Submarine (1993)

by Clancy, Tom - Nf

  This takes time—sometimes, a lot. While you are trying to get all the information necessary to possibly shoot at a target, you must yourself remain undetected. Much of the data for the TMA process comes from the bearing rate, which is how fast the bearing of a target is changing, and monitoring the Doppler, which reveals whether a target is coming nearer or moving away; this is called the range rate. While the BSY-1 is helping the fire control team do its job, the manual plot team, assisted by a specially programmed Hewlett Packard 9020 desktop computer, is also working on its own TMA/range analysis. This little desktop computer has a program library that helps the manual plot team with the more intensive calculations and generates what can only be called instant ranges to the target. All the while the manual and automatic tracking solutions are checked, and data is crossfed between them. During the TMA process the boat would probably maneuver in a zigzag pattern to help the sonar crew establish better range and bearing rates for the TMA plots.

  Sonar room, USS Miami. JOHN D. GRESHAM

  Some nations have chosen to eliminate the dual TMA process and depend only on an automatic system. But this can lead to ranging errors in critical situations, so the U.S. Navy continues to use manual plots and automatic systems just to be sure. Recently Miami ran an exercise against a diesel boat belonging to one of our NATO allies. Apparently, because Miami had a small acoustic fault (called a sound short), the opposing sub thought the boat was much closer than it actually was: the automatic fire control system calculated the range to Miami at around 6,000 yards when, in fact, it was over 40,000 yards. And when the diesel boat fired at what it thought was a nearby U.S. boat, all it did was expose itself to attack by the Miami. Needless to say, Commander Jones made his “opponent” pay dearly for his error.

  LEFT: Notional view of a BSY-1 fire control console analyzing sound conditions in the surrounding water. The sine wave indicates that conditions for a “convergence zone” exist. Data from a bathythermograph is shown at the left. JACK RYAN ENTERPRISES, LTD.

  RIGHT: A notional view of a BSY-1 fire control console showing relative position, bearing, and speed of a target. This is an emulation of an analog system dating back to the 1930s. JACK RYAN ENTERPRISES, LTD.

  The TMA process is continued until the commanding officer believes the tracking party has a good enough picture of the situation at hand. Every contact has to have a reliable TMA solution and must be currently tracked. Here lies the real value of the BSY-1 system. For while the earlier Los Angeles-class boats could keep track of only a few targets at one time, the BSY-1 can handle many more. And once the system has a good track running, it has a great ability to hold and maintain the quality of the tracks.

  Eventually the target track(s) will be good enough to fire on, if that is the desired intention, and the time has come to set up a weapon for firing. The fire control technician begins the process by inputting the necessary presets into the chosen weapon. If it is a Mark 48, Harpoon, or Tomahawk antiship missile (TASM), this can be accomplished entirely at the BSY-1 console. Should a Tomahawk land attack missile (TLAM) need to be programmed, this is accomplished at the adjoining Command and Control System (CCS-2) console. For now, though, we will concentrate on the weapons programmed on the BSY-1 console.

  Fire control alley in the control room, USS Miami. JOHN D. GRESHAM

  A sailor works at one of the plotting tables in the control room, USS Miami. JOHN D. GRESHAM

  If, for example, the desire is to launch an antiship missile, the technician must have a decent estimate of target course, speed, and range. It is also critical to know whether there is any neutral shipping traffic in the area. The technician programs in the route to the target, as well as any waypoints necessary to route the missile around neutral shipping traffic that might be in the way. In addition, the technician programs a search pattern for the seeker head of the missile to lock in. This mission plan can be loaded into any number of missiles, which are then fired from the weapons control console located to the right of the fire control consoles.

  Notional view of a BSY-1 fire control console setting up an antiship missile attack. The expanding pattern on the screen represents the area being searched by the seeker head of the missile. JACK RYAN ENTERPRISES, LTD.

