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1
Wen, Poul, and Arif Fadillah. "The Effect of Trim on Stability and Seakeeping of Tanker, Container, and Bulk Carrier." IOP Conference Series: Earth and Environmental Science 972, no. 1 (January 1, 2022): 012037. http://dx.doi.org/10.1088/1755-1315/972/1/012037.
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Abstract Stability and seakeeping are important factor that must be owned by a ship because it related to the safety of the ship, meanwhile the trim also affecting the ship operation. The study has a purpose to find out the impact of the trim to the stability and seaworthiness of the ship. The analysis is carried out on 3 types of ships, namely tankers, containers, and bulk carriers. A.N. Krylov method is using to calculate the stability, whereas the seakeeping is analysed by strip theory. Both of the results for stability and seakeeping are calculated by Maxsurf Software. Stability and seakeeping analysis was carried out when the ship is in even keel condition, trim by bow, and trim by stern in maximum and extreme condition. The results shows that the trim by stern of the ship can increased the ship stability rate by 0.5~5.4%. While the effect of trim on ship motions varies due to the differences characteristics of each ship. The results shows due to the trim impact by values of RAO’s, which some of ship motions have increased meanwhile for some ship motion have decreased of ship motion condition.
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Ljulj, Andrija, and Vedran Slapničar. "Seakeeping Performance of a New Coastal Patrol Ship for the Croatian Navy." Journal of Marine Science and Engineering 8, no. 7 (July 15, 2020): 518. http://dx.doi.org/10.3390/jmse8070518.
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This paper presents seakeeping test results for a coastal patrol ship (CPS) in the Croatian Navy (CN). The full-scale tests were conducted on a CPS prototype that was accepted by the CN. The seakeeping numerical prediction and model tests were done during preliminary project design. However, these results are not fully comparable with the prototype tests since the ship was lengthened in the last phases of the project. Key numerical calculations are presented. The CPS project aims to renew a part of the Croatian Coast Guard with five ships. After successful prototype acceptance trials, the Croatian Ministry of Defence (MoD) will continue building the first ship in the series in early 2020. Full-scale prototype seakeeping test results could be valuable in the design of similar CPS projects. The main aim of this paper is to publish parts of the sea trial results related to the seakeeping performance of the CPS. Coast guards around the world have numerous challenges related to peacetime tasks such as preventing human and drug trafficking, fighting terrorism, controlling immigration, and protecting the marine environmental. They must have reliable platforms with good seakeeping characteristics that are important for overall ship operations. The scientific purpose of this paper is to contribute to the design process of similar CPS projects in terms of the development of seakeeping requirements and their level of fulfillment on an actual ship.
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Magarovsky, V. V., K. V. Kurchukov, V. G. Platonov, V. P. Sokolov, and M. S. Rudenko. "Bow shape design for river-sea vessels with increased seakeeping performance." Transactions of the Krylov State Research Centre 4, no. 402 (October 14, 2022): 19–32. http://dx.doi.org/10.24937/2542-2324-2022-4-402-19-32.
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Object and purpose of research. The purpose of this study was to develop a bow shape with increased block coefficient for river-sea vessels so as to improve their seakeeping at high sea states. Subject matter and methods. This paper qualitatively analyses the physics of wave effects upon a moving ship, ranking the contribution of specific factors and solving the task of improving the seakeeping performance through optimization of hull lines. Main results. The study highlighted the peculiarities of intense wave effects upon ship bow and suggested the hull lines offering a good seakeeping performance for a hull with high block coefficient. Seakeeping tests of initial and modified hull models at Krylov State Research Centre Seakeeping Basin have confirmed the theoretical results. Conclusion. The study outlined one of the ways to improve seakeeping performance of river-sea ships with increased block coefficient at high sea states.
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Dubrovsky, Victor. "Seakeeping index as generalized indicator of ship seakeeping performance." Transactions of the Krylov State Research Centre 4, no. 398 (November 15, 2021): 81–86. http://dx.doi.org/10.24937/2542-2324-2021-4-398-81-86.
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Object and purpose of research. This paper discusses the possibility of a ship design process that would consider seakeeping performance to the greatest extent possible. The purpose of this study was to work out a numerical indicator, an index, reflecting all the seakeeping properties relevant for suitability of given ship to its intended operational conditions. Materials and methods. The study was based on the data about various operational parameters of the ship under investigation. These data were further synthesized so as to obtain the most comprehensive picture of ship seakeeping behaviour in different operational conditions. Main results. The study yielded the method and the algorithm for the “seakeeping index” as an average annual probability that seakeeping performance of given ship will be adequate to the conditions of given water area. The method sug-gested in this paper for a generalized comparison of seakeeping properties can handle whatever variety of target parameters and whatever seakeeping standards for any kind of ship intended to operate in given water area, and the result of this comparison is given in form of a single number that can be further used to improve seakeeping parameters of given ship, as well as to estimate possible time of its fully-featured operation in given conditions, including cost efficiency analysis. Conclusion. For more accurate comparison, it is recommended to analyse target parameters as functions of both ship speed and wave heading angle keeping in mind that the assumption introduced, i.e. that these curves as functions of wave heading angle are cosines, is not necessarily true. In other words, it is recommended to rely on more accurate data, experimental or analytical, so as to take into account the effect of apparent frequencies upon these curves.
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Dubrovskiy, V. A. "Complex Comparison of Seakeeping: Method and Example." Marine Technology and SNAME News 37, no. 04 (October 1, 2000): 223–29. http://dx.doi.org/10.5957/mt1.2000.37.4.223.
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A method of seakeeping comparison, proposed originally by author in 1978, offers the possibility of taking into account all limitations of speed in waves and other ship characteristics, including motion amplitudes, accelerations at any point, slamming, deck wetness and bending moments for every type of ship. General characteristics of seakeeping are presented as one number for needed sea or for average conditions of the world's oceans. An example of the comparison is presented for two small-sized ships: a catamaran and a twin-hulled ship of small waterplane area (SWATH). Results of systematic calculations for naval ships in the North Atlantic are also presented.
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Waskito, Kurniawan Teguh, and Yanuar. "On the High-Performance Hydrodynamics Design of a Trimaran Fishing Vessel." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 83, no. 1 (June 3, 2021): 17–33. http://dx.doi.org/10.37934/arfmts.83.1.1733.
