bluuebunny/crossref_metadata_2025 huggingface dataset:
A Vessel is its Own Best Lifeboat: Prevention of Casualties through Education
Authors: Miller Thomas C. , Paitl George J.
Published: January 2021

The U.S. Coast Guard has observed the death rate for commercial fishermen decline steadily during the years following the enactment of the Fishing Vessel Safety Act of 1988. This Act called for requirements of survival equipment and fire fighting equipment, among other items, targeted at minimizing the consequences of a vessel capsize, sinking, fire or other casualty that required the crew to abandon ship. In recent years, the death rate has plateaued with minimal to no decreases and even a slight increase in 1996. While of concern, this plateau seems logical because the primary focus over the last eight to ten years has been on reducing the consequences of commercial fishing casualties (response). However, fishing vessels continue to capsize or sink before crew members are able to access survival equipment and lives are being lost. In order to continue to decrease the industry death rate, regulators and those responsible for oversight of this industry must shift the focus from reducing the consequence of casualties (response) to decreasing the likelihood of casualties occurring (prevention). This paper details the most recent initiative the U.S. Coast Guard has undertaken in its Fishing Vessel Safety Program and describes the Fishing Vessel Training Suite developed to facilitate this industry-wide education. The Training Suite consists of three trainers and a document titled, "Best Practices Guide to Vessel Stability." The three trainers include:Interactive Stability Trainer,Small Vessel Damage Stability Trainer, andSmall Vessel Damage Control Trainer.

The U.S. Coast Guard has received very positive feedback from the commercial fishing industry and lives have been saved as a result of the use of this Training Suite.
Experimental Investigation of Enteromorpha clathrata Biofouling on Lifting Surfaces of Marine Vehicles
Authors: Gangadharan Sathya N.
Published: January 2021

Biological fouling can adversely affect the hydrodynamic performance characteristics of hydrofoil surfaces and lead to deterioration in the vehicle performance and maneuvering abilities and higher fuel and maintenance costs. Much attention has been drawn to the frictional resistance caused by large organisms, such as barnacles, bryozoa, and tubeworms in the past. Resistance to adhesion of many of these large organisms has been demonstrated by the use of antifouling paints. This paper describes the experimental results for fouling of Enteromorpha clathrata on marine surfaces and its impact on hydrodynamic performance characteristics, in conjunction with the design, construction, and operation of a water tunnel. It includes a description of the force balance system, laser Dopplervelocimeter(LDV) system, and the data acquisition system used to conduct the experimental study. Results of the experiments with Enteromorpha clathrata fouling are presented, and the effects of biofilms on turbulent boundary layer structure are outlined. The experimental results of the force balance experiment showed a constant increase in zero-lift angle of attack by 10 deg for as little as 10% fouling, and a reduction in maximum lift by as much as 70%. Similarly, the LDV experiment found an increase in the skin friction coefficient for all fouled surfaces, and an average increase of 187% for a surface dominated by an Enteromorpha species.
Engineering Methodologies Used in the Preparation of Escort Tug Requirements for the Ports of San Francisco and Los Angeles/Long Beach
Authors: Gray David L. , Reynolds Elizabeth
Published: January 2021

The assumptions made and methods used to prepare the selection matrix for escort tugs that is incorporated into the California statute for the ports of San Francisco and Los Angeles/Long Beach are presented. The default matrix for both ports is based on a demand/capability analysis. The demand is a function of (a) port geometry; (b) operational practices, including transit speeds, tethering, failure modes, and failure recognition times; (c) emergency maneuver (stopping and/or turning of the disabled vessel); and (d) ship size. The capability is defined as the total bollard pull of the escorting tug or tugs. An escort is acceptable if the capability exceeds the demand. The assumptions and rationale used in the calculation of demand and the choice of bollard as capability, the differences in the demand function for the two port complexes, and the differences in the rationale for the bollard pull capability at the two port complexes are explained. There is an option for alternate compliance in San Francisco that is based on the fact that tug capability may be greater at the transit speed than it is at bollard. The procedure and difficulties with this approach to maintain compliance will be described. In LA/LB there is also an option for alternate compliance. However, alternate compliance in LA/LB is based on tethering and deployment of the escorting tugs. The rationale for the different alternate compliance calculations for the two ports will be explained.
Navigation Sensor Data Fusion for the AUV Remus
Authors: Fulton Thomas F. , Cassidy Christopher J.
Published: January 2021

The development of a navigation sensor data fusion algorithm for the autonomous underwater vehicle (AUV) Remus is described. Remus is a small, low-cost AUV designed and built at the Ocean Systems Laboratory of the Woods Hole Oceanographic Institute. The navigation sensors for Remus include an acoustic navigation system, a Doppler velocity sonar, and a compass. The data from these sensors are integrated in an extended Kalman filter, with the objective of producing a more accurate vehicle track. Postprocessing results using data from two recent field trials are presented.
Lightweight Composites for Heavy-Duty Solutions
Authors: Horsmon Albert W.
Published: January 2021

