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A series of comparison studies are conducted to investigate nonlinear wave loads effects on TLP tether which include the axial tension bending moment interaction ratio utilization ratio and nonlinear and non-Gaussian effects on tether extremes and fatigue damage. After some introductory information an outline is given of theoretical wave loads in time domain. Next dynamic equation of coupled TLP system is looked at followed by interaction ratio and utilization ratio nonlinear and non-Gaussian correction factors experimental measurements benchmark axial tether tension in fatigue sea state and extreme tether bending moment. Lastly nonlinear and non-Gaussian effects on tether fatigue life are addressed.

Report on the loss of the Bahamian tanker Prestige, which broke in two and sank on Tuesday 19th November 2002 with a large amount of her original cargo of 76,972 tonnes of fuel oil still on board. The incident occurred off the North West coast of Spain.

This article describes how with the decline of large UK fields such as Brent and Forties and with an estimated 70 percent of reserves still untapped the emphasis on development is now on smaller fields many operating as satellites to larger declining fields. An oil boom to 1993 is foreseen as fields such as Piper B and Miller come on stream. The issues of cost-cutting the northern North Sea and the Osprey and Saltire developments are also discussed.

Results are presented of an investigation of the modifications to the in-line Morison force coefficients on individual vertical surface piercing cylinders within cylinder groups associated with group interference effects determined from an experimental study carried out in the University of Melbourne's Michell Laboratory wave flume. Attention is focussed on results relating to the current experimental program carried out on cylinder pairs oriented in-line and transverse to the wave direction in irregular wave conditions.

Tests are carried out on a rectangular wing with a relative thickness of 20% and one sweep wing with a limited wingspan at positive attack corners. The effect of elements present on the wing's surface - longitudinal edges disks spoilers rough strips - are considered and their effect on the lift coefficient Cy. Results are shown and conclusions listed.

Consideration is given to certain macroeconomic factors that influence the world economy and an explanation is provided as to why they should be incorporated into a more balanced supply/demand shipping investment decision making framework. Attention is paid to the financial and economic elements which have contributed to the decline in shipping from the mid-1970s onwards.

ABSTRACT The rate effect on the Pc (consolidation yield pressure) is investigated for nine undisturbed marine clay deposits obtained from various countries including Japan. A series of laboratory tests are run on these samples under various strain rates using a CRS (constant rate of strain) oedometer test. An attempt is made to investigate the effect of the strain rate on Pc and to correlate it with the fundamental properties of soil such as index properties.

Laboratory-based oil analysis programs are currently the accepted method for assuring oil and machinery condition. They provide accurate results in a controlled manner often with additional expert interpretation from the lubricant supplier. The market for off-line lubricant analysis equipment is well served but coming under pressure especially from a requirement to reduce manpower or to continually monitor critical systems. A typical example would be the US Military who need a 70% reduction in manpower for the next generation of front line ships. There is a need to develop reliable and relatively low-cost on-line instrumentation capable of replicating a laboratory analysis providing information on both lubricant and machinery condition. A 3-year research programme was undertaken to investigate the practicality of a number of techniques for monitoring oil and machinery condition realised as an on-line device. Included in this were techniques of magnetometry cyclic voltammetry impedance spectroscopy (Q) capacitance or resistance and microwave. Many of the laboratory techniques used in oil analysis can be replicated in an on-board design. However an on-line realisation of the techniques used for example titration are impractical for reasons of complexity or reliability. Previous research has shown that it is possible to develop on-line instrumentation that does replicate laboratory techniques but these types of systems again have cost and complexity considerations that severely limit theiX44478

Nowadays engines face an increased customer expectation regarding noise and vibration. This trend requires the use of simulation tools in early phases of the development process. The virtual engine development process at FEV is described as well as the indispensable interaction with the design and testing activities. FEV has been using virtual development methods for NVH optimisation of engines and transmissions for more than 20 years. Typically attention centres on the optimisation of excitation mechanisms as well as on the structural transfer behaviour vibrations. Fully parameterised simulation models are used in all phases of development. Depending on the current design status of the development the detailing of the simulation models can be adapted. Based on comparative simple rigid body models at the start of the development decisions regarding engine global data like bore stroke cylinder distance and positioning of engine mounts can be made. Later in the development when more design parameters are fixed the depth of simulation models is increased until a fully flexible model allows the NVH behaviour of the complete power unit to be predicted. Such a simulation is carried out using a hybrid simulation approach based on Finite-Element and Multi-Body simulation. On the one side excitation mechanisms are treated.

