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First FBM Marine FDC 400 on trials
Date published1989
AbstractAn article on the first fast displacement catamaran built by FBM Marine. Designed to carry 400 passengers at a cruising speed of 30 knots the Patria was built at the company's Cowes Yard on the Isle of Wight.
Date published1989
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The squeeze is on
AuthorsShipping World & Shipbuilder
PublisherIMarEST
AbstractThe global credit squeeze that has impacted on a number of industries will clearly have an affect on the way in which future shipping projects are financed but is the sctor strong enough to weather the storm?
AuthorsDate publishedShipping World & Shipbuilder
2008
PublisherIMarEST
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A New Method for the Prediction of Non-Linear Relative Wave Motions
AuthorsB Buchner
Date published1998
AbstractThe problem of green water on the bow decks of floating offshore production units in large survival waves is an important design problem. An accurate description of the relative wave motions around the bow is important for the prediction of green water on the deck. In the paper a new method is presented to predict these relative wave motions which are highly non-linear. Input for the method is the calculation of the relative wave motions in front of the bow with linear (3D) diffraction theory. Based on this input the proposed method is able to account for the non-linearities which occur as a result of the non-linearity in the waves the influence of the above water hull shape (bow flare) and the effect of green water on deck on the ship motions. The method is based on a modification of the Raleigh distribution and allows a fast evaluation of the effect of the above water hull shape (bow flare angle and freeboard height) on the relative wave motions.
AuthorsB Buchner
Date published1998
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A note on the effect of non linearity on the prediction of the vertical motions of a small high speed craft
AuthorsG J MacFarlane ; M R Renilson
PublisherRINA Conference Proceedings
AbstractIn order to investigate the limits of using both linear strip theory and linear superposition theory for predicting non linear vessel motions in in an irregular head sea tests were performed on a high speed vessel model in regular and irregular waves. Results gained in irregular waves were compared with those calculated with standard linear strip theory combined with linear superposition theory. Also those obtained from linear superposition theory were combined with the regular waves experimental results. The test results are presented showing both strip theory and linear superposition theory to be unacceptable at all significant wave heights.
AuthorsDate publishedG J MacFarlane ; M R Renilson
1995
PublisherRINA Conference Proceedings
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A safety assessment method on aging offshore platforms with damages
AuthorsXing Xian Bao ; Jun Rong Wang ; Hua Jun Li
Date published2009
AbstractA great deal of aging offshore platforms with damages needs to be assessed in order to determine whether or not they can be reused. To rationally estimate the safety levels of aging platforms a safety assessment approach (including the analysis of ultimate strength and system reliability of offshore platforms) is presented and is applied to the target platform. Firstly the impacts of load directions corrosion wastage as well as damaged structure member on the global ultimate strength are analyzed through pushover analysis. Secondly a system reliability assessment method based on the original and damaged jacket platform is applied. Based on the limit state equation of global failure mode the system reliability of the platform with different damaged structure member is estimated by Monte Carlo simulation method. Finally the critical members of the offshore platform are obtained based on the analysis of ultimate strength and system reliability. This paper provides a safety assessment method as well as a basis for the maintenance decision - making of offshore platform structures.
AuthorsXing Xian Bao ; Jun Rong Wang ; Hua Jun Li
Date published2009
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A study on structural safety and habitability of superstructure built on floating structure by integration analysis
AuthorsKoichi Maruyoshi ; Yong-Soo Cho ; Hwa-Cheol Song et al.
Date published2005
AbstractIn the future it is hoped that floating structures will be used by using the ocean to create extra space. Buildings will be constructed on a floating structure and will be used by people. In this paper such buildings have been called 'superstructures'. A superstructure unlike a land building is deformed by waveloads. Therefore it is necessary that the dynamic characteristics of a superstructure due to wave loads are well understood. The superstructure should be safe and comfortable for people. A superstructure must therefore satisfy requirements for structural safety and habitability in the primary design phase. Here the response of a superstructure is carried out by integrated analysis. The significant waves for a 100-year return period and for a 10-year return period are used to confirm and evaluate structural safety and habitability respectively. The results of structural safety and habitability are discussed.
