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The aim of this research is to develop practical estimation methodologies for responses of and the mooring force on a floating structure in shallow seas and to clarify the characteristics of responses induced by various tsunami wave profiles. In this paper the estimation methodology is introduced. In the paper some tools of parts of system are verified. The analysis method for the Tsunami exciting forces based on the 2-D BEM simulation program code is verified by comparing with the experimental results and other simulation results. The characteristics of responses due to the difference of Tsunami wave profile are discussed.

The research on the numerical prediction of ice-breaking loads and resistance has reached a point at which practical problems related to ship design and construction can be solved. A 3D numerical model of the ice-breaking process on the waterline of a ship advancing in level ice was developed for investigating ice loads and resistance forces on ship hulls. For the purposes of validation ice forces on the waterline of the Swedish Coast Guard Ship KBV-181 were computed for several ship speeds and values of level ice thickness and compared to measurements with a load panel installed on the sister ship MS Uisko. The correlation between the computed results and the measured short-term ice loads proved to be very satisfactory. The processes on the underwater hull causing resistance to ship motion in level ice were identified but their modelling is not complete. Therefore the ship resistance is evaluated by computing the resistance forces on the DWL with the theoretical model and the underwater components of resistance with the semi-empirical method of Lindqvist. The sum of these components makes out the total resistance in level ice which in turn was compared to measurements on several ships. A very satisfactory correlation was reached.

The wave drifting forces acting on a very large floating structure consisting of multiple barge type modules is studied theoretically and experimentally. The wave drifting forces are estimated with two module connectors. The effects of connector conditions and the number of bodies on the wave drifting forces are discussed. It is verified that the coefficient of the wave drifting force on the multiple connected structure with hinge connectors can exceed the value of 3. The forces on the structure with hinge connectors are smaller than those on the structure with rigid connectors in long wave length range. The effect of the hydrodynamic interaction is strongly affected by the connecting conditions. It cannot be neglected for calculations of seakeeping performance for the huge floating structure.

A method is proposed to obtain the wave spectral evolution in waters of different depth. The method is based on the transfer of the measured spectra on deep water and on the saturation of the spectra on finite depth. The offshore wave spectra were transferred from the measurement station offshore Ponza to the sites of interest located offshore the Gulf of Naples and offshore the Gulf of Salerno respectively. The inshore wave spectra were obtained from the offshore ones with a mathematical model which takes into account the saturation process. The numerical results in terms of offshore wave spectra were compared with those recorded offshore the Gulf of Naples by a wave-rider buoy. The inshore results in terms of significant wave heights were compared with those recorded by a meteo-oceanographic station on the Salerno coastline of Salerno at a depth of 9 m.

Forces acting on a single blade placed in a water tunnel were experimentally investigated with the main focus being on the lift to drag ratio in different flow conditions. The intention was to locate the influence of cavitation and blade inclination on the lift to drag ratio and to discover optimum flow regimes even in cavitation conditions. The experimental apparatus is described. The results are presented and analysed.

It is important to establish a recognised approach regarding pipe lengths in suspension under vortex shedding induced vibrations (VIV). Several projects have been carried out to improve knowledge of VIV on submarine pipelines. Many aspects have been examined in the laboratory and in the field. Some aspects of the hydroelastic excitation and response are examined. The focus is placed on prediction tools. Countermeasures are discussed particularly hydrodynamic devices to tackle VIV. Experimental laboratory data on slender tubulars is discussed.

Orimulsion operations and the research and development of Orimulsion are considered. Significant resources have been committed over the past 13 years to assess the environmental risks in the event of a spill to develop a good understanding of Orimulsion spill behaviour and to develop tools in the spill response armoury. Not all of these tools are appropriate for all spills and each location should be considered on a case by case to determine the most appropriate and realistic response plan. Studies have also been undertaken on the detection and monitoring of spills and on assessing shoreline impacts and clean up strategies should spilled Orimulsion reach the shore. Parallel work is currently on- going in France and Canada evaluating the natural persistence and recovery of contaminated shorelines and determining optimum hydraulic washing conditions for removal of bitumen.