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Trimaran hull form as multihull ship becomes more attractive these days in various ship types. It offers more advantages in terms of seakeeping performances, particularly on the application of a fishing vessel. However, thus far, the conventional design of fishing vessels is not favorable to ensure the safety of a vessel sailing in a rough sea. In conjunction with such issues, we discuss a trimaran fishing vessel design based on the seakeeping criterion to evaluate the dynamic stability, ship motion RAOs, and ship resistances at the initial design stages using linear strip theory. The intact stabilities are calculated to complement the seakeeping results. The analytical method based on the slender body method is used to evaluate the steady wave resistances. The results of heave, pitch, roll motions, and the ship resistances are discussed. At the zero speed and forward speed, the trimaran shows a favorable motion amplitude, although in forward speeds at the case of head seas there is no significant difference. The trimaran presents a favorable steady-resistance up to the ship speed of Fn=0.27, and it becomes deteriorating than the monohull at higher ship speeds. However, the added wave resistances of the wavelength range 1.0 – 3.0 shows significant added resistances at Fn=0.25 and Fn=0.35, respectively. The results of this study present promising seakeeping and resistance characteristics of the trimaran hull form. The trimaran hull form ensures the safety, reliability, and operation efficiency of ships sailing in broader ranges of violent-sea environment.
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Ahmad Fitriadhy, Syarifuddin Dewa, Nurul Aqilah Mansor, Nur Amira Adam, Ng Cheng Yee, and Kang Hooi Siang. "CFD Investigation into Seakeeping Performance of a Training Ship." CFD Letters 13, no. 1 (January 31, 2021): 19–32. http://dx.doi.org/10.37934/cfdl.13.1.1932.
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The numerous ship accidents at sea have usually resulted in tremendous loss and casualties. To prevent such disastrous accidents, a comprehensive investigation into reliable prediction of seakeeping performance of a ship is necessarily required. This paper presents computational fluid dynamics (CFD) analysis on seakeeping performance of a training ship (full scale model) quantified through a Response of Amplitude Operators (RAO) for heave and pitch motions. The effects of wavelengths, wave directions and ship forward velocities have been accordingly taken into account. In general, the results revealed that the shorter wavelengths (l/L ? 1.0) have insignificant effect to the heave and pitch motions performance of the training ship, which means that the ship has good seakeeping behavior. However, the further increase of wavelength was proportional with the increase of RAO for her heave and pitch motions; whilst it may lead to degrade her seakeeping quality. In addition, the vertical motions behavior in the following-seas dealt with higher RAO as compared with case of the head-seas condition. Similarly, the subsequent increase of the ship forward velocity was prone to relatively increase of the RAO for her heave and pitch motions especially at l/L ? 2.0. It was merely concluded that this seakeeping prediction using CFD approach provides useful outcomes in the preliminary design stage for safety assessment of the training ship navigation during sailing.
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Ahmad, Mujahid Syaiful. "KAJIAN SEAKEEPING KAPAL FERRY RO-RO 750 GT BERBASIS PENGUJIAN HIDRODINAMIKA." ROTOR 11, no. 2 (November 1, 2018): 8. http://dx.doi.org/10.19184/rotor.v11i2.9336.
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The Ferry Ro-Ro is a ship that functions to crossing inter island and to transport vehicles, passengers and goods. Building a ship requires a very large investment value so that the design of the ship is a very important consideration by conduct the intens study to determine the performance of a ship, one of them is the performance of the ship motion, endurance, and reliability while sailing which can be seen by conducting a hydrodynamic test in the form of a seakeeping test on the Ferry Ro-Ro Ship Model. This study conduct the seakeeping testing due to Ferry Ro-Ro 750 GT Ship Model which aims to predict the pattern of ship behavior by using the seakeeping test methods at Manoeuvering and Ocean Basin at Laboratorium Hidrodinamika Indonesia at Balai Teknologi Hirdoinamika - BPPT with th parameter Wave Height Hs = 2.50 m, Wave Period Tp = 9.00 s by heading 180 deg and 135 deg, and model scale is 1 : 21.19. The seakeeping test procedure for the Ferry Ro-Ro 750 GT Ship Model is based on ITTC No 7.5-02-07-02 standards. Testing of the ship model is conducted by using the method of free running where ship moving at a speed of 12 knots (actual scale). Analysis of measurement results is displayed in the form of Response Amplitude Operator (RAO) and statical analysis. The hydrodynamic test results in the form of a seakeeping test of Ferry Ro-Ro 750 GT Ship Model shows the value of Root Mean Square (RMS) of each direction of the ship relative to the direction of arrival of the wave (heading) 180 deg with roll value = 0.825 deg and pitch value = 2.231 deg. And heading 135 deg with roll value = 2.410 deg and pitch value = 1.797 deg, where NORDFORSK 1987 criteria standard for RMS roll value is 6 deg, and RMS pitch value is 1.5 deg.
Keywords: Seakeeping, Ferry Ro-Ro, Hydrodynamics
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Fitriadhy, Ahmad, Nur Amira Adam, N. Amalina, and S. A. Azmi. "SEAKEEPING PREDICTION OF DEEP-V HIGH SPEED CATAMARAN USING COMPUTATIONAL FLUID DYNAMICS APPROACH." SINERGI 22, no. 3 (October 29, 2018): 139. http://dx.doi.org/10.22441/sinergi.2018.3.001.
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Seakeeping is the dynamic response of the ship in waves that may affect to passenger’s uncomfortability due to a harsh environmental condition. Therefore, an extensive assessment of seakeeping performance in the initial step of ship design is necessarily required. The authors here proposed to analyze the seakeeping performance of ‘deep-V’ high speed catamaran using Computational Fluid Dynamics (CFD) approach. Several effects of Froude number (Fr), wave-length (
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Sarıöz, Ebru. "Minimum ship size for seakeeping." Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment 226, no. 3 (March 28, 2012): 214–21. http://dx.doi.org/10.1177/1475090212440068.
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Ćatipović, Ivan, Maro Ćorak, Joško Parunov, and Neven Alujević. "Seakeeping experiments on damaged ship." Ships and Offshore Structures 14, sup1 (December 25, 2018): 100–111. http://dx.doi.org/10.1080/17445302.2018.1559911.
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Pechenyuk, A. "STUDY OF SEAKEEPING PERFORMANCE OF FISHING VESSELS WITH THE HELP OF CFD METHODS." Shipping & Navigation 33, no. 1 (December 1, 2022): 96–105. http://dx.doi.org/10.31653/2306-5761.33.2022.96-105.
