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“pas*0nally the hunted—in this case, a Soviet ^ °xtrot ”-class submarine—and the ^nters—S-3 ~Viking ASW planes—operate n.f\h n °feac^ other. But the real object ^ ts deadly game is for each to conceal its p*Sefce from the other. For this reason, SsiVe sonar has been increasingly espoused as t/peanS detection. Unfortunately, overuse of l . Method could ensnare the hunter in a trap a,d A, • • , , / y ‘ts intended quarry. | marines; and the tactical threat, composed of nuclear- and diesel-powered cruise missile-firing and torpedo-firing submarines. To counter these two very different threats, the U. S. Navy has developed ASW tactics which rely on the strongly held beliefs of individuals in two philosophical schools: proponents of active sensors and proponents of passive ones. Passive sensors, other than visual, while they do not alert the submarine, usually require elaborate methods, multiple contacts, and considerable time to convert a detection into a fix accurate enough for weapon employment. Active sensors, on the other hand, while alerting the submarine, can produce a highly accurate fix with fewer contacts, less elaborate methods, and usually in considerably less time. The desire to use passive sensors almost to the ex |
p|entlsukmarine warfare (ASW) is extremely com- ^ . arid diverse. It encompasses the full gamut of § lts ^om submarines to surface ships to aircraft. tf0Uar*Os range from the lone P-3 or submarine pa- sub ^ar at sea t0 coorcl‘nated operations involving tyj rtlarirtes, surface ships, helicopters, and fixed- °ne^ a‘rcraft all operating in a confined area with sub °kjective in mind: to find and destroy enemy bjerr>ar>nes- To discuss and define the myriad possi- Jk , SCenar*os *s not the purpose of this article. seer> it is to focus on one extremely important ttia ■ ent c^e ASW problem: conversion of a sub- ^Ce'f6 ^etecti°n into an attack in the vicinity of surer.^. 0rces. The special problems and tactical consid- AS\w°nS 'n t^*s scenario will be addressed from an air Point of view. | clusion of active sensors was born of necessity. The faster, deeper-running, more maneuverable nuclear submarine could usually evade a single aircraft attempting to localize with active sonobuoys. Surface ships which could hold a diesel-powered submarine and force her to the surface could no longer actively maintain contact at the speeds needed to keep up with the evading nuclear submarine. Therefore, the most common axiom for successful prosecution and attack became the passive axiom: "The first indication a submarine should have of your presence is from the sound of your torpedo.” If one localizes with active sensors, the nuclear submarine will be alerted and will evade at high speed, whereas if one is covert and announces one’s presence with a torpedo, then the chance of the submarine’s successful escape is significantly lowered. Is this reliance on passive detection, localization, |
Th is r6 suhmarine threat to our nation and our allies Of °told: the strategic threat, composed primarily nUclear-powered, ballistic missile-firing sub- | and attack the only alternative? Is there still a place for active tactics? Could we be neglecting an extremely important tactical approach by placing so much emphasis on passive sensors? The crux of the |
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NAVY M
Jm, mm* * *
jd NAVY
however, the tactical ■ submarine is the hunter,
the surface forces are the hunted. Throughout
howevef'
firing submarines. It is patently obvious,
to
rotec'
The two most relevant factors in the ASW Pr° j
any force, protection may be considered in te^nlSjVe area or circumference. For example, if a
sui
ffr
detection range of 5 miles is predicted a£ajn^_ fC-
threat, approximately 300 sonobuoys would bc
to
three hours and then have to be replaced this is an unrealistic and unworkable approach
ASW problem is to decide when it is advantageous to allow the submarine to assume she is undetected and when is it more advantageous to let the submarine know she has been detected.
Operations against a transiting submarine or one maintaining a patrol area are offensive in nature. The submarine is the hunted from the outset. Whether she is a ballistic missile or attack submarine on patrol, her mission is best accomplished by scrupulous avoidance of all enemy submarines, surface ships, aircraft, and other surveillance equipment. She must make every effort to remain as silent and as invisible as possible. Only when threatened must she take avoidance action. The aircraft flying above the submarine is akin to a hawk circling high above a field eyeing a rabbit. If the rabbit becomes aware of the hawk’s presence, it will scurry to protection before the hawk can attack. The hawk must therefore position itself so that when it swoops toward the rabbit, it will remain undetected until assured of a kill.
