bluuebunny/crossref_metadata_2025 huggingface dataset:
ADVANCED GRAPHICS FOR COMMAND DISPLA YS
Authors: WILLEY F. JENNINGS , NESBITT DAVID W.
Published: March 2009

Application of computer graphics to tactical displays should not default to simplistic expectations or to clever uses of color. Under the sponsorship of the Aegis shipbuilding project we have defined a method of applying advanced graphics techniques to command displays that asks “What is the display to do?” rather than “What color shall be make it?” The target display is the Aegis display system tactical plot, or track picture. This display has evolved to include graphic elements representing the environment, combat system capabilities, and battle plans. If these elements are all needed in the same display the resulting picture has the potential for great complexity. This paper provides a method for designing uncluttered displays that contain the needed amounts of data. The method develops displays from primary system requirements and includes a computer program (a rule‐based system) that assigns hardware attributes (including gray scale, color, and area fill) to components of the picture (display elements). The resultant display is data intensive but not overwhelmingly complex.
THE ARCHITECTURE OF A REAL‐TIME EXPERT SYSTEM FOR DATA LINK MONITORING AND MANAGEMENT
Authors: LEWIS DOUGLAS D.
Published: March 2009

Efficient utilization of Navy communications links for tactical data exchange within the battle force requires real‐time knowledge of the connectivity between units and information on the architecture and state of the network that supports this connectivity. This information is necessary to diagnose faults or reconfigure a net to achieve improved exchange of tactical data. Real‐time information describing the state of a communications net is not usually available, comes at rates too fast to be assimilated by a human operator, and requires the operator to be extremely knowledgable in the protocol used by the network and in RF communications in general.

Automated network monitoring and management removes the manual burden of maintaining a network, as well as operating the network in a more efficient manner. This capability can be provided using an expert system and a hierarchy of sub‐processes to combine the real‐time data and the expertise necessary to monitor and provide support for managing Link 11.
APPLICATION OF MAGNETIC BEARING TECHNOLOGY FOR VIBRATION FREE ROTATING MACHINERY
Authors: HENDRICKSON T. A. , LEONARD J. S. , WEISE D. A.
Published: March 2009

By levitating the rotor of a machine with an actively controlled magnetic field, friction is reduced to negligible values and wear is eliminated. By controlling the magnetic fields through a servo‐control system, the rotor position can be exactly maintained; in addition, automatic balancing and stator vibration control can be provided, producing essentially vibration‐free operation.

Tests have been conducted utilizing magnetic bearings in an auxiliary turbine. These tests showed a reduction in vibration level of 25 decibels at the rotational speed when operating with magnetic bearings in place of conventional oil lubricated journal and thrust bearings.

Revolutionary friction‐free magnetic bearings have been used in a wide variety of industrial applications including highspeed machine tool spindles, large turbine generators, and natural gas pipeline compressors up to 12,000 horsepower. Application of this technology could ultimately permit extremely quiet operation of rotating machinery without the severe penalties in space and weight required by present noise reduction techniques.
RELIABILITY‐BASED FATIGUE DESIGN FOR SHIP STRUCTURES
Authors: WHITE GREGORY J. , AYYUB BILAL M.
Published: March 2009

In the continuing effort to apply reliability methods to marine structures, the next logical step is to include these techniques in the design process. The advantage of doing this would be the ability to design more efficient structures with some measure of certainty of the reliability level involved. The particular application in ship structural design which would benefit the most from using reliability methods is the design against fatigue failure.

In this paper, some of the reliability‐based methods currently being used (or proposed for use) in the design of structures against fatigue are examined. Each is evaluated as to its suitability for use in the structural design of ships. In addition, the authors propose a new reliability‐based fatigue design format which is based on their recently introduced Reliability‐Conditioned (RC) design method and the Load and Resistance Factor Design (LRFD) code format. This approach is hoped to provide the design engineer with an easy to understand and use tool based on the LRFD format. The RC method will enable him to quickly and accurately design the components of a ship's structure such that a desired level of safety against fatigue is achieved.

Each of the methods discussed is used to solve a practical example. The results of that example and several others are used to discuss the relative merits of each method.
ROBOTIC AND ARTIFICIAL INTELLIGENCE SYSTEMS FOR THE NAVAL OPERATIONAL ENVIRONMENT
Authors: HOGGE SHARON M.
Published: March 2009

Due to demographical factors, there will be a 25% decline in the national labor pool of eligible 17 to 21 year old men by 1992. As the Navy faces fierce competition with other services and private industry for the dwindling personnel resources of the nation, efforts must be made to consider automating certain tasks, especially those that are hazardous, boring, and labor intensive onboard ships at sea.