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Seakeeping performance is quite important for certain ship types. Fishing vessels often operate in areas with frequent storms, and sometimes it is necessary to continue fishing despite the worsening sea state. The development of hull forms providing good seakeeping performance of fishing vessels is the problem of current interest in ship design. The conventional approach to seakeeping studies is testing models in ship model basins. However, it is time-consuming and expensive, especially when many hull form variants are studied. For this reason, computer calculations based on the theory of ship motions and strip theory were developed and introduced. Today the more advanced methods of computational fluid dynamics (CFD) can be applied to the problem. The study of ship motions with the help of Reynolds-averaged Navier-Stokes (RANS) CFD method is considered in this paper. A suggested numerical model implies the generation of waves through initial and boundary conditions, which express fully developed waves with preset parameters. An object of research is the seagoing trawler with an overall length of 44.6 m. Three versions of hull form are used in simulations. All versions have similar transom afterbodies, but different forebodies: one similar to Axe Bow, a bulbous bow and one similar to X-bow. Ship movement with headings 180° and 150° at speed of 3.5 knots was studied to reveal differences in added resistance and ship motions. While added resistance and characteristics of heaving and pitching have shown no clear advantages among the considered shapes of forebodies, the version similar to X-bow has demonstrated a significant decrease in rolling at heading 150°. The results of the study have shown that the suggested numerical setup in combination with the CFD methods described can be used for quite realistic simulations of ship behaviour in rough seas. Keywords: seakeeping simulations, seakeeping of fishing vessels, CFD for ship design, improved seakeeping performance, simulation of ship motions.
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Schellin, Thomas E., and Ould el Moctar. "Numerical Prediction of Impact-Related Wave Loads on Ships." Journal of Offshore Mechanics and Arctic Engineering 129, no. 1 (November 8, 2006): 39–47. http://dx.doi.org/10.1115/1.2429695.
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We present a numerical procedure to predict impact-related wave-induced (slamming) loads on ships. The procedure was applied to predict slamming loads on two ships that feature a flared bow with a pronounced bulb, hull shapes typical of modern offshore supply vessels. The procedure used a chain of seakeeping codes. First, a linear Green function panel code computed ship responses in unit amplitude regular waves. Ship speed, wave frequency, and wave heading were systematically varied to cover all possible combinations likely to cause slamming. Regular design waves were selected on the basis of maximum magnitudes of relative normal velocity between ship critical areas and wave, averaged over the critical areas. Second, a nonlinear strip theory seakeeping code determined ship motions under design wave conditions, thereby accounting for the nonlinear pressure distribution up to the wave contour and the frequency dependence of the radiation forces (memory effect). Third, these nonlinearly computed ship motions constituted part of the input for a Reynolds-averaged Navier–Stokes equations code that was used to obtain slamming loads. Favorable comparison with available model test data validated the procedure and demonstrated its capability to predict slamming loads suitable for design of ship structures.
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Gasparotti, Carmen, and Liliana Rusu. "Prediction of the dynamic responses for two containerships operating in the black sea." Journal of Naval Architecture and Marine Engineering 11, no. 1 (June 23, 2014): 55–68. http://dx.doi.org/10.3329/jname.v11i1.17289.
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This work presents a methodology for the evaluation of the vessels operability in the basin of the Black Sea. The approach proposed is based on the results provided by a wave prediction system that was implemented and validated in the Black Sea. This offers a meaningful framework in the assessment of the seakeeping performance for ships operating in different conditions. The aim of the work is to improve the seakeeping performances for various types of ships that sail in the Romanian coastal zones. Two containerships are considered, of 1300TEU and 800TEU respectively, which have however the same displacement. For predicting the ship motions induced by the various wave conditions encountered in the operational area, it is necessary to know the transfer functions for different ship speeds and heading angles. These are computed with a numerical code based on the strip theory. The predicted motions are then compared with the limit values of the relevant seakeeping criteria, considered as the criteria for checking the operability of the ship. By defining the acceptable operating boundaries, the ship behavior in waves can be quantified. The vessel meets the criteria for those combinations wave height-wave period that are below the limit curves. The results are presented as operational maps for the Black Sea basin, allowing the identification of the areas that should be avoided due to unfavorable weather conditions. The methodology proposed herewith can be extended and applied to various marine environments and types of ships.DOI: http://dx.doi.org/10.3329/jname.v11i1.17289
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Sun, Yu-Hang, and Bao-Ji Zhang. "Seakeeping Design Optimization of KRISO Container Ship (KCS) Ship Form Considering Wave Action." Marine Technology Society Journal 56, no. 2 (April 27, 2022): 64–72. http://dx.doi.org/10.4031/mtsj.56.2.6.
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Abstract Combined with the optimization method, the seakeeping optimization design problem under regular waves is studied on the basis of potential flow theory. The Rankine source method and deep-water Stokes wave theory are used to design the energy-saving ship form in the actual navigation. Taking the bow and stern waterlines of the Korea Institute of Ships and Ocean Engineering container ship as the optimization design area, the free-form deformation method is used to realize the parametric modeling and geometric reconstruction of the hull. Taking the minimum wave added resistance and the minimum sum of heave and pitch amplitude as the objective function, the Sobol algorithm and improved non-dominated sorting genetic algorithm (NSGA-II) are used to optimize the hull design while ensuring the necessary displacement volume. This study confirmed that the seakeeping performance of the optimized ship is the best. The results show that the wave added resistance of the optimized ship is reduced by 6.344%, and the sum of heave and pitch amplitude is reduced by 3.475%. Therefore, the feasibility of the proposed optimization method can be verified.
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Ayaz, Z., O. Turan, and D. Vassalos. "Manoeuvring and Seakeeping Aspects of Pod-Driven Ships." Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment 219, no. 2 (June 1, 2005): 77–91. http://dx.doi.org/10.1243/147509005x10495.
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An existing coupled non-linear six-degree-of-freedom model, which combines manoeuvring and seakeeping, is being enhanced for the simulation of motions of azimuthing pod-driven vessels. The equations of motions and modified numerical model for calculation of pod-induced propulsive and hull forces are presented. The modified numerical code has been verified using an extensive amount of experimental data for both conventional and pod-driven roll-on roll-off passenger ship/ferry (ROPAX) hull forms. Comparisons have been made between conventional and podded control using zigzag and pull-out manoeuvring tests and significant motion amplitudes in waves, with the aim of investigating the directional stability and course-keeping ability of pod-driven ships, as well as the effect of large pod-induced heel angles to the turning and ship motions in waves. The results showed satisfactory agreement with experiments for the enhanced model. In the light of this investigation, the importance of hydrodynamic optimization for the azimuthing pod-driven ship design to eliminate any stability and control problems caused by design modifications has been demonstrated by the use of numerical simulations. Finally the efficiency of the azimuthing podded drives, in terms of overall controllability and seakeeping characteristics of ships, is discussed and conclusions are drawn.
