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Los Angeles Submarine make up a class of nuclear-powered fast attack submarines, sometimes called the LA class or the 688 class. The 62 submarines in this class represent two generations and close to half a century of the US Navy's attack submarine fleet. As of late 2013, 41 of the class are still in commission and 21 retired from service. Of the 21 retired boats, 14 of them were laid up half way (approximately 17-18 years) through their projected lifespans due to their midlife reactor refuelings being cancelled. One boat, USS Miami (SSN-755), was retired due to extensive fire damage caused by arson when she was a few months into a maintenance period. A further four boats were proposed by the Navy, but later cancelled.

The Los Angeles class contains more nuclear submarines than any other class in the world. Except for USS Hyman G. Rickover (SSN-709), all submarines of this class are named after American cities and a few towns (e.g. Key West, Florida, and Greeneville, Tennessee). This system of naming broke a long-standing tradition in the U.S. Navy of naming attack submarines for creatures of the ocean (e.g. USS Nautilus (SSN-571)). In 1982 after building 31 ships, the class underwent a minor redesign, the following 8 that made up the second "flight" of subs had 12 new vertical launch tubes that could fire tomahawk missiles. The last 23 saw a significant upgrade with the 688i improvement program. These boats are quieter, with more advanced electronics, sensors, and noise reduction technology. Externally they can be recognized quickly as their retractable diving planes were placed at their bows rather than on their sails.

Background
The Los Angeles class submarines were designed and built to replace the Sturgeon class at the height of the arms race between the US and the soviet union, incorporating improved sound quieting and a larger propulsion plant. They were designed to counter several new soviet weapon systems. 688 class submarines are much larger than previous classes, weighing almost twice as much; they represented a very ambitious response to the soviet threat. Two main goals of the class were to protect American Carrier groups from a growing fleet of Soviet attack submarines, and to seek and destroy Soviet naval formations. The missions performed by members of the class include undersea warfare (versus submarines), surface warfare (versus surface ships), strike warfare (tomahawk cruise missile strikes), mining operations, special forces delivery, reconnaissance, carrier battle group support and escort, and intelligence collection. During the seventies and eighties, U.S. attack submarines monitored Soviet naval development and open ocean naval operations in the Mediterranean, Atlantic, and Pacific oceans. U.S. SSNs obtained vital information on Soviet naval capabilities and weaknesses while underscoring American determination to defend the nation and her allies from attack.

While almost all Cold War operations remain classified, two declassified missions showcase Submarine Force capabilities. USS Guardfish (SSN-612) silently tracked a Soviet cruise missile (SSGN) submarine which was following U.S. aircraft carriers off Vietnam in the 1970's - ready to protect American ships should the SSGN launch her missiles. In 1978, in the Atlantic, USS Batfish (SSN-681) tracked a Soviet ballistic missile submarine (SSBN) sailing off the East Coast of the U.S.- learning Soviet SSBN patrol areas and operating patterns and providing early indications of any potential surprise attack on the US.

This particular Yankee trailing operation - given the code name Evening Star - began on March 17, 1978 when USS Batfish (SSN-681) intercepted a Yankee SSBN in the Norwegian Sea. Batfish, towing a 1,100-foot sonar array, had been sent out from Norfolk specifically to intercept the SSBN, U.S. intelligence having been alerted to her probable departure from the Kola Peninsula by the CIA-sponsored Norwegian intelligence activities and U.S. spy satellites. These sources, in turn, cued the Norway-based SOSUS array as the Soviet missile submarine sailed around Norway's North Cape. After trailing the Soviet submarine for 51 hours while she traveled 350 nautical miles, Batfish lost contact during a severe storm on March 19. A U.S. Navy P-3 Orion maritime patrol aircraft was dispatched from Reykjavik, Iceland, to seek out the evasive quarry. There was intermittent contact with the submarine the next day and firm contact was reestablished late on March 21 in the Iceland-Faeroes gap. The trail of the SSBN was then maintained by Batfish for 44 continuous days, the longest trail of a Yankee conducted to that time by a US submarine.