AuthorsKoichi Maruyoshi ; Yong-Soo Cho ; Hwa-Cheol Song et al.
Date published2005
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Analysis of pile load tests data on drilled shafts in sandy soils of the Arabian Gulf region towards assessment of piles load-bearing capacity and settlement prediction models
AuthorsA Al-Homoud ; F Tarek ; U Azhar et al.
Date published2001
AbstractBored concrete piles are often used in the Arabian Gulf region as a safe foundation for multi-storey buildings. Several theoretical empirical and semi-empirical methods are available to predict friction resistance end bearing and settlement of drilled shafts in sandy soils. Results carried out on (39) field pile load tests are presented. These tests were conducted on shafts drilled in the sandy soils of the Emirates accompanied by the geotechnical data on soil conditions at the sites where the piles were drilled and tested. The results obtained from the study are compared with those found in the literature both regional and world-wide. Tabulated data and graphs appear on pages 8 to 12.
AuthorsA Al-Homoud ; F Tarek ; U Azhar et al.
Date published2001
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BOSS 94 - Behaviour of Offshore Structures 7th Int Conf - Vol II Hydrodynamics and Cable Dynamics Vol 2 of 3
AuthorsBOSS
Shelf Location225c
AbstractConf held 12-15 July 1994 in Massachusetts USA. Papers are - A boundary element method for predicting wave forces on marine bodies with slow yaw motion Recent advances on the slow drift damping of offshore structures Effects of wave drift damping on TLP horizontal offsets Low-frequency excitation and damping characteristics of a moored semi-submersible in irregular waves - estimation from model test data Cable mechanics for moored floating systems Anchor forces of anchored VLCC's Slow drift damping force due to viscous force acting on mooring lines and floating structures Dynamic characteristics of a large catenary moored production platform Second-order wave effects on offshore structures Viscous effects on slow drift motions On the prediction of wave drift damping of a tanker Eigenfunction matching technique solvers and low frequency damping - a revisit and validation of method
AuthorsPublisherBOSS
Pergamon
Shelf LocationDate published225c
1994
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CFD for combustion chamber development: influence of valve pockets on the combustion process
AuthorsM Truant ; S Dehoux ; P Gastaldi
Date published2004
AbstractCommon rail injection systems have led to more efficient and cleaner engines. However in order to enhance the combustion process the combustion chamber geometry is a fundamental item to be developed. The present study focuses on valve pockets configuration. The context of the study is presented with the focus on test-bench results that have revealed the significant effect of valve pockets configuration on torque output and engine-out emissions at full load. A CFD study was then carried out bring more understanding to bear on the matter. The numerical methodology used for CFD calculations is presented. Finally CFD results are discussed together with the phenomena involved.
AuthorsM Truant ; S Dehoux ; P Gastaldi
Date published2004
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Displacement catamarans: experimental data on systematic variations of stagger and clearance
AuthorsFrancesco Caprio ; Claudio Pensa
Date published2005
AbstractThe interest in catamarans has grown over the past few decades. In fact this kind of ship is the most popular in the building of fast ferries. However not many systematic experimental investigations have been carried out to evaluate the influence of displacement and separation on the resistance of catamarans. A study is presented which evaluates the effects due to the variation of longitudinal stagger transverse separation and displacement on the resistance of two symmetric hull forms suitable for catamaran configuration over a speed range corresponding to Fn < 0.5. To achieve this an intensive experimental investigation was carried out on two models in three configurations: monohull symmetric and staggered catamaran. In particular for one model six clearances in the symmetrical configuration and four longitudinal staggers have been tested; and for the other one three clearances and three staggers have been tested. The influence of displacement on resistance has been evaluated by testing the models for three different displacements. Further research is identified.
AuthorsFrancesco Caprio ; Claudio Pensa
Date published2005
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Effects of CO2 ocean sequestration on marine fish
AuthorsAtsushi Ishimatsu ; Masahiro Hayashi ; Takashi Kikkawa et al.
