U . S . Carrier Group tactics Naval tactics play a crucial role in modern battles and wars . The presence of land , changing water depths , weather , detection and electronic warfare , the speed at which actual combat occurs and other factors — especially air power — have rendered naval tactics essential to the success of any naval force . The basis of all tactics ( land , sea and air ) is " fire and movement " : the fulfillment of a mission by the effective delivery of firepower resulting from scouting and the creation of good firing positions . Movement is the basis of modern combat ; a naval fleet can travel hundreds of nautical miles in a day . In naval warfare , the key is to detect the enemy while avoiding detection . A crucial part is to deny the detection of friendly forces through various means . There is also the concept of " battlespace " : a zone around a naval force within which a commander is confident of detecting , tracking , engaging and destroying threats before they pose a danger . This is why a navy prefers the open sea . The presence of land and the bottom topology of an area compresses the battle space , limits the opportunities and ability to maneuver , allows an enemy to predict the location of the fleet , and hinders the detection of enemy forces . In shallow waters , the detection of submarine s and mine s is especially problematic . One scenario that was the focus of American naval planning during the Cold War was a conflict between two modern and well equipped fleets on the high seas ; a battle between the fleets of the United States and the Soviet Union . The main consideration is for Carrier Battle Groups ( CVBGs ) . Order of engagement . Once a commander has considered the geography of a mission , he examines the assets the enemy is believed to have available - the enemy ' s order of battle ( OOB ) ; what friendly units are needed to succeed at the mission objective ; and the added constraints placed by mission requirements ( time etc . ) . This produces a " path of intended motion " ( PIM ) for the friendly forces - not the route , but the direction in which the force is heading at any time and so the area which must be checked and passed through . As enemy forces are encountered and identified , they are categorized by potency and immediacy and the friendly OOB altered to reflect this . There are four threat classes : A , B , C and D . This classification is similar to the time management method of judging things to be urgent / not urgent and important / not important . Fleet formation . After establishing a path of intended motion , the forces are organized . The formation has several standard elements positioned according to a " threat axis " - the estimate of the likely direction from which an enemy attack will come . A threat axis will almost certainly change over time , as the fleet moves . There may be a single threat axis or one for each type of enemy : AAW ( Anti - aircraft warfare ) , ASW ( Anti - Submarine Warfare ) , and ASuW ( Anti - Surface Warfare ) . However , in reality usually only one axis is used ; the complexity of adding more tends to confuse the formation . The positions in the formation are called " station assignments " . A ship ' s position depends on its abilities . Many modern warships can fight several ways , but some are better at certain things . AAW and ASW are the important defensive properties . ASuW conduct is usually offensive . A standard formation provides a number of layers of defence , designed to give maximum protection to the fleet ' s high value units ( HVUs ) or " main body " . Furthest out are the " picket ships " , Combat Air Patrol ( CAP ) craft and early warning aircraft ( AEW ) . These units operate at 200 nautical miles ( 370 km ) or more out from the main body . The units of the " outer screen " operate between 12 and 25 nautical miles ( 22 and 46 km ) from the main body . The " inner screen " is within 10 nautical miles ( 19 km ) of the HVUs . The ships of the " outer screen " are intended to detect and engage any enemy units that have bypassed the pickets . These ships must be multi - role , but there is usually an emphasis on ASW , especially passive detection . It is quieter out there than near the HVUs and so detection is easier . Preferably there are helicopter ASW assets for ' stand off ' engagement . The ASW ships are usually assigned to specific sectors which allows a ' sprint and drift ' detection of submarines - the ship ' sprints ' to the front edge of its sector , then slowly moves back across the sector . Passive towed sonar arrays operate very efficiently on the return leg . AAW ships in the outer screen operate to protect ASW operations and to attack enemy aircraft before they reach their weapons - launching points , so range of defensive weapon is more important than rate of fire here . The " inner screen " emphasis is on AAW . The central task is to engage any airborne threats that penetrate that far . This means the threat is almost certainly a missile so AAW rate of fire is important . The more defensive firepower in the air the more enemy threats will be destroyed . For ASW the inner screen needs good active sonar . Any threat this close is too serious for passive sonar as immediate targeting is needed . Checking the area around and under HVUs for submarines is called ' delousing ' . If possible at least one ASW helicopter is always airborne , to target detected contacts as quickly as possible . Detection and electronic warfare . In modern naval combat a deadly strike can be launched from 600 nautical miles ( 1 , 100 km ) away . This is a huge area to scout . The double - edged answer to this is electronic warfare . Electronic warfare ( EW ) consists of three elements — Electronic Support Measures ( ESM ) , Electronic Counter - Measures ( ECM ) and Electronic Counter - Counter - Measures ( ECCM ) . ESM is the passive detection of enemy electromagnetic ( EM ) emissions . The radiated energy of an emitter ( e . g . radar ) can be detected far beyond the range at which it returns a usable result to its user . Modern ESM can identify the actual class of the emitter , which helps identify the unit on which it is used . Passive cross - fixing between a number of units can locate a source to a reasonably small area and give some hint to direction and speed . ESM fixes are placed in three classes : Detected , Tracking and Targeted , depending on the accuracy of the fix and whether a unit ' s course and speed has been derived . Of course for ESM to work the enemy must ' co - operate ' by using their emitters . The fact that a missile launched on a passive fix from over - the - horizon is usually deadly , creates a central problem for a naval force — when , and even if , units should radiate , and if not how to detect the enemy ? This is detectability vs . survivability . The need to obtain a targeting solution has to be balanced against the enemy ' s ability to do the same . Although once a commander feels that his fleet ' s position is known to the enemy a move to active emissions may be vital to prevent destruction , or else the only warning of incoming missiles will be when they turn on their terminal guidance systems . Making this decision is called EMCON ( EMissions CONtrol ) . There are three states , A , B and C . A is no emissions , B is limited emissions ( no unique emissions ) , and C is unrestricted . EMCON is not a blanket condition across the fleet . The surface units can be at A while a sufficiently distant AEW aircraft can be at C . ECM is both offensive and defensive , covering all methods used to deny targeting information to an enemy . Offensive ECM is usually jamming . This prevents the accurate detection and identification of incoming strikes until the jamming unit is destroyed . Chaff is also used to confuse AAW operations by creating radar decoys . Defensive ECM also uses chaff as well as soids , blip enhancement and jamming of missile terminal homers . ASW operations . Submarine s are the greatest threat to offensive CVBG ( carrier battlegroup ) operations . The stealth of modern submarines ( anechoic coatings , sound - dampening equipment mountings , hydrodynamic design , etc . ) , can allow a submarine to get extremely close to an HVU target . The move towards shallow - water operations has greatly increased this threat . The threat is such that even the suspicion of the presence of a submarine means a fleet must commit resources to removing it , as the possible consequences of an undetected submarine are too serious to ignore . In most cases submarines have an upper hand in any naval combat . Sonar operation . The main detection equipment to both sides in ASW is sonar . In the ocean the main factor affecting sonar operation is temperature . Ocean temperature varies with depth , but at between 30 and 100 metres there is often a marked change — the " thermocline " , also simply called the layer . This divides the warmer surface water and the cold , still waters that make up the rest of the ocean . Regarding sonar , a sound originating from one side of the thermocline tends to remain on that side — it is ' reflected ' off the layer change — unless it is very noisy ( active sonar , cavitation , firing weapons , explosions etc . ) . Pressure , salinity and the turbulence of the water also affect sound propagation . Water pressure creates " convergence zones " ( CZ ) . Sound waves that are radiated down into the ocean bend back up to the surface in great arcs due to the effect of pressure on sound . Under the right conditions these waves will then reflect off the surface and repeat another arc . Each arc is called a " CZ annulus " . CZs are found every 33 nautical miles ( 61 km ) forming a