bluuebunny/crossref_metadata_2025 huggingface dataset:
Reducing Undesired Wave Reflection at Domain Boundaries in 3D Finite Volume-Based Flow Simulations via Forcing Zones
Authors: Peric Robinson , Abdel-Maksoud Moustafa
Published: January 2021

This article reviews different types of forcing zones (sponge layers, damping zones, relaxation zones, etc.) as used in finite volume-based flow simulations to reduce undesired wave reflections at domain boundaries, with special focus on the case of strongly reflecting bodies subjected to long-crested incidence waves. Limitations and possible sources of errors are discussed. A novel forcing-zone arrangement is presented and validated via three-dimensional (3D) flow simulations. Furthermore, a recently published theory for predicting the forcing-zone behavior was investigated with regard to its relevance for practical 3D hydrodynamics problems. It was found that the theory can be used to optimally tune the case-dependent parameters of the forcing zones before running the simulations.

1. Introduction

Wave reflections at the boundaries of the computational domain can cause significant errors in flow simulations, and must therefore be reduced. In contrast to boundary element codes, where much progress in this respect has been made decades ago (see e.g., Clement 1996; Grilli &Horillo 1997), for finite volume-based flow solvers, there are many unresolved questions, especially:How to reliably reduce reflections and disturbances from the domain boundaries?How to predict the amount of undesired wave reflection before running the simulation?

This work aims to provide further insight to these questions for flow simulations based on Navier-Stokes-type equations (Reynolds-averaged Navier-Stokes, Euler equations, Large Eddy Simulations, etc.), when using forcing zones to reduce undesired reflections. The term "forcing zones" is used here to describe approaches that gradually force the solution in the vicinity of the boundary towards some reference solution, as described in Section 2; some examples are absorbing layers, sponge layers, damping zones, relaxation zones, or the Euler overlay method (Mayer et al. 1998; Park et al. 1999; Chen et al. 2006; Choi &Yoon 2009; Jacobsen et al. 2012; Kimet al. 2012; Schmitt & Elsaesser 2015; Perić & Abdel-Maksoud 2016a; Vukčević et al. 2016).
A Method for the Prediction of Extreme Ship Responses Using Design-Event Theory and Computational Fluid Dynamics
Authors: Xu Wenzhe , Filip Grzegorz , Maki Kevin J.
Published: January 2021

The design of a naval vessel requires accurate estimation of the extreme loads and motions that it will experience during its lifetime. Operation in large seaways in which the ship-wave interaction is highly nonlinear and transient leads to design events such as maximum internal loads due to global wave bending, local slamming loads, extreme roll, combinations of the global wave bending and local slamming, and many others. In this article, a method is presented that allows for nonlinear analysis to be used to predict events with user-specified rareness. The core of the method combines probability, frequency, and time-domain analyses to generate short time-window sea environments that lead to extreme dynamical events. The Office of Naval Research Tumblehome geometry is analyzed for the extreme roll angle when advancing in stern quartering irregular seas.

1. Introduction

The design of a naval vessel requires accurate estimation of extreme loads and motions that it will experience during its lifetime. Specific quantities of interest are the maximum slamming load during wet-deck impact, maximum acceleration at different locations on the vessel, maximum green-water load on the bow structure or helicopter deck, maximum roll angle, or frequency of occurrence of capsize, to name a few. It is important to recognize that a ship lifetime is decades long, and the exposure time in different severe storms over the lifetime is of the order of weeks, if not months. Furthermore, because of the random nature of the sea and, hence, the dynamical response of the ship, the extreme response is also random and should be characterized statistically. This means that a single lifetime realization in a given seaway by either model tests or numerical simulation only gives one sample of the extreme response, and multiple lifetime realizations are required to characterize the extreme response.
Air Layer on Superhydrophobic Surface for Frictional Drag Reduction
Authors: Peifer Bradley C. , Callahan-Dudley Christopher , Makiharju Simo A.
Published: January 2021

We examined the feasibility of combining a superhydrophobic surface (SHS) and air layer drag reduction (ALDR) to achieve the frictional drag reduction (DR) shown achievable with traditional ALDR, but at a reduced gas flux to increase the achievable net energy savings. The effect of a commercial SHS coating on the gas flux required to maintain a stable air layer (AL) for DR was investigated and compared with that of a painted non-SHS at Reynolds numbers up to 5.1 X 106. Quantitative electrical impedance measurements and more qualitative image analysis were used to characterize surface coverage and to determine whether a stable AL was formed and maintained over the length of the model. Analysis of video and still images for both the SHS and painted surface gives clear indications that the SHS is able to maintain AL consistency at significantly lower gas flux than required on the non-SHS painted surface. Hydrophobicity of the surfaces was characterized through droplet contact angle measurements, and roughness of all the flow surfaces was measured. The results from these preliminary experiments seem to indicate that for conditions explored (up to Rex = 5.1 X 106), there is a significant decrease in the amount of gas required to establish a uniform AL (and hence presumably achieve ALDR) on the SHS when compared with a hydraulically smooth painted non-SHS.
Influence of Ship Speed and Heading Profiles on Fatigue Damage Accumulation for a Naval Vessel
Authors: Thompson Ian , Ellis Bryan E.
Published: January 2021