A 2D random walk model for the analysis of the hydrodynamic dispersion of pollutants on the sea surface is presented. In this mathematical model coastal circulation is produced by the action of the wind on the sea surface. The equation of advective-diffusive transport is based on the hypotheses of Taylor's theory and the solute is assumed to be non- reactive. The advective component of the transport is due only to wind-generated circulation. A numerical example has been reported based on suitable computer programs implemented for the analysis of the field of motion and dispersion phenomenon. A numerical application of the proposed method is presented to simulate space-time evolution of a polluting surface plume in the Pozzuoli Gulf located in the Tyrrhenian Sea.

Two simplified models with a different level of accuracy are suggested which are capable of providing to third order of approximation the drag inertia and total random forces acting in the flow separation regime on an isolated smooth vertical cylinder. The model adopts the TMAR model to identify the surface frequency spectrum on decreasing depths the corresponding spectrum on deep water being assigned. It uses the Morison equation to obtain the sectional random forces from which the total ones are deduced in analytical form; specifies the equation by using the kinematics to third order of approximation and introduces a polynomial development to evaluate the drag forces. Some considerations are made on the behaviour relevant to several significant statistical quantities pointing out the differences with regard to a complete model and some comparisons are made with experimental data from other authors.

A pro-active safety management system of ship structures which quantifies the aging effect such as fatigue and corrosion on ship structural integrity is proposed as a new approach to ship's structural surveys that have conventionally been done according to a more passive management system. A compact fatigue damage sensor has been developed that can detect accumulated fatigue damage in the weld structures by being stuck to the member and then inspected after a certain period. This sensor has been applied to hull structures of an LNG carrier for experimental purposes and its long-term durability under the severe environments of the ship is ascertained and quantitative data on accumulated fatigue damage from this ship are obtained. HFMS (hull fatigue management system) is proposed that uses this sensor and is part of HAMS (the hull aging management system). A study on the improvement of accumulated fatigue damage detection accuracy using this sensor is introduced. The evaluation method was applied on a trial basis to an LNG carrier and results were successfully obtained.

A short-term experiment to assess the ecological impact of a hydraulic blade dredge on a maerl community was carried out during November 2001 in the Clyde Sea area on the west coast of Scotland. A fluorescent sediment tracer was used to label dead maerl which was then spread out on the surface of sediment to act as a proxy for living maerl. The likely ecological consequences of hydraulic dredging on maerl grounds are discussed and a case is made for protecting all maerl grounds from hydraulic dredging and establishing them as reservoirs to allow for the recruitment of commercial bivalve populations at adjacent fished sites.

Wave loads were computed on three North Sea jackets which have been exposed to an increasing level of mudline subsidence. In order to estimate wave loads on the jackets and decks new environmental criteria were established from data not available at design. Due to the increased risk of waves impinging on the decks wave forces from both the jacket and the decks were computed and used in a reliability analysis. The wave forces on the decks were computed from a procedure that estimates the various components of the wave forces using a strong theoretical background incorporating the effects of shielding and blockage. The wave in deck procedure was indirectly calibrated and subsequently verified against model tests. The new procedure eliminates the need for developing the wave in deck loads in a separate software and incorporating them as nodal loads and allows the maximum load to be calculated accurately eliminating the effect of the phase angle difference between the jacket load and the deck loads.

When the strength of wave travelling over a sandy bed reaches a certain condition the bed form is changed to become a sand ripple bed. The formation mechanism of the bottom shear stress on the ripple bed differs from that on a plane bed. However investigation into the bottom shear stress on a ripple bed is the foundation of an investigation into wave damping with travelling and sediment transport. Therefore this investigation is significant. Bottom shear stress was measured directly and provided formulas to calculate the bottom friction factor and shear stress on the ripple bed. The expression is very simple and suitable for engineering practice.

The introduction of nuisance species (bio-pollution) represents a threat to human health and losses for the national economy. Research into prevention methods has lead to the statement that organisms which live in the open sea and are released in coastal waters (and vice versa) generally do not survive. On this basis the IMO recommends (in two methods) the sequential or the flow-through method of ballast water exchange on the open sea. Here it is questioned whether these two methods are safe. The feasibility of these two methods is verified. Research is carried out on the computer simulator Cargo Handling Trainer 2000b Norcontrol on the ship model VLCC (very large crude carrier) 220.000 DWT. The results of the research are presented together with guidance for security improvements.