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Zborowski, Andrew, and Simon R. Sainsbury. "Small Vessel Hull Form Optimization for Heave and Pitch Performance." Marine Technology and SNAME News 25, no. 04 (October 1, 1988): 293–303. http://dx.doi.org/10.5957/mt1.1988.25.4.293.
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The Ship Motion Program (SMP) originally written for a mainframe computer system has been adapted for use on the IBM PC microcomputer family and subsequently applied to study ship seakeeping performance. The converted program, referred to as the Ship Seakeeping Characteristics Program (SSCP), was utilized for a parametric study on the influence of the main form parameters on heave and pitch performance for the British Ship Research Association (BSRA) trawler series of geometrically related forms. From the results of this study an optimum form has been indicated and its geometrical features defined.
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Faulkner, D. "Seakeeping ship behaviour in rough weather." Marine Structures 2, no. 2 (January 1989): 174–76. http://dx.doi.org/10.1016/0951-8339(89)90012-9.
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Liao, Xiyu, Zhanyang Chen, Hongbin Gui, and Mengchao Du. "CFD Prediction of Ship Seakeeping and Slamming Behaviors of a Trimaran in Oblique Regular Waves." Journal of Marine Science and Engineering 9, no. 10 (October 19, 2021): 1151. http://dx.doi.org/10.3390/jmse9101151.
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The main hull encounters waves at first and causes waves to break, when trimarans are subject to the slamming in head waves. At this moment, emergence phenomena of side hulls will not occur. Thus, the slamming study of trimarans in oblique waves presents further practical significance. In this study, a CFD method is used for trimaran seakeeping and slamming analysis. An overset grid technique is adopted to simulate ship motions in waves. Firstly, to further verify the present method, a series of verification and validation studies is conducted. Then, the motion responses and slamming pressure with different control parameters, such as forward speed and ship heading angle, are calculated and discussed. The comparative results indicate that the seakeeping and slamming behaviors of trimarans differ significantly from those of conventional monohull ships. Finally, severe bow slamming and green water in oblique waves are also observed and investigated, which should be given enough attention during ship design and evaluation.
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Pacuraru, Florin, Leonard Domnisoru, and Sandita Pacuraru. "On the Comparative Seakeeping Analysis of the Full Scale KCS by Several Hydrodynamic Approaches." Journal of Marine Science and Engineering 8, no. 12 (November 25, 2020): 962. http://dx.doi.org/10.3390/jmse8120962.
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The main transport channel of the global economy is represented by shipping. Engineers and hull designers are more preoccupied in ensuring fleet safety, the proper operation of the ships, and, more recently, compliance with International Maritime Organization (IMO) regulatory incentives. Considerable efforts have been devoted to in-depth understanding of the hydrodynamics mechanism and prediction of ship behavior in waves. Prediction of seakeeping performances with a certain degree of accuracy is a demanding task for naval architects and researchers. In this paper, a fully numerical approach of the seakeeping performance of a KRISO (Korea Research Institute of Ships and Ocean Engineering, Daejeon, South Korea) container ship (KCS) container vessel is presented. Several hydrodynamic methods have been employed in order to obtain accurate results of ship hydrodynamic response in regular waves. First, an in-house code DYN (Dynamic Ship Analysis, “Dunarea de Jos” University of Galati, Romania), based on linear strip theory (ST) was used. Then, a 3D fully nonlinear time-domain Boundary Element Method (BEM) was implemented, using the commercial code SHIPFLOW (FLOWTECH International AB, Gothenburg, Sweden). Finally, the commercial software NUMECA (NUMECA International, Brussels, Belgium) was used in order to solve the incompressible unsteady Reynolds-averaged Navier–Stokes equation (RANSE) flow at ship motions in head waves. The results obtained using these methods are represented and discussed, in order to establish a methodology for estimating the ship response in regular waves with accurate results and the sensitivity of hydrodynamical models.
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Tuitman, J. T., and Š. Malenica. "Fully coupled seakeeping, slamming, and whipping calculations." Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment 223, no. 3 (June 19, 2009): 439–56. http://dx.doi.org/10.1243/14750902jeme153.
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This paper presents a methodology to solve the seakeeping, slamming, and whipping problems coupled within a single calculation. The coupled problem is solved within a partly non-linear time domain seakeeping program. The elastic modes used in this hydroelastic problem can be calculated using a beam model or full three-dimensional (3D) finite element model of the ship structure. The slamming loading is calculated by a two-dimensional (2D) method. The main focus of this paper is the creation of an accurate and consistent coupling between the 3D seakeeping program and the 2D slamming calculation. Differences in timescale and integration methods make this coupling complex. A large container ship is used to illustrate the application of the presented methodology. The contribution of the non-linearities and the whipping response to the expected maximum bending moment and fatigue damage of this ship for a full-wave scatter diagram is calculated. The results show that the slamming-induced whipping response has a significant contribution to both the ultimate bending moment and the fatigue loading of the ship.
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Kukner, Abdi, and Muhsin Aydm. "Influence of Design Parameters on Vertical Motions of Trawler Hull Forms in Head Seas." Marine Technology and SNAME News 34, no. 03 (July 1, 1997): 181–96. http://dx.doi.org/10.5957/mt1.1997.34.3.181.
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The influence of ship length, length to beam ratio, beam to draft ratio, prismatic coefficient, non-dimensional radius of gyration and Froude number upon significant amplitude of coupled heaving and pitching motions of trawler hull forms for six different sea states has been studied. For this purpose, 540 trawler hull forms have been generated from Doust trawler series to cover appropriate ranges of the design parameters. Seakeeping behavior of these forms has been studied by using an established ship motion computer program and regression models of significant seakeeping events have been derived. Through this study, it is believed that a method has been produced for the seakeeping evaluation of trawler forms during the early design stages, hence allowing for the design of safer and more seakindly trawler designs.
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Begovic, Ermina, and Simone Mancini. "Stability and Seakeeping of Marine Vessels." Journal of Marine Science and Engineering 9, no. 2 (February 19, 2021): 222. http://dx.doi.org/10.3390/jmse9020222.
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Sellars, Frank. "Seakeeping Characteristics of a Drifting Vessel." Journal of Ship Research 30, no. 01 (March 1, 1986): 26–34. http://dx.doi.org/10.5957/jsr.1986.30.1.26.
