bluuebunny/crossref_metadata_2025 huggingface dataset:
Introduction to Finite Element Methods of Structural Analysis
Authors: Tolefson D. C. , Brand L.
Published: January 2021

In order to make the underlying theory and broad applicability of the finite element method more widely understood, a unified introductory description of the three basic phases of the method—structural idealization, determination of element stiffnesses, and solution of the idealized structure—is presented. In addition to a detailed discussion of the fundamentals, an attempt is made to make the reader cognizant of the critical features of the method, such as the subject of element displacement compatibility. Also included is a numerical example illustrating the use of quadrilateral plate elements in the solution of an hemispherical shell structure.
Traffic on the Great Lakes and New Labrador Developments
Authors: Harris Robert B.
Published: January 2021

On 13 February 1979, the entire west span of the Hood Canal Floating Bridge sank under the action of a very severe storm. Although the significant wave height was estimated as high as 4.7 feet, wind and wave conditions during the storm were well within the design criteria of the bridge.
Fast Deployment Logistic Ship: Source Selection Techniques and Problems
Authors: Henning R. E.
Published: January 2021

The procedures of Concept Formulation and Contract Definition were applied to ship acquisition for the first time by the Fast Deployment Logistic (FDL) Ship Project. Coincident with this application, the Source Selection process was refined, formalized, and adapted for use by FDL. This paper portrays the Source Selection planning and implementation as the acquisition process progressed through the phases of Concept Formulation and Contract Definition. The objectives, organization, and detailed procedures for the FDL Source Selection are covered. The author points out that a well-organized Source Selection Plan and a definitive Request for Proposals will result in a better contract for both the Government and the contractor.
Stability of Fishing Vessels: Intergovernmental Maritime Consultative Organization of United Nations Safety Committee Recommendations
Authors: Price R. I.
Published: January 2021

Determining the elements of stability of a vessel is basic to the profession of naval architecture. It is therefore disconcerting to discover that there is actually little in textbooks on how to determine whether the stability in a particular vessel is sufficient. On further reflection, one recognizes this as the consequence of understanding the response of the vessel but not understanding the forces which the sea may apply. This deficiency of criteria was recognized at the 1960 Convention for Safety of Life at Sea. The Convention included in the recommendations (Recommendation 7, SOLAS 1960) that the Intergovernmental Maritime Consultative Organization (IMCO) should subsequently undertake studies relative to the requirements for intact stability.
Modern Trends in Ships’ Radio Communications
Authors: Hopkins Gordon C.
Published: January 2021

A brief historical background is covered which rapidly leads into present world-wide standards for maritime communications. Proposed new rules promulgated during the recent WARC (World Administrative Radio Conference), held in Geneva between September 18 and November 3, 1967, and their relation to the future are covered. Affiliated domestic and international governmental agencies and industry groups are listed for further reference by the reader.
Handling Problems at the Ocean-Air Interface
Authors: Pitchersky Arthur , Southerland Arthur
Published: January 2021

The increasing demand for a flexible Naval response to a broad spectrum of military situations imposes a demand to carry out missions in increasingly higher sea states. Launching and retrieving buoyant objects or loading cargo into boats responding to the ocean-air interface requires improved technology for successful operations in high sea states. There is an urgent need for handling systems that provide the degree of control necessary for those Navy missions subjected to an increasing all-weather response. Advances in the state of the art or the development of new techniques are needed to support these operational requirements. This paper will discuss present handling systems and proposed new methods.
Fresh Water Supply Aboard Ocean-Going Merchant Ships: The Economic Merit of Distillation From the Sea
Authors: Woodward J. B.
Published: January 2021

The average annual cost of obtaining fresh water for boiler feed and domestic use by distillation from the sea is calculated for two distinct types of merchant ship, and compared to the cost of carrying purchased shore water for these uses. Results are presented as annual cost differences between the alternatives as functions of voyage length, with other significant factors as parameters. These results confirm the general belief that distillation is to be preferred, even if shore water did not typically require redistillation before use. Circumstances in which shore water might nonetheless be an attractive alternative are pointed out.
Methods of Studying the Effects of Blast Waves on Ships’ Superstructures
Authors: Dewey John M.
Published: January 2021

Techniques are described which have been used to predict the possible effects of blast waves on ships' superstructures. The basic physical properties of a blast wave, the factors which affect these properties, and the techniques for measuring them are discussed. The interaction of shock waves with scaled rigid models is studied in the laboratory and the results are used to predict the blast loading on a full-scale structure. The dynamic response of the structure to this loading through the elastic, elasto-plastic, and plastic regimes can be calculated by reducing the structure to a system of simple single-degree-of-freedom components. These calculations are checked, when the opportunity arises, by studying the structure response on full-scale trials.
An Investigation of Shaft Relief Grooves in Tailshaft Assemblies
Authors: Caiamari Peter L.
Published: January 2021