As the Cold War progressed, the Soviet Navy expanded substantially in size and capability. Concerned about U.S. submarine superiority, the Soviet Union devoted considerable resources to improving the quality of their submarine force, which throughout the Cold War was much larger than the U.S. Submarine Force. By the 1980's, Soviet submarines had narrowed, but not eliminated, the submarine technology gap. The U.S. Navy counted on the superiority of its submarines and, above all, its submariners in the event of hostilities.

In the 1980's, the U.S. Navy adopted the Maritime Strategy, which envisioned a wartime thrust into ocean areas adjoining the Soviet Union in order to defend Northern Europe against a Soviet invasion. US military planners foresaw a key role for submarines in the Maritime Strategy. They counted on the stealth and superiority of US submarines to destroy Soviet warships capable of targeting U.S. battle groups. Additionally, U.S. submarines focused on Arctic warfare, where Soviet submarines, including SSBNs, were expected to operate in the event of war.

In the mid-1980s U.S. officials began to publicly discuss the Western anti-SSBN strategy. Probably the first official pronouncement of this strategy was a 1985 statement by Secretary of the Navy John Lehman, who declared that U.S. SSNs would attack Soviet ballistic missile submarines "in the first five minutes of the war." In January 1986, the Chief of Naval Operations, Adm. James D. Watkins, wrote that "we will wage an aggressive campaign against all Soviet submarines, including ballistic missile submarines."

Not all US trailing operations were successful. Periodically Soviet SSBNs entered the Atlantic and Pacific without being detected; sometimes the trail was lost. A noteworthy incident occurred in October 1986 when the U.S. attack submarine Augusta (SSN-710) was trailing a Soviet SSN in the North Atlantic. Augusta is reported to have collided with a Soviet Delta I SSBN that the U.S. submarine had failed to detect. Augusta was able to return to port, but she suffered $2.7 million in damage. The larger Soviet SSBN suffered only minor damage and continued her patrol.

Design
Los Angeles class submarines are divided into two watertight compartments. The forward compartment houses all the living spaces, weapons systems, control centers, and sonar/fire control computers. The after compartment houses the nuclear reactor and the ship's propulsion equipment. The ship carries enough food to feed a crew of over one hundred for as long as 90 days.

1. Engine Room. The engine room houses all the propulsion machinery, as well as the Ship's Service Turbine Generators that supply the ship's electricity, and the evaporator, which distills water for the propulsion plant and other shipboard use.

2. Control Room/Attack Center. Located in the upper level of the forward compartment is the control room--the heart of the ship. The Officer of the Deck stands his watch here, controlling all activities on board. In control, the ship's location is continually determined and plotted, the course and depth are controlled, and all sonar contacts are tracked. The control room also functions as the attack center, where all of the ship's weapon systems are controlled from.. The sail helps to add stability to the submerged vessel. Additionally it houses all of the periscopes and antennae. In the forward top portion of the sail is the bridge. When the ship is on the surface, the Officer of the Deck will shift his watch to the bridge. Here he has clear view of all the surrounding waters, in addition to getting a breath of fresh air and seeing the welcome sun.

4. Mess Decks, Berthing, and Wardroom. The middle level of the forward compartment is dedicated to the crew's living spaces. Here is found the mess decks and galley which, when underway, serve four meals a day, one every six hours (allowing for all watchstanders to get a hot meal). Also here are the berthing spaces. Here is the only personal space that a crewman gets--his bed (known as a "rack". These racks are stacked three tall throughout the berthing spaces and have only a curtain to close them off from the rest of the boat. With this as the only private area on board, it is not uncommon to find pictures of family and friends put up on the wall in a rack along with personal cassette and CD players for entertainment. The wardroom> is the officers own room. Here is a big table around which the officers eat, train, and work

5. Torpedo Room. The lower level of the forward compartment is the Torpedo Room. This room stores the ship's weapons which include Mk48 ADCAP torpedoes, Tomahawk cruise missiles, and mines. The torpedo room houses the handling equipment and access to the ship's four torpedo tubes. Weapons are moved from their stowage positions, loaded into the tubes, and readied for launch all in this room by the ship's Torpedomen. The torpedo room also houses controls for the vertical launch tubes which add 12 more Tomahawk cruise missiles to the ship's load.