The Surface Ship Continuing Concept Formulation (CONFORM) Program (SEA‐5014) sponsored the Naval Surface Weapons Center's Robotics Laboratory to identify potential applications of robotic and artificial intelligence systems to operation and mission activities for shipboard use. The results of the investigation concerning applications of robotics to automate the aforementioned tasks are presented. Changes in current manning levels for selected tasks and ship classes, i.e., CVs, CVNs, LPDs, LPNs, and auxiliaries are examined. Future ship designs incorporating robotics, such as the advance based repair (ABR) ship are discussed. Twenty‐four applications were cited in the study which include a remote controlled vehicle for flight deck operations, limited tasks in biological, chemical, and radiation environments, computer aided command decision aids, ordnance handling, undersea search, recovery, and salvage, and ventilation duct cleaning. Four of the applications and their subsequent hardware fruition will be discussed.
INTEGRATED MACHINERY CONTROL—THE WAY OF THE FUTURE
Authors: TAYLOR BARRY , KHAN RASHID
Published: March 2009

The shipboard integrated machinery control system (SHIN‐MACS) has been under development since 1977. It has moved from an idea, through a paper study, a wooden mock‐up, a demonstrator console, to an advanced development model, and will first be operational in the Canadian patrol frigate (CPF) in 1988. The development of this integrated control system, particularly the latter part, has not been without its problems. However, through redesign and evaluation, the system is now real‐time capable and should provide a marked improvement over traditional control systems, particularly in the area of operator interaction with the plant.

The integrated machinery control system (IMCS) for the Canadian Patrol Frigate Program is the same design as the IMCS that is being retrofitted into the DDH‐280 class of destroyers under the Tribal Class Update and Modernization Program (TRUMP). The IMCS is a microprocessor based distributed control system which provides automatic control and monitoring of the ship's machinery and systems. The system will have the most technologically advanced man‐machine interface yet to be seen in a warship. The IMCS communicates with all of its components over a triple redundant data bus using redundant digital propulsion controllers. It also has an equipment health monitoring capability designed to assist in the reduction of life cycle cost of the machinery.

The IMCS in the CPF has a significant growth potential. The IMCS is a software based system, and thus lends itself readily to modifications and adaptation to other vessels. This technology will impact on the operation of a modern warship by catering to reduced manning; it will also provide assistance in the implementation of on‐condition based maintenance through the gathering of data electronically. The Canadian patrol frigate IMCS will be the first fully digital machinery control system to utilize data bus technology for all control and monitoring functions.
PROTECTIVE DEVICES IN NAVY SHIPBOARD ELECTRICAL POWER SYSTEMS
Authors: YKEMA JOHN I.
Published: March 2009

Electrical protective devices have always been a key element in naval electrical power systems. The development of protective devices is traced to show the improvements in functionality provided as electrical power systems increased in complexity.

Protective devices have had a major impact on electrical power systems through the development of more sophisticated fuses, circuit breakers, and relays. Without the continued progress in protective devices, shipboard electrical power systems improvements would have been stymied.

The analysis of the characteristics of protective devices is significant in the understanding of device performance and the features which were so essential to improvements in electrical power systems. Protective devices were developed to monitor the essential parameters of electrical power systems and then, through built‐in logic, determine the degree of reconfiguration of the system necessary to limit the damage to components and equipment and to enhance the continuity of electric service for the vessel.

The three major types of protective devices utilized in Navy ship electrical power systems are fuses, circuit breakers, and relays ‐ with fuses and circuit breakers being the predominant devices. The increased versatility of circuit breakers, particularly with the introduction of the electronic protective systems, has offered an additional degree of sophistication in the protection of electrical power systems. Electronic protective devices offer further advances and improvements which will impact the protection and the control of future electrical power systems.
THE IMPROVED 16‐INCH GUN WEAPON SYSTEM
Authors: WHITE RICHARD W. , ANTONIUK THOMAS H.
Published: March 2009

The Iowa class battleships are being returned to active service without significant modifications to their 16‐inch Gun Weapon System (GWS). The ordnance, 16‐in. guns and associated fire control equipment are currently 1940's vintage technology. The reactivation was accomplished without significant modernization to the gun systems due primarily to funding limitations. In the late 1970s naval gunfire had fallen out of vogue and no pressing need for 16‐in. GWS improvements existed.

With the development and subsequent deployment of the landing craft air cushion (LCAC) and the MV‐22A Osprey, naval surface fire support (NSFS) of Marine amphibious operations was reexamined. Specifically, the means of generating supporting fire from surface combatants required extensive analysis. The resulting analysis indicated that the most cost‐effective partial solution to the problem was an extensive modernization of the battleship's 16‐in./50 GWS. With such a modernization, the range, lethality, and response time of the weapon would be significantly improved.