Various relief grooves, located in the shafts between the liners and the hubs, were investigated with regard to their effects on the fatigue strengths of conventional tailshaft assemblies. It was found that tailshaft assemblies could be designed which would fail in the groove, regardless of whether single or increment loads were used, and that the fatigue strength of these grooved assemblies was higher than the fatigue strength of comparable ungrooved tailshaft assemblies. The grooved assemblies which had the highest fatigue strengths failed predominantly under the fitted members. The notch fatigue factors obtained with these test results were considerably higher than the estimated combined fatigue notch factors, and it is speculated that this apparent intensification is due to the added notch effect from the fitted members.
The Pump-Driven Lateral-Thrust Unit with Ejector Augmentation
Authors: Witte Jan H.
Published: January 2021

The idea of using cargo pumps to improve the low-speed maneuverability of tankers is evaluated. The main drawback of this system is the high kinetic energy loss in the jets, which results in an unfavorable thrust-to-installed-pump-power ratio. To improve the system, the exit velocity can be lowered, and the mass flow rate can be increased, by mounting the nozzles in contoured tunnels with open ends at both sides of the ship (ejector principle). Theory and experimental data derived from a large-scale experimental setup indicate that the performance of an ejector system for thrust generation is between the capability of a conventional screw-driven thruster and a radial pump-driven system with convergent nozzle.
Computer Simulation Applied to Facility Design and Performance Evaluation
Authors: Dunn Thomas P.
Published: January 2021

This paper describes how a computerized simulation model was utilized to evaluate initially the design and later the performance of the new Steel Fabrication Shop of the Newport News Shipbuilding and Dry Dock Company. Included are descriptions of the model and its development, the shop, and exhibits which are illustrative of model output.
Tonnage Measurement of Ships: Highlights of the International Conference, 1969
Authors: Murphy C. P. , Stiff P. S.
Published: January 2021

The Intergovernmental Maritime Consultative Organization (IMCO) through the Subcommittee on Tonnage Measurement of its Maritime Safety Committee in 1959 undertook to determine if it could develop a universal system for the tonnage measurement of ships. It considered the matter for nine years in nine sessions of the Subcommittee and seven sessions of the Working Group of the Subcommittee. Most of the sessions dealt, almost exclusively with the problem of a universal system. In 1968 after the Subcommittee had completed its work the IMCO Secretariat distributed to governments three basic proposals, including draft Articles, Regulations, and a Tonnage Certificate in each case, which the Subcommittee had prepared for a universal system of tonnage measurement of ships. There was also distributed a modified version of one of the proposals suggested by Denmark. Governments were requested to consider the proposals as possible basic documents for an International Conference on Tonnage Measurement to be convened in London for a four-week period commencing May 27, 1969.
Evaluating the Seakeeping Performance of Destroyer-Type Ships in the North Atlantic
Authors: Hamlin N. A. , Compton R. H.
Published: January 2021

A technique for the evaluation of the seakeeping performance of destroyer-type ships is presented and applied to four radically different hypothetical ship designs. The procedure involves first the determination of the responses of the four ships to realistic North Atlantic sea spectra, using linear superposition techniques, and assuming the vessels are in short-crested, irregular head seas. Calculations are based upon theoretical response amplitude operators obtained by applying strip theory to determine the response of the vessels to regular waves. The final evaluation is then obtained in the form of long-term probabilities of not exceeding stated numerical indices of performance as functions of ship speed.
Design and Construction of the Dynamically Positioned Glomar Challenger
Authors: Graham J. R. , Jones K. M. , Knorr G. D. , Dixon T. F.
Published: January 2021

This paper is a description of the dynamically positioned drilling ship, Glomar Challenger, referring to novel and unusual practices which should be of interest to marine and petroleum industries. Even today a seagoing ship with a 1 42-ft derrick is an oddity, although such derricks have been used in this capacity for over ten years. Probably the most noteworthy technological advance of this ship is found in the dynamic positioning system. To be able to hold a fixed position steadily—and within 1 00 ft of that position—and to be able to maintain position and orient the ship throughout the compass azimuths makes exciting work and oceanic exploration quite practical. The ship itself is a proven combination of marine and petroleum technologies aided by a power plant originally developed for the locomotive and petroleum industries. The aerospace industry has contributed satellite navigation and acoustic position-sensing systems. In total, the Glomar Challenger represents a practical and workable combination of industries, proven in service by the drilling to date of more than 20 core holes in the deepest parts of the North and South Atlantic Oceans. In four months of operation there has been no lost time due to weather or malfunctioning of the positioning system while drilling.
Weight Considerations for Deep Submersibles
Authors: Nickell E. H.
Published: January 2021