6. Sonar Sphere. Housed in the very forward end of the submarine is the sonar sphere. This is an array of over 1,000 hydrophones which makes up part of the advanced BQQ-5E sonar suite. Out in front of the ship, positions the sphere as far as possible from the ship's own noise, thereby giving it the best listening conditions.

SSN-688 class submarines could operate for much longer than 30 years; one of the shipbuilders stated that 10 to 20 years of additional service would not be unreasonable. Past Navy actions indicate that extending a submarine's service life may be feasible. After a 5-year study was completed on the SSN-637 class submarine--the predecessor of the SSN-688 class--the design life was extended from 20 years to 30 years, with a possible extension to 33 years on a case-by-case basis. The 18 SSN-688 class submarines that will be refueled at their mid-life could make good candidates for a service life extension because they could operate for nearly 30 years after the refueling. After these submarines serve for 30 years, they could undergo a 2-year overhaul and serve for one more 10-year operating cycle, for a total service life of 42 years. The cost for the additional overhaul of SSN-688 class submarines would be about $406 million per boat.

Armament
The submarine is fitted with four 533mm torpedo tubes located midships together with a Mark 117 torpedo fire control system. The submarine has the capacity for 26 torpedo tube launched weapons including Tomahawk missiles, Harpoon missiles and Mark 48 ADCAP torpedoes. The Gould Mark 48 torpedoes combat both high-performance surface ships and fast deep-diving submarines. The torpedo is capable of operating with or without wire guidance and uses either or both active and passive homing. It is equipped with multiple re-attack modes which operate if the target ship is missed. The torpedo carries out programmed target search, acquisition and attack procedures. The submarine can also lay Mobile Mark 67 and Captor Mark 60 mines.

Control System
Over close to forty years, the sensor suite of the class has changed dramatically. The first suite was the Mk 113 mod 10 Fire control system, also known as the Pargo display system. The Mk 113 runs on a UYK-7 computer.

The Mk 117 FCS, the first "all digital" fire control system replaced the Mk 113. The Mk 117 transferred the duties of the analog Mk 75 attack director to the UYK-7, removing the two analog conversions, and allowing "all digital" control of the digital mk 48 control. The first 688 sub to be built with the Mk 117 was SSN-700, the USS Dallas.

The Mark 1 Combat Control System/All Digital Attack Center replaced the Mk 117 FCS which it was based on. The Mk 1 CCS was built by Lockheed Martin, and gave the class the ability to fire tomahawk missiles. The latest upgrade to CCS Mk 1 is program C4.2V1. The CSS internal tracker model provides processing for both towed array and spherical array trackers. Trackers are signal followers which generate bearing, arrival angle and frequency reports based on information received by an acoustic sensor. The CSS tracker model augments the sonar detection processing with corrections to detected SNRs due to the beam pattern shapes and effects. The tracking process in CSS is modeled as a weighted sum of bearings to signals being received by a given acoustic sensor. The strength of the corrected SNRs determines the weight given to a received signal. A tracker follows the strongest signal being received by an acoustic sensor. In addition to the effects caused by the array beam pattern, filters are applied to incoming signals to narrow the focus of a tracker. This filtering is performed to ensure that a tracker follows the assigned signal. This filtering process is also described in detail in the enclosed white paper. A tracker may switch to another incoming signal if that signal becomes stronger than the original tracker signal. Tracker variance is calculated based on the strength of the received signal. It incorporated the Gyro Static Navigator into the system in replacement of the DMINS of the earlier 688 class.

