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Prediction of fracture and failure is a challenging research area. There are various methods available in the literature for this purpose including well-known finite element (FE) method. FE method is a powerful technique for deformation and stress analysis of structures. However, it has various disadvantageous in predicting failure due to its mathematical structure since it is based on classical continuum mechanics (CCM). CCM has governing equations in the form of partial differential equations. These equations are not valid if the displacement field is discontinuous as a result of crack occurance. In order to overcome this problem, a new continuum mechanics formulation was introduced and named as Peridynamics. Peridynamics uses integrals equations as opposed to partial differential equations of CCM. Moreover, it does not contain any spatial derivatives. Hence, its equations are always valid regardless of discontinuities. In this thesis, the applications of Peridynamics for marine structues are demonstrated. Particularly, the Peridynamic equations are rederived for simplified structures commonly used in marine structures including beams and plates. Furthermore, underwater shock response of marine composites is investigated. Finally, the peridynamic formulation for contact analysis which can be used for collision and grounding of ship structures is demonstrated. In order to reduce the computational time, several solution strategies are explained.

In recent years, more and more research attention has been paid to the NOx emissions caused by marine diesel engines. Selective catalytic reduction (SCR) system has been proven to be an effective technology for the removal of NOx emitted from marine diesel engines. In order to comply with stringent International Maritime Organization (IMO) Tier III NOx emission regulations, a number of engine manufacturers have developed their own SCR systems with an option of installing SCR reactors before or after the turbines of engine turbochargers. This thesis focuses on modelling of evaporation and decomposition of urea-water-solution (UWS) droplets, design and optimisation of static mixers, modelling of an SCR reactor and developing model-based urea dosing control strategy. The amount of ammonia converted from UWS has a significant effect on the NOx removal efficiency of SCR systems. Due to a limited installation space for SCR systems on board, choosing the location of urea injection nozzle appropriately has become a critical issue for SCR system design. An evaporation and decomposition model of UWS droplets has been developed in this research in order to determine the total depletion time of a UWS droplet, which is helpful to calculate the proper length between the urea nozzle and reactor of an SCR system. In order to achieve a high NOx removal rate and reduce the quantity of NH₃ slip, static mixers are commonly used before SCR reactors to improve the mixing between ammonia and exhaust gases. 4 novel static mixers have been designed and the performance of the mixers is compared in the study. An experiment has been conducted to validate the mixing performance and pressure loss of the static mixers developed. It shows that there is a satisfied agreement between the simulation and experiment results. A mathematical model of SCR reactors has been established. The unknown parameters of the model are identified by minimising the error between the model predicted and measured values of both the temperature and the species concentration after the SCR reactor. The SCR reactor model is further used in a simulation for the purpose of developing model-based urea dosing control strategies. A state observer is used to determine the actual states in the reactor which supplies the mandatory information for developing model-based urea dosing control strategies. The NH₃ cross-sensitivity of NOx sensors can be described by a linear equation. The simulation results of the observer show that the NH₃ cross-sensitivity of NOx sensors can be neglected when estimating the actual states of the reactor if NH₃ is of a low concentration in the exhaust.