Conventional shallow submersible vehicles depend on the pressure hull for buoyancy, but deep submersibles depend on some type of bulk material for buoyancy. As a consequence, the design of very deep submersibles requires new considerations on the vehicle weight. The purpose of this paper is to evaluate the many parameters which affect the boat weight to see which ones are most influential on total weight. To accomplish this objective, a simplified mathematical expression is derived which describes the total weight for a deep submergence vehicle. The expression contains both structural and nonstructural weight items. The structural items include the pressure capsule, outer hull, foundations, and hard tanks. The nonstructural items are the equipment, buoyancy material, and payload. Each weight item is then examined in detail to determine what parameters affect the boat weight. The results show that the greatest weight reduction is possible with the equipment. This is because the state-of-the-art equipment used for deep submersibles has a weight almost equal to three times its displacement, and to furnish sufficient buoyancy material in the boat to float such equipment results in a large weight penalty.
Planning for the Construction of Tsu Shipyard
Authors: Hayashi A.
Published: January 2021

Tsu Shipyard is the newest and most modernized shipyard in Japan. It was planned and constructed by Nippon Kokan on newly reclaimed land. This paper presents the fundamental technical approaches used to plan its layout, to determine the capacity of facilities, and to design the dry docks with their accessories.
CMX Designs—Merchant Ships for the '70's
Authors: Kiss Ronald K. , Garvey John J.
Published: January 2021

A brief review of the CMX project undertaken by the Maritime Administration serves as an introduction to the preliminary ship designs developed by Newport News Shipbuilding and Dry Dock Company and Bath Iron Works Corporation. A series of five benchmark ships designed by MarAd is also presented.
The Evaluation of Risk in Marine Capital Investments
Authors: Klausner Robert F.
Published: January 2021

Future costs and revenues in capital investment opportunities can seldom be predicted with certainty. As a result, there is usually some doubt as to the outcome of an investment. The chance that an investment may not prove profitable represents the investor's risk. This paper considers the problems which uncertainty and risk present in the evaluation of capital investments. Several traditional methods of dealing with uncertainty and risk are considered and shown to be deficient. A relatively new evaluation technique, which utilizes probability theory and computer simulation, is then described and its advantages highlighted. It is suggested that this technique will prove valuable in the evaluation of future marine capital investments.
Drydocking: Past, Present, and Future
Authors: Dean Carlos L.
Published: January 2021

A dry dock regardless of capacity is usually the most expensive single tool used by a shipyard. This paper attempts to highlight some of the problem areas where designers, planners, estimators, and managers—in both production and customer organizations—can contribute to a more effective and efficient use of existing and future dry docks.
Vibration Survey Techniques
Authors: Knopfle William H.
Published: January 2021

The paper presents fundamental vibration survey considerations and discusses classical hull girder vibration and main propulsion machinery longitudinal vibration. The results of a typical hull girder vibration survey are presented. Elementary considerations of the effect, on blade-frequency hull girder vibration, of changing the number of blades on the propeller are discussed. The SNAME Bulletin No. C–1 "Code for Shipboard Vibration Measurements by Panels HS–7 and M–20 (1969)" is summarized with emphasis on the instrumentation aspect. The subject of local vibration is treated by means of some typical examples and the instrumentation requirements for this type of study are discussed. The performance characteristics of the Askania Hand Vibrograph are outlined. A vibration survey conducted by the author on a river towboat in order to investigate a rather unusual vibration problem is described.
Marine Patents and Proprietary Rights
Authors: Wyatt Douglas W.
Published: January 2021

The marine industry is embarked on a new course where technological innovation is the order of the day. In order for the marine industry to reap the harvest of innovative developments and inventions it is imperative that marine professionals be aware of the protection afforded by the law for their proprietary developments. This paper deals with the fundamentals of protecting patentable inventions and proprietary rights in the marine field and gives the marine professional general guidelines of the basic concepts of the law of proprietary rights so that he can recognize what subject matter is protectable and take the proper steps to secure proprietary rights thereto.
New Developments for the Offshore Oil Industry
Authors: Krutein M. G. , Reed J. A.
Published: January 2021

More than a decade ago, oil drillers and naval architects started to use vessels instead of fixed structures for offshore drilling. A multitude of novel platform concepts were developed which allowed the tremendous spreading of offshore oil activities. Today, search for oil spreads into areas of greater depth and farther away from the shores. This requires new developments of technology over a broad spectrum. The latest concepts of underwater oil production systems are briefly described.
Deep-Ocean Exploitation Technology
Authors: Kaufman Raymond
Published: January 2021

The paper discusses the latest techniques proposed for mining minerals from the deep ocean. Deep ocean is defined as the sea beyond the continental shelf, particularly areas of the sea floor exceeding 1200 ft in depth. The three principal deep-ocean minerals having economic potential in the immediate future are identified. Four recently proposed advanced deep-ocean mining concepts are presented. Use of the air-lift pump as a viable mining method is discussed and a large-scale air-lift pump experiment conducted in an abandoned mine shaft at Galax, Virginia is described. The principal features of the conversion of a small C1-M-AV1 type cargo ship to a deep-ocean mining prototype vessel, RV Deepsea Miner, is outlined.
A Method to Estimate Slamming Characteristics for Ship Design
Authors: Ochi M. K. , Motter L. E.
Published: January 2021