The Mk 1 CCS was replaced by the Mk 2. The Mk 2 was built by Raytheon. Mk 2 provides Tomahawk Block III vertical launch capability as well as fleet-requested improvements to Mk 48 ADCAP torpedo and Towed Array Target Motion Analysis (TMA) operability. The Mk 2 CCS paired with the AN/BQQ-5E system is referred to as the "QE-2" system. the CCS MK2 Block 1 A/B system architecture extends the CCS MK2 tactical system with a network of Tactical Advanced Computers (TAC-3). These TAC-3s are configured to support the SFMPL, NTCS-A, LINK-11 and ATWCS subsystems. In order to provide the ability to control and configure TAC-3 system software and hardware a resource management function will be developed. Resource management is defined as the control, monitoring, and querying of both software and hardware resources, locally and remotely. Software resources will include CPU utilization, virtual memory, processes, and Inter-Process Communication (IPC). Hardware resources will include CPU, RAM, disk, I/O channels, and peripherals, in addition to network resources such as socket communication usage, availability, and load.

The AN/BQQ-5E sonar with the TB-29 towed array and Combat Control System (CCS) Mk 2, known collectively as the QE-2 System, provides a functionally equivalent system for the Los Angeles (SSN-688) and Ohio (SSBN-726)-class submarines. Enhancements include increases in acoustic performance, improved combat control capabilities and replacement of obsolete equipment. The Combat System (CCS) MK-2 will be installed in both Los Angeles (SSN) and Trident (SSBN) submarines. This system upgrade program will maximize functional commonality across platforms while enhancing performance and providing for system growth and flexibility. The thrust of the submarine Combat Control System (CCS) Improvement program is the fleet introduction of submarine CCS MK2 Program D0 and the development of CCS MK2 Program D0 Blocks 1 and 2. CCS MK2 converged multiple submarine combat system developments into a single effort to minimize submarine life cycle costs, i.e., SSN 688, SSN 688I and SSBN 726 Classes. With CCS MK 2, there will be a JMCIS Interface to the MK 2 Fire Control system. The organic contacts contained in the Fire Control System will be placed in the FCS area in JMCIS.

The CCS MK2 Block 1A/B program was initiated to provide an overall responsiveness to evolving fleet requirements. The primary objectives include:

Greater commonality with surface ship combat systems Improved Tomahawk strike capability Incorporate planned updates to baseline program Conform to SECNAV initiatives for open architecture systems

To satisfy these objectives, the CCS MK2 Block 1 A/B system architecture extends the CCS MK2 tactical system with a network of Tactical Advanced Computers (TAC-3). These TAC-3s are configured to support the SFMPL, NTCS-A, LINK-11 and ATWCS subsystems. In order to provide the ability to control and configure TAC-3 system software and hardware a resource management function will be developed. Resource management is defined as the control, monitoring, and querying of both software and hardware resources, locally and remotely. Software resources will include CPU utilization, virtual memory, processes, and Inter-Process Communication (IPC). Hardware resources will include CPU, RAM, disk, I/O channels, and peripherals, in addition to network resources such as socket communication usage, availability, and load.

CCS MK2 Program D0 provides a modular software architecture, introduces Tomahawk Block 3 and Harpoon Block 1C capabilities, introduces Advanced Capability (ADCAP) on TRIDENT, and replaces obsolete equipment.

CCS MK2 Program D0 Block 1 integrates CCS MK2 into AN/BSY-1 systems, replaces additional obsolete equipment, incorporates a direct interface to the Global Positioning System, incorporates Joint Maritime Command Information System (JMCIS) into CCS MK2, and implements Advanced Tomahawk Weapon Control System (ATWCS), Tomahawk Block IV, ADCAP torpedo improvements and several other miscellaneous enhancements. Navigation Sensor System Interface (NAVSSI) provides real-time, accurate positional and velocity information for distribution to Combat Control and other shipboard subsystems.

CCS MK2 Program D0 Block 2 incorporates into submarine CCS anticipated upgrades to ADCAP, Tomahawk and Harpoon, and implements additional OER. AN/BSG-1 (formerly known as Tomahawk Land Attack Missile - Nuclear (TLAM-N) Portable Launching System (PLS)) provides SSN Submarines with a stand alone TLAM-N M issile launching capability.

