Notes and references
- Stefanick , Tom . 1987 . Strategic Antisubmarine Warfare and Naval Strategy , 72 Lexington Books .
- Polmar , Norman and Noot , Jurrien . 1991 . Submarines of the Russian and Soviet Navies , 173 Naval Institute Press . Finally, the influence of historical events, such as the U.S. forcing Soviet submarines to the surface during the 1963 Cuban Missile Crisis, on the thinking of Russian policy makers cannot be neglected. During the crisis, six Soviet diesel submarines were detected and forced to the surface by U.S. ASW forces.
- Quiet Submarines a Serious Problem,” U.S. Congress, House Armed Services Committee, News Release, 21 March 1989.
- Stefanick . 1987 . Strategic Antisubmarine Warfare and Naval Strategy 33 The Soviet SSBNs of the 1960s and 1970s (Golf, Hotel, Yankee classes) had two major drawbacks: they were noisy and they had short range SLBMs. The last reason was why these submarines had to transit long distances in the Atlantic and Pacific in order to patrol in the open ocean, close to U.S. territory, where the United States and its allies had well developed ASW capabilities. In those days, the Soviet SSBNs appear to have been relatively easy to detect and covertly trail. However, this situation began to change by the late 1970s or early 1980s, when Delta III, Typhoon and Delta IV classes submarines were commissioned. These relatively quiet submarines did not need to make long transits in the open ocean to their patrol areas because they are capable of targeting most of the United States from their home bases near Murmansk and Petropavlovsk‐Kamchatsky
- Litovkin , Viktor . 1992 . “Three days aboard the “Typhoon,” . Izvestia , 2–4 March
- Bur‐byga , Nikolay and Litovkin , Victor . 1992 . “Americans Not Only Helping Us, But Spying on Us,” . Izvestia , 21 February : 2 In spite of the warming of the political climate, American submarines continue their activities close to the Russian SSBN bases. This was demonstrated by the collision of submarines near Murmansk in February 1992 (see, for example,
- Miasnikov , Eugene . 1992/93 . “Submarine Collision off Murmansk: A Look from Afar,” . Breakthroughs, Defense and Arms Control Studies Program, M.I.T. , winter : 19 – 24 . and by another incursion of a foreign submarine into Russian internal territorial waters a month later
- Pilipchuk , A. 1992 . “Antisubmariners Were Ready to Use Weapons,” . Krasnaya Zvezda , 28 March : 2 Presumably, one of the purposes of these missions is deployment of underwater sensors for gathering intelligence about the acoustic signatures of the Soviet submarines.
- Ball , Desmond . 1985–86 . “Nuclear War at Sea,” . International Security , 10 (3) winter : 3 – 31 .
- Mozgovoi , Alexandr . 1993 . “20 Meters Separated from a Nuclear Accident,” . Rosiyskaya Gazeta , 1 April : 1 More recently, on 20 March 1993 a Russian “Delta” class SSBN collided with the USS “Grayling” in the Barents sea
- Stefanick . 1987 . Strategic Antisubmarine Warfare and Naval Strategy 17 Deployment of such a system seems improbable in the near future (see
- Stefanick , Tom . 1988 . “The Nonacoustic Detection of Submarines,” . Scientific American , 258 (3) March : 41 – 47 . Nevertheless, according to the press reports, submarines may sometimes under special conditions be observable by satellites
- Covault , Craig . 1990 . “Soviet Radar Satellite Shows Potential to Detect Submarines,” . Aviation Week & Space Technology , 8 October : 22 – 23 .
- Even if the position of an SSBN is known, it can be hard to destroy it, since its position changes continuously. U.S. use of covert ship or air‐based short‐range weapons for preemptive killing of a Russian SSBN is not practical in the Russian internal seas or the Arctic. This is also true for long‐range weapons; in this case, in addition to the problem of finding the submarine, the position of the submarine can change during the weapon's flight time.
- Gellman , Barton . 1992 . “The ‘Silent Service’ Breaks the Ice,” . Washington Post , 19 April : A4 By the year 2000, the number of Russian SSBNs is expected to diminish from 54 to 24 (see table A1.4). At the same time, the number of U.S. “SSNs will drop from 84 to 60.