This paper discusses a method to estimate slamming characteristics of a ship at an early design stage using the ship lines. The first section of the paper deals with the derivation of a regression equation which yields a coefficient necessary to estimate impact pressure for any given hull form. The second section discusses the procedure of application of the regression equation in conjunction with other computer programs to estimate frequency and severity of slamming for ship design. As an example of the application, the extreme values of impact pressure are computed at several forward stations of the Mariner as a function of ship operation time in various sea states. By assigning an allowable extreme pressure magnitude and tolerable number of slams, it is possible to estimate the limiting sea state or limiting ship speed below which safe navigation without seriously suffering from slamming is anticipated.
Estimating Critical Speeds of Stepped Shafts with Flexible Bearings
Authors: Salzman R. H.
Published: January 2021

This paper presents a semi-graphical approach for finding the first critical speed of a stepped shaft with finite bearing stiffness. The method is particularly applicable to high-speed turbine rotors with journal bearings. Using Rayleigh's Method and the exact solution for whirling of a uniform shaft with variable support stiffness, estimates of the lowest critical speed are easily obtained which are useful in the design stage. First critical speeds determined by this method show good agreement with values computed by the Prohl Method for the normal range of bearing stiffness. A criterion is also established for determining if the criticals are "bearing critical speeds" or "bending critical speeds," which is of importance in design. Discusser E. G. Baker
Characteristics of Recent Large Container Ship Designs
Authors: Dorman W. J. , Koff D. J. de
Published: January 2021

The problems inherent in the design of container ships are discussed briefly. The characteristics of some of the larger designs are tabulated. Sketches of the profiles, main decks and midship section outlines, and shp-versus-speed curves are included.
Propeller Strain Measurements and Vibration Measurements on the SS Michigan
Authors: Dashnaw F. J. , Reed F. Everett
Published: January 2021

This paper is intended to aquaint the reader with the nature of the test program and to discuss the results of some of the preliminary analyses. The tests performed on the strain measurements indicate that the data are reliable provided that zero shifts and other factors are taken into account. The data, with the propeller shape, indicate that a pitching torque exists on the propeller in operation and that the peak tensile stresses occur near the 0.5 chord. The analyses of the vibration measurements are reported under the headings: General Hull Criticals; Local Vibrations in the Stern; Vibrations of the Superstructure; Vibrations in the Machinery Space; Longitudinal Vibration of the Shafting; Vibrations During Maneuvering; and Hull Motion Patterns at Resonances. Various graphs are provided to show pertinent relationships.
Experimental Optimization of Cargo Collection Configuration for Tankers
Authors: Liddle Larry
Published: January 2021

During the design of an 80,000 dwt tanker, a study was conducted in an effort to maximize the utilization of the main cargo pumps during cargo discharge. A 1: 10 scale model of the bottom structure of the tanker provided a technique for accurately duplicating the conditions of the ship during pumpout. The model was used in a series of experiments which determined the optimum configuration of cargo suctions, bulkhead valves, and structure flow holes for the ship. Measurements taken during a routine pumpout of the completed ship indicate that the selected cargo collection configuration functions as expected. The model tests and corresponding ship test indicate that it may be possible to develop analytical techniques for use in future efforts to improve the cargo collecting system on tankers.
Development of a 1000-Ft Great Lakes Self-Unloader (MV Stewart J. Cort)
Authors: Tripp C. E. , Plude G. H.
Published: January 2021

With the construction and completion of a new lock at Sault Ste. Marie, Michigan, a major change in the design of ships for service on the Great Lakes was possible. The lock permits the passage of vessels 1000 ft long by 105 ft beam, a jump from the previous size limitation of 730 ft by 75 ft. This paper traces the development of such a maximum-sized vessel and the shipyard that was specifically designed to construct it on a production-line basis.
A Comparison of Contrarotating Propellers with Other Propulsion Systems: Results of Model Experiments
Authors: Strom-Tejsen J.
Published: January 2021

An experimental program was carried out at the Naval Ship Research and Development Center to determine the propulsion performance of a high-speed containership with twin-screw, contrarotating, and overlapping-propeller arrangements. The afterbody lines for the contrarotating arrangements were developed as a modification to a 25.5-knot, twin-screw containership design being considered for construction by the American Export Isbrandtsen Lines. Results for the contrarotating version include effect of off-design shaft speed and torque ratios as well as application of single and twin rudders. Results are also given for the design using a single screw in case it should be necessary at a later date to replace the contrarotating with a single-screw unit. Experiments on the overlapping-propeller arrangement were carried out to make the comparison between the contrarotating and twin-screw designs a part of a general investigation of propulsion arrangements for high-performance merchant ships. Conclusions and recommendations for some further investigations are given.
The Design Requirement for an Unattended Engine Room Steam Propulsion Plant
Authors: Bullock william G. , Yonika Frank D.
Published: January 2021