The CCS MK2 Program D0 Block 1C program has been adjusted to maximize foreground software commonality with the NSSN Combat Control program. Due to changes in the TOMAHAWK Baseline Improvement Program (TBIP), OPNAV has directed TOMAHAWK Block IV missile capability be deferred and accomplished as an Engineering Change to the existing program baseline. TOMAHAWK Block IV capability has been deferred allowing for shortened and consolidated test events. The net result is a single Milestone III for all variants of CCS MK2 Block 1C by May 2000.

The CCS Mk 1 controls the AN/BQQ-5 sensor suite, which is comprised of the AN/BQS-13 spherical sonar array and AN/UYK-44 computer. It also includes the TB-12 towed sonar array The creation of the Acoustic Rapid COTS Insertion (A-RCI) program was based on a detailed review of the U.S. acoustic advantage compared to foreign nuclear and diesel electric submarines. A-RCI is a four phased transformation of existing sonar systems (AN/BSY-1, AN/BQQ-5, or AN/BQQ-6) to a more capable and flexible COTS/OSA-based system. It also will provide the submarine force with a common sonar system. The process is designed to minimize the impact of fire-control and sonar system upgrades on a ship's operational schedule, and will be accomplished without the need for major shipyard availabilities. Phase I, which commenced in November 1997, will enhance towed-array processing. Phase II will provide additional towed- and hull-array software upgrades. Phase III will upgrade the spherical array, and Phase IV will upgrade the high-frequency sonar system on SSN 688I-class submarines. Each phase will install improved processing and control and display workstations. The current installation plan completes all SSNs through Phase III by FY03.

The USS Dallas SSN-700 was the first to be built with the Mk 117 digital FCS.

Raytheon CCS Mark 2 combat data system. This was replaced with a further development, the Raytheon AN/BYG-1 Combat Control System.

Sonar
AN/BQQ-5 sensor suite, which is comprised of the AN/BQS-13 spherical sonar array and AN/UYK-44 computer. The AN/BQQ-5 was developed from the AN/BQQ-2 sonar system. The BQS 11, 12, and 13 spherical arrays have 1,241 transducers, as well as 104 hydrophones, and a towed array. There are 5 versions of the AN/BQQ system, sequentially identified by letters A-E.

The improved 688i subclass was initially equipped with the BSY-1 SUBACS submarine advanced combat system that used the AN/BQQ-5E. Development of the BSY-1, and it's sister BSY-2 for the seawolf was widely reported as one of the most problematic programs for the Navy, it's cost, and schedule suffering many setbacks. This system was replaced by the AN/BQQ-10 system.

It also includes the TB-12 towed sonar array. The TB-12 towed array was replaced by the TB-16, and later, TB-23 and TB-29.

A series of conformal passive hydrophones are hard-mounted to each side of the hull, using the AN/BQR-24 internal processor. The system uses FLIT (frequency line integration tracking) which homes in on precise narrowband frequencies of sound and using the Doppler principle, can accurately provide firing solutions against very quiet submarines. The AN/BQQ-5’s hull array doubled the performance of it’s predecessors

The creation of the Acoustic Rapid COTS Insertion (A-RCI) program was based on a detailed review of the U.S. acoustic advantage compared to foreign nuclear and diesel electric submarines. A-RCI is a four phased transformation of existing sonar systems (AN/BSY-1, AN/BQQ-5, or AN/BQQ-6) to a more capable and flexible COTS/OSA-based system. It also will provide the submarine force with a common sonar system. The process is designed to minimize the impact of fire-control and sonar system upgrades on a ship's operational schedule, and will be accomplished without the need for major shipyard availabilities. Phase I, which commenced in November 1997, will enhance towed-array processing. Phase II will provide additional towed- and hull-array software upgrades. Phase III will upgrade the spherical array, and Phase IV will upgrade the high-frequency sonar system on SSN 688I-class submarines. Each phase will install improved processing and control and display workstations. The current installation plan completes all SSNs through Phase III by FY03. Countermeasure systems

The electronic support measures (ESM) includes a BRD-7 direction finding system, the WLR-1H and WLR-8(v)2 interceptors and the WLR-10 radar warner.