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This paper describes investigation of the roll response of a ship drifting broadside to the waves. Results of experiments with a modified Mariner-type cargo ship model free to roll, sway, heave, and pitch showed broadside drift caused a 20 percent increase in resonant roll amplitude. Calculation results for roll in beam seas with broadside drift confirmed that an increase in resonant roll amplitude is expected. These results are different from previous model tests which showed a reduction in roll when drift occurred. These previous tests had sway restrained and the effect of model test sway restraint on roll has been considered herein. It is concluded that sway restraint has a significant effect on roll.
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Konon, N. M. "ANALYTICAL MODELLING OF SEAKEEPING QUALITIES OF CONTAINER VESSEL." Shipping & Navigation 30, no. 1 (December 1, 2020): 78–87. http://dx.doi.org/10.31653/2306-5761.30.2020.78-87.
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The design of ships or any other floating systems intended to operate on or close to the surface of the sea is controlled to a large extent by what is usually referred to as seakeeping, or, in more common terminology, safety at sea. This is a primary consideration and criteria, which has to be fully met. Safety of a ship naturally includes the crew, cargo and the hull itself. Seakeeping is, indeed, a generalized term and reflects the ship's capability to survive all hazards at sea such as collision, grounding, fire, as well as heavy-weather effects related to the environment in general and waves in particular. The two most likely types of failure under these conditions are due to structural causes and capsizing resulting from insufficient stability under severe weather conditions. Such criteria as economical navigation of the ship as related to speed-keeping abilities, fuel consumption, avoidance of damage to ship components and cargo, and comfort to crew or passengers, or both, are key items. The operational limits of electronic equipment, mechanical components and weapon systems on board warships are other aspects of sea keeping. In this work it is highlighted that seakeeping is a generalized term that includes a wide variety of subjects such as ship motions (amplitudes, accelerations, phases), deck wetness, slamming, steering in waves, added resistance, hydrodynamic loadings (pressures, forces, moments) and transient loads. Since the ship environmental operability or its sea keeping characteristics are closely linked to the severity of the sea, the description of the seaway is usually considered as an integral part of sea keeping. It is taken into consideration that the severity of the sea cannot be considered in absolute terms, since for each floating system, be it a ship, a platform or a buoy, the intensity of the sea state can only be determined in terms of the system's responses. Hence, different thresholds apply to different problems, and sea state 4 may be just as severe for a small patrol craft as sea state 8 may be for a larger containership. Hence, the characteristics and frequency of occurrence of waves in specific sea zones are required if a possible reduction in the system environmental operability is expected. It is demonstrated that most texts or papers, which deal with the overall question of sea keeping, devote some attention to the basic phenomena, that is, the seaway and the motions of the ship or other floating platforms as a result of the excitation imposed by the seaway. Ship motions, as such, do not always constitute the criteria for sea keeping, and much more often other responses directly related to the magnitude and phasing of the motions or the resulting velocities and accelerations constitute the prime cause for exhibiting good or bad sea keeping qualities. Such responses could be a function of the motion only, as in the case of added resistance or hydrodynamic pressures, or they could be a function of motion and other design parameters, such as freeboard in the case of deck wetness or the longitudinal weight distribution in the case of vertical bending moments. In this work, latest methods of modeling and computation for body-wave interactions described and compared with data observed for container carrier. The foregoing calculation routine Судноводіння | Shipping & Navigation ISSN 2306-5761 | 2618-0073 30-2020 Національний університет «Одеська морська академія» 79 is fairly well accepted today among naval architects specializing in the sea keeping aspects of the ship design process. Differences between the results obtained by various techniques as presented by the available computer programs are insignificant. However, since the regular-wave results are of little or no value except as input for the more realistic long- and short-term response predictions in a real seaway environment, it is important to determine which wave data information and what statistical extrapolation techniques are used to obtain the latter. The format used to describe the seaway in most ship response calculations is the wave spectrum. However, since measured spectrum for a specific sea zone or route are very rarely available, it is often necessary to use spectrum measured in one location for predictions in another location. In such a case, while the basic spectruml shape and scatter remain unchanged, the percentage of wave height distribution would vary to represent realistic conditions for the sea area in question. Such data usually are based on observations, and assuming the sample is large enough the distribution of expected wave heights should be quite reliable. An alternative approach often used in ship design is to utilize one of several theoretical spectruml formulations [2, 3, 4] such as the Pierson-Moskowitz one-parameter spectrum, the ISSC spectrum, the JONSWAP spectrum, and other. In each of these cases, some input parameters are required usually in the form of wave height, period, peak frequency, fetch, etc. The reliability of the wave data depends in these cases both on the quality of the input parameter and the adequacy of the theoretical formulation.
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Kring, D. C. "Ship Seakeeping Through the t = 1/4 Critical Frequency." Journal of Ship Research 42, no. 02 (June 1, 1998): 113–19. http://dx.doi.org/10.5957/jsr.1998.42.2.113.
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This study demonstrates that a bounded, physically relevant solution does exist at the so-called T = Uω/g = 1/4 resonance in the linear seakeeping problem for a realistic ship with forward speed, U, frequency of encounter, ω, and gravitational acceleration, g. The solution of the seakeeping problem by a linear, three dimensional, time-domain Rankine panel method, validated through numerical analysis, testing, and comparison to physical experiments, supports this claim. The solution can also be obtained with equal validity through frequencies both above and below the critical frequency.
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Zaraphonities, George, Gregory J. Grigoropoulos, Dimitra P. Damala, and Dimitris Mourkoyannis. "Seakeeping Analysis of two Medium-speed Twin-hull Models." Journal of Ship Production and Design 31, no. 03 (August 1, 2015): 192–200. http://dx.doi.org/10.5957/jspd.2015.31.3.192.
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The use of twin-hull ships for high-speed passenger and car-passenger transportation is widespread, whereas their potential use for high-speed cargo transportation was estimated as limited. The present article discusses the seakeeping performance of two twin-hull models of an innovative medium-speed container ship design. Their hull form was the result of a thorough hydrodynamic optimization performed at the School of Naval Architecture and Marine Engineering of NTUA aiming to minimize the calm water resistance within the EU-funded project "EU-CargoXpress." The seakeeping analysis was performed by applying numerical tools and also by performing a series of experiments in the towing tank of NTUA and MARINTEK. The obtained results are presented and discussed.
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Jiao, Jialong, and Songxing Huang. "CFD Simulation of Ship Seakeeping Performance and Slamming Loads in Bi-Directional Cross Wave." Journal of Marine Science and Engineering 8, no. 5 (April 29, 2020): 312. http://dx.doi.org/10.3390/jmse8050312.