This paper is a summary of a report prepared by the Office of Ship Construction to provide a base reference document from which a detailed design for an automated steam propulsion plant will be developed for unattended engine room operation. As the design details are developed, it may be anticipated that some of the concepts and preliminary design requirements discussed herein may be modified and/or changed to reflect these developments. It should also be noted that the concepts and opinions expressed herein are those of the authors and do not necessarily reflect those of the Maritime Administration.
A New Approach to Numerical Fairing and Lofting
Authors: Letcher J. S.
Published: January 2021

A procedure is set forth for generating a table of offsets describing a fair hull surface without recourse to iterative fairing of the lines. A mathematical representation of the entire surface is built up from a small number of defining functions (either graphically or analytically described) whose shapes are closely related to features of the usual lines drawings. Although the method is fast enough for hand calculation, two ways are suggested for employing machine computation; one resulting in offsets sufficiently precise to eliminate further fairing from the full-scale lofting. Completely worked-out examples of both the graphical and the computer procedures are appended.
Powering Study Technique Applied to a Pusher Tug Geared-Diesel Installation
Authors: Latorre Robert
Published: January 2021

This paper presents a rational approach to the selection of the main components of a medium-speed marine diesel installation. The technique described matches the engine, reduction gear, and propeller and determines a measure of merit for each combination. This matching calculation is based on the speed-power characteristics of the vessel's hull, essential information about the trade route, and vendors' prices. A computer program developed using this design technique is presented with the results of a pusher tugboat powering study.
A New Alloy Steel for Marine Cryogenic Applications
Authors: Kampschaefer G. E. , Havens F. E. , Sarno D. A.
Published: January 2021

The authors describe a new five percent nickel steel which is currently being considered for marine cryogenic applications involving the transport of liquefied ethylene and methane. The alloy combined with a unique heat treatment develops both high strength and good notch toughness properties at temperatures below —150 F. Results of weld tests are presented which show that filler metals and processes used for nine percent nickel steel produce adequate joint properties with this new economical alloy.
Experimental Procedures Used in the Development of Oil Retention Boom Designs
Authors: Miller E. R. , Lindenmuth W. T. , Lehr W. E. , Abrahams R. N.
Published: January 2021

The experimental procedures used in the development of oil retention boom design criteria are presented in detail. Emphasis is placed on the procedures used to determine the oil containment ability and structural loads on the boom as a function of environmental conditions. The critical scaling parameters for oil containment tests are presented and the test procedures which have been developed are described. It is concluded that it is critical to scale both Froude and Weber number. Tests to determine structural loads can be conducted using standard ship towing tank procedures. However, it is necessary to scale the elastic properties of the boom and its mooring system. There are uncertainties with respect to some parameters which cannot be properly scaled in oil containment tests. Thus, carefully conducted full-scale trial results are required. Available procedures and current plans to obtain full-scale data are presented.
Aspects of Simplified Hull Forms—Past, Present, and Future
Authors: Kiss Ronald K.
Published: January 2021

This paper discusses past efforts to simplify ship hull forms. It touches on work initiated by Admiral D. W. Taylor in the early twentieth century and progresses to the studies of N. V. Johnson in the early sixties. The author concentrates on a detailed discussion of recent research conducted by the Maritime Administration in evaluating the Container Pioneer hull developed by Blohm& Voss AG. This evaluation was aided by an extensive model test program conducted at the Naval Ship Research and Development Center which included tests of the simplified form and rounded derivatives possessing the same hull characteristics. Following a discussion of the possible construction savings the author considers the overall effect on operating economics. Finally, conclusions are drawn regarding the future application of this technique of hull construction.
Stability of Offshore Tugboats
Authors: Storch Richard Lee
Published: January 2021

A review of available stability criteria, tugboat casualty data, and existing U. S. tugboat designs is made to recommend stability criteria for use in the design of offshore tugboats. Casualty data for all tugboat/towboat operations are presented, with breakdowns of offshore casualties and intact stability casualties. A discussion of the mechanisms of intact stability casualties is included. Fourteen existing tugboat designs are listed and compared according to design and stability characteristics. Specific recommendations are then made concerning design features to limit the occurrence of stability casualties and stability criteria to be used for future designs.
Optimization of a Fleet of Large Tankers and Bulkers: A Linear Programming Approach
Authors: Everett John L. , Hax Arnoldo C. , Lewinson Victor A. , Nudds Donald
Published: January 2021