In various parts of the marine industry, composites (often referred to as fiberglass or FRP), are usually thought of suitable only for recreational boats and small cruisers. However, composites have been used for the Navy's 57m (188ft) coastal minehunters and 46 m–49 m (150 ft–161 ft) yachts in the U.S. and for larger minesweepers and patrol vesselsin the U.K. and Sweden. Ten years ago these vessels would have been at the upper limits of perceived size limitation for FRPs, but presuming limitations on the size of vessels using compositesas the primary structural material are premature. Composites are presently used for sections of large steel vessels, including nonpressure hull decking, nosesections, sails and diving planes for submarines, weapons enclosures and masts for destroyers, funnels on cruise ships and hatch covers for barges. Research is ongoing for use of composites in larger deckhouse sections for combatant and structural hull materials for 200 m (670 ft) fast freight vessels. Potential uses on large steel cargo and auxiliary vessels include bulbous bows, bow fairings, hatch covers, stern fairings, deck machinery enclosures, and nonstructural interiors. Composites have also been used as a complete hull restoration for a vintage steel yacht. This paper reviews current usage and explores future potential for the use of composites on larger vessels. Issues of damage tolerance, corrosion resistance, flammability, classification, and regulation are investigated. This paper does NOT present the highest level of technology in the composites industry. It is simply presented as a primer for those who normally work with steel and aluminum to think out of the metal box.
Optimal Inspection Period for Fishing Vessel Equipment: A Cost and Downtime Model Using Delay Time Analysis
Authors: Pillay A. , Wang J. , Wall A.
Published: January 2021

Delay Time Analysis (DTA) is a pragmatic mathematical concept which has been developed as a means to model maintenance decision problems. This paper proposes a model using DTA to ascertain the optimal inspection period for fishing vessel equipment depending on the criteria selected. The two criteria modeled are downtime and cost. The current practice involves the maintenance being carried out in port during the discharging operation. As the time between discharges can vary considerably, it allows for failures on the machinery to propagate and to lead to a catastrophic breakdown. This paper offers an alternative solution to the current maintenance practice to reduce cost incurred and downtime suffered by fishing vessels. Test data from an oceangoing trawler are used to demonstrate the proposed approach. The optimal inspection period for a particular equipment is obtained. A sensitivity analysis on the optimal inspection period is also carried out.
Analysis of Tug-Barge Connection Force Measurements
Authors: Miller A. D. , Barbosa J. , Latorre R.
Published: January 2021

This paper summarizes the analysis of four integrated tug-barge (ITB) model tests in calm water and waves. The results show the relationship of the tug-barge connection forces to wavelength and heading, and indicate that the maximum longitudinal, transverse, and vertical connection forces occur at wave encounter angles of 0, 45, 225, and 0 deg, respectively. Additionally, the results of a simplified linear analysis are used to evaluate the possibility of obtaining connection force predictions based on force vector analysis and the relationship of connection force to block coefficient. Photo of ITB-A tug model in barge notch. (Courtesy of the estate of Emilio Garcia)
Extrapolation of Propulsion Tests for Ships with Appendages and Complex Propulsors
Authors: Holtrop Jan
Published: January 2021

Prediction of ship powering is traditionally based on the results of model experiments. This paper covers the extrapolation of model test results for ships that may have a multitude of appendages and one or more complex propulsors. The major differences from conventional extrapolation methods are the application of the scale effect corrections to the model propulsion test, the treatment of the appendages and acknowledging the effects of the propeller load on the propulsion parameters. The last feature is considered essential to successfully handle complex propulsors with both rotating and passive components.
Collision with a Crushable Bow
Authors: Gooding Peter W.
Published: January 2021

Oil tanker collisions and groundings pose the potential for large spills. Currently, the International Maritime Organization and national governments have design standards for tankers that do not account for a vessel's crashworthiness. By using crashworthiness, a vessel can be optimally designed for both weather and extreme loading situations. Minorsky [1] examined the problem of collision damage on a vessel side wall. Using previous collision data, Minorsky generated a simple damage volume to kinetic energy relationship for the safety of reactors on nuclear-powered ships. Since then, many researchers have provided solutions for the extent of damage on a tanker based on an assumption of a rigid bow collision. Such a formulation does not account for the energy consumed by the bow deformation. As a result, the damage extent to the side of a vessel is overestimated. By adding a crushable bow, the final result will allow for a more optimally designed vessel. This paper provides a simple closed-form solution for modeling the collision resistance of the bulbous bow portions of tankers. This closed-form solution can be combined with side collision solutions to optimally design a tanker for extreme loading conditions.
Engineering Analysis on Vibration Characteristics of Merchant Vessels with Theoretical and Onboard Test Approaches
Authors: Wu Tong-Ming
Published: January 2021