The AN/ WLY-1 acoustic interception and countermeasures system from Northrop Grumman is to replacement for the existing WLR-9A/12 acoustic intercept system. The submarine is equipped with a Mark 2 torpedo decoy. Sensor suite

The Los Angeles class submarines are equipped with a comprehensive suite of sonars: TB-23/29 thin line passive towed array (to be replaced by the Lockheed Martin TB-29A under development), BQG 5D wide aperture flank array, BQQ 5D/E low frequency passive and active search and attack sonar, Ametek BQS 15 close range high frequency active sonar also used for ice detection, MIDAS (Mine and Ice Detection Avoidance) System high frequency active sonar and Raytheon SADS-TG active detection sonar. A Near-term Mine Reconnaissance System, NMRS, is being installed. The NMRS is a fibre-optic controlled vehicle which is equipped with AQS 14 side-scan sonar. The launch and recovery of the reconnaissance vehicle is via a torpedo tube.

The submarines are being upgraded with the Lockheed Martin AN/BQQ-10(V4) sonar processing system, under the Acoustic-Rapid Commercial-Off-The-Shelf Insertion (A-RCI) program.

The surface search, navigation and fire control radar is the Sperry Marine BPS 15 A/16. The system incorporates a video processor, touchscreen radar controls and an hydraulically driven raise and rotate mechanism.

The AN/BSY-1 Integrated ASW combat system is deployed on on SSN 637 and SSN 688 class submarines. It is required to track targets, platforms, and weapons. The combat control subsystem provides setting and control of weapons and mines, targeting, combat systems management, and piloting and navigation functions. It includes the weapon launch equipment to support horizontal tubes and own ship data displays.

The AN/BSY-1 ECP 1000, the AN/BQQ-5 Medium Frequency Active Improvement program and Improved Control Display Console Obsolete Equipment Replacement have been modified to become the basis of the Acoustics Rapid Commercial Off The Shelf Insertion (A-RCI) program. A-RCI is a multi-phased, evolutionary development effort geared toward addressing Acoustic Superiority issues through the rapid introduction of interim development products applicable to SSN 688, 688I Flight, and SSBN 726 Class Submarines. A-RCI Phases I and II introduce towed array processing improvements; A-RCI Phase III introduces spherical array processing improvements.

The AN/BSY-1 High Frequency Upgrade is a stand-alone program which will be introduced as A-RCI Phase IV for SSN 688I only. Towed systems development efforts will focus on tow cable improvements for shallow water towing in littoral environments; hydrophone and telemetry cost and risk reduction initiatives; (c) mechanical endurance improvements; sonar standardization; (e) OA-9070 handling system reliability enhancements; and TB-29 towed array development.

There are three versions of Combat Control System [CCS]: CCS Mk 1, BSY-1, and CCS Mk 2. The latest upgrade to CCS Mk 1 and BSY-1 is Program C4.2V2A, which provides Sturgeon (SSN-637)- and Los Angeles (SSN-688 and 688I)-class submarines with an upgraded shallow water variant of the Mk 48 ADCAP torpedo. Additional capabilities are Tomahawk Block III, an interface to Acoustics Rapid COTS (A-RCI) upgrades, and an interface to the Global Command and Control System- Maritime (GCCS-M), formerly called the Joint Maritime Command Information System (JMCIS).

CCS Mk 2 Block 1 is a phased development program that provides significant warfighting improvements to SSN-688, SSN-688I, and SSBN-726 class submarines. The first phase, Block 1A/B, provided shallow-water ADCAP torpedo capability as well as interfaces to GCCS-M and the Advanced Tomahawk Weapon Control System (ATWCS). Both GCCS-M and ATWCS are Government Off-The-Shelf products developed by other Navy program offices (see separate program summaries). CCS MK2 Block 1C, planned for fleet introduction at the end of FY 1999, forms the basis of a common Integrated Development Plan (IDP) between SSN-688, SSN-688I, and the Virginia (SSN-774) classes of submarines. This common IDP will ultimately incorporate common Tactical Tomahawk, Improved Submarine-Launched Mobile Mine (ISLMM), and improved ADCAP capabilities across all submarine platforms, as well as updates to GCCS-M and ATWCS.