Ship speed and heading distributions are essential inputs for spectral fatigue analysis, and both may depend on wave conditions. Because rough-weather operational changes are rarely well defined, uncertainties in these distributions can introduce error in fatigue assessments. The influence of speed and relative heading distribution on fatigue estimates has not been thoroughly examined in the existing literature. This study investigates the influence of ship speed and relative heading distributions on fatigue damage accumulation of two sister naval ships. To represent uncertainties, 16 different operating profiles were used, including a baseline profile created from operator surveys and measurements. Fatigue damage estimates are calculated from a spectral analysis of four structural locations near midship. A linear frequency-domain seakeeping code provides the wave loads. The corresponding stresses are calculated using linear finite element analysis. Efforts to maintain seakeeping quality and crew readiness are reflected in the baseline profile with rough-weather speed and course changes. Ignoring these operational changes leads to reductions in estimated fatigue damage of up to 34% relative to the baseline estimate. This nonconservative result emphasizes the importance of understanding how operators manage rough wave conditions.
Experimental Study on Planing Motion of a Cylinder at Angle of Attack in the Cavity Formed behind an Axisymmetric Cavitator
Authors: Serebryakov Vladimir V. , Moroz Vladimir V. , Kochin Viktor V. , Dzielski John E.
Published: January 2021

This article presents experimental studies of the planing motion of an axisymmetric cylindrical body along the surface of a cavity formed behind an axisymmetric cavitator at some angle of attack. The main focus is on the analysis of processes of interaction between the planing body and cavity surfaces. It also develops methods for determining the forces and cavity shape in the interaction zone and behind the planing surface. A number of issues related to supercavitating motion at shallow depth are investigated for moderate Froude numbers under conditions of non-negligible gravity effect.
Research on Simulation and Experiment of Ship Complex Diesel-Electric Hybrid Propulsion System
Authors: Xiao Nengqi , Xu Xiang , Chen Baojia
Published: January 2021

This article introduces the composition and 12 operating conditions of a four-engine two-propeller hybrid power system. Through the combination of gearbox clutch and disconnection, the propulsion system has four single-engine operation modes, two double-engine parallel operation modes, and six PTI operation modes. Because the propulsion system has a variety of operating conditions, each operating condition has a form of energy transfer. As a result, its energy management and control are more complicated. To study the energy management and control strategy of a diesel- electric hybrid propulsion system, this work mainly studies the simulation model and sub-models of a diesel-electric hybrid propulsion system. In this study, MATLAB/ SIMULINK software is used to build the diesel engine model, motor model, and ship engine system mathematical model. The test and analysis were carried out on the test bench of the diesel-electric hybrid power system. By comparing the theoretical value of the SIMULINK simulation model with the test value of the test bench system, the correctness of each sub-model modeling method is verified. On the one hand, research on the text lays a theoretical foundation for the subsequent implementation of the conventional energy management and control strategy based on state identification on the unified management and distribution of the diesel-electric hybrid power system. At the same time, energy management of the diesel-electric hybrid system is also carried out. Optimization research provides theoretical guidance.
Added Resistance and Speed Loss of a Ship Found Using Onboard Monitoring Data
Authors: Dalheim Øyvind Øksnes , Steen Sverre
Published: January 2021

Prediction of the added resistance or corresponding speed loss in real sea conditions is essential to evaluate the performance of a ship. Assessment of the environmental impact on vessel performance is essential for route and cargo planning, optimization of fuel consumption and design, and configuration of engines and the main propulsion system. In the present study, added resistance and speed loss in real sea conditions are evaluated from1 year of onboard monitoring data of a platform supply vessel (PSV) operating in the North Sea. The true sea margin is shown on an annual basis. Relative contributions from environmental conditions and vessel operation control are presented. Results are compared with model experiments and existing numerical methods for prediction of added resistance and speed loss in waves. The study shows that added resistance due to waves for this PSV is significantly larger than predicted by conventional frequency-domain calculations or model tests. No reason for the deviation is found, but it is anticipated that a combination of effects of longitudinal mass radius of gyration, differences in wavelength and steepness in model tests and reality, and nonlinear effects (not accounted for in the numerical calculations) is partly responsible for the deviations. For ships having similar main dimensions, the conventional ways of predicting added resistance or speed loss in waves is nonconservative, and improved methods should be sought.
A Performance Depowering Investigation for Wind Powered Cargo Ships Along a Route
Authors: Olsson Fredrik , Giovannetti Laura , Werner Sofia , Finnsgård Christian
Published: January 2021