pattern of concentric circles around the sound source . Sounds that can be detected for only a few miles in a direct line can therefore also be detected hundreds of miles away . The signal is naturally attenuated but modern sonar suites are very sensitive . As in all EW , the issue with sonar is passive versus active . Modern active sonar is limited to 250 dB ( decibel s ) , but this level of noise can be detected at about ten times the range that is useful to the operator , acting as a beacon to any submarine in 100 – 190 km . So a target needs to be nearby and preferably on the same side of the layer to be detected by active sonar , which amounts to a favorable attack position for the submarine . In passive sonar operation the thermocline is the major issue . On passive detection the radiated noise of a unit is only apparent across the layer in a narrow cone : undetectable unless units pass almost directly over or under each other . For a surface unit there is the option of towing a passive sonar array above or below the thermocline - variable depth sonar ( VDS ) . A VDS passive array can be put below the layer to detect approaching submarines and when the target is within strike range a brief and unit - selective move to active transmissions can quickly return a targeting solution . An added advantage of VDS is that while it is operating below the layer , a unit ' s hull - mounted systems can be used above the layer . VDS is a blue - water solution . In shallow water , the high levels of biological , wave and tide noise , the influx of fresh water from rivers and the lack of a thermal gradient — and therefore CZs — make it a truly formidable environment to detect a sub - surface threat . Passive detection is almost impossible and surface units are forced to use active sonar to search . Doctrine is that a fleet must act as if they have already been detected and maybe even targeted when navigating close to shore or in shallow waters . Because of this constraint , naval commanders " hate " operating in such waters . The ASW triad . For successful ASW , a fleet must combine surface , air and subsurface assets in the most tactically efficient manner - if these assets are present . ASW engagements occur in three phases : " Area ASW " is the coordination of search ahead of the main force , along the " threat axis " . Detection and localization are the objectives , with destruction if possible . At best , area ASW is conducted by units with endurance and potency : maritime patrol aircraft ( MPA ) at 150 nautical miles ( 280 km ) out or towed - array equipped surface units 30 to 50 nautical miles ( 60 to 90 km ) out are most common . If the air unit has magnetic anomaly detection ( MAD ) as well as sonobuoy s then so much the better . " Local ASW " is within the outer screen , 12 to 25 nautical miles ( 22 to 46 km ) from the main fleet . Detection is strictly passive as the distance is still great enough for the HVUs to be safe . Once a contact has been made , helicopter ASW assets ( with dipping sonar , MAD or sonobuoys ) are rushed into the area . Three or more close passive contacts are enough for aerial delivery of torpedoes . Ship - mounted ASW weapons such as ASROC are reserved for when a contact is " too " close — generally less effective , their role is to distract the submarine from attacking and buy time for a more effective strike . In modern combat depth charge s are never used ; they are ineffective and have been completely replaced by guided torpedoes . If a submarine is detected after it penetrates to the inner screen , the issue becomes getting weapons in the water , even if they are not accurately targeted . All and any efforts to distract the submarine from attacking the HVUs are made . Torpedo evasion maneuvers are also necessary . A general maneuver tactic against submarines is a zig - zag . A submarine usually relies on passive detection , not risking active sonar or a periscope observation . So to determine where a unit is heading the submarine needs Target motion analysis ( TMA ) . This requires several minutes of passive contact and if the contact starts to zig - zag this process must restart . The most effective means of finding and destroying submarines is another submarine . Called Hunter - Killers , they utilize the stealth advantage of submarines to track enemy submarines . The difficulty is that they have to be out of communication with the units they are protecting for most of the time to use this stealth . Therefore most submarines operate independently , having been given general rules of engagement ( ROE ) for reconnaissance , ESM and early offensive operations . Modern diesel submarines are almost as efficient as SSNs as Hunter - Killers . However diesel submarines lack the capability to stay with a fast moving battle group due to their slower speeds ( 20 knots instead of 35 