Program C4.2V2A installations have begun and are expected to complete in FY 1999 for all CCS Mk 1 and AN/BSY-1 systems. CCS Mk 2 Block 1A/B successfully completed two dockside installations and Operational Evaluation in the third quarter of FY 1997. The next upgrade to CCS Mk 1, BSY-1, and CCS Mk 2 Block 1A/B will be CCS MK 2 Block 1C. CCS Mk 2 Block 1C Milestone II was completed in the third quarter FY 1996. Planned installations to support development and operational testing are on schedule for FY 2000.

Developer/Manufacturer: CCS Mk 1 and BSY-1 C4.2V2A: In-Service Engineering Agent, Naval Underwater Warfare Center (NUWC), Newport, Rhode Island. CCS Mk 2 Block 1C: Raytheon, Portsmouth, Rhode Island. AN/BPS-5 surface search radar AN/BPS-15 A/16 navigation and fire control radar

TB-16D passive towed sonar arrays TB-23 passive "thin line" towed array AN/BQG-5D wide aperture flank array AN/BQQ-5D/E low frequency spherical sonar array AN/BQS-15 close range active sonar (for ice detection); MIDAS Mine and Ice Detection Avoidance System SADS-TG active detection sonar

Type 2 attack periscope (port) Type 18 search periscope (starboard)

AN/BSY-1 (primary computer); UYK-7; UYK-43; UYK-44

WLR-9 Acoustic Intercept Receiver ESM

Computer
The first 688 subs were built with the UYK-7 computers. UYK-43; UYK-44, AN/BSY-1.

Propulsion
The ship is equipped with a 26MW nuclear pressure water reactor, model GE PWR S6G generating 35,000 shp, developed and supplied by General Electric. The auxiliary prop motor by Magnatek supplies 242kW. The life of the fuel cells is approximately ten years.

Improved Performance Machinery Program Phase I [on 688 Improved]

Design and operational support for the S6G is provided by Knolls Atomic Power Laboratory (KAPL).[2] The S6G reactor plant was originally designed to use the D1G-2 core, similar to the D2G reactor used on the Bainbridge class guided missile cruiser, which is rated at 148 MW. All Los Angeles class submarines from USS Providence (SSN-719) on were built with a D2W core rated at 165 MW, as opposed to the older 150 MW cores found on older boats. The D1G-2 cores are being replaced with D2W cores when the boats are refueled.

Variants
SSNs 688-718 - Original Los Angeles class SSNs 719-750 - Starting with SSN 719 and beyond the last 31 hulls of the class have 12 vertical launch tubes for the Tomahawk cruise missile, along with an upgraded reactor core. SSNs 751-773 - The final 23 hulls [SSN 751 and later] referred to as "688I" (for improved), are quieter, incorporate an advanced BSY-1 sonar suite combat system and the ability to lay mines from their torpedo tubes. They are configured for under-ice operations in that their forward diving planes have been moved from the sail structure to the bow and the sail has been strengthened for breaking through ice.

The USS MEMPHIS (SSN 691) has been modified to serve as a test and evaluation platform for advanced submarine systems and equipment, while retaining her combat capability.

Date Deployed: Nov 13, 1976 (USS Los Angeles) Length: 360 feet (109.73 meters) Beam: 33 feet (10.06 meters) Displacement: Approximately 6,900 tons (7011 metric tons) submerged Speed: 25+ knots (28+ miles per hour, 46.3 +kph) Crew: 16 Officers; 127 Enlisted

Capabilities
According to the U.S. Department of Defense, the top speed of the submarines of the Los Angeles class is over 25 knots (29 mph or 46 kph), although the actual maximum is classified. Some published estimates have placed their top speed at 30 to 33 knots. In his book Submarine: A Guided Tour Inside a Nuclear Warship, Tom Clancy estimated the top speed of Los Angeles-class submarines at about 37 knots.