The role of the hawk is most often played by maritime patrol aircraft: the U. S. P-3 Orion, British Nimrod, Canadian Argus, Soviet “May,” and others. Capable of remaining on station for long periods, a crew can patiently and methodically stalk the submarine. Covert operations are the rule of the day. Searching in probable areas of patrolling or transiting submarines, the crew patiently waits for an initial detection. Listening to passive sonobuoys and alert for any electromagnetic emissions, the crew is careful to minimize its own emissions. Once a detection is made, the process of localization can begin. Passive localization can be extremely accurate and reliable, but it is seldom quick. Only in certain cases such as visual, infrared, or electronic surveillance measures contact held to on top can the process be considered quick. With direct-path acoustic conditions and extremely short ranges, a close-aboard sonobuoy detection is also tantamount to localization, but ready rooms are filled with stories of being too far from the sonobuoy to return to it before contact was lost.
Although there are many extremely sophisticated means of localizing and fixing submarines by using passive sensors, for the most part it takes patience and, most importantly, time to reduce the estimated position sufficiently to be able to attack. Nevertheless, as long as the submarine is unaware of the presence of the aircraft, time is of secondary consideration. It is important only to the extent that it affects sonobuoy life, aircraft on-station time, and submarine speed of advance, if any. If considerable time is needed to resolve the submarine’s position passively, the surveillance may be continued by a reliev
kllV VV Vi ViiV Mii ViMAV — - - —* —
immediate danger to friendly forces, the patient p cess of localization and fixing can continue.
In operations involving offensive submar
the
Lilt ouuaLL iv./ittc> aiv. Lilt HUlKtU.
encounter, from initial detection by the ASW * to eventual foiling of submarine attack, the e e ^ most critical to success is time. If the long-1 missile attack can be considered an antiair w problem, then the immediate ASW threat around a surface ship such as an aircraft carrier , jn tends to approximately 30 nautical miles. a
that radius, imminent attack is possible ) “Charlie”-class submarine and within approxIlTia^ 10 miles, imminent attack is possible by torpe
that the submarine should not be allowed to clo^ ;s these ranges in the first place. Nevertheless, oftentimes easier said than done. It would also aPP ^ that in this situation a good offense would be ^ best defense. This assumption can prove to be ^ error. If all submarine contacts could be locahze ^ attacked at some distance from the surface ^ greater than the lethal range, the submarine t could be neutralized. The answer to this cha lies in assets available and simple geometry tion of surface ships are radius of protection aggregate probability of detection desired. Since modern nuclear submarine presents a 360° threa
ASW posture were desired which would give '' j cient reaction time against antiship missile ^ torpedo-firing submarines, perhaps a radius ° nautical miles would be appropriate. However, fensive ASW out to 100-mile radius overtaxes PrC^ assets if a credible job is desired. For instance-^ total area sonobuoy coverage is desired and a me
quired. This sonobuoy field would last ^or.jU^r|y
• *iiy ^ The present solution to the problem is usu<
lay protective sonobuoy barriers along the . $
ahead, and behind the force and walk the barr
with the surface force’s speed of advance, <m ^
ically sweeping the ocean clear of submarineS^^t
moving sonobuoy barrier around a force or a ,
carrier would typically look like Figure 1 • P°r
and rear barriers would be walked in relati°n
LOCKHEED AIRCRAFT CORPORATION
Speed r
Hou, °* a<avance and sonobuoy life. The problem is °ne °f circumference, not area. To maintain a scheme would require a minimum of 50 to 60
now snch
WereU°ys only a single line containment barrier Co Maintained around a carrier alone. Although SUch* erably better than 300, the management of reQSc^ernes is still unwieldy at best, and the assets w°;^ are considerable. Two P-3s or S-3 Vikings stantl ^ retlu're<^ iust t0 replace sonobuoys cony; Not all sonobuoys could be effectively moni- S|multaneously, and the possibility of the sub-
tored Marine
vide Penetrating the barrier is still high. To pro- abipa c^ou*:>*e sonobuoy barrier, thus increasing prob- to' ! of detection at a radius of 100 miles, and also W0^e continuous monitoring of all sonobuoys, t,- require seven S-3s or P-3s on station at all rjers ' JUst to monitor and lay single sonobuoy bar-
9uire
a reduced range of only 70 miles would re-