Except for the gun turrets themselves, the 16‐in. GWS will be almost completely modernized. Extensive modification of the ordnance and fire control system will be accomplished.

This paper first discusses the reasons for the improvement in the 16‐in. GWS. It describes, in detail, the new 16‐in. ordnance under development, highlighting the operational issues which drive the engineering approach. Finally, the new gun fire control system (FCS) is described. The advantages of streamlining with digital equipment are highlighted. Some unique features of the FCS, which are appropriate in its operational environment, are discussed.
THE ADVENT OF THE PAPERLESS SHIP
Authors: CHICKERING JOHN E.
Published: March 2009

Management information is a vital vessel resource. Unfortunately, our dependency on paper as a storage medium hinders our efficient use of information. Technology exists today to store, retrieve, reproduce, distribute and control information in electronic form. The maturation of optical disk storage technology now allows computer systems to store large amounts of directly accessible information in a very small space.

This paper describes the problems of shipboard paper‐based information management currently being experienced, and proposes the use of optical disk storage technology to improve the use of vessel management information. The cost of converting a paper‐based information management system to an electronic optical disk‐based system is described along with the economic benefits required to make paperless ships feasible. Benefits accrue to shipboard information users both from automating paper‐based systems as well as from less obvious new capabilities, such as the ability to link automated technical data to maintenance management systems. A broad range of benefits will be discussed. It is the author's view that the cost of paperless information management can be overcome and that optical disk technology can now be effectively applied to shipboard operations. The advent of the paperless ship can make merchant shipping more competitive and the Navy more efficient.
OUT‐OF‐PRODUCTION MICROELECTRONICS ‐ AN ACHILLES HEEL OF DEFENSE SYSTEMS
Authors: MACKENZIE C. MALCOLM , WOOTTEN RICHARD , HOY KEVIN , NEELY JAMES , KOSCO DON , SMITH WILLIAM
Published: March 2009

Both the timely manufacture of defense systems and their subsequent on‐line operability depend upon the availability of component parts. The growing problem of microelectronic component nonavailability is casting a shadow over logistics support to these systems. This paper will discuss the causes of the problem and provide some examples of cases confronted by the DoD logistics community. It will also identify some actions which have been taken in the past to manage the issue as well as initiatives now underway. Finally it will look at what lies ahead.
Bilge Water Oil Separator Systems for German Navy Vessels
Authors: HAUPT EYLERT
Published: March 2009

Environmental protection is an obligatory part of the Federal Armed Forces mission. However, this duty ends when their operational readiness is endangered by environmental protection. In accordance with military requirements, all vessels are equipped with a pollution control system

The paper describes the rather costly and complex development and tests of gravity‐type bilge oily‐water separators. Other methods of oily‐water separation are mentioned briefly.

Starting from the initial development and trial activities on the test stand of the Technical Center, supplementary work aboard vessels and especially trials on a rolling stand are described. The report ends with a description of the current trial activities and prospects for the future.
Whither Fast Sealift: A Call to Action
Authors: HOPE JAN PAUL
Published: March 2009

This paper begins with comments on accomplishments in sealift and a summary of current problems in fast sealift. These include: few fast sealift ships in the inventory, a diminishing industrial base capable of producing such ships, and a lack of production programs to build ships that would increase our national fast sealift capability. The paper discusses strategic mobility concepts and highlights system interactions and linkages in moving war materials and replacement forces from depots and factories to the front lines.

From this foundation, the paper then discusses operational requirements “pull” as related to analysis and allocation of performance among components of the strategic mobility system. Sealift technology options are characterized and performance potential of these options are described. These characterizations include speed, ship lift capacity, equal cost fleet size, and fuel demands for a range of speeds from 24 to 50 knots. Performance potential for each option includes the total fleet lift capability stream over a 100‐day time span for a notional mission with and without an assumed rate of attrition. Alternative program plans are described for each technology option addressing technological risk, system and component development needs, design requirements, production strategies, acquisition time lines, and resource requirements.

The paper then revisits the operational requirements from a technologist's perspective. In a technology “push” approach, a set of practical and achievable requirements are selected that could be the basis of an effective and cost efficient production program for fast sealift ships.

Finally, the paper concludes with a call to action that would suggest a modest reallocation of transportation resources to establish and sustain a fast sealift production program, sustain a sector of the maritime industrial base hard pressed by a lack of commercial shipbuilding, and achieve a relatively near‐term increase in fast sealift capability at sea.
Ship Roll Stabilization in the U.S. Navy
Authors: BAITIS A. ERICH , SCHMIDT LOUIS V.
Published: March 2009

One purpose of this paper is to report upon the current status of using rudder roll stabilization (RRS) in the U.S. Navy as an alternative to the more common approach of roll‐fin stabilization. In either approach, active control principles are used to reduce ship roll motion with an eye towards improving ship system operational effectiveness as encountered in the high sea states of the Northern Latitudes.