Date published2005
AbstractOcean sequestration of CO2 has been proposed as a possible measure to retard the increasing rate of the atmospheric CO2 concentration. Since this is likely to result in some negative impacts on marine animals and ecosystems biological effects of ocean CO2 sequestration must be carefully investigated before embarking on this mitigation practice. Considering the expected depths for CO2 ocean sequestration (greater than 1000 m) it is desirable to use deep-sea animals for the experimental assessment of CO2 ocean sequestration. In addition experimental protocols should preferably mimic environmental conditions at the releasing site: CO2 concentrations vary due to mixing with surrounding seawater at low temperatures (0-2 degrees C) and under high pressures. Recent experiments to elucidate the effects of high CO2 on marine fishes are described. The susceptibility of deep-sea fish to elevated ambient CO2 conditions was tested to compare results with those of the shallow-water species. The effects of water temperature on CO2 mortality were studied. The mortality of fish exposed to temporally changing conditions of CO2 was compared with those obtained under constant high CO2 conditions.
AuthorsAtsushi Ishimatsu ; Masahiro Hayashi ; Takashi Kikkawa et al.
Date published2005
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Experimental study of the influence of turbulence on the performance of a blade of hydrofoil
AuthorsL Hammadi ; M Belhadri ; O Imine et al.
Date published2006
AbstractAn experimental study was carried out to investigate the flows in the wake of profile of a hydrofoil. This involved testing out of blower a profile of the Eppler type 193 G.U.K. modifies. The distributions of pressure on the surface of the profiles were measured for different levels of turbulence. The distribution of the Cp showed that the increase in the level of turbulence causes a limiting separation of layers on the suction face of the profile. The distribution speeds in the wake showed on the one hand that the flow is 2D and on the other hand highlighted the signature of the wake.
AuthorsL Hammadi ; M Belhadri ; O Imine et al.
Date published2006
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Fatigue design data derived from full scale tests on 6" OD pipe girth welds
AuthorsJ Haagensen ; Hans Olav Knagenhjelm ; Oddvin Orjasaeter
Date published2007
AbstractA literature survey of high quality girth welds intended for pipeline risers was carried out and the results are compared with full scale resonance fatigue test data on 6" pipes. The samples were made from 168.3 x 9.9mm (OD x WT) seamless pipes each having two welds. Post failure examination of the welds was performed to determine the type and size of defects in the failure initiation area. Fracture mechanics calculations were carried out to determine the effect of defects on fatigue life. The main results from this project are summarized in this paper and the S-N data is compared with published data for pipes of similar sizes. The test results were compared with published data on 6" pipes with high quality welds. The scatter in the fatigue test data was reduced when comparisons were based on the local stress at the point of fracture initiation. The implications for design rules of the findings in this work are discussed.
AuthorsJ Haagensen ; Hans Olav Knagenhjelm ; Oddvin Orjasaeter
Date published2007
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FEA models to identify possible fatigue failures on a large diameter turbine installed on a floating platform
AuthorsRanjith K Obeyesekera
Date published2004
AbstractThe paper discusses the influence of body loads and dynamic loads on the surface of a large diameter turbine. In this study the corrosion fatigues due to the sea environment are not considered. The study shows that increasing the body loads decreases the endurance limits of the turbine. The computational FEA study reveals that endurance is significantly effected by the gyroscopic loads at lower speeds of the turbine. In this study the floating platform is a large hollowed floating chamber both sides of which are rigidly fixed to the two parabolic walls and floats as a single unit.
AuthorsRanjith K Obeyesekera
Date published2004
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Influence of chord stress on axial strength of circular tubular TX-joints
AuthorsShi Yongjiu ; Zhu Lei ; Wang Yuanqing et al.
Date published2005
AbstractIt has been found that chord stress has a significant influence on the static strength of tubular joints. Research has already been carried out on planar tubular joints such as X-joints showing that both compressive and tensile chord stress can account for the reduction of joint strength. However the research on multi-planar tubular joints is insufficient. Here the influence of chord stress on axial strength of multi-planar circular tubular TX-joints is analysed using the FE package ANSYS. The numerical analyses conclude that the chord compression and tension both reduce the strength but to different extents. The chord in compression always reduces the strength. A low chord tension may not reduce the strength but a high chord tension may reduce the strength significantly.
