Editing Nimitz-class aircraft carrier (section)

===Refueling Complex Overhaul===
{{Main|Refueling and Overhaul}}
[[File:USS Abraham Lincoln (CVN-72) dry dock 1990.jpg|thumb|upright|alt=Abraham Lincoln in drydock. Equipment and vehicles are on deck for the overhaul|''Abraham Lincoln'' in dry dock, 1990]]
In order to refuel their nuclear power plants, the carriers each undergo a [[Refueling and Overhaul]] (RCOH) once in their service lives. This is also the most substantial overhaul the ships undergo while in service and involves bringing the vessels' equipment up to the standards of the newest ships. The ship is placed in a dry dock, and essential maintenance is carried out, including painting the hull below the waterline and replacing electrical and mechanical components such as valves. Because of the large time periods between the ships' constructions, the armament and designs of the newer ships are more modern than those of the older ships. In RCOH, the older ships are refitted to the standards of the newer ships, which can include upgrades to the flight deck, aircraft catapults, combat systems, and radar systems; precise details can vary significantly between the ships. The improvements normally take around four years to complete. The RCOH for USS ''Theodore Roosevelt'' took four years to complete (2009–2013) and cost about $2.6&nbsp;billion.<ref>{{cite web |url=http://www.defenselink.mil/contracts/contract.aspx?contractid=4103 |title=Contracts: Navy |date=26 August 2009 |publisher=DefenseLink |access-date=26 December 2009 |archive-url=https://web.archive.org/web/20090901115208/http://www.defenselink.mil/contracts/contract.aspx?contractid=4103 |archive-date=1 September 2009 |url-status=live}}</ref><ref>{{cite web |url=http://www.defenseindustrydaily.com/cvn-70-carl-vinsons-midlife-rcoh-refueling-maintenance-01554/ |title=CVN 70 Carl Vinson's Mid-Life RCOH Refueling & Maintenance |date=14 July 2009 |publisher=Defense Industry Daily |access-date=31 December 2009 |archive-url=https://web.archive.org/web/20101031002648/http://www.defenseindustrydaily.com/cvn-70-carl-vinsons-midlife-rcoh-refueling-maintenance-01554/ |archive-date=31 October 2010 |url-status=live}}</ref><ref>{{cite book |title=Refueling and Complex Overhaul of the USS "Nimitz" (CVN 68): Lessons for the Future |last1=Schank |first1=John |last2=Arena |first2=Mark |last3=Rushworth |first3=Denis |last4=Birkler |first4=John |last5=Chiesa |first5=James |year=2003 |publisher=RAND Corporation |location=[[Santa Monica, California]] |isbn=978-0-8330-3288-1 |pages=xiii–xviii}}</ref><ref>{{Cite web|url=https://news.usni.org/2015/01/12/upgraded-carrier-roosevelt-starts-pre-deployment-exercises|title=Upgraded Carrier Roosevelt Starts Pre-Deployment Exercises|date=2015-01-12|website=USNI News|access-date=2016-12-13|archive-url=https://web.archive.org/web/20170128175747/https://news.usni.org/2015/01/12/upgraded-carrier-roosevelt-starts-pre-deployment-exercises|archive-date=28 January 2017|url-status=live}}</ref> Planned Incremental Availability is a similar procedure, although it is less substantial and does not involve refueling the nuclear power plants.<ref>{{cite web |url=http://www.navy.mil/search/display.asp?story_id=12076 |title=Nimitz Begins Planned Incremental Availability |date=1 March 2004 |publisher=U.S. Navy |access-date=30 May 2010 |archive-url=https://web.archive.org/web/20110629212432/http://www.navy.mil/search/display.asp?story_id=12076 |archive-date=29 June 2011 |url-status=dead}}</ref>