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Accurate prediction of ship seakeeping performance in complex ocean environment is a fundamental requirement for ship design and actual operation in seaways. In this paper, an unsteady Reynolds-averaged Navier–Stokes (RANS) computational fluid dynamics (CFD) solver with overset grid technique was applied to estimate the seakeeping performance of an S175 containership operating in bi-directional cross waves. The cross wave is reproduced by linear superposition of two orthogonal regular waves in a rectangle numerical wave tank. The ship nonlinear motion responses, bow slamming loads, and green water on deck induced by cross wave with different control parameters such as wave length and wave heading angle are systemically analyzed. The results demonstrate that both vertical and transverse motion responses, as well as slamming pressure of ship induced by cross wave, can be quite large, and they are quite different from those in regular wave. Therefore, ship navigational safety when suffering cross waves should be further concerned.
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Deng, Rui, Shigang Wang, Yuxiao Hu, Yuquan Wang, and Tiecheng Wu. "The Effect of Hull Form Parameters on the Hydrodynamic Performance of a Bulk Carrier." Journal of Marine Science and Engineering 9, no. 4 (April 1, 2021): 373. http://dx.doi.org/10.3390/jmse9040373.
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In this study, the effect of joint optimization of the principal dimensions and hull form on the hydrodynamic performance of a bulk carrier was studied. In the first part of the joint optimization process, fast principal-dimension optimization of the origin parent ship considering the integrated performance of ship resistance, seakeeping, and maneuverability, as well as their relationships with the principal dimensions were analyzed in detail based on the ship resistance, seakeeping qualities, and maneuverability empirical methods of Holtrop and Mennen, Bales, and K and T indices, respectively. A new parent ship was chosen from 496 sets of hulls after comprehensive consideration. In the remaining part, a further hull form optimization was performed on the new parent ship according to the minimum wave-making resistance. The obtained results demonstrate that: (a) For the case in which the principal dimension of the original parent-type ship is different from that of the owner’s target ship, within the bounds of the relevant constraints from the owner, an excellent parent ship can be obtained by principal-dimension optimization; (b) the joint optimization method considering the principal dimension and hull form optimization can further explore the optimization space and provide a better hull.
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Bigi, Nedeleg, Kostia Roncin, Jean-Baptiste Leroux, and Yves Parlier. "Ship Towed by Kite: Investigation of the Dynamic Coupling." Journal of Marine Science and Engineering 8, no. 7 (July 1, 2020): 486. http://dx.doi.org/10.3390/jmse8070486.
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This paper presents a series of dynamic simulations for a ship towed by kite. To ensure time efficient computations, seakeeping analysis with forward speed correction factors is carried out in the frequency domain and then transformed in the time domain by convolution. The seakeeping modeling is coupled with a zero-mass kite modeling assuming linear dependence of aerodynamic characteristics with respect to turning rate. Decoupled (segregated) and coupled (monolithic) approaches are assessed and compared in different environmental conditions. Results show that in regular beam waves, strong interactions between the kite and the ship motions are captured by the monolithic approach. Around the wave frequency, especially for the lower one tested (0.4 rad/s), a kite lock-in phenomenon is revealed. It is concluded that the mean kite towing force can be increased whereas the ship roll amplitude can even be decreased compared to a non-kite assisted ship propulsion configuration.
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Faltinsen, Odd M. "On Seakeeping of Conventional and High-Speed Vessels." Journal of Ship Research 37, no. 02 (June 1, 1993): 87–101. http://dx.doi.org/10.5957/jsr.1993.37.2.87.
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The focus is on numerical and theoretical seakeeping problems for conventional and high-speed vessels. Wave-induced motions, accelerations and added resistance in waves of nonplaning high-speed monohulls and catamarans are discussed. Emphasis is on the interaction with the steady flow and transom stern effects. The "cobblestone" effect and the speed loss of a surface-effect ship (SES) in a seaway are discussed. The importance and possibility of predicting the influence of flow separation on the vertical motions of conventional ships are studied. Numerical methods that accurately describe slamming on hull sections are discussed. Correlations with published model test data for bow flare slamming are presented.
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Lamb, G. Robed. "Some Guidance for Hull Form Selection for SWATH Ships." Marine Technology and SNAME News 25, no. 04 (October 1, 1988): 239–52. http://dx.doi.org/10.5957/mt1.1988.25.4.239.
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Even though in 1987 there were only a dozen SWATH (smali-waterplane-area twin-hull) craft and ships afloat around the world, word of their markedly superior seakeeping performance is spreading rapidly. The number of SWATH vessels is likely to double within five years. As in many other areas of technology, the United States and Japan are the acknowledged leaders in the development and practical application of the SWATH concept. This paper reviews the characteristics of existing SWATH craft and ships from the standpoint of the stated seakeeping objective. Hull form differences between four SWATH craft and ships, including the Navy's SSP Kairnalino, are analyzed and interpreted. Important considerations for the early-stage design of a SWATH ship are discussed. Differences in the range of feasible hull form geometries for coastal areas and unrestricted ocean operations, and for low-speed versus moderately high-speed applications, are pointed out.
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Alman, Philip, William A. Cleary, Michael G. Dyer, J. Randolph Paulling, and Nils Salvesen. "The International Load Line Convention: Crossroad to the Future." Marine Technology and SNAME News 29, no. 04 (October 1, 1992): 233–49. http://dx.doi.org/10.5957/mt1.1992.29.4.233.
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The 1966 Load Line Convention (ICLL 66) has been in existence for 26 years and was preceded by the first Load LineConvention in 1930. For many years, there has been a ecognized need to reassess the technical provisions of ICLL 66.With the passage of time, development of new technology, and the introduction of novel ship designs, many of the inherent strengths and weaknesses of the document have become apparent. A wide panorama of design concepts never envisioned 30 years ago were steadily introduced into the marine industry. These new types of ships present problems for direct application of the Convention in the assignment of safe free-boards. There has been an increasing trend to utilize analytical seakeeping studies coupled with model tests as a means to assess deck wetness on novel ship designs. The recent ability to conduct analytical seakeeping studies verified by model test programs has expanded the horizon of potential application to load line assignment, and it is the key to understanding the level of safety inherent in ICLL 1966.
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Lungu, Adrian. "Numerical Investigation of the 6-DOF Seakeeping Performances of the KCS Containership." Journal of Marine Science and Engineering 10, no. 10 (September 30, 2022): 1397. http://dx.doi.org/10.3390/jmse10101397.