Recent development of ship design, such as flexible hull structures with somewhat light ship weight in terms of larger/longer/wider principal particulars and long-stroke diesel engine of high brake horsepower, has been demonstrated dramatically. Nevertheless, this kind of ship design concept harmfully degrades system stability of electronic instrumentation and operating performance of human beings in sea service. Therefore practical prediction on structural vibration behavior of designed vessels is of primary concern and has to be taken into account at the preliminary design stage. Two theoretical approaches, preliminary prediction by empirical formula and numerical solutions by finite-element technique (matrix analysis methodology), are briefly reviewed. An onboard test system for structural vibration measurement is developed and comprehensively described. In fact, a standard procedure of data acquisition and analysis system for structural vibration measurement is already set up to deal with several kinds of vibration research work in practical engineering fields. Natural frequencies of vibration behavior for a 1200 TEU container vessel are checked out by preliminary prediction of empirical formula and measurement data from onboard tests. Moreover, a comparison study by finite-element analysis and full-scale measurement is also performed on vibration characteristics of hull structures. The amplitude of vibration acceleration induced by unbalanced moment of the main engine is calculated for any point of hull at the resonance condition and the installation of an electrical balancer onboard is taken into account for vibration countermeasures also. All approximate predictions, compared with onboard test results, are found to meet with an acceptable level of engineering accuracy. The practical package of approximate approaches in both theoretical and onboard test aspects to investigate vibration characteristics of structures, for instance, hull, machinery, piping, and shafting system, in universal service is quite reliable and easily performed on portable computers for extensive engineering applications.
Effects of Motion at Sea on Crew Performance: A Survey
Authors: Stevens Samson C. , Parsons Michael G.
Published: January 2021

Current efforts to minimize ship crews now more than ever require all persons on board to be fully functional and capable of conducting their prescribed duties and responsibilities. However, inherent in the nature of any maritime profession, ships and, therefore, people are exposed to a multitude of motions as a result of weather and sea conditions. Coincident with these motions are a host of physiological, biomechanical, and psychological responses that can quickly reduce even the best efforts of the crew to a fraction of their utility when performed on a stable platform. Ship motions limit a crew's ability to perform essential command, control, and communications functions, navigation tasks, maintenance responsibilities, and even the preparation of food. Additionally, and more importantly, emergency situations may become more threatening in a situation where only a portion of the crew is able to respond effectively. This survey is intended to provide a working knowledge of effects of ship motions on crew performance, fatigue, and motivation. This information can then be used to improve ship and equipment design, and lead to enhanced vessel effectiveness and performance and, more importantly, to enhanced safety of the individuals on board. As ship design evolves and crew sizes decrease, greateremphasis must be placed upon the human factor input in order to ensure safety and efficiency during both routine and emergency operations.
Estimating Hydrodynamic Force and Torque Acting on a Horn-Type Rudder
Authors: Kresic Miro
Published: January 2021

The purpose of this paper is to provide the naval architect with a practical method of estimating hydrodynamic force and torque acting on a horn-type rudder. Such a rudder is also known as a Mariner, semi-balanced underhung rudder or skeg-rudder. Input required to carry out the estimate is explained and the reliability of the estimate is discussed by comparison with model test predictions. A spreadsheet, named H-Rudder program, is provided to carry out the estimate.
Long-Term Fatigue Damage of Ship Structures Under Nonlinear Wave Loads
Authors: KangGu Xue , Moan Torgeir
Published: January 2021

Fatigue is a principal mode of failure in ship structures, especially when high tensile steels are applied. Although significant efforts have been made to predict fatigue damage, there are still uncertainties existing, e.g., in the stress histories that cause fatigue. This paper addresses estimation of fatigue damage in ships under wave loads, with an emphasis on containerships, which have large bow flare and low hull girder rigidity. Linear and nonlinear wave-induced loads as well as dynamic effects due to hull flexibility, i.e., whipping, are researched. With the direct analysis method of fatigue, the nature of the wave loading, hull rigidity, structural damping, stress range counting algorithm and SN curve on structural fatigue damage are investigated. In long-term fatigue damage estimates, the influence of different sea environments is numerically analyzed. The importance of nonlinearity of wave loads and especially the whipping on the structural fatigue damage is demonstrated by calculation for a large container vessel with large flare and lowest natural frequency of 0.749 Hz. Depending upon sea environments and SN curves used in long-term predictions, the fatigue damage based on nonlinear wave loads (excluding whipping) is 10–100% larger than that due to linear wave loads; the fatigue damage based on nonlinear combined loads (including whipping) may be 1–9 times larger than that of steady-state nonlinear wave loads.
The T-AGS-39 Class Ocean Survey Ships and Their Conversion to Schoolships
Authors: Daidola John C. , Behr Robert S. , Lynch John G. , Koehler Erhard W.
Published: January 2021