Abstract. For a sailing yacht, depowering is a set of strategies used to limit the sail force magnitude by intentionally moving away from the point of maximum forward driving force, potentially reducing the ship speed. The reasons for doing this includes among others; reduction of quasi-static heeling angle, structural integrity of masts and sails and crew comfort. For a wind powered cargo ship, time spent on a route is of utmost importance. This leads to the question whether there is a performance difference between different depowering strategies and if so, how large. In this research, a wind-powered cargo vessel with rigid wings is described in a Velocity Prediction Program (VPP) with four-degrees of freedom, namely surge, sway, roll and yaw, with a maximum heel angle constraint. The resulting ship speed performance for different depowering strategies are investigated and the implications in roll and pitch-moments are discussed. The wind conditions when depowering is needed are identified. A statistical analysis on the probability of occurrence of these conditions and the impact of the different depowering strategies on the required number of days for a round-trip on a Transatlantic route is performed.
VPP-Driven Sail and Foil Trim Optimization for the Olympic NACRA 17 Foiling Catamaran
Authors: Graf Kai , Freiheit Oliver , Schlockermann Paul , Mense Jan C.
Published: January 2021

Abstract. The Nacra-17 catamaran is currently the only type of multihull that participates in the Olympic Games. It features semi-L-shaped daggerboards, allowing the boat to foil. For maximizing boat speed, the sailors have to cope with a large set of trimming parameters. Boat speed depends on sail trim, but additional trim parameters also have a strong impact on boat speed: the rake of the daggerboard and the rudder, the platform trim and heel angle and the rudder angle. The project described here tries to assist the sailors in finding an optimized set of trim parameters. This is done with the help of a proprietary velocity prediction program, which - besides solving for equilibrium of all forces acting on the boat - searches for the set of daggerboard and rudder rake, rudder angle, heel angle and platform trim, for which performance yields a maximum. The paper describes the method as well as some of the results.
The Design of Water-Jet Propulsion Systems for Hydrofoil Craft
Authors: Levy Joseph
Published: January 2021

This paper contains a brief description of the water-jet propulsion system as applied to hydrofoil craft, and a discussion of the salient hydrodynamic aspects of the problem of fitting the main propulsion system to the specified thrust-versus-speed requirements. The factors that affect the overall propulsive efficiency and the weight of the system are discussed at some length; procedures for optimization of performance at the design cruising speed are outlined; finally, the processes by which the performance at off-design conditions may be evaluated are discussed and illustrated with performance curves for one specific design.
Effect of Eccentric Shaft Location on the Dynamic Performance of the Propeller of a Single-Screw Tanker
Authors: van Lammeren W. P. A.
Published: January 2021

In this experimental research the effect of an eccentric shaft location on the propeller-excited vibratory forces in the propeller shaft has been investigated for a single-screw 32, 000-dwt tanker with a block coefficient of 0.769. Tests were carried out for a four and for a five-bladed propeller with conventional shaft location, as well as with a set-off of the propeller shaft of 5 and 10 percent of the propeller diameter, respectively.
Great Lakes Barge Operations—A Review
Authors: Stearn R. A.
Published: January 2021

Barging on the Great Lakes started about 100 years ago with the advent of steam and the decline of the sailing fleet. As vessels increased in size, and sail power was replaced by steam, barging was used as a stop-gap to circumvent rising cost of operating labor and cost of new construction. Today we face a similar situation, where vessels relegated to the scrap heap because of small size, antiquated power plants, and excessive crew costs, are being investigated for conversion to barges as a means of obtaining economical bulk transportation with low capital outlay. This paper briefly discusses problems which must be met in consideration of bulk barge operations on the Great Lakes, principal work involved in conversion of old steamer hulls to barges, and presents a typical economics study for a specific route. Background data and studies presented herein have been prepared by H. F. Purinton and J. P. Fischer, of the author's firm.
Prediction of Lift and Cavitation Characteristics of Hydrofoil-Strut Arrays
Authors: Johnson Robert S.
Published: January 2021

Two hydrofoil-nacelle-strut arrays and one hydrofoil-strut array have recently undergone hydrodynamic testing at the David Taylor Model Basin. A calculation procedure for predicting lift and cavitation characteristics of conventional hydrofoil arrays is suggested herein and is compared with the experimental results.
An Advanced Concept of Improved Shipbuilding Fabrication and Material Handling
Authors: Schmidt Alfred
Published: January 2021

The direct connection of material storage and processing facilities will create more flexibility in fabrication shop performance. The use of conveyors and Vacumag cranes has substantially improved material handling. More accurate finished plate dimensions have resulted from optical marking and automatic burning, thereby also improving fitting at the assembly platens and at the shipways. Storage of mold-loft information, hitherto a problem with full-size wooden templates, has been virtually eliminated. Card files serve now for the storage of glass negatives and three template storage buildings have been completely eliminated. Some active templates are now being stored in the mold loft. The interchange of lofting information in form of negatives or tape represents quite an asset, in case of national emergency.
Mooring Techniques in the Open Sea
Authors: Graham John R.
Published: January 2021