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The topic of the present paper subscribes to one of the most challenging themes that are nowadays under the spotlight of the scientific community. It describes a substantiated method aimed not only at predicting accurately the consequences of the associated effects of navigation in waves but also at contributing to ruling the conditions in which the operation of a ship should be performed is presented. A series of multiple degrees of freedom (DOF hereafter) simulations of the MOERI (Korea Research Institute for Ships and Ocean Engineering) container ship (KCS hereafter) hull moving in regular waves are performed and thoroughly validated with the experimental data provided by the organizers of the Tokyo 2015 Workshop on CFD in Ship Hydrodynamics. A verification and validation (V&V hereafter) is performed for the calm water navigation case to prove the robustness of the theoretical approach. Several numerical innovations are proposed, and the solutions are discussed in every detail aimed at setting up a properly established methodology usable in further similar studies. Finally, a set of remarks will conclude the present research.
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Esteban, Segundo, Jose M. Giron-Sierra, Joaquin Recas, and Jesus M. De la Cruz. "Frequency-Domain Analysis for Prediction of Seasickness on Ships." Marine Technology and SNAME News 42, no. 04 (October 1, 2005): 192–98. http://dx.doi.org/10.5957/mt1.2005.42.4.192.
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Oscillatory vertical motions of ships cause seasickness. There is a mathematical model that can be used to compute the percent of passengers who will get sick caused by vertical motions. However, the application of the mathematical model requires obtaining 2 hours of records of experimental or simulated ship motion data. Based on a filters analogy, this article proposes a new frequency-domain method for the calculation of seasickness incidence. The method can be applied to any sea power spectrum and any ship. Because it is based on response amplitude operators or transfer functions, which can be obtained with seakeeping simulation programs, the method can be applied even before the ship is built. The results of the method can be useful for ship design and for the analysis of best operation for passenger comfort.
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Kim, Sun-Geun Peter. "CFD as a seakeeping tool for ship design." International Journal of Naval Architecture and Ocean Engineering 3, no. 1 (March 31, 2011): 65–71. http://dx.doi.org/10.3744/jnaoe.2011.3.1.065.
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Kim, Sungeun Peter. "CFD as a seakeeping tool for ship design." International Journal of Naval Architecture and Ocean Engineering 3, no. 1 (March 2011): 65–71. http://dx.doi.org/10.2478/ijnaoe-2013-0046.
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Klemt, Matthias. "RANSE Simulation of Ship Seakeeping using Overlapping Grids." Ship Technology Research 52, no. 2 (April 2005): 65–81. http://dx.doi.org/10.1179/str.2005.52.2.003.
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Piorno, J. R., S. E. San Roman, J. M. Giron-Sierra, and J. M. de la Cruz Garcia. "Fast Ship Electronic System for Seakeeping Experimental Studies." IEEE Transactions on Instrumentation and Measurement 58, no. 10 (October 2009): 3427–33. http://dx.doi.org/10.1109/tim.2009.2017658.
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Sarıöz, E. "Inverse design of ship hull forms for seakeeping." Ocean Engineering 36, no. 17-18 (December 2009): 1386–95. http://dx.doi.org/10.1016/j.oceaneng.2009.08.011.
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Niklas, Karol, and Artur Karczewski. "Determination of Seakeeping Performance for a Case Study Vessel by the Strip Theory Method." Polish Maritime Research 27, no. 4 (December 1, 2020): 4–16. http://dx.doi.org/10.2478/pomr-2020-0061.
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Abstract The increase of seakeeping performance is of particular importance for car and passenger ferries, service ships in the gas and oil extraction industry and offshore wind power farm industry, as well as for special purpose ships (including military applications). In the water areas of the Baltic Sea, North Sea, and Mediterranean Sea, which are characterised by a short and steep wave, the hull shape has a substantial impact on the operational capacity and propulsion efficiency of the ship, as well as on comfort and safety of navigation. The article analyses selected aspects of seakeeping for four variants of a selected case study vessel, indicating practical limitations of the strip method. The analysed aspects included hull heaving and pitching, added resistance, Motion Thickness Indicator (MSI), and Subjective Magnitude (SM). Experimental tests were also performed in the towing tank. Their comparison with the numerical results has indicated high inaccuracy of the strip method. What is more, the simplified representation of hull shape used in the strip method makes it impossible to analyse the effect of hull shape changes on the predicted seakeeping characteristics. Especially for the case of head wave, neglecting highly non-linear phenomena, such as slamming or head wave breaking, in strip method-based computer simulations will significantly decrease the reliability of the obtained results. When using the strip method, the seakeeping analysis should be complemented with model tests in a towing tank, or by another more complex numerical analysis, such as CFD for instance.
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Hutchison, Bruce L. "Cargo Mechanics (Application of Seakeeping--Revisited)." Marine Technology and SNAME News 23, no. 03 (July 1, 1986): 230–41. http://dx.doi.org/10.5957/mt1.1986.23.3.230.
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The basic concepts of modern risk and reliability theory are reviewed. Application of these concepts to topics arising in the analysis of ship motions, cargo sea-fastening design and voyage risk studies is explored. The role of risk analysis in decision theory is briefly discussed and the paper concludes with a suggested program of analysis for marine activities and enterprises subject to sea-action induced risk.
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Zalek, Steven F., Michael G. Parsons, and Robert F. Beck. "Naval Hull Form Multicriterion Hydrodynamic Optimization for the Conceptual Design Phase." Journal of Ship Research 53, no. 04 (December 1, 2009): 199–213. http://dx.doi.org/10.5957/jsr.2009.53.4.199.
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For a given set of ship design and operational criteria, there exists a trade-off between the ship's calm water powering performance and its seakeeping performance. Ship hulls that are designed for optimal powering performance can have poor seakeeping performance, and vice versa. It is typically not possible to obtain the global optimum for both of these objectives because of the competition between the powering and seakeeping performance functions and the design constraints. The set of globally nondominated solutions, or Pareto front, considering these competing criteria is searched for by navigating the multimodal search space using a multicriterion, population-based evolutionary algorithm optimization process. The optimization process uses a nontraditional objective function formulation that eliminates the need to tune the penalty function parameters for each new problem formulation and appears to provide a more thorough representation of the numerically approximated Pareto front. Results show that properly integrating this optimization process with the design criteria yields a set of hydrodynamically superior design solutions. The problem formulation and development is applicable to naval surface vessels and applied to a monohull frigate type example.