  The process for firing torpedoes is somewhat more dynamic than that for missiles. First the fire control technician develops a fire control solution through a process called “stacking the dots.” The screen where this is accomplished displays the target bearing versus time, similar to that back in the sonar room. On this display the target bearing is shown over a period of time as a series of dots. The technician fine-tunes the solution by adjusting the estimates of the target’s range, course, and speed until the display shows a straight column of dots stacked on the display. After several minutes of work and possibly a couple of maneuvers to verify the accuracy of the solution, it is now time to shoot.

  Despite what some computer games would have you believe, there are no joysticks for the fire control technicians to “fly” the torpedo onto the target. Instead, the technician changes the weapon presets on a screen that looks like a shopping list of parameters such as the seeker activation point (called “enable run”), search depth, and which seeker head mode the weapon is to be fired in. Also, the BSY-1 has several different operating modes, including a “snapshot” mode for fast-moving tactical situations that require the Miami to react quickly. Let’s assume that the fire control technician has been ordered to set up a pair of Mk 48 ADCAP torpedoes for a shot at a submarine. He selects the desired target track and allows the BSY-1 to input the weapon presets to the list.

  At any time, he can override or alter the presets to suit the tactical situation. For example, the ADCAP has modes to avoid making circular runs and attacking the firing sub accidentally, as well as the ability to preset a three-dimensional search zone for the weapons to search in, but not go outside. Once the weapons have been loaded with the required data, they can be fired by the weapons officer at the order of the captain. With the weapons now in the water, a junior officer calls up the weapons display on his console and monitors the torpedoes’ status.

  One of the nice features of the BSY-1/ADCAP combination is that the technician can “swim” the torpedoes out onto the target and use the seeker heads as offboard sensors to fine-tune the firing solution. This is made possible by the data link wire that the weapons trail out behind them, which is connected to the torpedo tubes of the Miami. This means that if the technician sees the target move out of the selected area, or do something tactically different from what he thought it would do, he can quickly change the necessary presets right from his weapon control menu.

  When the ADCAPs finally acquire the target, the process becomes completely automatic, with the operator’s help required only if a torpedo malfunctions. The logic in the guidance systems of the ADCAPs is very good, though if anything goes wrong the fire control technicians are always ready to step in on their own. Assuming that the weapons do their job, the final run to the target will be like watching a train wreck. When they hit, the sonar technician must assess the damage that has been inflicted. There may be breaking-up noises or the distinctive crunch of an imploding pressure hull. In any case, the tracking teams are now ready to start again, a never-ending task while on patrol.

  One thing we haven’t mentioned yet is just why the Miami has an active sonar mode when so many great things can be accomplished just by listening passively. For almost thirty years, going active with a sonar has meant giving up the tactical advantage. The simple truth is that while using an active sonar does alert a potential enemy to your presence, it does have some significant advantages. The latest nuclear boats produced by the former Soviet Union/Commonwealth of Independent States are almost as good acoustically as a Flight 1 Los Angeles. This means that finding them passively is going to be extremely difficult. And the current generation of diesel boats, when running on their batteries, are just a little worse, being very quiet targets to any passive son
ar system in existence. Using an active sonar can overcome some of these problems at relatively short ranges, and has tactical benefits in some situations, especially in verifying ranges before shooting. Unfortunately, an active sonar can be heard at least five times farther than the sonar can detect a target.

  The active sonar mode of the sphere sonar is incredibly powerful and can cause steam bubbles to form on the outer surfaces of the sonar dome. The spherical array does give accurate ranges and bearings, providing excellent fire control solutions in the process. In addition, it has the ability to form its sound signals into beams that are focused instead of just radiating in all directions. This means that only the target boat will know it is being “pinged,” and other boats in the area will not. In the sort of close-range “knife fights” that may develop between the quieter boats inhabiting the oceans today, going active may just be a good thing to do.

  Notional view of a BSY-1 fire control console preparing a fire control solution. Note the lines of dots adjusted by the knobs at the bottom of the diagram. When the dots stack in a straight line, the solution is ready. JACK RYAN ENTERPRISES, LTD.