Elements of the design, construction and later conversion of the T-AGS-39 Class Ocean Survey Ships are reviewed. The original design to a U.S. Navy Circular of Requirements is considered, presenting insight into the selection of vessel characteristics. The construction program, in concert with unique requirements, is also considered. Finally, conversion of the vessels to schoolships under the U.S. Maritime Administration, following their retirement from naval service, is discussed.
A Genetic Algorithm Approach to the Problem of Minimum Ship Wave Resistance
Authors: Dejhalla Roko , Mrša Zoran , Vukovic´ Senka
Published: January 2021

A genetic algorithm-based optimization method is proposed for an optimization of a ship hull from a hydrodynamic point of view. In the optimization procedure, the wave resistance has been selected as an objective function. The genetic algorithm is coupled with a computer program for solving the three-dimensional potential flow around a ship hull. The potential flow solver is based upon the well-known Dawson method. The optimization procedure has been applied to the Series 60 CB = 0.60 hull taken as a basis hull. The computational examples show the optimization ability of the proposed method.
IMO Environmental Regulations—Is There a Case for Change to the Standard Entry-into-Force Requirements?
Authors: Brookman Colin S.
Published: January 2021

In 1973 Annex IV to MARPOL on the Prevention of Pollution by Sewage from Ships was adopted and, despite being ratified by 75% of the parties to MARPOL, has yet to enter into force some 28 years after its adoption. In 1997 Annex VI to MARPOL on the Prevention of Air Pollution from Ships was adopted and, after more than three years, has only been ratified by 3 of the required 15 States. In October 2001 a Diplomatic Conference is scheduled to be held in London to finalize, and it is hoped, adopt a Convention to protect the marine environment against the use of toxic antifouling systems on ship hulls; the draft text of the Convention is nearly complete but the question of entry-into-force conditions remains to be resolved. Likewise, another Convention on "Unwanted Aquatic Organisms in Ballast Water" is likely to go to a Diplomatic Conference in the biennium 2002/2003 and again, entry-into-force requirements have not yet been formalized but will undoubtedly form a major part of future discussions. The conundrum, therefore, is whether environmental legislation which directly or indirectly affects all countries, and not just those with a coastline, should be subject to the same standard entry-into-force requirements presently being applied to other maritime legislation.
Effect of Longitudinal Bulkheads on Damage Stability of Model RO/RO Ferries
Authors: Ross Carl T. F. , Mourtos Ioannis , Papanikolaou George
Published: January 2021

The paper reports on experimental investigations which have been made on three model RO/RO ferries. One of these was based on a 1/100th scale model of the Herald of Free Enterprise ferry. The other models were modified versions of the Herald of Free Enterprise which were so modified that they did not decrease the efficient concept of the throughput of a conventional vessel. One modified model had nine longitudinal compartments, while another had six longitudinal compartments; these vessels should meet SOLAS90+50 regulations. The RO/RO ferry models with nine and six compartments had considerably better damage stability characteristics than the conventional model. The experiments were carried out on all models without the consideration of waves and wind. Small weights were placed on the model ferries, to represent motor vehicles, and water was added on the car deck. Measurements of the resulting heel angles were taken. All results were plotted on graphs and they were compared and discussed. The effect of cargo shift on the transverse damage stability of these vessels was found to be significant. The paper also contains a brief history of a few very important RO/RO ferry accidents that have taken place since the end of the Second World War.
Channel Design and Vessel Maneuverability: Next Steps
Authors: Gray William O. , Waters Jennifer K. , Blume Alan L. , Landsburg Alexander C.
Published: January 2021

A recent workshop on channel design and vessel maneuverability brought together channel designers, naval architects, pilots, and ship operators to review and share design approaches and standards that affect safety of operations. The desire was to develop policy recommendations that can be implemented both in the way channels are laid out and enlarged and how ships of various types using them should be designed and handled. Resulting recommendations based on the discussions promise to improve overall safety of ship operations in restricted waterways.
Site Team Management for Construction of a Large Modern Cruise Ship
Authors: Miorelli Joseph
Published: January 2021

This paper addresses the typical functions and organization of a new building department for any large cruise ship company, including the general corporate structure that encompasses the new building department. The role of the new building office and the relationship of this office to the shipyards is explained. The paper focuses the majority of the information on the role and responsibilities of the owner's inspection team at the shipyard. The organization and the functions of the inspection team are provided along with the arrival schedules of the shipboard personnel. Typical inspection requirements and inspection workloads are presented. The paper illuminates the requirements of the site office leading up to and including delivery.
A Time-Dependent Corrosion Wastage Model for the Structures of Single-and Double-Hull Tankers and FSOs and FPSOs
Authors: Paik Jeom Kee , Lee Jae Myung , Hwang Joon Sung , Park Young II
Published: January 2021

