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The ''Ohio'' Replacement Submarine (formerly the SSBN-X Future Follow-on Submarine) is a future United States Navy nuclear submarine designed to replace the Trident missile-armed ballistic missile submarines. The first submarine is scheduled to begin construction in 2021 and enter service in 2031 (some 50 years after its immediate predecessor, the Ohio class, entered service).〔http://www.senedia.org/wp-content/uploads/2014/09/Ohio-Replacement-Program-Defense-Innovation-Days-5-Sep-2014-Final.pdf〕〔http://www.navy.mil/navydata/cno/n87/usw/usw_winter_09/ssbns.html〕 From there, the submarine class will serve through 2085.〔(Navy Finishes Specs for Future Nuclear Sub ) - DoDBuzz.com, 8 April 2014〕 ==Overview== The United States Department of Defense anticipates a continued need for a sea-based strategic nuclear force.〔〔http://www.submarinesuppliers.org/ssbns_nuclear_deterrence/pdf/2012/SIBC%20version%20of%20Miller%20White%20Paper.pdf〕 The current ''Ohio'' class is expected to retire its first vessel by 2029,〔 resulting in an expectation that a new platform must be seaworthy by that time. A replacement will cost over $4 billion per unit compared to ''Ohio''s $2 billion ($2.9 billion in 2011 prices).〔Frost, Peter. ("New Sub Role Could Buoy Our Economy" ) dailypress.com Retrieved December 2, 2010.〕〔(【引用サイトリンク】title=Cumulative Inflation Calculator )〕 More recent projections estimate the cost of each submarine at $6 to 8 billion. Twelve boats are planned as replacement for the Ohio class. Sources such as the Federation of American Scientists suggest that the number should be lower due to ever decreasing number of deterrent patrols in the Post Cold War era and as a cost reduction measure. However, Navy officials disagree stating that a dozen new SSBNs is the minimum number required despite issues in funding. Work on reducing the unit cost of boats 2-12 to $4.9 billion per boat (in base year 2010 dollars) is currently in progress.〔(【引用サイトリンク】title=U.S. Nuclear Modernization Programs )〕 Several options were explored by the Navy including a variant of the nuclear attack submarines fitted with a missile housing, a dedicated SSBN, either with a new hull or based on an overhaul of the current ''Ohio''. With the cooperation of both Electric Boat and Newport News Shipbuilding, in 2007 the Navy began a cost control study.〔 Then in December 2008, the Navy awarded Electric Boat a contract for the missile compartment design of the ''Ohio''-class replacement, worth up to $592 million. Newport News is expected to receive close to 4% of that project. Though the Navy has yet to confirm an ''Ohio''-class replacement program, then-United States Secretary of Defense Robert M. Gates, as of April 2009, confirmed that the Navy should begin such a program in 2010.〔 〕 The new vessel is scheduled to enter the design phase by 2014. An estimated 60 million labor hours will be required in order to design the new class.〔 It is anticipated that if a new hull design is used the program must be initiated by 2016 in order to meet the 2029 deadline.〔(【引用サイトリンク】title=SSBN-X Future Follow-on Submarine )〕 A report published in November 2011 stated that construction (of first-of-class) would start in 2019, the first boat would be launched in 2026 and commissioned in 2029. However, in 2012 the Pentagon announced that the entire program is some two years behind schedule.〔 Early production boats will be armed with Trident II D5LE missiles (the LE suffix standing for life-extension). The Trident II D5LE will have a new guidance system and remain in service until 2042. Representative Gene Taylor (D) of Mississippi had threatened to block the project unless the Navy shares with the Congress an internal Analysis of Alternatives. However, Taylor was defeated by Steven Palazzo (R) in the 2010 midterm election. Taylor switched parties in a bid to return to his former House seat, but was again defeated by Palazzo in the June 2014 Republican primary election. The high cost of the submarines is expected to cut deeply into Navy shipbuilding. The total lifecycle cost of the entire class is estimated at $347 billion.〔 The program entered the Technology Development Phase (known as Milestone A) in January 2011. In December 2012, the Naval Sea Systems Command awarded Electric Boat a $2 billion contract covering design work on the boat itself, design work related to the Common Missile Compartments, and provides for "shipbuilder and vendor component and technology development, engineering integration, concept design studies, cost reduction initiatives using a design for affordability process, and full scale prototype manufacturing and assembly." Both the Navy and Electric Boat have acknowledged that affordability will be key in the development of the new vessel. Accordingly, the Navy has included bonuses in the cost-plus-fixed-fee contract to incentivize Electric Boat to keep costs down, despite the lack of competition in the program. Electric Boat has stated that it will use its Design for Affordability Program - originally developed to reduce costs on the ''Virginia'' class submarine - to reduce both construction and life-cycle costs. Detailed design work is expected to begin in 2017 with the first patrol scheduled for 2031. Under the current program, 12 new submarines will replace the 14 existing Trident-equipped ''Ohio'' class boats. In April 2014, the Navy completed ship specification documents for the Ohio Replacement Program submarines. The technical details consist of three 100-page volumes of documents detailing its configuration, design, and technical requirements. There are 159 ship specifications including weapons systems, escape routes, fluid systems, hatches, doors, sea water systems, and a set ship length of 560 feet, partly to allow for more volume inside the pressure hull.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Ohio Replacement Submarine」の詳細全文を読む スポンサード リンク
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