Drilling ships of the author's company have weathered some pretty wild seas in exposed drilling locations around the world. The author discusses, from experience, the problems of mooring at sea and anticipates the development of "dynamic positioning" for future transfer-of-cargo operations or for drilling, mining, salvage and exploration at sea. The effect of multiple chains working together in a tensioned mooring system is discussed as opposed to a single chain conventional anchoring and the importance of chain metallurgy, connecting devices and better anchors is stressed. The author infers that too much is expected of too little in most deep sea moorings.
Marine Engineering and the Challenge of the Deep Frontier
Authors: Bartlett Francis G.
Published: January 2021

The expansion of man's knowledge of the sea and the exploitation of it have depended on the development of various craft and their components for use upon the seas, which is pointed out in the beginning of the paper. Then follows discussion to indicate that "The Freedom of the Seas" has established the condition that capacity and capability for marine undertakings were prime criteria to be considered by groups desiring to maintain viable establishments throughout the oceans of the world. A review of recent events influencing maritime events is followed by a brief outline of the Federal Government's efforts to stimulate increased activity in connection with the sea. The paper closes with a look into the future and notes developments of concern to the marine engineering 2 professions.
Least Cost Ship Characteristics by Computer Techniques
Authors: Murphy R. D. , Sabat D. J. , Taylor R. J.
Published: January 2021

A systematic procedure is developed utilizing computer techniques to determine the optimum combination of length, beam, draft, block coefficient, and depth to satisfy a predetermined "least cost" criterion for a dry cargo ship, which will meet a given set of owner's requirements for speed, fueling range, stowage factor and cargo deadweight. The least cost ship is obtained from a family of ships resulting from the permutation of four values each of five basic design variables. Selection of the least cost ship is dependent upon the computer programming of standard preliminary design processes which define only those ships consistent with good design practice and existing regulatory requirements. The methodology, examples of actual applications, and analysis of results obtained, are the principal features of the paper.
Series 64 Resistance Experiments on High-Speed Displacement Forms
Authors: Yeh Hugh Y. H.
Published: January 2021

The speed-length ratios of displacement-type surface ships in the past were limited to under 2.0. In order to perform projected tactical missions, however, the Navy needs ships of much higher speeds resulting in speed-length ratios of 2.0 or above. To gain information in this respect, 27 models of conventional hull forms designated "Series 64" were designed, constructed, and tested at the David Taylor Model Basin. This paper reports the results of the bare hull resistance tests of Series 64 models.
Ship Design Process
Authors: Miller Richards T.
Published: January 2021

With greatest emphasis on feasibility or conceptual design, which has been so sparsely treated in the literature, the author presents the naval ship design process from first statement of operator's requirements to final production of builder's plans. The iterative nature of conceptual design is emphasized, and a rational process for arriving at principal characteristics shown. The development of a specific design is illustrated by selected sketches and plans of the AGOR-3 class of oceanographic research ships at the conceptual, preliminary, and contract stages of design.
Deepstar Hull Fabrication
Authors: Gayer George F.
Published: January 2021

Deepstar is a self-propelled, manned vehicle for deep-sea research. It is being built as a private venture by Westinghouse Underseas Division, Baltimore, under a technical exchange license with Captain Cousteau and the OFRS (Office Francais de Recherches Sous-Marines) of Marseilles, France. Deepstar is designed to carry a crew of three to depths of 4000 ft for periods up to 24 hr. It is powered by two 4½-hpbattery-operated electric motors which propel it at about 3 knots, with a maximum range of about 20 miles. Overall dimensions of the vehicle are 13 ft long by 7 ft high by 11½ft wide over the fairing. The pressure sphere which houses the crew was built for our Baltimore Underseas Division by Westinghouse, Sunnyvale Marine Division. It measures 70 in. od and was fabricated from two hemispheres of high-strength steel. These hemispheres were spun from alloy plates 1?in. and then machined both inside and outside to 1.2 in. thick. Accurate machining was essential to maintain the sphericity required for pressure stability. After machining, the two hemispheres were welded together by an automatic welding process. The sphere has a total of 11 penetrations through the shell, including an access hatch, 2 viewports, a camera port, 2 electrical passages and 5 shaft openings. Reinforcements for the larger openings were made by welding alloy-steel forgings into the shell. Small openings were reinforced by weld metal buildup through which holes were drilled. All reinforcements were then machined to provide accurate penetrations and sealing surfaces. An extensive metallurgical testing program was conducted to insure that all material and welding used in the sphere had the strength and toughness required for operation at maximum depths. Pressure tests have been conducted in a chamber to 1.2 maximum operating depth. Sunnyvale also made the electric motors for Deepstar. These free-flooded ac motors are suspended outside the pressure hull. Unusual problems solved by special processing included electrical insulation in the salt water environment and water-lubricated bearings. AC power for the motors is provided from the batteries through a rotary inverter with semi-conductor controls.
A Nuclear-Fueled Steam Generator-Superheater for Merchant Ship Propulsion
Authors: Delson E. B. , Hunt E. C.
Published: January 2021