The roll motions of ultradeep water FPSOs are examined based on a comparison of calculations model tests and full-scale measurements on the Girassol FPSO. Full-scale measurements of the motions of the Girassol FPSO were taken over a one-year period. During this same period also vessel draft wave height and wave direction were recorded. This allows motion transfer functions to be calculated as a function of the FPSO loading condition. A comparison is made between measured full-scale response and the combination of diffraction analysis and model tests. Wave frequency motions in six degrees of freedom and the heading have been measured on board of the Girassol FPSO located West of Africa. The monitoring campaign also includes wave measurements by means of a directional wave rider buoy as well as the drafts trim and heel. A new methodology is presented to compare the results of the theoretical analysis in long-crested waves with the measurements offshore in short-crested waves. Results are presented and discussed and conclusions drawn.

Conf held in London 6 - 7 July 1976 Papers are Deep sea RoRo operation and the future The short sea arena and its problems Mediterranean RoRo services - their development economics and infra structure After the North Sea - where next? RoRo berths and terminals in Australia and the SW Pacific Portafloat - a new offshore RoRo system for port decongestion Standardisation of the ship to shore links Portable link spans - a reduction of investment risk? The planning design and construction of a new Roll On/Roll Off terminal The structural design appraisal of RoRo ships The design of multi purpose ships incorporating RoRo facilities Which trailer system for RoRo? The development of RoRo Combo ships leading to the bulk oil and RoRo vessel -BORO bulkliner and BORO Tankliner The effect of Scanidnavian influence on RoRo design Insuring the liabilities of RoRo operators Is there enough co operation between the forwarder and the port and the ship operators? Cargo securing on the RoRo vessels calculation of forces on cargo and lashings Streamlining documentation could make major savings all round

The main purpose of this work is to identify important periods and geographical areas for predation on juvenile herring by cod in the Barents Sea based on stomach content data from cod covering the period 1984-1997. The study focuses on broad scale temporal and spatial trends. The trends are related to population dynamics and distribution of juvenile herring and climatic variation in the Barents Sea. The analyses cover: (1) year-to-year and seasonal variation in the occurrence of herring in cod stomachs (2) the relationship between occurrence of herring in cod stomachs and abundance of juvenile herring and capelin (3) identification of the main geographical areas for predation by cod on juvenile herring and its seasonal variation and (4) climatic effects on the main geographical areas for predation by cod on juvenile herring. The results are discussed in the context of the broad scale ecosystem dynamics in the Barents Sea during the period of interest.

The coastline of Bangladesh is one of the areas of the world that is most exposed to extreme meteorological and hydrological conditions. Cyclones and tidal surges cause devastating effects. Forests are always considered a low-cost and natural protection to the lands subjected to attack of current and surge. Here development of mangrove forests is being considered as one of the measures of coastal protection for this area. The pilot model developed for this study is used to assess the effect of afforestation on the storm surge height and to develop a basis for having the necessary engineering judgement in designing the minimum amount of forest cover to reduce the height of the embankment system. The study was done based on the results of a 2D nested surge model. The model has been developed based on the general numerical model named MIKE 21 and specific information on the area that the model covers. The model has been calibrated for normal hydrological condition as well as for cyclonic condition. The model results show that the laid afforestation has reduced the surge height around the southern end of the island to some extent. But a reverse impact has been found at the north-eastern corner of the island due top afforestation.

There are an increasing number of liquefied natural gas ships and oil tankers that are intended for navigation in ice and cold climates, and as such, there is a necessity to assess the risk of fatigue damage to these ships. A significant aspect of the fatigue assessment is the performance of steels when subject to low temperatures. This paper presents the results of an investigation on the fatigue strength of welded steel joints at low temperatures and discusses some of the associated issues. The paper presents the results of cyclic tension fatigue testing of welded specimens made from AH36 and DH32 steel grades under room and cold temperature conditions. Nominal fatigue curves for these specimens and crack lengths as a function of loading cycle number are also provided. The fatigue strength of welded specimens of DH32 and AH36 steel grades has been obtained. The data can be used for the evaluation of the fatigue life of ship structures manufactured from the specified steel grades and can be used for establishing whether measures need to be taken to reduce the risk of fatigue damage in the structural elements of ships trading in cold climates.

