also is a sonar spectrum analyzer available at a workstation in the forward end of the compartment. Each console has a pair of multifunction displays, which can be configured quickly by the operator for the particular sensor and mode of interest. For example, one sonar technician might be looking at the broadband noise being collected from one of the towed arrays. Another might be watching for broadband contacts on the spherical array.