The 630A is a nuclear steam generator-superheater of about the same size and somewhat heavier than the conventional boiler which it can replace in merchant ships. It has a gas primary cycle, transferring heat from the reactor to a once-through boiler-superheater. Feedwater delivered to the boiler is discharged as high superheat steam (1500 psi--1000 F). The 630A technology stems from the nuclear aircraft and land-station technologies. It has gone through a series of design iterations. This paper describes the Mk IV. The latest version, the Mk V, with improved economics is now proposed for ship installation. The paper discusses the general considerations of maritime nuclear propulsion, problems in achieving full utilization, and presents an economic comparison of 13,000-dwt nuclear and conventional ships over a range of speeds.
Development of a High-Speed Reverse Gear for Marine Gas Turbine
Authors: Croker D. M. , Psichogios T. P.
Published: January 2021

This paper describes the operation and salient design features of a high-speed reversing gear used with the Solar 1100-hp Saturn gas-turbine engine. Development history leading to successful marine applications is reviewed.
Equity Capital, Borrowed Capital and Design Decisions
Authors: Benford Harry
Published: January 2021

Many ships are financed by combinations of bank loans and equity capital. Some ship designers base design decisions on maximizing the owner's return on his own capital; others aim for maximum return on the total investment. The author shows that either approach may be correct, depending on the circumstances of the loan.
Filaments for Reinforcement and the Applicability of Filament-Wound Laminates for Deep-Submergence Vehicles
Authors: Kies J. A.
Published: January 2021

The properties of filaments being considered for reinforcing plastics for deep-submergence vehicles are compared. Graphite or carbon shows outstanding potential. High stiffness and immunity to chemical attack are needed. The mechanical properties of new resins show dramatic increases over those in current use. Formulas for peeling failure are given and a forecast of the competitive position of GRP is made.
Miscellaneous Notes on Launching
Authors: Romberg A. K. , Evans K.
Published: January 2021

This paper is a selection of results from actual launching in certain areas which the authors feel are not adequately covered in published information. These notes include comments on the analysis of forces acting on the members of launching poppets, on maximum grease pressures, on a simple method of timing the travel of the ship and on the maximum draft at the stern during pivoting. A side-launching facility for barges is also described.
Hydrodynamic Aspects of Internal Pump-Jet Propulsion
Authors: Kim Hun Chol
Published: January 2021

A certain hydrodynamic aspect of internal pump-jet propulsion is reviewed and a design procedure is outlined. The method uses one-dimensional theory of ideal fluid but modified with the data on head losses of real fluid. The theory is simple, and accordingly, the crux of the method lies in estimating the losses in the system. Attempted loss analysis shows a general lack of such data and therefore proposes certain fundamental investigations, especially on inlet and jet nozzles. Among other conclusions, this study points out that an internal pump-jet propulsion system is not an effective one and will never be as efficient as a regular propeller system for normal large ocean-going ships from a hydrodynamic point of view.
Sealab II Dished Heads Explosively Formed at Hunters Point Division, San Francisco Bay Naval Shipyard
Authors: Jue Lawrence S. , Giannoccolo Sal
Published: January 2021

Twelve-foot-diameter steel dished heads could not be procured in time to meet a stringent production schedule. The problem was solved by a "do-it-yourself" underwater explosive-forming method.
An Economic Feasibility Study of United States Bulk Carriers
Authors: Mack-Forlist D. M. , Hettena R.
Published: January 2021

Originally prepared for the information and use of the United States Maritime Administrator, this study offers a mathematical method for forecasting and analysis of the economic performance of different bulk-carrier designs under varying conditions. Criteria for design selection are discussed and the optimum design emerges as a semi-automated bulk carrier of 38,000 dwt and a sea speed of 16¼ knots. Based on standardized U. S. construction with construction subsidy and operating costs well below those of existing U. S. bulk transportation units such vessels not only replace obsolescent tonnage but also generate freight savings in government-sponsored bulk exports sufficient to recover the government's investment in construction subsidy in a short time. The study shows that U. S. bulk carriers cannot successfully compete with recently built foreign units, but the lower operating costs of the proposed design and the consequent lowering of U. S. freight levels would induce operators to carry a significant measure of foreign cargoes, primarily as return cargoes and in triangular movements.
The Choice of the Propeller
Authors: van Manen J. D.
Published: January 2021

In this paper the four main requirements for a propeller are dealt with. These requirements concern efficiency, cavitation, propeller-excited forces and stopping abilities. In a propeller diagram the characteristic efficiency curves for different conditions are explained. A comparison of the optimum efficiencies for various types of propulsors is given, and the applications on a 130,000-dwt tanker are considered. Cavitation-inception curves both for a specific propeller and for systematic propeller series are discussed. Predicted torque and thrust fluctuations, based on model-test data, and the results of measurements on the full-size ship are compared. Finally a quasi-steady testing technique, developed to analyze different types of stopping maneuvers, is described.
Economic Problems Facing Canadian Shipping
Authors: Bain G. F.
Published: January 2021