cha <>Ur a'rcraft capable of processing 16 sonobuoy des- s each. If greater probability of detection is W0u,;. ’ m°re aircraft or multiple channel drops avail reclu'rec*- Since such assets are clearly not •j, . > certain compromises are necessary, and lncrease the aggregate probability of detection atn C()Verage factor with passive acoustic barriers m0 . a force or carrier, the assets available to tilen^t<)r and lay sonobuoys must be considerable, or Wj^ arriers must shrink to a size that is manageable
tly,
air assets presently available. Or an alterna-
Systrnust be provided. The towed array surveillance b Crn appears to hold the key for future passive tin fr'ers' The advantages are readily apparent: con- ancU<>Us coverage, radio jam-proof, unlimited endur- pe ’ and cost-effectiveness in terms of sonobuoy ex- appj ltUres- However, the same geometrical restraints °Pe ^ t0 towed arrays that apply to sonobuoys. The c0r)rat‘n8 range from the force or carrier must be ti0IStent with coverage factor, probability of detec-
s ! ar*d assets available. Regardless of the type of Pro!,';'? acoust>c sensor employed, the system must
'ty
f'^sive
Vl_de the requisite coverage with a high probabil- Unj” ^etection for 360° around the force. Individual fhejf niay ^ave a high probability of detection within sPh Searc^ sphere, but unless the individual search eres are contiguous, the overall coverage factor for
ings / July 1979
Experience has shown that the use of multiple aircraft, such as the S-3 and P-3 shown here, can effectively track and attack a nuclear submarine closing an aircraft carrier.
the force is reduced, and the aggregate probability of detection of an attacking submarine is correspondingly reduced.
The matter of greatest concern must be the time delay from the force or carrier that the submarine can be passively detected. If long time-delay detection can be achieved, localization may be considered in the same light as the open-ocean passive prosecution. If available assets prevent deploying the passive barrier at significant distances, however, a very different problem presents itself. The radius of search must be reduced, or a reduced coverage factor must be accepted as optimum. Reduced coverage factor, resulting in lowered aggregate probability of detection, has usually been the modus operandi because of the enormous drain on assets needed to monitor a barrier continuously. Traditional zones of responsibility (Figure 2) have been established which usually place the P-3s farthest from the force, the S-3s and light airborne multipurpose system (LAMPS) helicopter- equipped ships at medium range, and the SH-3 helicopters and non-LAMPS equipped ships at close range. Although this arrangement appeals to plan-
37
If
criteria for a torpedo is a time-consuming even^' ^ the carrier is maintaining a speed of advance <■ knots and a submarine is ahead of her, the cl rate can be in excess of 30 knots. An undetect ^ “Charlie”-class submarine originally at 75 miles be within lethal range of the carrier in less than and a half hours. In my experience, the more rea ^ situation involves a submarine detection at less 50 miles and often at less than 30 miles. The time^ react is now of extreme urgency. There is no tim , successive barriers, refined DIFAR (directional frequency analysis and recording) patterns, or ^ parative LOFAR (low-frequency analysis and reC°^f_ ing) fixing and multiple sonobuoy contact. The rier is in imminent danger, and all assets must brought to bear rapidly. No longer is this the si ^ tion of one-on-one, the hawk and the rabbit, m
the
. ■ For
open ocean with time a secondary consideration- ^ an effective weapon employment, the final PoS ^ of the submarine must be determined in Pr . terms. The procedures required to reduce the^seat^
d
fix an' an1
ners and is geometrically “pretty,” it is poor utilization of assets with current capabilities. Even though the coverage factor and aggregate probability of detection are low, we persist in thinning our forces in the hope that a detection will be made at great distances from the surface force or carrier. The real threat to the carrier is from 50-75 miles or less. The decision to opt for a reduced aggregate probability of detection must be weighed against the risk of unalerted attack. Considering the stakes involved, a reduced radius of search and a corresponding incease in aggregate probability of detection would seem preferable. Sending a great portion of the ASW forces over the horizon searching with a low probability of detection is reminiscent of the cavalry storming out of the fort and galloping over the horizon in search of Indians, only to have the Indians creep out of the sagebrush and burn the fort just as the dust settles on the far hill.