A second purpose of this paper is to broaden the outlook upon the gains derivable from reductions in ship roll motion by relating the impact of roll damping upon ship roll motion. This linkage will provide three perspectives; one for the operational community, one for the ship sea‐trials community, and one for the naval architect. The latter perspective is proposed as a candidate for developing ship handling quality specifications. Finally, the use of active control concepts to improve ship seakeeping will be stressed as being in complete harmony with the allied principle of optimizing the ship hullform design for reasons of mission performance.
Calculating Operational Availability of Intermittent‐Use Ship Systems
Authors: CONWAY DANIEL H. , POH ADAM R.
Published: March 2009

This paper reviews the method of calculating operational availability from the Operational Availability Handbook (OpNavInst 3000.12) of 29 December 1987. It questions the procedure for intermittent‐use ship systems wherein non‐operating time is considered as uptime in using the instruction. Specific sample calculations based on actual gas turbine experience of CG‐47, DD‐963, DDG‐993, FFG‐7, and PHM‐1 class ships are presented to demonstrate conclusions to be avoided. This study suggests that following OpNavInst 3000.12 can result in a more optimistic Ao than has actually been achieved.
Integrated Ship Machinery Systems Revisited
Authors: LEVEDAHL WILLIAM J.
Published: March 2009

In the late 1980s, the world of U.S. Navy surface combatants is confronted with three new needs: to reduce ship signatures by factors of 10 to 1000; to provide ten‐gigawatt power pulses to new combat systems; and to reduce the high cost of hull, mechanical and electrical (HM&E) systems by taking advantage of newly‐available technology. These needs have caused an active response of the surface‐ship community to the many apparent benefits of integrated machinery systems.

The acoustic signature problem accelerated interest in integrated machinery systems. A substantial reduction in noise at cruise speeds requires the elimination of propeller cavitation and requires reductions in machinery noise. The use of contrarotating tractor propellers driven by bicoupled epicyclic gears and an alternating‐current electric motor in a pod which faces directly into the flow stream is potentially capable of such performance; even better would be a contrarotating superconductive electric motor in the pod. No other concept seems even remotely competitive with these. The major reductions in installed power, fuel consumption, and reduced displacement reported in the April 1980 Naval Engineers Journal are retained. Large reductions in infrared signature and further reductions in fuel consumption are provided by intercooled recuperated gas turbines.

An integrated electric propulsion system provides the opportunity to temporarily “borrow” power from the propulsion system and transform it into pulses for advanced combat systems. Not only the power of the turbines, but also the kinetic energy of the ship are available.
SFS — The 55 Knot Sealift Ship
Authors: BOWDEN JOHN O. , EMBRY GERRY D.
Published: March 2009

SFS is the acronym for the Surface Effect Fast Sealift Ship, a 20,000‐ton, surface effect ship (SES). The SFS acronym was chosen to distinguish it from the smaller, 100‐6,000 ton, SES craft.

The paper is based on an Ingails Shipbuilding conceptual design and concludes that an SFS is buildable now using existing technology. The waterjet propulsion system and the seal development program are also discussed. Immediate application to the Army's sealift requirements, the possible alternative military sealift and commercial applications, and the application of SFS technology to future military and commercial ship design are examined.

The SFS is designed to carry U.S. Army unit equipment such as tanks, trucks, and helicopters in a roll on/roll off configuration. The vessel must carry a 5,000 short ton payload over a range of 3,500 miles in sea state 3 at 100% full power at an average speed of 55 knots. The maximum cushionborne draft is ten feet and the SFS must be capable of loading and unloading while on cushion to permit operating in shallow draft ports. The original conceptual design was 825 feet long, 150 feet wide, and 84 feet high. It had 240,000 bhp of propulsion power and 60,000 bhp of lift power. The present configuration is slightly larger and has over 200,000 square feet of usable payload deck space.

The parametric studies leading to the selection of the hull form and proportions are discussed. The logic used in the selection of the waterjet/gas turbine propulsion system is reviewed. The philosophy of the arrangements, the propulsion system, the lift air system, the fuel system, the ballast system, and the ventilation system are also addressed.

The paper identifies the differences between the SFS operational profile and that of conventional ships. The payloadrange‐speed‐fuel relationships are explored and similarities with aircraft explained.