After briefly sketching the composition of Canada's shipping fleet and pointing out how its productivity has altered and may alter in the future, an examination of the Canadian Great Lakes fleet and its economic outlook is attempted. The author holds that, having reached the physical limits of size, Canadians can no longer respond to competitive pressures except by adopting new management and operating methods and by developing new shipping patterns. Rail and foreign ocean shipping will provide increased competition. A case is made for close Industry-Government consultation to avoid conflicting policies and a case is made to build a new canal between Lake Ontario and Lake Erie to match the size of the Poe lock.
Conceptual Study of a Supercritical Reactor Plant for Merchant Ships
Authors: Pravda M. F. , Lightner R. G.
Published: January 2021

Pressurized water-saturated steam nuclear power plants have been demonstrated to be reliable marine power plants. Capital and operating costs for these plants continue to be reduced by technology and design improvements. The question that remains to be answered is whether within the inherent limitations of the pressurized-water thermodynamic cycle sufficient further technology and design improvements can be made in order to make pressurized-water plants competitive for a broad number of marine applications. The supercritical plant described herein represents a step advance in the thermodynamic cycle. This advance is shown to result in a significant reduction in plant size, weight, and hopefully capital costs. The most desirable feature of load-following capability is retained. The major technical problems of a supercritical reactor plant are in the reactor and reactor-associated plant equipment. The balanced pressure reactor and fuel element proposed reduces mechanical stresses in materials under high radiation to acceptable values. Acceptable material corrosion behavior under supercritical conditions remains to be demonstrated.
Highlights of the Load Line Conference, 1966
Authors: Bannerman David B.
Published: January 2021

When it had been decided that a Load Line Conference would be held in 1966, the United States drafted a complete proposed Convention which was based on the work of the United States Load Line Committee, a group sponsored by the Coast Guard, consisting of representatives of both government and the marine industry. This draft was circulated by Intergovernmental Maritime Consultative Organization to all governments in early 1964. Other governments then sent their comments on the U.S. proposal, and all comments were circulated together with the U.S. draft; the USSR prepared a complete draft also, and these were the two basic conference documents.
Application of Higher Strength Steels to Great Lakes Vessels
Authors: Kline R. G.
Published: January 2021

The problems of brittle fracture, fatigue strength, compressive stability of longitudinally stiffened plates, and structural response to dynamic loadings are discussed in regard to their influence on the application of higher strength steels in the primary hull structure of Great Lakes bulk carriers. The present state of knowledge in each area is reviewed to discover where additional knowledge is needed and to establish preliminary guidelines where possible. Based on the developed guidelines, economic evaluations of higher strength steel substitutions in a conventional bulk carrier are performed for a 50,000 and a 1 00,000-psi yield-strength steel, and result in a negligible added investment per ton of steel weight saved.
Design and Development of the Saturn Marine System
Authors: Evans Herbert
Published: January 2021

Figure 1With the beginning of the nation's "Saturn" space program and its huge-sized family of space vehicles, water transportation became the only feasible means of transferring large stages between geographically separated areas. The development within the last four years of a Saturn marine transportation system, including the transportation of test fuels, has paralleled the development of the Saturn space vehicles. Although the cargoes were of unprecedented dimensions, existing marine transport equipment and concepts were successfully employed and modified into an extensive transportation network. Research and development are under way for the transport and water recovery of even larger Saturn space vehicles. Many of these vehicles will be so immense that marine design as represented by the present state of the art will not suffice. Only by imaginative use of its full potential will naval architecture meet the demands of the coming space age.
Durability of Reinforced-Plastic Structural Materials in Marine Service
Authors: Fried N. , Graner W. R.
Published: January 2021

This paper discusses the utilization of glass-reinforced plastics in marine structural applications, with emphasis on the durability of these materials under arduous service conditions. In particular, the results of an investigation of the effects of extended service on the properties of a large reinforced-plastic structure, a fairwater on the submarine USS Halfbeak (SS-352), are presented in detail and discussed. On the basis of these results, and other considerations, the case for using glass-reinforced plastics in marine structures is delineated.
The West Coast Shock Facility
Authors: Giannoccolo Sal
Published: January 2021

Ship resistance to shock has been a major area of research since World War II. To study this problem a shock test facility was established on the West coast by the Bureau of Ships. This paper outlines the functions and operations of this test facility as well as describing test equipment utilized in testing procedures. A brief critique of dynamic design methods currently in use by the U. S. Navy is also presented.
Assessment of Seakeepability
Authors: Hamlin Norman , Compton Roger
Published: January 2021

