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A Brief History of The Push-Pull of Submarine Combat Control Systems

Combat Control is the link between the sensors, like the periscopes, radar, communications intercept and sonar, and the weapons, torpedoes and missiles. The earliest combat control system was the Commanding Officer’s brain, and while the later systems became sophisticated computer arrangements, like the Submarine Combat Control System (CCS) MK 2, we still rely on the human brain as the final integrator.

The term “Submarine Combat Control Systems” needs a layman’s definition before we discuss the history. A proposed definition is: A submarine system, part of the submarine “com-mand, control, communication and computer system” (see Jerry Holland’s article, “Submarine Command and Control in the New World Order”, October 1992, SUBMARINE REVIEW) that correlates all sensor inputs, including off-board information, and produces target track, contact management and command weapon employment information needed to shoot any one of several weapons.

The first question is, “Haven’t we just defined a fire control system?” And the answer is, “Yes, sort of.” In fact, the fire control (weapon employment) function is an important part of the submarine combat control system. What we have described as Fire Control Systems in the past, as we will see shortly, were really command-integration systems forming a complete picture of the sensor inputs much as the Navy Tactical Data System (NTDS) has done on the surface ships to integrate the radar, and sonar pictures. As the data collection and correlation have shifted to increasingly capable electronic systems, the Combat Control System becomes more of a command tool than one strictly for weapon employment For this reason, I propose we use the term Combat Control System in the future rather than the term Fire Control System.

Each submarine combat control system we discuss here can be categorized as having resulted from either a weapon pull or a technology push requirement. By weapon pull, it is meant that the change in the Combat Control System is the result of weapon changes requiring new control functions. By technology push, it is meant that the existing combat control functions have been updated with newly available equipment and computer software. As a matter of interest, the push and pull influences on submarine combat control systems seem to alternate about every ten years.

View full article for table data

The earliest submarine fire control system was nothing more than the MK I Eyeball aiming the bow of the submarine in the direction of a target, but the torpedoes were erratic.

The problem of torpedo directional accuracy was solved in the late 19th century when gyroscopes were used to control the torpedo’s vertical rudder. By the tum of the century, the torpedo bad evolved into a deadly accurate naval weapon. Frre control was something else. The Holland class boats still bad to be maneuvered so the torpedo was fired directly at the target

In the 1920s the Bureau of Ordnance fitted the submarines with remote, outside gyro-setting devices which enabled the course of the torpedo, after it was loaded in the tube, to be adjusted up to the time of firing. Neither target range nor speed could be estimated accurately so various devices were developed to help the firing officer. One was the Submarine Attack Course Finder, the “Is-Was”, a circular slide rule that was used to determine bearing after the submarine commander made his best estimate of course and speed. To quote John Alden in, The Fleet Submarine in the U.S. Navy,

“The device was called the ‘is-was’ because all too often by the time the commander was able to get an answer to the question, ‘where is the target’ it wasn’t there any more.”

Another band-held device developed in the 1930s was called the banjo angle solver because of its shape. Angled shots at other than 00 and 9()0 could be made. This is an example of weapon pull where the change in the weapon (the remote setting gyros) caused a change in the combat control.

The next change driven by better device technology in the 1930s was the Torpedo Data Computer, the IDC, which was an electro-mechanical computer. The me was a significant advance over the hand held slide rules. Here the instrument combined a position keeper section with an angle solver that calculated the correct firing angles continuously and transmitted the information to the torpedo tubes and automatically set the angle on the torpedoes. Last minute submarine maneuvers were eliminated. Range to and speed of the target still required the seaman’s eye but single-ping ranges, radar ranges, and the development of periscope stadimeters helped solve those problems. The IDC was the standard through World War U although some other ingenious devices were being developed.

The proliferation of torpedo types at the end of the war leading the wire guided MK 37, MK 45, and eventually the MK 48 torpedoes provided a rigorous weapon pull that brought about the MK 101 and the MK. 106 Fire Control Systems. (The term Fire Control is used for historical purposes only.)

The MK. 101 was designed as a system and the chief im-provement was the automatic transmission between units, the reception of all target data simultaneously, automatic analysis of target course and speed, longer position keeping ranges, and other synchronous functions.

The original MK 101 could handle the straight runners as well as the various wire guided torpedoes up to the MK 48. Various modifications were installed on the post WW II submarines from the TANG class through NAUTILUS and SEAWOLF and up to, but not including, the PERMIT class.

The MK 106 FCS was just a post war system for the older submarines that could not accommodate the full MK 101. The system was build around the existing torpedo data computer. Like the MK 101, the MK 106 could handle the wire guided torpedoes up to the MK 48.