The Army's need for a fast sealift ship is discussed. Features have been added by Mod II, which extend the design beyond the single Army mission concept and make it a truly versatile fast sealift ship which can perform virtually any known sealift mission.
Estimation of Structural Service Life of Ships
Authors: AYYUB BILAL M. , WHITE GREGORY J. , PURCELL EDWARD S.
Published: March 2009

A methodology for the structural life assessment of a ship's structure is suggested. The methodology is based on probabilistic analysis using reliability concepts and the statistics of extremes. In this approach, the estimation of structural life expectancy is based on selected failure modes. All possible failure modes of the ship must be investigated and the most likely paths to structural failure identified. For the purpose of illustration two failure modes are considered in this study. They are plate plastic deformation and fatigue cracking. Structural life based on these two failure modes is determined for an example vessel.

The methodology determines the probability of failure of the ship's structural components according to the identified failure modes as a function of time. The results can be interpreted as the cumulative probability distribution function (CDF) of structural life. Due to the unknown level of statistical correlation between failure modes, limits or bounds on the CDF of the structural life are established. The limits correspond to the extreme cases of fully correlated and independent failure modes. The CDFs of structural life are determined for two inspection strategies; namely, inspection every year and inspection every two years with a warranty inspection at the end of the first year.

The meaning of the results for the case investigated in this study is that, for example, given an inspection strategy of two years and a desired life of 15 years, there is a 72% chance that the vessel will not experience enough partial damage‘ in the failure modes identified to constitute reaching the “end of structural life” as defined.
Naval Lithium Battery Safety Program
Authors: SHULER STANLEY C. , MORANSKI JOHN W.
Published: March 2009

The stringent performance requirements of present and future naval battery powered systems necessitate the use of advanced lithium batteries with extended energy and life characteristics. In recent years, battery manufacturers in the United States and various foreign nations have been developing new lithium batteries using lithium metal anodes coupled with either carbon monofluoride (CF)x, sulfur dioxide (SO2), thionyl chloride (SOCI2) or other cathode materials. These batteries represent a major breakthrough as primary power sources and provide certain unique advantages over conventional electrochemical systems. The advantages are: (1) a substantial increase in specific energy, (2) higher operating cell voltage, (3) low temperature operation and (4) projected long shelf life. While lithium batteries in general offer five to ten times the specific energy of conventional systems, each design differs from the other in its level of performance and in its hazards. The Naval Lithium Battery Safety Program addresses these hazards within the areas of acquisition, design, use, packaging, storage, transportation, and disposal.

The safety program also establishes minimum safety test requirements for lithium batteries in lithium battery powered equipment when used by the Navy or on Navy facilities.
Toward a Survivable Radio Room
Authors: BRUNINGA R.E.
Published: March 2009

Significant progress has been made in recent years in the survivability of naval systems through the principles of redundancy, separation, hardening and careful consideration of arrangements of equipments. In the area of radio communications, however, these principles are being applied on individual communications subsystems, but not as an overall survivability strategy to the total radio communications suite. Significant advances in automatic control, networking and distributed architectures have not been fully exploited in U.S. Navy communications and ship design to improve user friendliness and survivability under adverse conditions. This paper suggests that automated, remote control of communications equipment through a distributed/redundant networking system could eliminate the centralized radio room concept and allow much greater flexibility in ship design and arrangements to accomplish the objectives of NavSea Survivability Policy.
Flammability and Toxicity of Composite Materials for Marine Vehicles
Authors: SEVART JEFFREY L. , GRIFFIN O. HAYDEN , GÜRDAL ZAFER , WARNER GAIL A.
Published: March 2009

Characteristics of both thermoplastic and thermoset composite materials as they pertain to marine vehicle applications are discussed. Comparison of various material selection factors such as strength, damage and moisture resistance, and flammability and toxicity as well as cost and availability of thermoset and thermoplastic composite materials are presented. Methods for testing and reducing the flammability and toxicity are discussed. Many commercially available composite systems are reported to provide favorable characteristics for marine applications. Although there seems to be a need for improved production technology for thermoplastics, they present potential advantages in physical properties over thermoset composites.
CAD/CAM Manufacturing of Prototype Shipboard Components
Authors: CALVERT T.E. , RODRIGUEZ F.A. , SLEBZAK J.S.
Published: March 2009

The machine shop at the Annapolis Laboratory of the David Taylor Research Center (DTRC) provides model making and prototype support to a large variety of naval ship related engineering projects. In order to meet these challenging requirements, computer aided design/computer aided manufacturing (CAD/CAM) techniques are being used to produce “one of a kind” prototypes or very low volume production parts. The use of computer aides in these cases is to facilitate the accurate manufacture of a difficult part, rather than to improve manufacturing efficiencies. In addition, the approach provides the flexibility required to support research and development projects. Several examples of prototype shipboard components manufactured using CAD/CAM techniques are presented in this paper. The hardware and software that facilitated these projects are discussed. The examples described have met the requirements to produce a wide variety of prototype shipboard machinery components quickly and accurately.
Stability Analysis and Displacement Measurements of Graving Drydock Walls
Authors: WU ARTHUR H. , CECILIO JOHN , BAYLES ROBERT A.
Published: March 2009