The 1999 Chi-Chi earthquake in Taiwan caused widespread liquefaction in inland alluvial areas and in several coastal hydraulic fills that led to significant damage to lifeline systems buildings and harbour facilities. As a result a 3-year integrated research programme was set up to perform an overall evaluation on the liquefaction behaviour of granular materials in Taiwan and to make necessary modifications to the current practice of assessing the potential of sand liquefaction. The influence of the freezing process on the dynamic properties of a silty sand is discussed. The specimens were recovered from a liquefied site during the Chi-Chi earthquake. Remoulded samples were prepared by moist tamping method with two different water contents 5% and 28%. Samples were applied a freeze-thaw process before being subjected to undrained cyclic triaxial tests. The effects of freeze-thaw process on the liquefaction resistance were investigated together with other factors such as relative density and fines content. Resonant column tests were also carried out to study the effects of the freeze-thaw process on the maximum shear modulus.

Following new evidence that the contractor who carried out work on the cargo pump of the Esso Mersey failed to exercise acceptable quality control procedures the inquiry was reopened. The inquiry determined that quality control procedures were inadequate but the contractor was not alone in this respect.

This paper presents an analysis tool to predict the dynamic motion response and non-linear connecting and mooring forces on a parallel-connected LNG-FPSO system due to non-linear exciting forces of wave wind and current. Simulation for the mooring performance is also investigated. The three-dimensional source-sink technique has been applied to obtain the radiation forces and the transfer function of wave exciting forces on floating multi-bodies. The hydrodynamic interaction effect between the FPSO and the LNG carrier is included to calculate the hydrodynamic forces. For the simulation of a random sea and also for the generation of time dependent wind velocity a fully probabilistic simulation technique has been applied. Wind and current loads are estimated according to OCIMF. The effects of variations in wave wind and current loads and direction on the slowly varying oscillations of the LNG and FPSO are also investigated in this paper. Finally some conclusions are drawn based on the numerical results obtained from the present time domain simulations.

This paper presents an integral transform approach for investigating the effects of non-stationary behaviour of the seabed on the Morison hydrodynamic force associated with vertically moving submerged and partially buried offshore structures located in the neighbourhood of an exploration zone. For this the fluid-structure-soil dynamic interaction boundary value problem is modelled as a one-degree-of-freedom system and the geo-mechanical behaviour of the seabed is idealized as a spring and visco-elastic damper. In particular the corresponding fluid velocity potential and acceleration kernels in the Morison force empirical relation as modified by the seabed poro-mechanics are computed and their implications for the design of such offshore structures analyzed.

The next generation of LNG carriers are sized up to 250000m3 and can be designed to take advantage of the through life efficiency benefits of all electric drive systems. To minimise the effect on the ship build it is proposed that the power generation sources be grouped together in a power station type arrangement and be installed on the Poop Deck of the ship in the latter stages of the build sequence. This paper describes how such a system can be readily designed and integrated into an overall electric LNG carrier system. In addition the rationale for dividing the scope of supply on such a vessel is discussed with particular emphasis on minimising the risk to the end users by allocating scope responsibilities to the right partners in a collaborative ship design and build programme. The control of such a system is discussed and a review of the failure modes is also included. This shows how the overall system is designed to offer extremely high availability of electrical power to the ship systems.

This paper defines a generalised and simplified procedure which has been devised so that the alignment checks of a warship propulsion shaft line can be undertaken while the ship is afloat against more traditional methods which often require dry docking of the ship. Strain gauge measurements on the shaftline are fed into the developed software titled ‘MARSHAL’ which uses finite element calculations to enable the entire alignment measurement process to be carried out with the ship afloat.The procedure also makes the difficult task of assessing hull deflections required by traditional methods unnecessary.The alignment solution is obtained by the way of a two stage ‘Multi-objective Optimisation’ procedure. The validation of the developed software and procedure has been carried out by comparisons of the software solutions with real propulsion shaft data and by way of simulations and experimental work.