Behaviour of two cylinders in tandem subjected to a stream of steady uniform flow is investigated. This research includes experimental and mathematical simulation so that a better understanding of the interaction between two bodies undergoing vortex induced vibration (VIV) can be achieved while one is submerged in the wake of the other. Amplitude and frequency of oscillation are observed for both cylinders when they are placed at different distances from each other. Positioning cylinders at various spacings can help to shed some light on the interaction mechanism of the upstream wake and trailing cylinder. An experimental investigation was carried out in sub-critical Reynolds number and low mass-damping to simulate the conditions in which offshore structures are deployed. Initially, two identical cylinders are placed in-line with the stream at various spacings. The response of leading cylinder is observed to be similar to that of an isolated cylinder experiencing VIV at all spacings. On the other hand, trailing cylinder response is observed to increase with flow velocity at small and medium spacings. Moreover,as the spacing grows large downstream response becomes more similar to that of the leading cylinder. Motion trajectory of trailing cylinder is significantly influenced by the leading body, and does not follow the typical figure of eight observed for an isolated cylinder at all velocities. Frequency power spectrum of obtained time histories reveals that two sources of excitation exist for trailing cylinder. Corresponding motion to each excitation source is determined using Fast Fourier Transform. The second set of experiment was conducted using similar cylinders with different natural frequencies to observe how it influences the interaction between two cylinders. It was observed that behaviour of trailing cylinder alters in comparison with initial set up. However, two sources of excitation are still detected in this set-up. Mathematical simulation is pursued by modelling the oscillating cylinders with a simple mass-spring-damper system. Furthermore, the force exerted to cylinders by wake is simulated by wake oscillators which can capture the self-exciting and self-limiting nature of VIV phenomenon. Two equations are coupled together by assuming that wake force is proportional to cylinder acceleration. Then, the system of equations is solved analytically,and results are compared to those obtained by a SimuLink model of the system. SimuLink model is solved by numerical RungeKutta method. It was observed that model is successful in simulating leading cylinder vibration amplitude,while it, initially, fails drastically to predict the oscillation amplitude of trailing cylinder due to buffeting vortices. Two terms were added to accommodate the effect of upstream wake on the trailing cylinder, to modify the force in the equation of motion which is respectively proportional to acceleration and velocity of the cylinder. Moreover, acceleration term is determined by fitting a linear function of the variable to the difference between upstream and downstream wake force obtaining from the experimental investigation results. Additionally, the damping term is determined by optimization of variance between simulation and experiment results. Such an observation can confirm that upstream turbulent wake has a significant influence on added mass coeffcient of the trailing cylinder which both are observed to be dependent on upstream Strouhal number. Overall, the agreement between mathematical model and experimental results is evaluated for both cylinders. Model error for trailing cylinder is calculated between 20% to 30% in cross-flow direction. This error is lower than that of the leading cylinder which is a well established method in literature for simulating VIV of an isolated cylinder.

The ever-growing intercontinental maritime trade and transporthave identified the need for the ship and passengerssafety, energy efficiency and environmental pollution to be considered as dominant issues within shipping industry and academia. Recently introduced safety regulations, known as Safe-Return-to-Port, and ‘green’ regulations, by the IMO, came into force to address and, indirectly, couple the above objectives through the enforcement of specific safety performance requirements of ship systems after a casualty and mandatory environmental measures for GHG emissions limitation, for the former and the latter regulations respectively. This thesis focus is on improving the safety and the energy efficiency of ships during design and operation by adopting approaches assessing the safety critical systems availability at emergencies and estimating performance requirements of electrical energy onboard ships over their life cycle. Through the adoption of methodologies successfully applied in damage stability, the probabilistic assessment of systems safety is employed with the logical modelling of the system into the ship environment and the application of statistical flooding damages to be initiated. Critical zones for the systems location are investigated with topological and geometrical optimisation to be performed identifying ‘enhanced-availability areas’ onboard targeting, also,the components redundancies reduction. First principles were introduced for the numerical modelling of the electrical energy systems onboard aiming to evaluate the energy performance of the ship. However, the great number of input parameters and computational problems shown up during the systems development, especially for larger vessels such as passenger, triggered necessary simplification considerations for the design. Investigation was considered for the identification of the key design parameters, with a verification process based on energy simulations to have been used for constructing guidelines and indicating acceptable assumptions. Investigation results were used for the systems optimisation in energy efficiency and cost perspectives during the design through the development of the Power Management System, with the latter’s functionality to be extended also during operation aiming fuel consumption minimisation. The amount of consumed fuel were quantified for both case, and results were used to create design and operation guidelines for power generation sets sizing and loading respectively. All findings were used to form methodology for the design of the electrical energy systems aiming to increase the energy efficiency through the appropriate sizing of the power generation sets and also, for the case of passenger vessels, to increase systems safety through the optimisation of their onboard location. Implementation of the methodology was exhibited with two case studies, one for a cargo and one for a passenger ship. The work undertaken and the derived results clearly demonstrate the applicability of probabilistic assessment for the quantification of systems availability post-casualty not only for rules compliance but also for the increased results accuracy and the integration to ship survivability concept. In addition, the introduction of Dynamic Energy Modelling concept as a platform in shipping to support life-cycle energy management were concluded through the electrical energy systems simulations during operation and design considering simplification during the latter’s process. Those concepts could be applied under the multi-objective optimisation platform in order to explore the whole design space concerning systems common parameters. All these constitute significant developments in shipping.