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Anil, Kıvanç Ali, Devrim Bülent Danışman, and Kadir Sarıöz. "Simulation based calculation of ship motions in extreme seas with a body-exact strip theory approach." Pomorstvo 35, no. 1 (June 30, 2021): 36–48. http://dx.doi.org/10.31217/p.35.1.5.
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For all design phases of naval vessels, the fidelity of seakeeping calculations in extreme seas is open to discussion due to the inadequacy of the linear theory of ship motions. Currently the computer-generated time series of ship responses and wave height (the real time computer experiments) are utilized to calculate the distribution of the vertical distortion, shear force and bending moment by means of “ship hydroelasticity theory”. Inspired by these studies a simulation based calculation of symmetric ship motions is performed in long crested irregular head seas, in addition with a body-exact strip theory approach. The scope of this study is limited to the ship motions only. Verification is achieved utilizing the spectral analysis procedure which contains the discrete Fourier transform (DFT) and the smoothing algorithms. The results are compared with the experimental data, and the ANSYS AQWA software results. The simulation results provide adequate data for the extreme responses. This state-of-the-art method in addition with a “body-exact strip theory approach” ensures the consistent assessment of the seakeeping performance in extreme sea condition. As a result, it is evaluated that this calculation method can be used in the design stages of naval platforms.
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Grigoropoulos, Gregory J. "Hull Form Optimization for Hydrodynamic Performance." Marine Technology and SNAME News 41, no. 04 (October 1, 2004): 167–82. http://dx.doi.org/10.5957/mt1.2004.41.4.167.
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A method for optimizing hull forms with respect to their hydrodynamic performance in calm and rough water is presented. The method is based on an initial optimization of a parent hull form for seakeeping and the improvement of the resulting optimum hull form for calm water resistance. In the first part of the method, variant hull forms differing from a parent in the main dimensions and/or in one or more hull form parameters, such as CWP, LCF, CB, LCB, KB, CP, are automatically generated and their seakeeping qualities evaluated. When appropriate ranges for the principal characteristics and parameters of the hull form under investigation are prescribed, a formal optimization procedure is used to obtain the variant with the best seakeeping behavior. The weighted sum of the resonant values of selected ship responses for a number of ship speeds and headings in regular waves forms the objective function. The Hooke and Jeeves algorithm is used to accomplish the optimization. The procedure results in a set of trends regarding the proposed variations of the selected hull form parameters, within the specified constraints. These trends are then applied on the parent hull to derive an optimized hull form with fair lines. Subsequently, this hull form can be locally modified to improve its calm water resistance or, as it should be done, its propulsion characteristics. The applicability of the method is demonstrated in two cases: a conventional reefer ship and a naval destroyer. Scaled models of the parent and the optimized hull forms have been tested for calm water resistance and seakeeping. In both cases the validity of the methodology is demonstrated.
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Thompson, Ian, and Bryan E. Ellis. "Influence of Ship Speed and Heading Profiles on Fatigue Damage Accumulation for a Naval Vessel." Journal of Ship Research 64, no. 02 (June 1, 2020): 127–38. http://dx.doi.org/10.5957/jsr.2020.64.2.127.
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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.
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Boroday, I., S. Zhivitsa, and V. Platonov. "Ship seakeeping and the ways of studying it (to the 50th anniversary of Seakeeping Laboratory)." Transactions of the Krylov State Research Centre 2, no. 384 (2018): 147–52. http://dx.doi.org/10.24937/2542-2324-2018-2-384-147-152.
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Tuitman, Johan T., Šime Malenica, and Riaan van't Veer. "Generalized Modes in Time-Domain Seakeeping Calculations." Journal of Ship Research 56, no. 04 (December 1, 2012): 215–33. http://dx.doi.org/10.5957/jsr.2012.56.4.215.
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The concept of "generalized modes" is to describe all degrees of freedom by mode shapes and not using any predefined shape, like rigid body modes. Generalized modes in seakeeping computations allow one to calculate the response of a single ship, springing, whipping, multibody interaction, etc., using a uniform approach. The generalized modes have already been used for frequency-domain seakeeping calculations by various authors. This article extents the generalized modes methodology to be used for time-domain seakeeping computations, which accounts for large-amplitude motions of the rigid-body modes. The time domain can be desirable for seakeeping computations because it is easy to include nonlinear load components and to compute transient response, like slamming and whipping. Results of multibody interaction, two barges connected by a hinge, whipping response of a ferry resulting from slamming loads, and the response of a flexible barge are presented to illustrate the theory.
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Reid, Alan R., David S. Huff, and John C. Cameron. "Conversion of San Clemente Class Tankers to Hospital Ships for the U.S. Navy." Marine Technology and SNAME News 24, no. 03 (July 1, 1987): 193–204. http://dx.doi.org/10.5957/mt1.1987.24.3.193.
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This paper describes a program—unique in the history of U.S. Navy ship procurement—to convert two 90 000-dwt crude oil carriers into hospital ships. The San Clemente class tankers, of 894 ft length overall, proved ideally suited to the conversion because (1) the long, parallel midbody design offered large, open spaces for the installation of modularized hospital and habitability units; (2) the ships' hydrostatic characteristics were favorable to the addition of new upper deck structures; and (3) the ships' hydrodynamic characteristics provided excellent seakeeping qualities with reduced ship motions critical during casualty reception and underway medical operations. Under the programmatic direction of Naval Sea Systems Command, the conversions were accomplished by National Steel and Shipbuilding to meet U.S. Coast Guard and American Bureau of Shipping regulatory requirements for passenger ships. The ships will be operated by the Military Sealift Command in support of authorized medical missions.
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Fang, Ming-Chung, and Jiun-Han Ju. "The Dynamic Simulations of the Ship Towing System in Random Waves." Marine Technology and SNAME News 46, no. 02 (April 1, 2009): 107–15. http://dx.doi.org/10.5957/mtsn.2009.46.2.107.
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In order to investigate the dynamic stability and safety for a ship towing system operated in waves, the present paper develops a nonlinear mathematical model, including seakeeping and maneuvering characteristics, to simulate dynamic behaviors of the towing system in random waves. In addition to waves, wind is also included in the calculations. The time history simulations of six degrees of freedom motion for both the towing and the towed ships are solved by the fourth-order Runge-Kutta method. Because of the waves, the dynamic properties including the towline tension, ship speeds, headings, and distance between two ships are different from those that occur in calm water. The effects of the towpoint's position, towline length, and towing speed on the ship course stability and towline tension are analyzed with respect to different wave and wind headings. In the present study, the suitable operation conditions for the ship towing system are investigated and can be suggested as a reference for improving the stability and safety of towing operation tasks at sea.