- In order to continuously and covertly trail an SSBN, an attack submarine must be able not only to detect the SSBN, but must also be able to determine its bearing and range with a high accuracy during the entire time of trailing. Moreover, the attack submarine must also operate carefully and keep at a distance at which it is undetectable by the SSBN. Thus, the trailing problem is a different and more difficult problem than the detection problem.
- Sakitt , Mark . 1988 . Submarine Warfare in the Arctic: Option or Illusion? , Stanford, California : Center for International Security and Arms Control, Stanford University . In particular, this book considers the problem of how the detection range influences the search time required for finding hostile submarines.
- We do not consider a submarine's periscope, which is used for surveillance above the water surface and does not help in detecting a submerged target. Moreover, a periscope sticking out of the water could be easily detected by modern surface search radars.
- In particular, it is possible if the frequencies and relative intensities of acoustic lines in the submarine noise generated spectra are known a priori.
- Urick , R.J. 1983 . Principles of Underwater Sound , 22 McGraw‐Hill Book Co. .
- The decibel is a logarithmic unit. If K is a ratio, then that same ratio expressed in dB is equal to 10 log10(K). For example, if source level exceeds the reference intensity by 100 times, we get SL = 10 log (100) = 20 dB.
- R.J. Urick, 1983, op. cit., p. 21.
- Cavitation is a phenomenon which occurs because of the formation of partial vacuums in a flowing liquid as a result of the submarine propeller blades passing through it. The occurrence of cavitation is accompanied by a sharp increase of the radiated sound power.
- R.J. Urick, 1983, op. cit., p. 332.
- As a rule, the speed of a submarine on patrol is kept low, because as the submarine's speed increases, the SL also increases due to the cavitation and hydrodynamic noise. For example, at speeds of 5 to 8 knots, US and Soviet submarines produce negligibly low levels of noise (Stefanick, 1987, op. cit., p. 9)
- Wille , P.C. 1985 . “Ambient Noise: Characteristics of the Noise Field,” . In Adaptive Methods in Underwater Acoustics , Edited by: Urban , H.G. 13 – 36 . D. Reidel Publishing Co. .
- Besides using the narrowband processing technique to detect tonals, a sonar operator may also be able to detect the relatively short, but very intense, noises radiated by a maneuvering submarine (such as grinding of the rudder or noises related to a change in the flow regime).
- Published data for ships and submarines typically show bandwidths of several Hz, although these measurements may been made with equipment with limited frequency resolution. However, even if the actual submarine bandwidths are very narrow, the detected bandwidth at a range of several kilometers would be no less than 0.1 Hz because of frequency broadening during the transmission through the water (this is discussed in more detail subsequently).
- R.J. Urick, 1983, op. cit., p. 350.
- The difference between these estimates and the data presented by Stefanick (Stefanick, 1987, op. cit., p. 274) must be emphasized here. The major source of submarine noise in Stefanick's analysis is cavitation, therefore his data on the source level corresponds to the noise integrated over a wide spectral band. In a narrow band, noise caused by cavitation is negligible compared to the machinery noise, at least at low patrolling speeds. For example, a serious problem in submarine construction is damping the sound generated by reduction gears, one of the major sources of noise. According to some informed sources, decreasing the tolerances in the size of the gears from 0.1 to 0.01 millimeters allows a reduction in the submarine source level of a factor of 30 or 40 dB.
- R.J. Urick, 1983, op. cit., p. 100.
- Typically the convergence zones are located at intervals of 55 to 65 kilometers. The width of the first zone is roughly several kilometers, the second zone is two times wider than the first, and so on until eventually, at ranges of several hundred kilometers, the zones overlap and become indistinguishable.
- Dyer , I. 1984 . “ The Song of Sea Ice and Other Arctic Ocean Melodies,” . In Arctic Policy and Technology , Edited by: Dyer , I. and Chryssostomidis , C. 11 – 37 . New York : Hemisphere .
- Acal , T. 1980 . “Sea floor effects on shallow water acoustic propagation,” . In Bottom Interacting Ocean Acoustics , Edited by: Kuper‐man , W.A. and Jensen , F.B. 557 – 575 . New York : Plenum .
- Jensen , F.B. and Kuperman , W.A. 1983 . “Optimum Frequency of Propagation in Shallow Water Environments,” . Journal of Acoustical Society of America , 73 (3) : 813 – 819 .
- Allen , J. 1980 . “Transmission Loss Variability in Shallow Water,” . In Bottom Interacting Ocean Acoustics , Edited by: Kuperman , WA. and Jensen , F.B. 485 – 492 . New York : Plenum .