Top-hat stiffened plates provide an effcient structure for engineering applications. During service debonding between the stiffener and the plate is a common failure mechanism. Therefore, an extensive understanding of the residual strength is required to rapidly and effciently determine precautions to be taken to ensure the safety of the structure. Critical assessment of necessary repairs reduces the through life costs and in design damage assessment can lead to optimisation through tolerance of common damage incidents. Research on damaged stiffened structures to date is primarily focused on airframe applications and considers open sections with co-cured stiffeners which are not typical of marine structures. These studies have shown that debond size and location have a significant effect on the damage mode of the panel. However, they do not consider the interaction of failure modes or ultimate failure. Typical marine composite joints are manufactured by post-curing sub-components using a chopped strand mat layer at the interface. To predict failure of these joints requires accurate assessment of the material and fracture properties and a consistent set of data which is lacking in the literature. Therefore, the research in this thesis considers the damage tolerance of top-hat stiened panels containing a debond between the stiffener and plate through numerical and experimental work. The focus of the work is post-cured top-hat multi-stiffened panels used in large marine applications manufactured from heavy weight glass vinylester woven roving. An automated tool using non-linear finite element analysis capable of modelling debond damage and assessing the ultimate and the residual strength of the panel is verified. A parametric study investigating panel topology, damage parameters and stiener type show the complexities of the damage case. Results show that top-hat stiffened panels exhibit a trend between ultimate strength and the debond size with crack initiation not necessarily propagating as geometric imperfections accelerate buckling but can provide an arrest point for crack propagation. Nominal lateral pressures are shown to significantly increase the damage tolerance. Full characterisation of typical materials is conducted experimentally providing a complete data set of mechanical characterisation and fracture data for both co-cured interfaces, typical of mid-laminate debonds and sub-component joints. Tensile, compressive, shear and exural tests are conducted and a model for the non-linearity of the woven roving in tension and shear is proposed. The fracture results show the post-cured joint exhibits a 20% increase in mode I and II strain energy release rates. The experimental data is used in a number of studies to further verify and optimise the finite element model. Mode I and II tests are simulated to ascertain the cohesive element interface strengths and Turon's interface parameters. The material data is shown to give accurate results for the structural response, crack initation and debonding of an as built large scale top-hat stiffened panel which is tested experimentally under four point bend. Therefore, the effect of skin-stiffener debonding has been investigated for top-hat stffiened panels, providing improved characterisation of the material and interfaces and guidance on the damage tolerance to damage and design parameters.

The concept of an Unmanned Underwater Vehicle (UUV) “Mothership” submarine (designated Submersible Ship Host (Nuclear), SSH(N)) has already been explored at UCL using the Design Building Block approach by Pawling and Andrews (2011). This thesis builds upon that study, further investigating the design of a large mother-ship submarine. The incorporation of a novel technology such as UUVs into submarines suggests that the traditional evolutionary approach to concept exploration for new submarine designs is questionable. A novel approach to exploring, within the design solution space, novel SSH(N) concepts has been investigated in this thesis. The significance of incorporating UUVs into submarine design has been explored by conducting an Operational Analysis (OA) of the mix of UUVs required supporting a range of scenarios. This OA gave a coherent justification for a mixed and significant total displacement of UUVs as the main payload for SSH(N)s. A MATLAB computer program, Submarine Preliminary Exploration of Requirements by Blocks (SUPERB), has been produced to generate and assess submarine concept designs. SUPERB also uses a novel generic arrangement approach called, “Compartment X-Listing”, which systematically allocates compartments within the pressure hull and then compares individual concept-level submarine designs to typical existing arrangements. Validation of SUPERB and Compartment X-Listing is presented and discussed using two existing submarine designs and two radical concept design proposals. A novel approach of modifying a nominal Pareto Front representation for complex novel designs called the Notional Pareto Front (NPF) has been used with SUPERB to generate designs and is considered to be an innovation in marine design practice. The NPF approach seeks to bound the solution space and focus concept exploration on a smaller region. This is seen to have the potential to inform an extensive early stage exploration of the design solution space, as a research approach for future concept level investigations, such as for SSH(N)s. Recommendations are made as to how this design approach may be taken forward.