This paper presents a mathematical model for predicting time-variant corrosion wastage of the structures of single-and double-hull tankers; floating, storage, and off-loading units (FSOs); and floating, production, storage, and off-loading units (FPSOs). The measurement data of corrosion depth (thickness loss) for single-skin oil tanker structures of various ages are collected, and the statistical characteristics (mean, variance, distribution) of measured corrosion data are quantified in terms of ship age. A set of timedependent corrosion wastage models for 34 different structural member groups by type and location, considering plating, and webs and flanges of stiffening, are then developed by the statistical analysis of the corrosion measurements. The nominal design corrosion values for primary member locations/categories are also proposed. The results of this study can be updated as additional experience is accumulated. The procedures and insights developed in the present work will be useful for predicting the depth of corrosion in oil tanker structures. They will also be useful for establishing requirements and guidelines for the relevant corrosion protection measures and for designing corrosion-tolerant tanker structures in general.
MODUS: Space Shuttle for Deep-Water Operations
Authors: Clauss G. F. , Hoog S. , Vannahme M. , Gerber H. , Gasparoni F. , Calore D.
Published: January 2021

This paper presents MObile Docker for Underwater Sciences (MODUS), a specialized remotely operated vehicle (ROV) for deployment, recovery, and servicing of heavy sea bottom stations, for example, scientific observatories for deep-water application (depth rated 4,000 m). Developed, built, and tested as part of the EC-funded project GEophysical and Oceanographic STation for Abyssal Research (GEOSTAR 2001), the new ROV system includes the operating vessel with winch and umbilical and the versatile "space shuttle" MODUS for handling the bottom station with modularized payload. The paper focuses on aspects of the development as well as open water trials and missions. Results from hydrodynamic analyses are presented to illustrate design studies for minimized structure drag and therefore minimized power requirements for thruster-driven horizontal movements. Motion analyses comprise the dynamic behavior of the ship and the entire deep-dived system considering hydroelastic effects. Due to the direct coupling, vertical excitations of the ship in the prevailing sea are substantially transmitted along the submerged umbilical to the ROV, causing potentially harmful slack cable situations. Results from numerical simulations illustrate the dynamic response of the system due to ship oscillations in random seas and the associated downtime of MODUS operations. The paper presents the latest technological and scientific applications of MODUS during its first cruises: Reaching depths of 3,700 m within the EC-funded projects GEOSTAR and BIOtechnology from the DEEP (BIODEEP) in the Mediterranean Sea demonstrates its high availability with reliable performance and low costs.
Research Opportunities Identified During the Casualty Analysis of the Fishing Vessel Arctic Rose
Authors: Borlase George A.
Published: January 2021

During the course of the U.S. Coast Guard Marine Safety Center's analysis of the sinking of the fishing vessel Arctic Rose, a broad variety of stability issues were encountered that have not yet been addressed in the research community. The effect of freeboard on static and dynamic stability needs to be studied to ensure minimum reserve buoyancy and limit the effects of water on deck. The area of flooding stability, where a vessel's displacement, centers of gravity, and stability characteristics are constantly changing due to progressive flooding, needs to be further investigated. Time-domain analyses of progressive flooding in a seaway are needed, as are model tests of progressive flooding from the weather deck into interior spaces of a vessel. Additionally, a better understanding is needed of the behavior of the vessel between when the vessel capsizes due to loss of righting arm and sinks because flooding weight exceeds reserve buoyancy, and the attitude of a vessel as it falls through the water column to the ocean floor.
Proposal of a Method for Implementing Infrared Scanning Inspection Programs in Merchant Vessels
Authors: Salvá M. , Hernández R. , Sanz C.
Published: January 2021

This paper summarizes a proposal for implementing a predictive maintenance program based on infrared scanning inspection in merchant vessels. Current use of infrared inspection in merchant vessels is discussed, with an analysis of the problems and the benefits. Finally, a method for developing an inspection plan is proposed. The method consists of a selection of parameters, with consideration of infrared thermography and which general and specific criteria must be followed. Infrared thermal imaging is currently used for many engineering activities, mainly in industrial plants, in which predictive maintenance is widely used. However, this technique is being applied only in some types of merchant vessels, such as fast ferries and, in general, high-speed crafts. The main objective of the maintenance program proposed in this paper is prevention of loss by reducing the risks of fire and explosion. Twenty percent of the world ship losses in the last 25 years were caused by fire or explosions, the second most common cause of loss after bad weather. The proposed method consists of inspection and diagnostic tasks done on a systematic basis. The measurements of surface temperatures can detect hot spots and, subsequently, potential ignition sources. All the electrical power, distribution, and receptor devices; insulations; and any hot surface in the engine room, such as boiler casings and exhaust pipes, are included in the maintenance program. The second objective is related to the savings achieved by preventive maintenance reduction and the benefits of healthy facilities. Thermal scanning can detect small temperature differences between close points on a surface. This capability allows the detection of potential failures, such as cracks and lack of insulation in pipes and casings, thermal isolations, and small leaks of pressurized fluids such as steam, compressed air, and nonvisible fluids. The authors are currently working on a research project sponsored by the Spanish Maritime Authority within the scope of the development of new technologies focused on increasing maritime safety. One of the tasks of that project is the method of carrying out the inspection programs presented in this paper.
Determination of Optimum Heat Transfer Area for Vacuum Evaporators in Ships
Authors: Ozturk Recep , Alkan Ahmet Dursun
Published: January 2021