Coral reefs in tropical and subtropical ocean systems have recently experienced severe environmental problems due to mass coral bleaching events which occurred worldwide in 1997 and 1998. Water temperature is known to be a main factor of coral bleaching and so it is therefore important to clarify thermal environments and heat balance in coral reefs. The thermal environments in coral reefs are significantly influenced by heat fluxes through sea surface and bottom due to shallow water depth and high transparency of water in coral reefs. Thermal influences from inland and offshore also have a major effect on the heat balance for reef water. The focus here is on the effects of sea bottom on thermal environments in a coral reef. An intensive field observation was carried out at Shiraho reef on the southeast coast of Ishigaki Island Okinawa Japan. The heat budget analysis for reef water was performed with special attention to the sea-bottom effects. The heat balance for reef water shows that the sea bottom is of crucial importance to thermal environments in a coral reef. The heat budget analysis of reef water shows that the treatments of the sea-bottom effects can appreciably affect the results of the heat budget analysis.

Shallow water and surf zone target detection-localisation is very problematic due to severe sensor limitations imposed by the environment. The Navy is relying more and more on AUVs (autonomous underwater vehicles) to accomplish this difficult shallow water task and to keep human divers out of harms way. To augment the AUV's detection and localisation capability various sensors and sensor suites are being investigated. One technology that is minimally affected by the harsh shallow water environment is magnetics. The early stage efforts to augment the AUV with an enhanced magnetic detection-localisation capability that is inherently unaffected by environmental conditions found in the shallow water environment is considered. The focus here is therefore on the collection of magnetic noise data from various candidate platforms. The first and major objective is to document the setup and conditions surrounding the collection of the data and to compile a gross comparison of the magnetic characteristics exhibited by these platforms. A secondary objective is to begin to look at techniques that are useful in mitigating the magnetic noise generated by the platform and detected by the proposed magnetic sensors that will be integrated on the AUV. The emphasis during this phase is to determine which mitigation techniques are viable and to identify potential locations for the auxiliary mitigation sensors. Based on the findings during the initial measurements phase suitable auxiliary sensors are placed at select locations and signals from these sensors are processed and used for noise reduction dX36627 Measurement of marine environment around Mega- Float model in Tokyo Bay M Fujino ; Y Kyozuka ; S Tabeta et al.

It is very important in pipeline design to investigate the stability of an unburied offshore pipeline under severe storm conditions. The cyclic movement of pipeline due to drag and lift forces caused by waves and currents will lead to pore pressure build up in the seabed around the pipeline. The pore pressure accumulation will reduce the effective strength of the seabed soil and degrade its bearing capacity. In particular an increase of horizontal displacement of the pipeline may lead to a sudden breakout which has a serious influence on the safe operation of the pipeline. It is therefore very important for design engineers to evaluate the stability of an unburied offshore pipeline by considering pore pressure accumulation in the seabed soil around the pipeline under severe storm condition. Therefore this paper investigates the stability of an unburied offshore pipeline resting on carbonate sand under severe storm conditions. Pore pressure accumulation and pipeline movement during cyclic loading caused by waves and currents are numerically investigated. Both drag and lift forces are numerically obtained for 100 years return period storm condition using the Fourier decomposition method. Non-linear spring element is used to simulate a slip phenomenon between pipeline and seabed. The effects of both bi-linear and tri-linear spring element models on pipeline movement and pore pressure response are numerically investigated. Pipeline movement during cyclic loading greatly depends on the mechanical properties of non-linear spring element. In addition pore water pressure response as wellX31721 Stability and Ballast Control M Hancox

When considering maritime safety marine simulation training and maritime casualty investigation are interlinked key issues. Marine simulation can contribute to effective realistic training depending on data gathered from marine casualties. Marine casualties on the other hand can be studied in simulators where solutions for existing safety gaps can be developed. Both issues - simulation and casualty investigation - have an important impact on MET. Improved realistic training contributes significantly to the elimination of human failure. The links between simulation casualty investigation and MET are highlighted. Safety issues to be investigated in more detail in engine room simulators are listed and approaches as to how this can be done are suggested. Firstly the paper focuses on how simulators are used in MET. This is then followed by a short introduction to the creation of simulation scenarios together with an analysis of data needed for this purpose. This data analysis is underlined by some examples from casualty reports. Suggestions are made as to how simulation can contribute to investigating those issues. These suggestions are followed by conclusions in which reference is made to existing networks and initiatives that can be used e.g. for data and experience exchange to facilitate research and training.