This thesis imagines an ecological future for the post-industrial landscape of Govan Graving Docks, situated on the banks of the River Clyde in inner city Glasgow. The research is framed by a context of urban renewal and at times violent change in early 21st century Glasgow which has seen the city’s riverside transformed, with centres for culture, tourism and entertainment built on its infilled docks and sites of dereliction. Prompted by the development priorities of this change, and the nostalgia for an industrial past that has become a ‘way of seeing’ the river, this research seeks to better know the material life of this landscape. On Govan Graving Docks - an abandoned ship repair and fitting facility that remains as yet ‘unresolved’ - this thesis unearths the agencies, temporalities, ecologies and material legacies of a less familiar elemental landscape, and considers how these expressions could be tended and extended in a vision for a different future, focused on fostering new kinds of environmental engagement. The research themes draw insight from emerging theories in new materialism and the environmental humanities, particularly those that are responding to the matter of the Anthropocenic landscape, and they are explored through a repertoire of creative and collaborative field methods crafted with the site of study; variations on ecological performance, landscape and ecological survey work, public consultation, material imagining and sitewriting. These methods are founded on openness and attentiveness, they are opportunist and affirmative in nature, they are practiced on site and taken into the wider estuarine landscape, and they enrol many others beyond the researcher. These methods are first used to explore the expressions of life and vitality that can be found in the Graving Docks’ new ecologies, material memory and more-than-human publics, and then to imagine the creative capacities of these agencies in new configurations of shared possibility. The researcher is another site of investigation: a distributive understanding of agency informs the emergence of an ecological sensibility through material engagement, which has implications both for the design process and the imagined landscape. These resources are used to imagine an alternative future for Govan Graving Docks: it is a vision that works with ruination, re-wilding, and the liquid dynamics of the city; a vision that honours both natural and industrial histories; a vision that is both challenging and necessary, where new experiences of ‘worlding’ in the city are made possible. Through this process of investigation and conjecture, the Clyde imaginary emerges as a space for critical and creative thought; a discursive space where the challenges facing this ecological landscape and its future are explored. This thesis is both a product of, and contribution towards, cultural geographical enquiry, but it also has an interdisciplinary reach both theoretically and methodologically speaking, which enables the research to contribute to a wider debate about environmental futures that is currently taking place across the sciences and humanities. It can be defined as ‘interdisciplinary in practice’ for the way that it brings a wider range or perspectives to bear on a precarious urban wilderness and its associated communities, and seeks to develop a broader repertoire of research methods capable of exploring it’s diverse material world, and the multiple expressions of value that exist therein. Written in a style that has been highly affected by this kind of open and inclusive style of research engagement, the emotive environmental story that is contained within this thesis is open to a wider audience. This thesis identifies the productive role that cultural geography can play in larger environmental debates concerned with the current state and play of ‘life on earth’, and by enacting and engaging ideas related to the cultural landscape, place-based identities/communities/values, and landscape practices, it also identifies the particular conceptual and methodological resources that make cultural geography’s contribution both unique and necessary to these debates.

For ship systems to remain reliable and safe they must be effectively maintained through a sound maintenance management system. The three major elements of maintenance management systems are; risk assessment, maintenance strategy selection and maintenance task interval determination. The implementation of these elements will generally determine the level of ship system safety and reliability. Reliability Centred Maintenance (RCM) is one method that can be used to optimise maintenance management systems. However the tools used within the framework of the RCM methodology have limitations which may compromise the efficiency of RCM in achieving the desired results. This research presents the development of tools to support the RCM methodology and improve its effectiveness in marine maintenance system applications. Each of the three elements of the maintenance management system has been considered in turn. With regard to risk assessment, two Multi-Criteria Decision Making techniques (MCDM); Vlsekriterijumska Optimizacija Ikompromisno Resenje, meaning: Multi-criteria Optimization and Compromise Solution (VIKOR) and Compromise Programming (CP) have been integrated into Failure Mode and Effects Analysis (FMEA) along with a novel averaging technique which allows the use of incomplete or imprecise failure data. Three hybrid MCDM techniques have then been compared for maintenance strategy selection; an integrated Delphi-Analytical Hierarchy Process (AHP) methodology, an integrated Delphi-AHP-PROMETHEE (Preference Ranking Organisation METHod for Enrichment Evaluation) methodology and an integrated Delphi-AHP-TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) methodology. Maintenance task interval determination has been implemented using a MCDM framework integrating a delay time model to determine the optimum inspection interval and using the age replacement model for the scheduled replacement tasks. A case study based on a marine Diesel engine has been developed with input from experts in the field to demonstrate the effectiveness of the proposed methodologies.