AuthorsShi Yongjiu ; Zhu Lei ; Wang Yuanqing et al.
Date published2005
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Influence of generator damping on peak power and variance of power for a direct drive wave energy converter
AuthorsMagnus Stalberg ; Rafael Waters ; Oskar Danielsson et al.
Date published2007
AbstractThe first full-scale offshore prototype of a novel wave energy converter system has been launched off the Swedish west coast. The concept is based on a point absorber directly coupled to a linear generator located on the ocean floor. The hydrodynamic behaviour of the point absorber depends to a large extent on the damping of the generator. The damping in turn can be controlled remotely by changing the load resistance. It has previously been shown that this has a large influence on the power absorbed by the wave energy converter. This paper investigates the peak power the translator speed and the variance of the power at different sea states and for different levels of damping.
AuthorsMagnus Stalberg ; Rafael Waters ; Oskar Danielsson et al.
Date published2007
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Numerical modelling studies to predict the potential impact on the sediment transport of a proposed Outer Harbour at Great Yarmouth UK
AuthorsT J Chesher ; M P Dearnalay ; J E Barker
Date published2000
AbstractInvestigations are presented into the impact on the adjacent sediment regime of a proposed new outer harbour at Great Yarmouth. A combination of numerical models to simulate the sediment transport processes on the existing coast are discussed. Particular attention is paid to the effect of mobile offshore sand banks in the modification of the propagation of waves to shore. Information gathered is described which verifies wave propagation tidal current and littoral drift models. A simulation is explained which highlights the magnitude of the impact of the harbour on the littoral drift on beaches to the south. Finally optimisation of the harbour layout is discussed.
AuthorsT J Chesher ; M P Dearnalay ; J E Barker
Date published2000
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On sea-keeping of conventional and high-speed vessels
AuthorsOdd M Faltinsen
Date published2006
AbstractThe problem of motions of a ship in a seaway has not been solved completely. The focus here is on numerical and theoretical sea-keeping problems of conventional and high-speed vessels. Wave-induced motions accelerations and added resistance in waves of non-planing high-speed monohulls and catamarans are discussed. Emphasis is on the interaction with the steady flow and transom stern effect. The 'cobblestone' effect and the speed loss of a SES (surface-effect ship) in a seaway are explored. 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 considered. Finally correlations with published model test data for bow flare slamming are presented.
AuthorsOdd M Faltinsen
Date published2006
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On the use of wavelet to identify the damage on the typical structure of ship
AuthorsR Yan
Date published2002
AbstractWhen structural damage occurs the peak position and amplitude of the vibration response change accordingly. A method based on wavelet transformation is presented to identify the frequencies changing and to confirm the occurrence of the damage. The method can resist the disturbance of noise because wavelet transformation has multi-resolving power. The Lipschitz index of the response at the singular point is calculated to confirm the existence of damages and their extent. A stiffened plate with damage is discussed and the results show that this method may used to identify the occurrence of damage in the stiffened plate.
AuthorsR Yan
Date published2002
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Predicting the effects of area closures and fishing effort restrictions on the production biomass and species richness of benthic invertebrate communities
AuthorsJ G Hiddink ; T Hutton ; S Jennings et al.
Date published2006
AbstractTo effectively implement an EAF (Ecosystem Approach to Fisheries) managers need to consider the effects of management actions on the fishery and the ecosystem. Methods for assessing the effects on target stocks are generally well developed but methods for assessing the effects on other components and attributes of the ecosystem are not. In this study we assess the aggregate impacts of area closures and effort controls in the North Sea beam trawl fishery on the production biomass and species richness of benthic communities. We account for the response of fishers to management action and for the response of the benthic community to trawling in different environments with different histories of trawling disturbance. Materials and methods are presented and results presented and discussed.
AuthorsJ G Hiddink ; T Hutton ; S Jennings et al.
Date published2006