Given our present assets, not only should the ASW forces remain fairly close to the ships needing protection, but the tactics involved once a detection is made need to be reviewed. Passively converting a submarine detection into a fix that meets attack
area of thousands of square miles to a precise launch a torpedo attack must be quick, accurate ^ reliable. Precious time must be spent developing estimated position. Once an estimated position lS^ the decision to use active ta
veloped however, me ucumuu m use must be strongly weighed. Attack criteria must gained in the shortest possible time. The cons>
6r
erations involved are: distance of the datum frorn C c
amber *
assisting ASW forces available, and consequences^ going active. Limiting lines of approach can ‘ new meaning in the age of nuclear submarines- stead of designating the approach distance vC relative speed, they can be used to determine the
force, closure rate and estimated threat, nur
By
using
quirement for active or passive acoustics. ^
the all-important variable, time (determined by ^ sure rate), and estimating the mean time for con sion from detection to attack for various tactic5- valid decision can be made whether to employ at
COURTESY OF HSL-37
LAMPS helicopters give surface escorts, such as the frigate Ouellet (FF-1077), an important new capability. But it is a resource which must not he squandered through poor positioning of ships and helos.
tack
tele.
age of this tactic is that MAD contact meets at- ctiteria, so in this situation a weapon could be
process, it should be remembered that for the ai ent> 3 foiled attack by the submarine is a success « as great as a kill of the submarine, although that ^ ^SS Permanent- ^ should also be remembered carri ^ 'P1111^’316 safety of the force—especially the r’ ls of prime concern. If a single aircraft Ure°SeS t0 active at this time, the chances for fail- 0p t0 are surely as great as going active in the an ~°cean passive situation. An aircraft anticipating active engagement has several alternatives, hlr feommand activated sonobuoy system) and pi S directional CASS) sonobuoys can be prede- tlj ln an area °h high probability computed to be rern SUkmarine’s position of future movement and COniain acoustically silent until the submarine is JctjJ3Uted to be within the pattern. At that time, the tai j Sonar may be commanded on and fixes ob- the Slrr|ultaneously from several sonobuoys before tjo^^tfarine can evade. Since CASS is omnidirec- 9[1 ’ at feast three sonobuoys are required to obtain
s0n^arnhigu°us fix solely from the sonobuoys. Two c°nt U°^S an<^ (magnetic anomaly detection)
ar>0thCt °n °ne C^e amb*guous fixes provide vatl(. er means of resolving actual position. The ad- "d- An advantage of using only sonobuoys gro ke to eliminate the need to actually control tke Jd Crack until ready for weapon release. Use of C-ASS sonobuoy removes many of the problems
DECISION AREA FOR ABANDONING PASSIVE FOR ACTIVE TACTICS ' LETHAL AREA' OF TORPEDO OR
MISSILE FIRING SUBMARINE „
*>re w . .
*rJr. 3 Critical Areas for Determining Defense Against °~ or Missile-Firing Submarine.
of the CASS sonobuoy since a single sonobuoy will give range and bearing to the contact. The same use of MAD is extremely desirable since it is important to confirm a contact with two independent sensors.
The dipping-sonar helicopter also has unique advantages at datum. Since the sonobuoy-to-aircraft link is via radio energy, the possibility always exists that this link would be jammed. The helicopter sonar dome is not susceptible to radio jamming. An additional very desirable advantage of the helicopter is its hover launch capability. Although the DICASS sonobuoy is designed to make any airborne ASW vehicle a dipper, experience does not substantiate this. Once a helicopter is on station, the number of dips or investigations it makes is solely dependent on the amount of fuel remaining. Cost per dip is not a real tactical consideration since the helo’s existence is already established. The actual cost per dip is not a published figure even if known and would depend primarily on the compiler. Cost per “dip” in the case of a DICASS sonobuoy, however, is an item a logistician can verify. Regardless of “true” cost, the fact remains that even in volume production, DICASS sonobuoys will be extremely expensive items. Not only will the supply be limited, but there will be a certain mental reservation by the crew in employing them. Whereas today one is not reluctant to dip randomly and investigate fully a high-probability datum, there may be a great reluctance on the part of aircrews to employ DICASS sonobuoys randomly as necessary for active investigation of an estimated po