The U.S. Navy gives the maximum operating depth of the Los Angeles class as 650 ft, while Patrick Tyler, in his book Running Critical, suggests a maximum operating depth of 950 ft. Although Tyler cites the 688-class design committee for this figure, the government has not commented on it. The maximum diving depth is 1475 ft according to Jane's Fighting Ships, 2004–2005 Edition, edited by Commodore Stephen Saunders of the Royal Navy.

Weapons and fire control systems
Los Angeles class submarines carry about 25 torpedo tube-launched weapons and all boats of the class are capable of launching Tomahawk cruise missiles horizontally (from the torpedo tubes). The last 31 boats of this class also have 12 dedicated vertical launching system (VLS) tubes for launching Tomahawks.

Engineering and auxiliary systems
Two watertight compartments are used in the Los Angeles class submarines. The forward compartment contains crew living spaces, weapons-handling spaces, and control spaces not critical to recovering propulsion. The aft compartment contains the bulk of the submarine's engineering systems, power generation turbines, and water-making equipment. Some submarines in the class are capable of delivering SEALs through either the dry deck shelter system or the advanced SEAL delivery system (program canceled in 2006 and rendered unusable in 2009). A variety of atmospheric control devices are used to allow the vessel to remain submerged for long periods of time without ventilating, including an electrolytic oxygen generator nicknamed "the bomb". It is called "the bomb" because it electrically removes the bonds of hydrogen and oxygen which make up water. This produces oxygen for the crew and hydrogen. The hydrogen is pumped overboard but there is always a risk of fire or explosion from this process. While on the surface or at snorkel depth, the submarine may use the submarine's auxiliary or emergency diesel generator for power or ventilation (e.g., following a fire). The diesel engine in a 688 class can be quickly started by compressed air during emergencies or to evacuate noxious (nonvolatile) gases from the boat, although 'ventilation' requires raising a snorkel mast. During nonemergency situations, design constraints call for operators to allow the engine to reach normal operating temperatures before it is capable of producing full power, a process that may take from 20 to 30 minutes. However, the diesel generator can be immediately loaded to 100% power output, despite design criteria cautions, at the discretion of the submarine commander on the recommendation of the submarine's engineer, if necessity dictates such actions to a) restore electrical power to the submarine, b) prevent a reactor incident from occurring or escalating, or c) to protect the lives of the crew or others as determined necessary by the commanding officer.

Normally, steam power is generated by the submarine's nuclear reactor delivering pressurized hot water to the steam generator, which generates steam to drive the steam-driven turbines and generators. While the emergency diesel generator is starting up, power can be provided from the submarine's battery through the ship service motor generators. Likewise, propulsion is normally delivered through the submarine's steam-driven main turbines that drive the submarine's propeller through a reduction gear system. The submarine has no main drive shaft, unlike conventional diesel electric submarines.



In popular culture

 * Los Angeles class submarines have been featured prominently in numerous Tom Clancy novels and film adaptations, most notably the USS Dallas (SSN-700) in The Hunt for Red October. Other mentions include USS Chicago (SSN-721) in Red Storm Rising and USS Cheyenne (SSN-773) in SSN.
 * The 2000 Australian television film On the Beach features a fictional 688i Los Angeles class submarine, the USS Charleston (SSN-704).
 * In the 2009 film Terminator Salvation, Resistance Headquarters is located aboard a Los Angeles class submarine, called the USS Wilmington according to the novelization and several behind-the-scenes books.
 * The Los Angeles class submarine is the focus of many submarine-related video games, such as the simulators 1989 688 Attack Sub, Electronic Arts' 1997 688(I) Hunter/Killer, and the 2005 Dangerous Waters.
 * Call of Duty: Modern Warfare 2 (2009) features the USS Chicago (SSN-721) as the launching platform for TF 141's operations. Another Los Angeles class submarine, the USS Dallas (SSN-700), can also be seen in the level "The Only Easy Day... Was Yesterday".
 * The USS Alexandria (SSN-757) was used in filming Stargate: Continuum.
 * A fictional Los Angeles class submarine named the USS Orlando appeared in the 1996 comedy film Down Periscope.