knots for SSNs ) requiring them to be deployed long before operations in a particular area will commence , or force the battle group to slow down to allow their diesel submarines to keep up . Diesel Hunter - killer submarines or SSKs would generally be deployed along the “ choke points ” formed by landmasses or shallow waters to interdict enemy submarines long before they could attack the battle group while the SSNs would tend to stay with the battle group . Anti - air warfare operations . The central weapon in modern naval combat is the missile . This can be delivered from surface , subsurface or air units . With missile speeds ranging up to Mach 4 or higher , engagement time may be only seconds . The key to successful Anti - air warfare ( AAW ) is to destroy the launching platform " before " it fires , thus removing a number of missile threats in one go . This is not always possible so a fleet ' s AAW resources need to be balanced between the outer and inner air battles . There are several limitations to Surface - to - Air missile s ( SAMs ) . Modern missiles are commonly semi - active homing . They need the firing unit to actively illuminate the target with a missile fire - control director throughout the flight . If a guiding director shuts down then the missiles still in flight will self - destruct . So the number of intercepts a unit can simultaneously prosecute is limited by the number of directors possessed . The use of directors exposes the firing unit to counterattack . Clearly this is not a good situation and the US Navy has spent vast sums overcoming this limitation . The result is the Aegis combat system — phased - array radar and time - sharing technologies combined with missiles that have an inertial flight mode , allowing intercepts to be spaced more closely together . However , this is a partial solution at best , as the most numerous classes of ships with the Aegis combat system only have three or four illuminators , so only three or four missiles can be engaged at once . Airborne early warning . The key to successful anti - air warfare is airborne early warning . If attacking units can be identified before they reach their launch points then the battle can occur at the outer air - battle screen rather than the inner screen . An AEW unit in a race - track loiter 100 nautical miles ( 190 km ) ahead of the PIM , with a fighter escort , is perfect . The outer air battle . In this area the interceptor aircraft of the Combat Air Patrol ( CAP ) are the principal element , whether originating from a CVBG or land base . CAP units protecting units other than their home base are called LORCAP ( LOng Range CAP ) . The CAP is usually positioned 160 to 180 nautical miles ( 300 to 330 km ) from the units to be protected , along the expected threat axis . At this point the units will wait in a fuel saving loiter to engage incoming groups with AA missiles . As the engagements progress , relief units are dispatched to the CAP to ensure that later attacks are met with full weapon loads . If attacking units penetrate the outer defences they can be intercepted with aircraft in ready - 5 status , if used . The inner air battle . Within the main body , ship - based AAW is the main protection . AAW shooters are , in best practice , positioned to provide both layered and overlapping coverage . The optimum firing position is directly between the target and the inbound missiles . If the missile passes a unit on a tangent ( a crossing shot ) the probability of a kill ( " Pk " ) is greatly reduced . The US Navy prefers that Aegis equipped units should be kept in close proximity to the units of high value , with less able AAW units no more than 10 nautical miles ( 19 km ) out along the threat axis with , if possible , further AAW assets 18 to 24 nautical miles ( 33 to 44 km ) out . Other AAW tactics include the use of picket ships in a silent SAM or missile trap . In a missile trap , if the main body is forced to use active emissions ( they are already detected and localized ) then one or two ships can be positioned in emission silence 100 to 150 nautical miles ( 190 to 280 km ) out . When other units detect an incoming raid , the unit ( usually a cruiser ) can go active as the raid moves into their engagement envelope . However once these units go active , they are unsupported and are vulnerable to individual attack . Silent SAM is a technological tactic . Some modern missiles can be fired from one platform with targeting and guidance from another platform and need never illuminate the targets themselves . Anti - surface warfare operations . Traditionally , surface naval combat was fought with large - caliber guns within visual range , but with modern anti - surface warfare , missiles , aircraft and submarine - launched torpedoes are now the predominant anti - ship weapons , with guns serving a secondary function .