A Solution to the Inherent List on Nimitz Class Aircraft Carriers

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A <strong>Solution</strong> <strong>to</strong> <strong>the</strong> <strong>Inherent</strong> <strong>List</strong> on Nimitz Class Aircraft Carriers by Dianna Wolfson Abstract Submitted <strong>to</strong> <strong>the</strong> Departments of Ocean Engineering and Civil and Environmental Engineering on May 07, 2004, in partial fulfillment of <strong>the</strong> Requirements for <strong>the</strong> degrees of Naval Engineer and Master of Science in Civil and Environmental Engineering Nimitz class aircraft carriers possess an inherent list <strong>to</strong> starboard that <strong>the</strong>ir list control systems (LCS) are typically unable <strong>to</strong> correct while under Combat Load Conditions. As a result, it has become necessary <strong>to</strong> use fresh water ballast in a number of inner bot<strong>to</strong>m voids and damage control voids <strong>to</strong> augment <strong>the</strong> LCS. Maintaining liquid ballast in damage control voids is unacceptable, as it reduces <strong>the</strong> design counter flooding capability of <strong>the</strong> ship, and thus reduces ship survivability. In order <strong>to</strong> res<strong>to</strong>re <strong>the</strong> ships operational flexibility and achieve <strong>the</strong> necessary/desired list correction, this study determines <strong>the</strong> effect of adding solid ballast <strong>to</strong> a series of voids/tanks identified on <strong>the</strong> 2""^, 4*, and 8* decks. Based on ballast density, tank location and capacity, ease of ballast installation, minor tank structural modifications, and a decision making cost analysis, solid ballast was determined <strong>to</strong> be <strong>the</strong> most advantageous for use in correcting <strong>the</strong> inherent list on <strong>the</strong> Nimitz class aircraft carriers. Fresh water ballast was also examined as a possible alternative, but not as extensively due <strong>to</strong> <strong>the</strong> large quantity of water required and its limited ability <strong>to</strong> achieve a list correction. Nimitz class aircraft carriers currently have an average list of L5 degrees and a KG of 47 feet. Since <strong>the</strong>ir allowable KG cannot exceed 48.5 feet, <strong>the</strong> average service life allowance (SLA) for KG is approximately 1.5 feet. This study shows that by adding approximately 400 I<strong>to</strong>n of solid ballast, list can be corrected by 1.5 degrees with only a 0.1 percent increase in KG. Thus, <strong>to</strong> permanently fix <strong>the</strong> average Nimitz class aircraft carrier starboard list, <strong>the</strong>re would be a 0.05 foot increase in KG, which in all cases is within <strong>the</strong> SLA. Additionally, this study shows that this L5 degree list correction can be accomplished at a low cost of approximately $1,200 per I<strong>to</strong>n. Considering <strong>the</strong> reduction in operational constraints and <strong>the</strong> benefits <strong>to</strong> ship survivability, this is truly an inexpensive proposition. Thesis Supervisor: David V. Burke Title: Senior Lecturer Thesis Reader: Eduardo Kausel Title: Professor of Civil and Environmental Engineering
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Page 5 and 6: Table of Contents Abstract 3 Acknow
Page 7 and 8: 1.0 Introduction 1.1 Motivation Air
Page 9 and 10: class. Changes to
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Page 15 and 16: the intact stabili
Page 17 and 18: for ships propulsion, respectively.
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Page 25 and 26: Tank name Tank volume Ballast type
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Page 29 and 30: of each tank's location was added,
Page 31 and 32: 2.3 Preliminary Decision-Making Cos
Page 33 and 34: All further costin
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Page 39 and 40: 2.4.1 Structural Modifications 2.4.
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Page 45 and 46: 3.1 Final POSSE Results The minimum
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A Solution to the Inherent List on Nimitz Class Aircraft Carriers

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