In ships, utility water can be produced from seawater through a vacuum evaporator instead of supplying from ports, and this solution will certainly allow extra load capacity for ships. In this application, the size of vacuum evaporators and their heat transfer areas are significant factors in terms of investment costs and the volume or weight capacity, which for ships are particularly important parameters. In the present research, the change of heat transfer areas of vacuum evaporators that are used to produce utility water was analyzed with respect to design parameters and the results from the thermodynamic analysis were evaluated to define the optimum heat transfer area. Because an analytical method has been employed in the definition of the optimum heat transfer area, the influence of design parameters on the evaporatorsize can be identified easily.
Intact Ship Stability: The Way Ahead
Authors: Francescutto Alberto
Published: January 2021

This paper, prepared as an introduction to the Session on Stability Standards: the Way Ahead, contains some notes and considerations of the author following the discussion of the item Revision of the Intact Stability Code at the recent meetings of the International Maritime Organization Subcommittee on Stability and Load Lines and Fishing Vessels Stability held in London in July 2002 and in September 2003.
Model Experiments and Simulations of a Damaged Ship With Air Flow Taken Into Account
Authors: Palazzi Lionel , de Kat Jan
Published: January 2021

To study the motion behavior of a damaged frigate, tests have been performed in calm water and in waves of different heights and periods. The paper contains comparisons between experiments and simulations for selected conditions that highlight the effect of air flow. Particular attention is also paid to transient flooding and roll transients, and to the effectiveness of cross-flooding arrangements. Significant air flow has been observed during the experiments, and the paper aims at assessing the importance of the phenomenon in modeling the behavior of the vessel.
The Sixth International Stability Workshop was held in October 2002
Authors: Francescutto Alberto , Bulian Gabriele , Lugni Claudio
Published: January 2021

This paper addresses, starting from an extensive series of tests in longitudinal regular waves (already done) and irregular waves (in progress), the problems connected with the threshold formulation for parametric rolling and its amplitude modeling above threshold. Both head and following waves have been considered, also in view of the greater attention to head sea conditions called for during International Maritime Organisation Subcommittee on Stability and Load Lines, and on Fishing Vessels Safety (IMO/ SLF) discussion on the revision of the Intact Stability Code. Particular attention is given in the regular wave case to the nonlinear damping, nonlinear restoring, and nonlinear parametric excitation terms. The mathematical models so developed are "compared" with experimental results by means of an ad hoc parameter estimation technique. It is, on the other hand, well known that several different thresholds can be proposed in the case of irregular waves and that the nonlinear modeling of roll motion variance above threshold is at present not properly addressed. Here, too, a series of experiments will be conducted in the presence of narrow band irregular waves having the bandwidth as parameter. A mathematical description of the nonlinear parametric rolling can be obtained with the use of approximate analytical techniques.
Prediction Methods of Roll Damping of Ships and Their Application to Determine Optimum Stabilization Devices
Authors: Ikeda Yoshiho
Published: January 2021

About 25 years ago, the author developed a method for predicting the roll damping of a ship, and the method is widely used even now. The method is a component-based one, and each component is predicted by theoretical ways if possible, otherwise by empirical ways. For these 25 years, the methods have been modified to improve accuracy and to extend their applicability to other kinds of ships. In this paper the author reviews these continuing studies on the roll damping prediction of ships, and introduces the application to determine optimum size and location of bilge keels.
Bearing Wear and Its Effect on Shaft Alignment
Authors: Bradshaw Ronald
Published: January 2021

The combined wear of water-lubricated bearings supporting a flexible shaft has a modal characteristic, that is, the cumulative wear can be represented by distinct patterns (modes) that increase geometrically at unique rates. The instantaneous wear rates decrease exponentially with time and approach zero asymptotically. The total load on the outboard bearings decreases and the total load on the inboard bearings increases: the redistribution of outboard and inboard loads is controlled by the shaft stiffness matrix (the reaction influence numbers). The characteristics of modal wear are examined and the changes in alignment loads are calculated, particular attention being paid to reduction-gear loads. Numerical results are displayed.
Principal Axes for Seakeeping Response Processes
Authors: Hutchison Bruce L.
Published: January 2021