Linear programming was used to optimize fleets of large bulkers and tankers (including OBOs) for the 1980s. The fleet was intended to carry 15 percent of the U. S. foreign trade in the major dry and liquid bulk commodities. Guidance was obtained as to best ship designs and sizes, and, by sensitivity tests, benefits of standardization and backhauls were identified. Also, optimum ship characteristics were shown to be more sensitive to port depth than to exact trade forecasts, and fleet savings from relaxation of port constraints were estimated.
Design and Performance of Bow Thrusters
Authors: Beveridge John L.
Published: January 2021

This paper concerns the hydrodynamic forces and moments produced by a bow thruster. Several broad problem areas are discussed and the extent of present-day knowledge indicated. These include general duct arrangement, duct shape, and impeller design. A step-by-step design procedure is outlined that permits the selection of a practical bow thruster. This procedure is described for a minimum number of operational requirements; e.g., single bow thruster, a specified turning rate when the ship is dead in the water, and a duty cycle that requires thruster operation at ahead speed for control capability in canals, harbors, and other restricted waterways. Discussers John Fenton Seth Hawkins Donald Ridley A. Romberg
The Relationship Between Machinery Vibration Levels and Machinery Deterioration and Failures
Authors: Lundgaard Bertel
Published: January 2021

The paper proposes the use of periodic vibration monitoring as a diagnostic maintenance tool. For a small initial investment, the monitoring program will provide in most cases an early warning of impending equipment failure. Vibratory frequency is used to determine the nature of a malfunction, while the amplitude history indicates the seriousness of the problem. This information is useful in determining when to overhaul a machinery item and how extensive the overhaul should be.
Marine Fouling and Its Prevention
Authors: Benson P. H. , Brining D. L. , Perrin D. W.
Published: January 2021

The qualitative and quantitative aspects of marine biological fouling and environmental factors influencing its character are discussed. The authors examine present "state of the art" antifouling techniques and the theoretical chemical and biological tenets upon which they are based. Effectiveness of presently used systems is compared and future needs for fouling prevention, projecting present methods and new approaches which warrant further research, are indicated.
Application of Preoutfitting During Construction of Ammunition Ships AE 32-35
Authors: Goldbach Richard A.
Published: January 2021

The paper describes installation of pipe, electrical work, machinery, and ventilation systems in structural assemblies of AE Class ships prior to ways erection at Ingalls Shipbuilding Division. The prerequisites of planning, material, required facilities, and working drawings are examined. Organizations and implementation problems are also discussed together with that work which is most appropriate to preoutfit.
Cost of Stability for Fishing Vessels
Authors: Fraser D. J. , Jones D. I. , Van Der Net G. A.
Published: January 2021

There has been a reluctance to exceed the higher stability standards now in force, and designs continue to be built just conforming to the Governmental requirements. The prime reason cited for this reluctance is increased initial costs. The paper examines the general situation regarding stability for hypothetical yet realistic fishing vessel designs conforming to the existing regulations, and what may occur in actual seagoing conditions. Secondly, the initial costs of varying stability-dependent parameters are generated as functions of initial cost and of the overall financial returns for the vessel.
Diesel Engine Versus Steam Turbine Propulsion for a 34, 000-dwt Tanker
Authors: Steadman J. W. , Smith J. F. , Lindgren J. R.
Published: January 2021

The authors report on a unique experience where identical hull forms and equal horsepower (nominal) in two ships having different power plants were compared. One ship was powered by a conventional steam turbine plant and the other by diesel. Sea trial data are corrected to a common base and compared. Special problems and advantages of each plant are discussed.
A Broad View of Torsion Effects in Ships
Authors: Herbert Becker
Published: January 2021

Elementary stress analysis techniques have been used to help present a physical picture of torsion in ships and to depict the nature of the influencing factors. It is shown that cargo distribution may exert a significant influence on twist in a containership. It also follows, from that result, that there may not necessarily be a direct proportionality between seaway loads and torsional response. Variations in the details of the bow structure are shown to exert a prime influence on variations in torsional response. The importance of boxes is discussed and depicted in charts which indicate that the bow structure probably will be much more important than small transverse boxes in minimizing twist. A simple method is presented for estimating torsional frequency. Finally, test procedures are discussed for the measurement of torsional response in models and at sea.
Practical Method for Finding GZ with a Planimeter
Authors: Methven James D.
Published: January 2021

A new method for finding the center of an area and a practical application to stability calculations is given. The procedure presented makes possible collection of data for cross curves with a minimum of labor and apparatus. The paper contains an ideal and a practical theorem along with mathematical proof for acceptance of the method in calculations for GZ. Worked examples are illustrated for geometric forms and hull sections. Notes for development of mathematical devices are included.
Current Trends in Offshore Drilling Rigs
Authors: Zumwalt Crane E.
Published: January 2021

The increasing global energy requirements have caused a large demand for mobile offshore drilling vessels. More sophisticated, cost-effective vessels are necessary to operate in the often severe wind, wave, ice, current, and deep-water environments. Through the efficient use of data processing, aerospace structural and advanced hydrodynamic techniques and instrumentation, the state of the art of drilling vessel design and operation has progressed considerably in recent years. Increasing sophistication will be necessary to develop future generations of offshore drilling systems.
Design and Economics of Integrated Tug-Barge Systems
Authors: Giblon Robert P. , Tapscott Robert J.
Published: January 2021