Maintenance and safety certification of the Navy's graving drydocks are essential in supporting fleet operation and readiness. Thus, structural analyses of graving drydocks are made regularly by the Naval Facilities Engineering Command using a finite element computer program. An analytical method is implemented to evaluate the structural adequacy of existing drydocks which are subjected to static and earthquake loads. The results of the analyses are used in certifying the safety of drydocks. Due to the complexity of the drydock structure, an analysis is begun by setting up structural models which can accurately include structural and geotechnical parameters for finite element numerical analysis. The accuracy of the results can then be checked through a comparison of the different models used in the analysis, and the comparison of field observations made from carefully monitored instrumentation. For example, in order to evaluate a mathematical analysis of the response of a drydock to static and earthquake loads, measurements of the movement of drydock walls in Charleston Naval Shipyard, South Carolina, were made by flooding and draining the drydock during a docking operation. A dial gauge instrument was used to measure the displacement of a wall and a laser electronic distance measuring instrument (EDM) was used to measure the displacement across the width of the dry‐dock.

The purpose of this paper is to present the drydock wall stability analysis method and to compare the analytical results with the observed wall displacement. Conclusions were derived from the results of the finite element analysis and the measured wall displacement. The results were useful in the structural analyses and safety certification of the graving drydocks.
The Determination of Ship Loads and Motions: A Recommended Engineering Approach
Authors: BUCKLEY WILLIAM H.
Published: March 2009

This paper outlines the essential features of a recommended engineering approach to load and motion determination, required developments, progress to date and remaining key developments. An engineering approach is defined as one in which all significant cause and effect relationships have been identified and quantified so that the resulting design criteria and methods can play a deterministic role in the give and take of ship design. In defining the essential features of such an approach consideration is given to (a) the random nature of the seaway, (b) linear and nonlinear characteristics of the seaway and ship responses to it, and (c) the use of resulting loads and stresses in the assessment of as‐built static strength, fatigue and flaw growth degradation of static strength, and energy absorption under seaway impact loadings.

Progress to date in these areas is overviewed and recent developments summarized which serve to demonstrate that the rather demanding elements of an engineering approach are attainable. Because of the importance of seaway characteristics, primary attention has been given to providing an effective engineering definition of world wide wave climates. In addition, because of the importance of nonlinear seaways and ship responses, a method of characterizing the nonlinearity of measured random data has been developed.

With these advances in hand, remaining critical developments are identified and approaches to their resolution suggested.
Comparative Structural Life Assessment of Patrol Boat Bottom Plating
Authors: AYYUB BILAL M. , WHITE GREGORY J. , BELL‐WRIGHT THOMAS F. , PURCELL EDWARD S.
Published: March 2009

The estimation of an absolute life expectancy of a structure is a complex process and the results are expected to have relatively large levels of uncertainty. In this study, a comparative analysis is undertaken between two different patrol boats. This is an approach which results in a higher confidence level because certain factors common to both boats can be eliminated by assuming them to be at constant normal levels. The study is limited to the critical forward bottom plating and takes into account the differences in material, plate dimensions, operational profile, structure and loading of the two vessels. Two failure modes, plastic plate deformation and fatigue, are considered, and a novel approach to plate wastage is included. Many factors affect the structural life of a vessel. They include structural type, operational profile, structural details, loads, inspection and maintenance, design methods, safety factors, corrosion, and environmental factors. There are three types of uncertainty associated with these factors; namely, physical randomness, statistical uncertainties, and model uncertainties. The method described is designed to address these uncertainties.

The objective of the paper is to present the reliability‐based structural life assessment method, and then to use it to evaluate and compare the structural performance of the forward bottom plating of the two patrol boats. The results of the evaluation are presented in the form of graphs and tables in order to facilitate the comparative evaluation. The method is performed within a computer‐based format which allows parametric sensitivity analysis of several variables including the size of the plating panel, thickness, operational profile and loading. The sensitivity of the structural life expectancy of the forward bottom plating to variations in these parameters is evaluated.
Fiber Optic Coupler Sensors
Authors: GERDT DAVID W.
Published: March 2009