This paper complements an earlier paper by the same author titled "Joint Seakeeping Response Processes for Determining Structural Loads," presented at the 2002 SNAME Annual Meeting. That paper put forward a variety of methods appropriate to the characterization of joint processes, including phase co-factors, cross cospectral moments, and joint normal techniques. The present paper exploits cross cospectral moments to determine principal axes for joint seakeeping processes and explores their behavior and properties in appropriate parameter spaces. The convergence of time domain realizations of these joint processes on the principal axes is also demonstrated through Fourier-Stieltjes simulations and conditional probabilities. One example application is to determine the orientation in space of principal axes for vector processes, such as translational accelerations in vessel coordinates. As shown by a referenced paper cited in the conclusions, the method can be extended to Von Mises stress and rainflow fatigue.
Viscous Computational Fluid Dynamics as a Relevant Decision-Making Tool for Mast-Sail Aerodynamics
Authors: Chapin V. G. , Jamme S. , Chassaing P.
Published: January 2021

Viscous computational fluid dynamics based on Reynolds averaged Navier-Stokes (RANS) equations have been used to simulate flow around typical mast-sail geometries. It is shown how these advanced numerical methods are relevant to investigate the complexity of such strongly separated flows. Detailed numerical results have been obtained and compared to experimental ones. Comparative analysis has shown that RANS methods are able to capture the main flow features, such as mast-flow separation, recirculation bubble, bubble reattachment through a laminar-turbulent transition process, and trailing-edge separation. A second part has been devoted to the comparative behavior of these flow features through parameters variations to evaluate the qualitative and quantitative capabilities of RANS methods in mast-sail design optimization. The last part illustrates through two examples how RANS methods may be used to optimize the design of mast-sail geometries and evaluate their relative performances.
Research Improving the Safety of Offshore Helicopter Operations: An Update
Authors: Rowe Stephen J. , Howson David
Published: January 2021

"Research Improving the Safety of Offshore Helicopter Operations," which follows this update, was first published at the Offshore Technology Conference in May 2002, and naturally the research that was reported has moved on in the meantime. In this update, the authors summarize the current (June 2004) status of the various research topics.
Accuracy Assessment of Methods for Predicting Dry Dock Block Reactions
Authors: Taravella Brandon M.
Published: January 2021

The current state of the art in dry docking engineering prediction and analysis of block reactions is the widely used so-called Crandall's method. Unfortunately, Crandall's method, although simple to use, is highly simplified and can be quite inaccurate in some cases. In this paper the author summarizes work that was undertaken at the University of New Orleans and Northrop Grumman Ship Systems Avondale Operations(Taravella 2003) in order to investigate the use of more accurate although more complicated methods and then to compare these results to full-scale actual measured values from the Northrop Grumman Ship Systems' dry dock. Recommendations are then made regarding the selection of suitable methods for predicting block reactions accurately.
Frictional Resistance on Randomly Oscillating Surfaces in Steady Flow
Authors: Myrhaug Dag , Holmedal Lars Erik
Published: January 2021

The effect of random oscillations on the surface shear stresses in combined oscillatory-steady flow is studied by assuming the oscillatory motion to be a stationary Gaussian narrow-band random process, and by using simple explicit friction factor formulas for harmonic oscillations. The approach is valid when the oscillations are approximately the same or exceed the strength of the steady flow over a wide range of the governing flow parameters.
Development of a Marine Propeller With Nonplanar Lifting Surfaces
Authors: Andersen Poul , Friesch Jürgen , Kappel Jens J. , Lundegaard Lars , Patience Graham
Published: January 2021

The principle of nonplanar lifting surfaces is applied to the design of modern aircraft wings to obtain better lift to drag ratios. Whereas a pronounced fin or winglet at the wingtip has been developed for aircraft, the application of the nonplanar principle to marine propellers, dealt with in this paper, has led to the KAPPEL propeller with blades curved toward the suction side integrating the fin or winglet into the propeller blade. The combined theoretical, experimental, and practical approach to develop and design marine propellers with nonplanar lifting surfaces has resulted in propellers with higher efficiency and lower levels of noise and vibration excitation compared to conventional state-of-the-art propellers designed for the same task. Conventional and KAPPEL propellers have been compared for a medium-sized containership and a product tanker. In total, nine KAPPEL propellers and two conventional propellers have been designed, and models of all propellers have been examined with respect to cavitation and efficiency in the open-water and behind conditions. Casting procedures, measurement procedures, and stress analysis methods for the unconventional geometry of the KAPPEL propeller have been developed. Furthermore, the KAPPEL propeller has been applied in full scale to the product carrier investigated. Sea trials with the conventional propeller and the KAPPEL propeller have been performed and have proved an efficiency gain of 4% in favor of the new propeller. The improved efficiency was obtained at lower propeller-induced pressure fluctuations. The correlation between the theoretical, experimental, and full-scale results is discussed.
Evaluation of the Service Performance of Ships
Authors: Andersen Poul , Borrod Anne-Sophie , Blanchot Hervé
Published: January 2021