The paper discusses the reason for the current interest in integrated tug-barges and outlines their history leading up to current developments in such designs, citing specific examples. Propulsion plants are discussed and single-screw and twin-screw propulsion systems are compared. The paper discusses a number of applications, both commercial and military, for which integrated tug-barge systems would be particularly suitable because of the flexibility offered by the detachable, interchangeable power plant (tug), and the relative lower first cost and operating cost when compared with a ship. The relative economics of tug-barge tankers operating under the U. S. flag are examined for two services; namely, an international route and a domestic service. Discussers E. Scott Dillon Harrison R. Glennon, Jr. Seth Hawkins Adrian S. Hooper George Mara Edward F. McCann II Edward E. Reed Charles S. Smith
Icebreaking Model Tests: Systematic Variation of Bow Lines and Main Dimensions of Hull Forms Suitable for the Great Lakes
Authors: Johansson Bengt M. , Makinen Eero
Published: January 2021

Nine bulk carrier models were tested in the Wartsila Icebreaking Model Basin (WIMB) in Helsinki, Finland. Eight of the models form a series with systematically varying parameters. This test series was the first one in which the influence of bow form, ship length and, ship beam on ice resistance was investigated systematically. The basic form was that of the existing Great Laker SS Ryerson, which was not originally designed for navigating in ice. The other models were modified in order to improve their icebreaking capability. The main objective was to study the icebreaking resistance in level ice, but in addition some tests were made for determining the ice resistance in a broken channel and for determining the steering ability of the models. All models were tested in level ice of 1, 2 and 3 ft thickness and at a speed range of 0–12 knots. Finally, a method for the calculation of the ice resistance and necessary power level of the Great Lakers is presented.
Dynamic Behavior of Tankers During Two-Way Traffic in Channels
Authors: Eda Haruzo
Published: January 2021

A nonlinear digital simulation model was formulated to examine the dynamic behavior of large full-form tankers during meeting and passing in restricted channels. Computer-printed trajectories obtained in a series of digital simulations indicated basic patterns of ship behavior. Performance of various control systems was evaluated in terms of deviations in ship trajectory and rudder angle. Comparisons with previous measurements obtained in full-and model-scale tests verify realistic modeling of the system.
Noise Control on Diesel Tugs
Authors: Dyer Thomas R. , Lundgaard Bertel
Published: January 2021

The paper briefly gives basic acoustic definitions and explains the fundamental concepts used in noise control. The mechanics of noise generation and the various methods used in noise suppression are explained. The silencing program employed on two sister tugs, Edith Lovejoy and Anne Carlander, is described in detail. The acoustic treatment of the tugs is not identical and the resulting noise level differences are discussed. Alternative acoustic approaches are described and evaluated. The paper is illustrated with graphs and tables of noise levels, and shows typical vessel arrangements and acoustic treatment details. A short bibliography is included.
Estimation of Great Lakes Bulk Carrier Resistance Based on Model Test Data Regression
Authors: Swift Peter M. , Nowacki Horst , Fischer Joseph P.
Published: January 2021

Tank data have been collected, analyzed, and standardized for 50 tests of Great Lakes bulk carriers. Regression analysis has been applied in order to estimate the coefficient of residuary resistance of such vessels in terms of their nondimensional form parameters. The results are presented for Froude numbers from 0.11 to 0.18 in the form of coefficients obtained by three different regressions, and in the form of charts at Froude numbers 0.14 and 0.16. Examples illustrate the use of the regression formulas in estimating the full-scale resistance.
The Impact of the 1973 IMCO Convention on the Maritime Industry
Authors: Benkert William M. , Williams Douglas H.
Published: January 2021

This paper briefly summarizes some of the major provisions of the International Convention for the Prevention of Marine Pollution, 1973, as adopted by the International Conference on Marine Pollution, 1973, and considers their impact on the shipbuilding and maritime transportation industries.
Is Port Study Model Testing Really Worthwhile?
Authors: Boylston John W.
Published: January 2021

As all types of vessels now tend to increase in size, many ports, approaches, and other waterways will require geographical change to accommodate this new tonnage. In our current ecologically minded society such changes will not be made easily. The use of hydraulic waterway models coupled with controlled ship models forms a graphic presentation that is understandable by technicians and nontechnicians. This paper describes, very generally, some of the preliminary planning required, and the general format for a successful port study model test. Cost estimates are given so that the possible benefits of such tests may be measured.
Stern Thruster Installation on the SS John Sherwin
Authors: Nielsen Richard A. , Kendall Harry H.
Published: January 2021