A new fiber optic sensor, based on sensitive single mode fused couplers, which has wide applicability to shipboard use, is introduced. Recent tests have shown that these sensors may be used as all optical hydrophones. Other tests have demonstrated that these sensors are useful as very sensitive accele‐rometers such as might be used for active machinery monitoring. Fiber optic coupler sensors can be used as all optical strain gauges as well. These sensors are composed of a potted single mode fused directional coupler which changes its coupling ratio in response to applied stress. The sensor may be designed into many configurations, including devices for monitoring seismic activity, magnetic field, temperature, pressure and other activities. Since the manufacturing technology involved in these sensors is rather simple, straightforward applications allow very inexpensive devices. A unique multiplexing scheme allows single source/single receiver operation of a string of all optical sensors.
Underwater Application of Adhesives in Ship Husbandry
Authors: KEENAN PATRICK J.
Published: March 2009

Wet adhesive technology is currently employed in specific applications of underwater ship husbandry (UWSH). The success and scope of underwater adhesive technology is limited by material and procedural considerations. One class of ad‐hesives, epoxy resins, possesses chemical and physical properties suitable for use in the UWSH environment. Improvements in material capabilities (i.e., biocide impregnation of epoxy resins) are ongoing. Bond formation at the adhesive‐surface interface is the primary factor in producing successful adhesion. The intrinsic difficulty of forming adhesive bonds to a wet surface may be overcome by improvements in application procedures (i.e., pretreatment) and through enhancement of the chemical bonding capabilities of adhesives. Incorporating technological and procedural improvements in underwater adhesive technology into standardized application processes could greatly increase the capability and scope of UWSH.
Smaller Wars: Prospects for Surface Warfare
Authors: Mahncke Frank C.
Published: March 2009

Engineering requirements for naval surface warfare weapons systems are partially driven by the geopolitical world to which the Navy must address itself. That situation is changing rapidly; it appears likely that an increasing emphasis will be placed on the Navy's ability to deal with smaller wars, wars of less than global scope. Driven by different rules of engagement and scope, these wars will impose unique weapon systems requirements, particularly in the areas of intelligence and surveillance, command and control, offensive weapons and defensive systems. This paper addresses the increasing likelihood of smaller wars, the special characteristics of such wars, and outlines some of the naval weapons systems requirements that may result.
Artificial Neural Networks and Their Application to Weapons
Authors: WEBSTER WILLARD P.
Published: March 2009

Complex processing algorithms associated with requirements for real‐time target detection, acquisition and recognition have far outdistanced our ability to package the necessary processing power into real‐time weapon‐sized hardware. Weapon developers need new, radically different, approaches to solve these difficult weapon signal processing problems. Artificial neural networks (ANN) is one of the new, radically different, signal processing approaches that is currently receiving much attention for weapon applications. The human brain is a powerful image and pattern recognition processor whose basic processing element is the neuron. Synapses are the weighted interconnections between neurons that permit learning and communication between the neurons. Artificial neural network technology attempts to mathematically and/or electrically model neurons and synapses and then interconnect these models in architectures suitable for signal processing tasks.

ANN technology is particularly applicable to pattern recognition, speech recognition, machine vision, robotics, and optimization signal processing tasks. Specific military applications include missile seekers, missile fuzing, sonar target discrimination, automatic target recognition, and autopilots. Two unique characteristics of ANN processors are that they are non‐linear processors and that they are trained, not programmed, to accomplish processing tasks in a manner analogous to the way the human brain learns. Learning is achieved by modifying the synaptic weights of each artificial neuron until the final desired system processing response is achieved.

Several years ago the Naval Weapons Center (NavWpnCen) identified ANN technology as a high risk‐high payoff approach to missile signal processing requirements and initiated several research and development efforts in this area. One result of this work is the new 80170NW ANN analog VLSI chip produced by Intel Inc. Another is the current Missileborne Integrated Neural Network Demonstration (MINND) Advanced Technology Demonstration (ATD) project to develop a hybrid analog/digital artificial neural computer for real‐time processing of data from imaging missile seekers. The neural computer will use several Intel chips interconnected in a flexible architecture, which is loosely based on the operation of the human retina, to demonstrate desired target/background discrimination and target detection and tracking processing capabilities. This paper provides an introduction to artificial neural network technology and discusses some of the results that have been achieved by applying ANN technology to weapon system problems at the Naval Weapons Center.
Fouling Control of Navy Surface Ships — 1990
Authors: COLOGER CHRIS P.
Published: March 2009

1The Author The Author received a B.S. degree from the New York State College of Forestry, Syracuse University. He joined the staff of the Material Laboratory at the New York Naval Shipyard in 1951 and carried out applied research as a wood technologist in the foreign wood program for all wood minesweepers. In 1962, at the Naval Applied Science Laboratory, he was engaged as a rubber technologist in the development of elastomeric vibration damping materials and the Laboratory's research studies on marine fouling. Since 1970, at the David W. Taylor Naval Ship Research and Development Center, he has been a materials engineer involved with the Center's programs on deck coverings, corrosion and conservation of energy. He is a member of ASNE.