The MK 113 fire control system, introduced in the 60s, was designed to operate with the AN/BQQ-2 sonar system on the PERMIT class and with the simpler sonars on the strategic submarines.

Architecturally, the MK 113 was a digitized MK 101; a lot of analog equipment remained. Later versions of the MK 113 used CRT displays and like its predecessor, displayed the data on a series of dials showing relative target and own ship’s heading. Since the MK 113 was introduced as a fully passive fire control system, Target Motion Analyses (TMA) plotting became very important.

Various modifications of the MK 113 were installed with even mods on the attack submarines and odd mods on the strategic subs. MK 113 Mod. 10 which allowed the system to handle the analog SUBROC standoff weapon was close to the MK 117 FCS (see below). This could be categorized as a weapon pull rather than a technology push like the rest of the MK 113 modifications.

The MK 117 which began in the early 70s was the first all digital fire control system and was forward fitted on the later 637 class and the SSN 688 and backfitted on the long hull and earlier 637s and the 594 classes. The MK 118 was a simpler version for the omo class strategic submarines.

The introduction of the central computer complex on the class, using the Navy standard AN/UYK-7 and AN/UYK-44 computers combined with the MK 117 FCS, defined the CCS MK The introduction of weapons like the Tomahawk and Harpoon missiles, the advanced capability MK 48 torpedo for SSN 688s, mines for SSN 637, and the MK 48 torpedoes for the Trident submarines, was definitely a weapon pull for this combat control system. The complexity of the weapons requiring over-the-horizon targeting and the growing complexity of the sensor suites was taxing the capacity of the existing computers. So many configurations existed that a sailor with a weapons rating who transferred from submarine to submarine had to literally go back to school to learn about the next boat. Fortunately, the computer technology was geometrically progressing at this time and the problem was addressed with a new technology push.

The BSY-1 is an integrated combat system that replaces the AN/BQQ-5 sonar suite and CCS MK 1 control system on the later SSN 688 class submarines. This is a system that combines the information from a variety of arrays and melds the data into a single tactical display. New Navy standard computers are introduced and the AN/BSY-1 incorporates the combat control functions of the older CCS MK 1 for the various missiles and torpedoes.

The AN/BSY-2, being designed for the SEAWOLF (SSN 21) submarine, was split from the AN/BSY-1 when the AN/BSY-1 development experienced problems in 1985 and 1986. The system has increased capability against the projected Soviet threat, but now with the demise of the Soviet Union and the apparent end of the SEAWOLF program, there is some question about where the program is headed.

The latest CCS, the MK 2, was started a year after the AN/BSY-2 in 1988 as an update of all of the older CCS MK 1 and CCS MK 1-based systems, such as the AN/BSY-1, as well as to provide performance enhancements for command, passive ranging, over-the-horizon, and MK 48 ADCAP for Trident.

The CCS MK 2 uses militarized commercial workstations and Reduced Instruction Set Computers to provide commonality across the three SSN 688 versions (basic 688, vertical launch 688s and BSY-1688s, called 688Is) and Trident and provides a basis for future growth. There is a slight weapon pull for the MK 48 ADCAP torpedo for Trident but essentially the CCS MK 2, the AN/BSY-1, and the AN/BSY-2 are all technology pushes as we attempt to bring more current computer technolo-gy to the submarines.

What for the future? Historical trends would indicate a weapon pull. H we examine some of the new submarine missions, we recognize that there will probably be a requirement for a new standoff weapon (Sealance?), a new shallow water torpedo, some sort of an AAW weapon for shallow water operations, as well as introducing mines to the SSN 688s when the SSN 637s are retired.

The next period of submarine development is shrouded by the dramatic changes in the world political situation. I read an interesting book recently called Men. Machines, and Modem Times by Elting E. Morison, a nephew of S.E. Morison. The book was published in 1966 by the MIT press. Ed Walsh, the Editor of Seapower, loaned me the book because we had been discussing the causes of major changes in the naval systems. Dr. Morison’s thesis is that we hold on to the past and retain too much of the past conventions. This stifles development of new naval systems.

A good example is the proliferation of mods to the CCS MK. 1 discussed above which finally caused the technology push to develop the AN/BSY-1, AN/BSY-2, and the CCS MK. 2

Now we are developing open architectural systems using new standards which are software based. The future push-pulls for the combat control systems and the weapons will be based on common hardware and software elements. This will provide a more stable base for program specific developments and hopefully reduce the costs and schedules of these developments in the future.

We need to encourage our young officers and sailors to use the modem tools we have presented them to create what is needed for the submarine missions of tomorrow. At the same time, we should recognize that there is a certain rhythm In the development of our combat systems that hold lessons for our future work.

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