sition. Considering all the variables, a much more effective active team than a fixed-wing aircraft with active sonobuoys is a fixed-wing aircraft accompanied by helicopters with dipping sonars. Whereas a single aircraft using active sonobuoys would have yielded dubious results, experience has repeatedly shown that multiple aircraft can effectively track and attack a nuclear submarine closing a carrier. The S-3 has brought extremely accurate navigation and sophisticated tactical displays to the carrier-based ASW role, and the TACNAV (tactical navigation) improvements soon to be incorporated in the SH-3 will allow a major increase in this plane’s capabilities. Surface ship active sonar in conjunction with aircraft has the same coordination potential as the dipping helicopter, yet it can be hampered by ship/ submarine speed differential when attempting to maintain contact. Because of the power of surface ship sonar, certain advantages and disadvantages must be considered. Greater ranges are possible than with helicopters, yet if the active sonar is used in open-ocean search, it will undoubtedly assist the submarine in homing on the force. However, once the submarine has been passively detected closing the force, the cat is out of the bag. You are hampering no one except yourself in failing to use active tactics. In the case of the diesel-electric submarine, once she has submerged you must use active tactics. The reliance on active or passive tactics has also profoundly affected the sensor employment espoused by different communities. Because of the much greater datum revisit times capable with the more maneuverable S-3 and SH-3 aircraft, magnetic anomaly detection tracking tactics, coupled with active prosecution, constitute a more logical tactic. Very often, too, these tactics are dictated by water conditions in the operating environment. The need to use more than one plane to effectively track a high-speed target actively has led to a symbiotic relationship between S-3s and SH-3s. The preponderence of solo operations, vastly better endurance, but reduced maneuverability, has led to an emphasis on passive tactics on the part of the patrol (P-3) community. The successes enjoyed as a “self-contained” unit have led to a reluctance to engage in crowded sky, coordinated operations. Additionally, the previously mentioned low success rate for single aircraft active tactics has engendered a de-emphasis of MAD tracking and active sonobuoy tactics. Each community is selfreinforcing in its tactical approach. Although each ASW plane has been developed with a different purpose in mind and more suited to some tactics than others, it must be remembered that it is the submarine, and not the aircraft, that dictates the tactics. | It would be foolish to actively prosecute wit chance of losing contact when time allows for Pa prosecution without risk of counterattack. By same token, passive prosecution and attempt r sive fixing as the submarine closes within aI*^ range of the carrier are equally absurd. Repeate phasis on passive tactics and equipment, ho" has led to many an aircrew tracking a subm right under the carrier while continually attemp to passively gain attack criteria. The end resu ^ wartime would be a flaming datum. One cannot sight of the point of an attack submarine. Her s ^ purpose is to sink ships. If our ASW forces can effectively counter this threat to our surface 0 then we must question the reason for their existe To increase the aggregate probability of dete versus search radius, our forces must operate closer^ the ships needing protection and thus improve ^ coverage factor. Because they must work closer, ^ time does not usually exist to passively fix 0 attack before the submarine is within lethal ra Regardless of the aircraft type, it must be PreP to engage in coordinated operations to prevent ^ minent attack on surface forces. Unfortunately, ^ concept is not universally understood. Passive *a .^g are preferable as long as one has the luxury 0 , £ for fixing refinement, but when time becomes critical element in the ASW problem, reliance tive sensors is a must. More emphasis must be P ‘ on coordinated active tactics and dipping sonar solve the close-in ASW problem. ^ The present emphasis on passive tactics is not creating a philosophical reluctance toward active tics but is also creating a critical gap in our abifoy , effectively counter the submarine which is det ^ close to the force. The passive trap so effectively u by our ASW forces in the proper situations >s takenly assumed to be the best tactic at all n De-emphasis of active platforms, especially dipP „ sonar, could eventually catch us in a “passive trap ^ Commander Lonsdale joined the Navy in 1962 ^ the aviation officer candidate program. After ^ ^ his wings in November 1963, he joined VS-2-* - • the S-2 from the USS Lake Champlain (CVS-39)* ' * A Essex (CVS-9), and USS Randolph (CVS-15). He ^ Navy in 1967 to join the Magnavox Corporation, ^ MUM he worked on the DIFAR and moored buoy Pr0^ ^ In 1968, he returned to the Navy and reported to VX-1, where the S-2 and P-3. In 1970, he reported to CVSG-56 on board & ^ Intrepid (CVS-11) as staff antisubmarine warfare officer. In ^ jn again reported to VS-22 for transition training to the S-3A. Embar ^ the USS Saratoga (CV-60), VS-22 was the first East Coast squa T ^ deploy with the S-3 A. From 1976 to 1978, Commander Lonsdale j first as administrative officer and then as maintenance officer 10 He is now on the staff of Commander in Chief Pacific. |
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