This paper describes the first retrofitting of a stern thruster on an existing Great Lakes carrier. Description of the machinery involved along with the method of overcoming space restrictions is provided. Sea trial results utilizing the stern thruster alone and in combination with the bow thrusterare tabulated. Economic aspects of the installation are discussed briefly. The paper is illustrated with photographs of the installation and includes arrangement drawings and a description of tunnel end closures.
The Potential of Manganese Nodules as a Future Mineral Resource
Authors: Swan David A.
Published: January 2021

The manganese nodule is being given serious consideration as a mineral resource because of the increasing scarcity of manganese, copper, nickel, and cobalt in land resources. The feasibility of mining the manganese nodule has to take into account the technology, economics, and legal aspects of an operation of this magnitude. This paper is an overview of the considerations that must be made before the mining of manganese nodules becomes a reality. It deals with the reasons manganese nodules are important, what processes are proposed for the recovery and processing of the nodules, the economic considerations in an operation of this type, and the legal problems that will be encountered by this type of operation.
Evaluation of the Potential of Combination Carriers for Transporting U. S. Oil Imports
Authors: Lewis Edward V. , Binkley John , Zubaly Robert
Published: January 2021

It was the objective of this study to establish whether moderate-sized combination bulk carriers (OBO and O/O vessels) could be expected to carry economically a significant portion of the foreign crude oil imports to the U. S. East and Gulf coasts, in competition with very large crude carriers (VLCC). Conclusions are evaluated in light of their implications for the development of ports and superports. Available published material is used to obtain a quantitive analysis of the current role of combination carriers in U. S. foreign trade in bulk commodities. Then, with the assistance of available trade projections, an estimate is made of the potential volume of backhaul cargo available to combination carriers. This is compared with the expected volume of petroleum imports. A general survey is made of suitable triangular routes for combination carriers and an evaluation of transportaion costs is made for several specific routes, comparing combination carriers with the use of VLCC vessels.
Subcavitating Propeller Design for Maximum Propeller Efficiency or Minimum Fuel Use
Authors: Kroeger N. Bernard , Cummings Damon E.
Published: January 2021

An optimization procedure is described for the design of a subcavitating propeller for given service conditions. Strength and cavitation criteria are included. Diameter, rpm, chord lengths, pitch distribution, camber distribution and thickness distribution are developed for the optimum performance. The optimum propeller is defined as that using the minimum power at a given ship speed. If power plant characteristics are known, the propeller may be designed for minimum fuel rate at a given ship speed. Characteristics of the propeller at other than design conditions may be derived.
The 1973 University of Michigan Ferro-Cement Canoe Project
Authors: Coveyou Tracy T.
Published: January 2021

This report relates the semitechnical approach to the design of a ferro-cement canoe used by the Quarterdeck Society of the Department of Naval Architecture and Marine Engineering of the University of Michigan. The interest to design and construct two ferro-cement canoes was generated by an annual ferro-cement canoe race cosponsored by Purdue University and the American Cement Institute. The Quarterdeck Society ferro-cement canoe project was successful in designing and constructing two 14-ft canoes of suitable strength, weight, and configuration to be competitive in a ferro-cement canoe race.
Aerodynamics of High-Performance Wing Sails
Authors: Scherer J. Otto
Published: January 2021

Some of the primary requirements for the design of wing sails are discussed. In particular, the requirements for maximizing thrust when sailing to windward and tacking downwind are presented. The results of water channel tests on six sail section shapes are also presented. These test results include the data for the double-slotted flapped wing sail designed by David Hubbard for A. F. Di Mauro's IYRU "C" class catamaran Patient Lady II.
PURETEC System for Treatment of Shipboard Waste
Authors: Fassell W. M. , Bridges D. W.
Published: January 2021

As part of the national objective of gleaning up our environment, ship and boat owners will be required in the near future to drastically curtail or eliminate the discharge of human waste into the navigable waters of the United States. The paper describes the authors' work on wet oxidation of shipboard sewage and its application to the "No Discharge" requirement that may be mandatory in the near future.
The Performance of Sailing Yachts in Oblique Seas
Authors: Pedrick David R.
Published: January 2021

The difference in the effects of rough water on similar sailing yachts has been one of the intriguing puzzles that sailors, designers, and researchers have long tried to understand. It is not uncommon for two yachts of equal performance in smooth-sea conditions to have their speed or pointing ability reduced by different amounts when encountering waves. To investigate the causes of such behavior, it is important to have a rational procedure to analyze how changes in hull form, weight distribution, rig, and other design features affect the speed and motions of sailing yachts. This paper discusses the relationship of wind to rough water and of motions and added resistance to wave length and height. It then describes a procedure to predict motions, sailing speed, and speed-made-good to windward in realistic windward sailing conditions. The procedure utilizes results of heeled and yawed model tests of 12-metre yachts in oblique regular waves to predict performance in a Pierson-Moskowitz sea state corresponding closely to the equilibrium true wind speed.