A simple method has been established for the evaluation of the service performance of ships. Input data are easily collected daily on board and transformed to a well-defined condition that makes possible the comparison between ships, for instance, sister ships, and between different time periods of voyages for the same ship. The procedure has been applied to two ships that are identical, with the only exception that one has a conventional propeller, whereas the other one is fitted with a high-efficiency propeller of the KAPPEL type. The results are obtained from a period of 2 years steaming for both vessels. They clearly confirm the increase of propulsive efficiency obtained with the KAPPEL propeller in the order of magnitude of 4%.
Concept Ship Design for the Iron Nugget Trade
Authors: Kotinis Miltiadis
Published: January 2021

The projected growth in production of pig iron nuggets on the Iron Range of northeastern Minnesota provides new opportunities for marine transportation on the Great Lakes. The shipping of this higher-value commodity necessitates low freight rates and minimum inventory costs. This paper examines viable ship design concepts to provide competitive transportation solutions.
Marine Accident Investigation Techniques: Finding the Root Causes
Authors: Smith Kenneth M. , Schmidt Frederick E.
Published: January 2021

A vessel that has been damaged by a fire and/or explosion, suffered a mechanical failure, or had some sort of accident that resulted in injuries or property loss is almost always the subject of an investigation to determine the root cause and significant contributing factors. This paper describes the investigation process, including the skills and special knowledge that is often required for a complete investigation. Using several case investigations, the synergy of combining marine/mechanical and metallurgical testing and analyses is also discussed. Several engineering disciplines typically are required to recreate the sequence of events, components involved, and most probable causes. Such issues as maintenance, controls, design, and fail-safe performance are the domain of the marine/mechanical specialist. Determination of the failure mode, role of corrosion, thermal degradation, and materials selection issues are typically evaluated by a metallurgist. Design, materials selection, and component fabrication methods can become significant issues.
Modal Testing and Finite Element Calculations for Lightweight Aluminum Panels in Car Carriers
Authors: Jia Junbo , Ulfvarson Anders
Published: January 2021

Due to their characteristics and lower maintenance cost, lightweight aluminum structures have been widely used for manufacturing deck structures. When this type of structure is developed, the natural frequencies for the unloaded deck may increase, while the natural frequencies for loaded decks are most likely to decrease and new problems of vibration and damping may appear. In addition, it has already been shown by the authors that compared to the load effects of normal cargo, the dynamic structural behavior of a vehicle-loaded deck is different due to the participation of vehicle vibrations. The current paper presents a modal analysis by both testing and finite element (FE) calculation for a lightweight deck using aluminum panels. By comparing the results between the unloaded and car-loaded cases, it is shown how vehicle loading influences the dynamic structural behavior of the deck structures. The authors report that an aluminum panel mechanically connected to a steel frame may participate in some mode shapes of vibrations that significantly increase the corresponding damping ratio. The reasonably good agreement between modal testing results and FE calculations validates the finite element model, which may then be used for further dynamic analysis. The authors found that the spring-damping systems of car suspension and tires can interfere in the dynamic transmission of the vehicle mass into the deck structure. The study enables structural engineers interested in the design of car carriers to have a better understanding of how the vehicles parked on decks can influence the dynamic characteristics of the vehicle deck systems.
Structural Survivability of a Modern Passenger Ship
Authors: Iversen Rune , Moore Colin , Tagg Robert
Published: January 2021

This paper presents the results of an investigation into the structural survivability of a modern cruise liner in a flooded and heeled condition after collision damage. In the intact condition these ships are typically loaded in a hogged condition, where the upper decks are in tension and the bottom and lower hull are in compression. In the case of a potential midship flooding casualty following a collision, the weight of the flooded water could put the ship in a sagged condition with the upper decks in compression. The structural survivability in flooded and heeled conditions is assessed for several damage scenarios with wave loading included. The analysis confirms that this ship has adequate strength to withstand the loading in these cases. Comments are also made on possible effects of local load contributing factors.
A Numerical Study of the Influence of Launch Parameters on Lifeboat Deployment from a Ship in Beam Seas
Authors: Ekman Philip
Published: January 2021

The process of launching a lifeboat from a ship with no forward speed subjected to beam seas is numerically investigated in this paper. The motions of the ship and the wave conditions are included in the model since they influence the lifeboat's dynamics and its impacts against the hull of the mother ship and water surface. A strip-theory approach is adopted to determine the ship motions, while the total wave condition, which includes the diffracted and radiated wave systems, is calculated using a boundary integral formulation in the frequency domain. The launching process is simulated in the time domain where the influence of such parameters as the position of the launching point, launch velocity, use of fenders on the lifeboat, and time of launch are investigated. Several sea states are considered and, since the wave condition differs between the windward and leeward side, both sides are used for lifeboat launching. The severity of the collisions between the lifeboat and the mother ship are determined by categorizing the resulting accelerations as low, medium, or high. Relative velocities between lifeboat and wave elevation are necessary to determine the water entry process and are consequently calculated. The results from the systematic variations of parameters provide important information to improve the process of evacuating a ship by lifeboat launching.