- This feature can be used by a target submarine to defeat trailing by another submarine. By increasing its speed, the target submarine forces the hunting submarine also to accelerate in order to keep trailing. At high speeds, the flow noise becomes very large relative to the signal from the submarine that is being trailed and the detection range against the target submarine decreases. Thus the hunting submarine becomes “deaf” and can no longer continue operating in close proximity to its target.
- Urick , R.J. 1986 . Ambient Noise in the Sea , Peninsula Publishing .
- The noise level in the Arctic is highest near the ice edge, the so called marginal ice zone. The MIZ width is typically several dozens of kilometers.
- Lewis , J.K. and Denner , W.W. 1987 . “Arctic Ambient Noise in the Beaufort Sea: Seasonal, Space and Time Scales,” . JASA , 82 (8) : 988 – 997 .
- Friedman , N. 1991 . World Naval Weapons System 1991/92 , 611 Naval Institute Press .
- The newest array, the TB‐12X, is 12 times longer than TB‐16 and is currently under development. Its sea trials and operational evaluation are scheduled for 1993 (Norman Friedman, 1991, op. cit. p. 633).
- For example, the sound wavelengths in ocean water at frequencies of 30 and 300 Hz are respectively 15 and 1.5 meters.
- Sholz , B. 1976 . “Horizontal Spatial Coherence Measurements with Explosives and CW ‐Sources in Shallow Water,” . In Aspects of Signal Processing , Edited by: Tacconi , G. 95 – 108 . Boston : Dordrecht . part 1,
- Due to refraction and to reflections from the sea surface and bottom, there may exist several paths (rays) from a source to a receiver. This is a typical situation in the Arctic and in shallow waters.
- Urick , R.J. 1982 . Sound Propagation in the Sea , Peninsula Publishing . R.J. Urick, 1983, op. cit., p. 231. See also
- The signal processing procedure is actually much more complex. The sonar operator can watch signals at several frequencies and keep track of several targets at the same time. However, the principle described here is the fundamental one of sonar narrowband processing.
- In order to calculate detection index values for a given set of probabilities of detection and false alarms, we assumed that noise is Gaussian and signal level is constant. In this case, the following expressions are valid (R.J. Urick, 1983, op. cit., p. 386)
- Abramowitz , Milton and Stegun , Irene A. , eds. Handbook of Mathematical Functions with Formulas, Graphs and Mathematical Tables , New York : Dover Publications, Inc. . Values of (T/σ) and (T/σ‐d0.5) were estimated for given probabilities of detection and false alarm by use of tables of numerical data from
- The derivation of this formula can be found in the literature on signal processing. We would refer the reader to R.J. Urick, 1983, op. cit., p. 385.
- Sevaldsen , E. 1980 . “Effects of Medium Fluctuations on Underwater Acoustic Transmissions in a Shallow Water Area,” . In Bottom Interacting Ocean Acoustics , Edited by: Kuperman , W.A. and Jensen , F.B. 643 – 657 . New York : Plenum .
- R.J. Urick, 1986, op. cit. pp. 3–18
- See, for example, R.J. Urick, 1983, op. cit., p. 389.
- In this particular case, a decrease of 15 dB in transmission loss is assumed in the convergence zones.
- As can be seen, there is a significant difference compared to the deep ocean case. In fact, the detection range against a “quiet” submarine in the “nearest zone” in shallow waters might be a bit larger than in the deep ocean. However, in shallow waters there will be no possibility of detecting a submarine at a range corresponding to that of the first convergence zone in deep waters (55 to 60 kilometers).
- In this connection, the recent collision of a Russian “Sierra” class submarine and the U.S. “Baton Rouge” that took place in February 1992 in disputed waters off Murmansk should be mentioned (Miasnikov, 1992, op. cit.). Apparently, neither submarine heard the other before the collision. The same thing appears to have happened with the Russian “Delta” class SSBN and the U.S. “Grayling.” Fortunately, these accidents did not cause serious damage or severe injuries.
- It is important to note that disasters in shallow SSBN operating areas like the Arctic and Barents seas can cause much more damage to the environment than accidents in the open ocean, because the potentially dangerous wastes from exploding submarine nuclear reactors and missile propellant can spread throughout a wide area and kill all of the sea life in this area.