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The development in the last several years of weapon systems such as Tomahawk, Harpoon, Aegis, the Phalanx close-in weapon system (CIWS), and the Mk-41 vertical launch system shows a high degree of dynamism in antiair warfare and antisurface warfare. The U. S. Navy can counter the airborne threat with successive layers of defense: combat air patrol; Standard and NATO Sea Sparrow missiles; five-inch, three-inch, and 76mm. rapid-fire guns; and the 20-mm. CIWS. Progress in ASW, however, has been characterized by marginal improvements rather than technological breakthroughs. There have been some changes in the torpedoes, the sonars, and the ships, with which we hunt submarines, but our tactics are virtually unchanged.
There is nothing in the weapon inventory that yields a hard kill against a torpedo. Current doctrine on evading torpedoes holds that an escort ship should maneuver to avoid incoming torpedoes while activating decoying countermeasures equipment that is trailed astern. If the T-Mk-6 Fanfare or SLQ-51 Nixie is not being trailed at the time of attack, there won’t be enough time to deploy it. If it is deployed and is successful in drawing off an acoustic homer, the torpedo may very well continue on and strike the ship that is being escorted. If the escorting destroyer or frigate screens the high-value unit (HVU) literally by absorbing the torpedo, the escort will likely be sunk, leaving the HVU vulnerable to further attack. So the skipper of the destroyer is in a quandary. What is needed is a means of not merely evading the torpedo, but of destroying it.
With the advent of antisubmarine rockets and homing ASW torpedoes, the rails used for launching mines and depth charges began to disappear from U. S. Navy ASW ships. The old tactic of running over the top of a submarine to drop depth charges is long obsolete, but redesigned depth charges could be useful in countering torpedoes. This antitorpedo depth charge or mine (ATM) would be designed to sink below the probable running depth of the torpedo, then stabilize,
Current capabilities preclude hard kills on incoming torpedoes, but a reconfigured five-inch gun capable of firing a sonobuoy spread could keep the submarine on the defensive and the surface combatant out of torpedo range.
arm itself, and wait for the torpedo to pass by. The ATM would contain a noise maker to distract acoustic homing torpedoes and would detonate on the rapid Doppler shift of a passing torpedo. Even a small explosive charge, if detonated near the torpedo, could damage the screw, control surfaces, or guidance mechanism and would thus render the weapon harmless or degrade its performance. In addition to the acoustic decoy mechanism, the ATM could use an artificially generated magnetic field to detonate the magnetic influence fuzes used in many modem torpedoes. Because the ATM would not have the propulsion and control systems of an antitorpedo torpedo (ATT), its development time would be shorter and its unit cost much less than that of an ATT.
Besides using mines to counter torpedoes, one could use other torpedoes. Such weapons would have to be fast to effectively chase the attacking torpedoes, but speed would not be extremely important in a point-defense role. The defensive torpedoes would have active or passive guidance and a sophisticated recognition capacity. Current lightweight ASW torpedoes are becoming less credible weapons against fast, deep-diving, and extremely large double-hulled submarines. They might, with appropriate development and modification, prove effective against other torpedoes. But because torpedoes have a relatively high cost and a long development time, the) do not provide a short-term defend against torpedoes.
Presently, a submarine contact is pr°*' ecuted by using data collected from huh' mounted sonars, towed arrays, an sonobuoys deployed from aircraft.
Fixed sonar systems on the ocean bo1 tom are useful to detect and track sub®a fines over broad areas, and aircraft-botne magnetic anomaly detectors are useful i" final localization. From a tactical stand point, however, the sonar system5 mounted on ships will continue to be the primary means to detect and classuj sonar contacts. Because of their lim'16 endurance, aircraft are more effective!) used to investigate and pursue contact that have been initially detected by means. An aircraft is essentially >nVUj nerable to submarine counterattack, an is the preferred unit to follow a subm3 fine. Our ASW ships, however, need 10 be able to quickly deploy sonobuoys ont0 suspicious contacts in order to gain supe rior acoustic data while maintaining 3 standoff distance outside torpedo rang6. This would enable a destroyer to trac and classify a submarine from a less vu nerable position. There are three possib ways to deploy sonobuoys from surfaC ships:
► Over the fantail: If discretion directs retreat then a pursuing submarine n>a)
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0,lle through a field of sonobuoys that £an yield data useful to counterattack. ^‘Ve-ineh gun: These weapons can hurl J'Pound antiaircraft projectiles with r^dio (VT)-fuzed explosives. They may a s° be useful for deploying suitably deigned sonobuoys. One gun could lay a Be pattern around a contact many miles the ship, in minutes, j "°cket- or mortar-launched sono- A rocket would subject the sono- , °y to much lower acceleration forces ar> would a gun. The rocket launchers Sht be similar in size to the super- aP‘d-blooming off-board chaff launchers I ready widely in use. The rocket Uncher would probably be trainable in vation and azimuth. A parachute '8ht be necessary to break the shock of ater entry. Such a system could be the
hen® Size as the World War 11 ASW gehog, which was a mortar-launched Weapon.