  Weapons control console in the control room, USS Miami. JOHN D. GRESHAM

  Notional view of a BSY-1 fire control console preparing to fire a Mk 48 ADCAP. The table of data shows the various weapon presets. JACK RYAN ENTERPRISES, LTD.

  Torpedo room, USS Miami. JACK RYAN ENTERPRISES, LTD.

  This is a rough picture of how the BSY-1 system and her operators work together. Many other elements go into the process, but I hope this has given you a feel for how the operators would use BSY-1 to fight the boat. If you think it seems like a huge game of blindman’s buff, you are right on target, for it is said that in the land of the blind, the one-eyed man is king. In the dark realm of the world’s oceans, the Miami with its BSY-1 combat system is the king with the biggest eye.

  Torpedo Room

  When you wander down a couple of flights of stairs and move forward, you eventually wind up in the torpedo room. Here you are struck by the feeling of being in the very bowels of the Miami. Three sets of two-high racks allow for the stowage of twenty-two weapons, and four more are kept in the tubes. Usually, however, one or two of the rack spaces or tubes are left empty, to facilitate movement of the weapons and allow maintenance. Between the center and side racks are sets of loading and ramming gear. Go forward down the aisles between the racks and you will find the torpedo tubes. These have an internal diameter of 21 inches/533mm and are angled approximately 7 to 8 degrees off the boat’s centerline, so that when weapons are launched, they clear the bow with its big active sonar dome. One unique design aspect is the ability to move any weapon from any position in the racks to a torpedo tube or any other position on the racks. While the geometry of such a move is somewhat complicated, the actual movement of the weapons resembles a child’s puzzle in which eight pieces are moved through nine spaces to form a picture.

  BOTTOM: No. 1 torpedo tube, USS Miami. The inner door is open, showing the tube guides and the attachment points for the weapon “A” cable and torpedo guidance wire (when required). JOHN D. GRESHAM

  TOP: The torpedo room of USS Miami. The weapons on their racks are to the right, with the No. 2 and No. 3 torpedo tubes on the starboard side. The panel at the left of the photo is the control panel for the torpedo tubes and VLS system. JOHN D. GRESHAM

  No. 2 torpedo tube, USS Miami. The inner door is shut and the tube status sign shows it to be empty. JOHN D. GRESHAM

  Loading the weapons into the boat itself is a rather involved process, though one that the Miami’s designers actually thought out pretty well. Just forward of the fairwater is the weapons loading hatch; through here the weapons are brought on board. The first step in the process is to open this hatch and unstow the loading gear, which is cleverly composed of sections of the flooring structure from the second and third decks of the boat. The second-deck flooring becomes a loading rack that is hoisted up on deck to receive the weapons from the loading crane alongside. A section of the third deck serves as the transit rack, which spans the gap left by taking up the floor structure. Thus while loading is taking place, a gap like a canyon runs down the middle of the boat to the torpedo room.

  A Mark 48 ADCAP torpedo is raised on the loading tray for stowage aboard the USS Groton (SSN-694). JOHN D. GRESHAM

  The actual weapons-loading process is quite rapid once the gear is assembled. The weapon is swung over on a crane from the dock or tender and gently lowered into the loading rack. Once it is aligned, the loading rack is rotated up about 45 degrees, and the weapon is winched down on a chain-powered hoist. When the weapon has completed its nearly 50-foot journey, the transit rack is swung back to the horizontal, and the weapon is laid into the waiting skids on the torpedo room racks. At this point it is secured to the skids and moved over so that another weapon can be loaded. In all, the boat can be completely loaded, including setting up and striking the loading gear, within twelve hours, all with minimum support from a tender or dock crew. Afterwards, when the deck structures have been put back in place, you would never know this is the path the weapons take to the torpedo room.