Ongoing investigations on three test ships covering a period of five years have identified the performance characteristics of an antifouling (AF) paint for long‐term service. This paint ablates by the sequential hydrolysis of the surface and shearing action of the ship's passage through the water to remove the persistent settlement of microorganisms while continuously releasing an environmentally acceptable component to control calcareous fouling. During the past decade a variety of toxicants have been investigated and formulated into a number of AF paints that can be grouped on the basis of how the toxicant is combined and released from the paint matrix. Observations relative to color change, fouling and paint deterioration, define the qualitative criteria for evaluation. Quantitative data obtained with improved instruments for taking dry film thickness measurements and roughness determinations both in drydock and underwater accurately track these parameters during long‐term service. Field studies have shown that ablation of the AF paint is an effective mechanism to limit the formation of microbial biofilms on AF paint surfaces. Field studies have also revealed that reliance on toxics will not control the accretion of microorganisms on a ship's hull. The ablative AF paint has been found to be superior to all non‐ablative AF paints evaluated by the Navy to date.
Ship Electromagnetic Pulse Survivability Trials
Authors: JUMP MICHAEL E. , EMBERSON WILLIAM C.
Published: March 2009

The Navy conducted an EMP (Electromagnetic Pulse) trial on a Spruance class destroyer (USS Deyo; DD‐989) during July 1990 using the Electromagnetic Pulse Radio Frequency Environment Simulator for Ships (EMPRESS II).

The Navy has selected a layered hardening approach consisting of platform level hardening and system level hardening to provide EMP survivability for the mission critical systems of surface ships. One key question is how much of the hardening can be allocated to and achieved by platform hardening? The other key questions are which systems will also require system level hardening and can system level hardening be effectively achieved?

Prior to the trial, a platform level EMP hardening package was installed to evaluate the effectiveness of platform hardening techniques. Electromagnetic interference (EMI) fixes were installed when the EMI fixes were determined to provide system level hardening to emissions similar in frequency content to EMP. Temporary system level EMP hardening measures were also installed on selected combat systems and extensive pretrial EMP susceptibility assessments were performed on many of the ship systems.

During the trial period, USS Deyo was subjected to over 700 sub‐threat level pulses at increasing power levels. The highest test level during this trial was approximately 10dB below the EMP threat level. The induced transient currents exterior and interior to the ship and on a variety of systems were measured and used to evaluate the effectiveness of the platform hardening and system hardening. During the trial, a number of combat system operability tests were also conducted to help identify potential problem areas and evaluate system performance.

This paper describes some of the events prior to and during the USS Deyo trial and the lessons learned as a result of the trial. The lessens learned from this trial will have a positive impact on future ship hardening efforts and EMP trials.
Magnetohydrodynamic Submarine Propulsion Systems
Authors: SWALLOM DANIEL W. , SADOVNIK ISAAC , GIBBS JUDY S. , GUROL HUSAM , NGUYEN LONG V. , VAN DEN BERGH HUGO H.
Published: March 2009

Magnetohydrodynamic propulsion systems for submarines offer several significant advantages over conventional propeller propulsion systems. These advantages include the potential for greater stealth characteristics, increased maneuverability, enhanced survivability, elimination of cavitation limits, greater payload capability, and the addition of a significant emergency propulsion system. These advantages can be obtained with a magnetohydrodynamic propulsion system that is neutrally buoyant and can operate with the existing submarine propulsion system power plant.

A thorough investigation of magnetohydrodynamic propulsion systems for submarine applications has been completed. During the investigation, a number of geometric configurations were examined. Each of these configurations and mounting concepts was optimized for maximum performance for a generic attack class submarine. The optimization considered each thruster individually by determining the optimum operating characteristics for each one and accepting only those thrusters that result in a neutrally buoyant propulsion system.

The results of this detailed optimization study show that the segmented, annular thruster is the concept with the highest performance levels and greatest efficiency and offers the greatest potential for a practical magnetohydrodynamic propulsion system for attack class submarines. The optimization study results were used to develop a specific point design for a segmented, annular magnetohydrodynamic thruster for an attack class submarine. The design point case has shown that this thruster may be able to provide the necessary thrust to propel an attack class submarine at the required velocity with the potential for a substantial acoustic signature reduction within the constraints of the existing submarine power plant and the maintenance of neutral buoyancy. This innovative magnetohydrodynamic propulsion system offers an approach for submarine propulsion that can be an important contribution to the development of the submarine force of the next century.