This paper attempts to apply presently available knowledge of ship model behavior in regular waves to the prediction of trends of ship performance in realistic irregular wave patterns. Performance is studied in the terms of tendency to ship water forward and to slam, and of magnitude of heaving accelerations. The variables of particular interest considered are severity of sea, ship speed, ship heading, and hull proportions. It is believed that the trends obtained in this exploratory project should provide the naval architect with some guidance in the selection of basic hull characteristics for one particular type of ship (in this case, the single-screw dry-cargo ship). The results should also be of assistance in planning further systematic research.
Great Lakes Ore-Carrier Economics and Preliminary Design
Authors: Krappinger Odo
Published: January 2021

Based on factual data from many sources the author has derived a compendium of information useful in the preliminary design of Great Lakes bulk carriers. The paper explains facile methods for estimating speed and power, weights, building costs, and operating costs for ore carriers ranging up to the 1000-footers allowed by the new lock at Sault Ste. Marie. The author uses this information to derive a parametric study of optimum design characteristics. He concludes that the biggest possible ship is not necessarily the most economic unless particular attention is paid to expediting its port turnaround. The Appendixes explain how to apply probability theory to estimating weights, building costs, and annual transport capability. This material can be applied to any sort of ship and is of interest to the entire profession, not just to engineers in the Great Lakes area.
The Design of a Hinged Tanker
Authors: Boylston J. W. , Wood W. A.
Published: January 2021

This paper outlines the thinking behind the decisions that went into the design of a proposed Suez Canal tanker. To make the ship as big as possible, while meeting the constraints of the canal, it is designed with a hinged hull. This arrangement permits an increase in size while also reducing the cost and weight of the structural hull. An analysis of wave action shows that horizontal bending moments become dominant in establishing scantlings. The problem of designing a suitable hinge is discussed and a relatively simple solution proposed. Model tests indicate that only a 5 to 6-percent increase in resistance is experienced because of the hinge configuration. Further refinements in design could reduce even this small increment. Tests in waves indicate that hinged-ship motions will be greater than those of a nonhinged ship of similar dimensions.
The Art of Talking About Science
Authors: Bragg Lawrence
Published: January 2021

The author draws on his wide experience as a lecturer to spotlight the more serious pitfalls that confront the scientist who has to deliver a talk. Advice is given on how to achieve the primary objective of the lecture—how to cause the audience to remember its essential point. The purpose of the lecture is outlined, and a clear distinction is made between the two methods of delivery; namely, the informal, spoken word and the reading of a written account. The author establishes his resolute preference for the former method and lists his reasons for opposing the reading of a prepared text.
Economics of Superbarge Operation
Authors: Miller C. D.
Published: January 2021

The study covered by this paper was originally made in the Fall of 1963 and included a section on Great Lakes vessels. The latter has been deleted and, along with other modifications, a brief comparison of tank barges versus tankers has been added. The purpose of this report is to describe a particular application of the unmanned super-barge2 concept, involving dry bulk shipments, and in more general terms to cast some light on the relative economics of superbarges versus ships. The scope of the latter is much too broad for a report of this type and accordingly analyses are limited to a comparison of a few selected vessels in coastwise, ocean, and north of Hatteras trading. Although 1962 cost data are used in cases 1 and 3 of the paper, it is believed, nevertheless, that the approximate economic relationships developed are still valid.
Dynamic Shock Analysis of Shipboard Equipment
Authors: Harrington R. L. , Vorus W. S.
Published: January 2021

A description and evaluation of the dynamic analysis method of determining the shock resistance of shipboard equipment is given. Development of equipment mathematical models is treated in detail, and the computational procedures used in conducting dynamic analyses are illustrated. Considerations in the preparation of dynamic-analysis reports are discussed. Discussers R. S. Adelizzi G. W. Bishop V. T. Boatwright K. J. Calvin C. Dotson Capt. H. C. Field, Jr., USND. W. Ginter O. Gould D. M. Gray K. Gyswyt R. T. Hawley RADM L. V. Honsinger, USN(Ret.) C. Lee J. C. Lester C. Li W. A. Littlejohn N. J. Monroe A. Morrone B. Novak E. W. Palmer C. G. Puffenburger L. L. Salter H.M. Schauer J. R. Sullivan J. D. Swannack C. Y. Tiao H. H. Ward W. P. Welch J. B. Woodward, III
Some Thoughts and Comments on Load Lines
Authors: Hayden Ralston
Published: January 2021

The author discusses how load-line regulations contribute to safety at sea and how the International Load Line Convention facilitates international shipping. The nature of the requirements of the regulations is described, and the 1930 and 1966 Conventions are compared briefly. Additionally, the "IMCO Tonnage Scheme" is described, and a few remarks are made on the application of load lines to unusual vessels.
Sewage Pollution From River Towboats
Authors: Kurtz Harold I.
Published: January 2021

