Editing Los Angeles-class submarine (section)

===Engineering and auxiliary systems===
[[File:Ssn 759 deck.jpg|thumb|The aft end of the control room for {{USS|Jefferson City|SSN-759|6}} in June 2009]]
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.<ref>SSN-688 ''Los Angeles'' Class Design. [http://www.globalsecurity.org/military/systems/ship/ssn-688-design.htm Los Angeles Class] {{webarchive|url=https://web.archive.org/web/20080415203456/http://www.globalsecurity.org/military/systems/ship/ssn-688-design.htm |date=15 April 2008 }} at Globalsecurity.org.  Accessed on 7 January 2009</ref> Some submarines in the class are capable of delivering [[Navy SEAL]]s through either a [[SEAL Delivery Vehicle]] deployed from the [[Dry Deck Shelter]] or the [[Advanced SEAL Delivery System]] mounted on the dorsal side, although the latter was cancelled in 2006 and removed from service in 2009.<ref>Polmar & Moore, (2003).  pp. 263</ref> 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 cell|electrolytic]] [[oxygen generator]], which produces oxygen for the crew and hydrogen as a byproduct. The hydrogen is pumped overboard but there is always a risk of fire or explosion from this process.<ref name=fas /><ref>Treadwell Supplies Oxygen Generator Components for Nuclear Subs [http://www.defenseindustrydaily.com/treadwell-supplies-oxygen-generator-components-for-nuclear-subs-2-04690/ Defense Industry Daily] {{webarchive|url=https://web.archive.org/web/20101216024150/http://www.defenseindustrydaily.com/treadwell-supplies-oxygen-generator-components-for-nuclear-subs-2-04690/ |date=16 December 2010 }} 28-January-2008</ref>

[[File:USS Greeneville (SSN-772).jpg|thumb|{{USS|Greeneville|SSN-772|6}} with an attached [[Advanced SEAL Delivery System|ASDS]]]]
While on the surface or at snorkel depth, the submarine may use the submarine's auxiliary or emergency [[Diesel-electric transmission|diesel generator]] for power or ventilation<ref>Fairbanks Morse Engines [http://www.fairbanksmorse.com/installations_marine.php Marine Installations] {{webarchive|url=https://web.archive.org/web/20080926105037/http://www.fairbanksmorse.com/installations_marine.php |date=26 September 2008 }} Accessed on 29 April 2008</ref><ref>Auxiliary Division on USS Cheyenne [https://fas.org/man/dod-101/navy/unit/dept-ssn-773.htm#ENGINEERING%20DEPARTMENT USS ''Cheyenne''  SSN-773 Department & Divisions] {{webarchive|url=https://web.archive.org/web/20150409020439/https://fas.org/man/dod-101/navy/unit/dept-ssn-773.htm |date=9 April 2015 }} from [[Federation of American Scientists]]. Accessed on 29 April 2008</ref> (e.g., following a fire).<ref>Firefighting and Damage Control Update [http://www.dcfp.navy.mil/library/dcra/181044ZJUN98.htm 181044Z JUN 98 (SUBS) Message] {{webarchive|url=https://web.archive.org/web/20090114121731/http://www.dcfp.navy.mil/library/dcra/181044ZJUN98.htm |date=14 January 2009 }} [[COMSUBLANT]] (1998) Accessed on 29 April 2008</ref> The diesel engine in a 688 class can be quickly started by compressed air during emergencies or to evacuate noxious (non[[Volatile (astrogeology)|volatile]]) 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.<ref>{{cite book|last1=DiMercurio |first1=Michael |last2=Benson |first2=Michael |title=The Complete Idiot's Guide to Submarines |place=New York |publisher=Alpha Books |year=2003 |pages=49–52 |isbn=978-0-02-864471-4}}</ref>

[[File:Periscope Depth.jpg|thumb|{{USS|Key West|SSN-722|6}} submerged at [[periscope depth]] off the coast of [[Honolulu]], [[Hawaii]] in July 2004]]