  Loading a torpedo, while straightforward, is anything but simple. The first step is to move a weapon from the storage rack onto one of the loading trays. This requires a bit of brute force (Mk 48s weigh about 3,400 lb/1,545 kg) as well as some precision; even in this day and age, human brawn is still useful. Once the weapon is loaded onto the tray, the inner door (called the breech door) to the chosen torpedo tube is opened and a quick inspection is conducted. If another weapon has just been fired, the crew may need to remove a wire dispenser and/or some guidance wire (if it is a Mark 48 torpedo), or to check for wear on the tube. This little process, known as diving the tube, is a job best handled by those with narrow shoulders and long arms.

  Once this is done, the loading ram carefully moves the weapon into the tube. At this point one of the torpedoman mates (TMs) connects the data transmission link, called an “A” cable, from the back of the weapon (all U.S. submarine-launched weapons are equipped with such connections), attaches the guidance wire (if it is a Mk 48), and seals the breech door. Once the hatch is closed, the technicians check to make sure all the connections and seals are properly set, then hang on the tube a small sign: WARSHOT LOADED. One of the nice features on the 688I/BSY-1 boats is that once a tube is loaded, it automatically can tell what kind of weapon is loaded. On several control panels and status boards around the boat, the change in the tube’s status to Loaded and what it is loaded with are noted and marked.

  LEFT: An Mk 48 ADCAP is loaded into a torpedo tube on USS Miami. The torpedo is loaded with the ramming gear shown below. JOHN D. GRESHAM

  LEFT: An Mk 48 ADCAP torpedo on a loading tray is pushed forward into the tube. The precision of the operation is obvious, with careful attention being given to accurate alignment. JOHN D. GRESHAM

  RIGHT: Inside the No. 1 torpedo tube, USS Miami. The guide rails and slide valves are visible, as well as the outer door or “cap” at the end of the tube. JOHN D. GRESHAM

  A Tomahawk surface-to-surface missile (SSM) is test-fired from the submerged submarine USS Guitarro. U.S. NAVY PHOTO BY LARRY SAMMONS

  Once a decision to launch a weapon has been made (this always requires a look at the mission orders and the standing rules of engagement), then the technicians at the BSY-1 firing control panels up in the control room power on the weapon to warm it up. Then the fire control technician assigned to control the weapon loads targeting and other data into the weapon’s memory system. In the case of an Mk 48, this includes speed settings and seeker head mode. For a guided missile like a Tomahawk, it involves loading a complete mission flight profile. Once this is done, the weapon is ready to be fired.

  The process of firing a weapon from a torpedo tube is probably one of the most well tested procedures on the entire boat; it dates back many decades. With the weapon warm and ready to fire, the order is given, “Make the tube ready in all
respects!” This is not done lightly, for this is the first of a number of actions that radiates a great deal of noise into the surrounding water. Once the tube is flooded, the outer door or cap is opened, and the tube is ready to launch the weapon. The commanding officer gives the command, “Firing point procedures,” when the other necessary steps (such as sealing the breech door) have already been completed.

  At this point the captain issues the firing command, “Match bearings and shoot!” When the order to fire is given, the weapons officer at the BSY-1 launch control panel presses the firing button, and the firing sequence begins. The firing command directs high-pressure air from the air banks onto a piston. The air forces the piston to move along the piston shaft, forcing water out of another tube and through a slide valve in the rear of the torpedo tube, thereby forming a water ram that ejects the weapon out into the sea at something like four to six times the force of gravity.

  What happens next depends on which weapon has been fired. If it is a guided missile, then the outer door can be closed, and the tube is drained and made ready for reloading. If the weapon is a Mark 48, then the decision will probably be made to leave the outer door open. This is because the Mark 48 trails a guidance wire behind it, which allows the boat to guide the torpedo as it runs up to ten miles from the launching point. At any time, though, the wire can be cut. If the sub is traveling too fast, or makes too sharp a turn, then the water flow may break the wire. In any case, until the need for the guidance wire is gone, the tube must stay in use.