The
es i
newer, larger, long-range torpe-
it 11. enter’ng the Soviet inventory make frolkelV that there will be torpedo attacks ■ m behind. The passive acoustic hom- 1 ® Astern frequently causes a wake fol- bJg path that puts the weapon in the
tftoui
is of a ship equipped with hull-
the ktec*sonar- Attack from this angle, in e baffles, might not be detected, and
"'Quid
evadi
give the submarine more time to
le counterattack.
Sonobuoys have been laid by aircraft for years, but aircraft are subject to logistic and weather constraints. Such is not the case with sonobuoys dropped off the fantail or deployed with mortars or rockets that are ahead or to the side of the destroyer. Like chaff launchers already in use, sonobuoys can be dropped over the side or fired at the touch of a button and can start relaying data immediately. Sonobuoys have a number of advantages over hull-borne or towed-array sonars:
►Provide better signal-to-noise ratio because they can be deployed nearer the contact; and because they are stationary, they are not subject to flow noise
►Provide a longer base line for accurate triangulation
►Allow for investigation of suspicious contacts from stand-off ranges
►Do not require other means—maneuvers , active sonar, launching aircraft— that may tip off a contact that it has been detected
►Are the fastest, simplest means of collecting additional data for detecting, classifying, and localizing a contact. Deploying a towed array or launching a helo can take half an hour or more, and may become impossible in some weather.
►Do not limit the destroyer’s speed or maneuverability, as do towed arrays. Hull-mounted sonars and towed arrays are degraded by flow noise at high speed.
A continuous sprint could supplant sprint- and-drift tactics in some situations.
► Could replace aircraft in some applications by responding faster, and at lower cost
In addition to launching sonobuoys, this proposed rocket-assisted launcher could be used to lay a mini-minefield between a ship and an oncoming torpedo. A launcher, trainable in azimuth and elevation, could quickly deploy an antitorpedo barrier. Each mini-mine would sink to a preset depth and would detonate on the rapid Doppler shift of a torpedo at the closest point of approach or would magnetically influence its fuze.
There is a real need to strengthen the ASW capacity of our ships. Although we can track hostile submarines at long range with considerable success, some get through the screen and attain torpedo- attack positions just a few thousand yards from their intended victims. The CIWS provides an effective last-ditch defense against inbound aircraft and cruise missiles. The U. S. Navy needs a correspondingly effective close-in weapon against torpedoes. We do not have one today. Let’s get started.
Rouble-Duty Tankers
^ ^ajor Bemie Fullenkamp, U. S. Air Force
na^’ng land-based tankers to support nif a'r Power promises to increase sig- (CVnntly the carrier battle group’s Sen firepower, survivability, and
atl(jera* flexibility. The choice of service eVeraircraft to perform this mission, how- cont ^Ueks t*le age-old missions-and-roles toversy between the Air Force and c Navv
sho ® Navy has been trying to fill its Pro , .e °k a>r-refueling opportunities by lan?udng its own small fleet of dedicated part °ased tankers. Nevertheless, De- l^etTlent of Defense studies and Defense (j Urces Board decisions support the as ^ Air Force and its KC-10 Extender
finf service-aircraft team for the job. fere0rtUnate|y, Navy and Air Force dif- of a es on an appropriate Memorandum e*er ®reernent (MOA) prevent the full C)se of this force-multiplier concept.
—In the past, land-based f]Vlners supported replacement aircraft § to CVBGs over intra-theater or in
tercontinental distances but figured little in any employment role. Today’s better- equipped tankers will realize new force- multiplier roles in the following areas: ► Firepower—The tankers will “Rendezvous with and escort strike aircraft on transits to and from targets while remaining outside of the threat envelope.”1 In short, the tankers will permit strike aircraft to carry more bombs to the target.
In the past, if air refueling was needed on a strike mission, Navy KA-6 tankers provided it. Normally only four KA-6s deploy with each carrier. However, as strike ranges increase and the short- combat-radius F/A-18 Hornets join the fleet in large numbers, the carrier’s own air-refueling capability is stretched well beyond its limits.
As a result, A-6s or A-7 Corsairs (both of which can be configured as “buddy tankers”) must serve as tankers, sacrificing their intended role as attack aircraft. In at least one instance, the USS Constellation (CV-64), with F/A-18s on board,
flew between 70% and 93% of its A-6 sorties as tankers and not as attack aircraft during one of its recent deployments.2 This issue becomes critical considering that even the Navy’s largest carriers typically carry only 34 attack aircraft. The vast majority of the remaining 56-plus aircraft fly missions for the protection of the CVBG.3 ► Survivability—Naval air operations using land-based tankers facilitate survivability in two ways. First, air refueling allows attack aircraft to operate over longer ranges and thus keeps the CVBG more distant from the threat. Second, by maintaining an air-refueling orbit relative to the battle group, the land-based tanker can provide direct or indirect refueling support to antiair warfare (AAW) fighters.4
Regarding the latter, the Soviets will most likely employ the Backfire bomber and its AS-4 Kitchen missiles to threaten the U. S. carriers.5 Although the carrier is well-defended against the missile
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ln8s / February 1988