This paper discusses the fundamentals of sewage treatment as applicable to watercraft, particularly towboats and tugs. The initial discussion deals with the composition of sewage and the procedures by which its effect on the receiving body of water are measured. Municipal methods of treatment are discussed because these have been the "tried and proven." Since the attempts to adapt municipal methods to the requirements of watercraft have resulted in a very limited degree of success, the author tries to show the impracticability of using this approach and substitutes a method which fulfills the necessary requirements.
A Standard Series of Developable Surfaces
Authors: Ferris L. W.
Published: January 2021

Construction of any article from flat material is facilitated if the surfaces of the article are flat or developable. To produce a developable surface it is only necessary to bend the flat material; no stretching, twisting, or bulging is required. It is practicable to use developable surfaces for some areas in ships and boats. The mathematical definition of a developable surface is stated and explained. From this an analytical method is evolved for computing the coordinates of points in a developable surface. An example is given showing how a reasonable set of lines for a boat is produced by using certain coefficients in the formulas. This parent form can then be modified in different ways by making minor changes in the coefficients. The implications of using developable surfaces in naval architecture are discussed.
Adequate Strength for Small High-Speed Vessels
Authors: Danahy Philip J.
Published: January 2021

The paper presents a method for the determination of the critical minimum scantlings for small high-speed vessels. Particular attention is given to the shell plating strength for hydrodynamic impact loads. The suggested method uses an integrated approach involving assumed loads, suggested safety factors, and preferred stress-analysis method. The stress analysis uses plastic theory based partly on the works of J. Clarkson and Thein Wah. Included in the paper is a comparison of the relative structural strength of several commercial, military, and experimental hydrofoil vessels along with a few planing boats and a seaplane hull. This shows the variation of existing vessel structures and compares them to the results obtained by the suggested method. Most commercial, military, and recreational vessels exceed the minimum scantlings of the suggested method. The most significant deviation is the hull of the seaplane:
A Sailing Hydrofoil Development
Authors: Nigg D. J.
Published: January 2021

A simple means of controlling vertical stability and pitchpole moment in sail-powered hydrofoil craft is described. The system is self-stabilizing, requires no moving parts, and adds no additional operations to normal small-craft sailing technique. The method has been reduced to practice in a full-scale experimental craft, and shows promise of opening the way for development of a family of ultra-high-speed sailboats. Speeds in excess of twice the velocity of the wind are indicated, or roughly double the speeds attained by modern catamarans in like wind conditions.
Standards for Engineering Economy Notation
Authors: Benford Harry
Published: January 2021

The Engineering Economy Division of the American Society for Engineering Education is preeminent in the United States in publishing papers on engineering economics. In response to a long-felt need, that group has recently adopted a set of recommended standards for the symbols and abbreviations used in engineering economies. Those recommendations are published in The Engineering Economist, vol. 12, no. 4 (1967).
Gas Turbine Propulsion for High-Speed Small Craft
Authors: McCoy Allan W.
Published: January 2021

This paper presents the results of marine gas turbine propulsion studies related to small craft of the high-speed planing hull type. These include appraisal of craft performance requirements for both transportation and patrol mission profiles. A substantial increase in both service speed and craft productivity may be realized with gas turbine propulsion. A combined power system is analyzed for loiter/cruise/dash patrol missions, and the operational tradeoff flexibility that may be realized is illustrated. Comparisons of existing gas turbine engine types and their utilization in marine propulsion systems with pump-jets and propellers of both fixed-and controllable-pitch configurations are included. Marine gas turbine power system integration is discussed, with an example illustrating design considerations associated with a turbomarine power system that includes capability of an optional three-mode power-level operation. An appendix describes significant features of several gas turbine test craft.
Sea-Link
Authors: Glosten L R.
Published: January 2021

A report on the development of a connecting linkage which permits tugs to push barges ahead at sea in rough water. The advantages of pushing as compared with conventional towline operations are discussed. The concept of the linkage is explained and the hardware described. The history of development including model tests and full-scale trials is outlined.
Computer Definition of Ship Characteristics
Authors: Boumis Thano P.
Published: January 2021

Computer techniques are widely used by the marine industry to implement the phases of conceptual, preliminary, and detail design of ships. Application of computers to augment the definition of ship characteristics is rapidly increasing. Governmental agencies and leading private concerns have already resorted to the use of computers and expend considerable efforts in program developments. Computer application is a new cost element in ship design; thus, consideration should be given to developments that will render the computer a useful and cost-effective tool to the industry. Cost-effectiveness compels the analyst and the designer to distinguish between mere use which they should avoid, and usefulness which they should seek. The increasing trend to employ systems analyses to ship design is greatly facilitated by using computers. System and subsystem definition and optimization offer excellent opportunity for useful computer application. The desired extent of analysis and design dictates the function and the appropriate program construction to be employed. Current practices and future trends indicate that short, specific programs are usually the most useful and that large programs should be developed using special techniques and processors only if the programs would serve an existing or projected need. This discussion outlines pertinent thoughts on current program utilization and also on development and construction techniques to facilitate computer definition of ship characteristics. Discussers Henry Rumble H. Chatterton Reuven Leopold