The introduction of the IMO Performance Standard for Protective Coatings (PSPC) for dedicated water ballast tanks (WBT) has increased the importance of the coatings applied in these tanks. Typical structural configurations within Water Ballast Tanks (WBTs) have a high degree of complexity; these spaces contain a large extent of edges, corner details and welds, which are commonly cited as areas most likely to suffer coating failure. However there is no quantitative measure of complexity as an indicator of how difficult a structure is to coat reliably. The concept of ‘structural complexity’ is considered with the intention of improving the in-service performance of applied coatings by proposing ships structures that include the coating process as a design consideration. As a means to try and provide a quantitative measure indicative of how easy a structure is to coat, the idea of ‘structural complexity’ is developed based on fundamental structural features. This measure is then used to understand the influence that different stiffener profiles and stiffener spacing may have on the coating process if structural configurations are sought that have reduced complexity. Investigation of the principal developments of the coating process indicates that any improvement is unlikely to be driven by coating technology or process alone. If improvements are to be made the suggestion here is that they should be driven by improving the design of the structure to be coated. The intention is to promote a ‘design for the coating process’ methodology to achieve this. The global ship and structural design process have been reviewed, where the classical approach looked at the relationship between weight and strength. This work concurrently considers the implications of different structural configures on not only weight and strength but also ease of coating. The relationship between the topology of the structure and the physical task of applying paint to it has formed the foundation of a ‘design for coating’ methodology, where the influence of structural complexity on all aspects of performance is considered with equal merit. A coating cost estimator has been developed in order to demonstrate the potential savings that could be realised by considering the coating process during the design phase. A simple optimisation routine has been used to seek solutions for minimum, complexity, weight, steelwork and coating costs. This allowed the balance to be explored between the completing aspects of the steelwork and coating processes. These alternative design solutions have been assessed using mathematical computational methods to ensure that the designs provide adequate structural performance.

A study into the environmental impact of marine power systems was performed in proximity with the defined research objectives: (i) present an overview on Annex VI The International Convention for the Prevention of Pollution from Ships, cargo ships, marine power systems and technologies; (ii) review life cycle assessment (LCA) methodology development; (iii) develop an LCA framework for marine power systems; (iv) carry out case studies to determine environmental impact, significant components and critical processes; (v) apply scenario analysis to investigate the sensitivity of the results to selected parameters; and (vi) compare power systems under study to verify their environmental benefits. Built upon literature and the proposed LCA framework, LCA case studies on conventional, retrofit and new-build power systems were performed using a bottom-up integrated system approach, where data were gathered and LCA models were created for individual technologies using GaBi software. Life cycle impact assessment was performed using CML2001, International Reference Life Cycle Data System (ILCD) and Eco-Indicator99 to estimate the environmental impact of the systems. It was found that disposing metal scrap of significant components was the principal cause of ecotoxicity potential, which was the impact category that showed the top two highest indicator results; and operating diesel engines and auxiliary generators or diesel gensets was mainly accounted for other impact categories. When compared with the conventional system, both retrofit and new-build systems consumed less fuels and released less emissions during operation but involved more materials and energy during other life cycle phases, leading to a decline in most impact categories to the detriment of a few burdens. The life cycle of marine power systems must be planned, managed and monitored appropriately for reduced environmental implications. Further research should address limitations presented in this study and explore other factors that might affect the environmental burdens of marine power systems.

Inspired by the novel flapping caudal fin and body undulatory mechanisms in nature swimmers, simplified physical models are built in Computational Fluid Dynamic(CFD) solvers, and used to investigate the self-propulsion performance under different conditions with various kinetic and geometric parameters. Two simplified physical models, three-dimensional flapping wing model with flexibilities in lateral and rotational directions and multi-body system model with rigid components connected by revolute joints, are investigated for mimicking typical bio-inspired locomotion. The study was firstly carried out on a three-dimensional wing with a freedom intranslational direction under a prescribed flapping motion. The investigation focused on how the system kinematics and structural parameters affect the dynamic response of a wing with a relatively small span length. It shows that the induced wing motion is a result of the system stability breakdown, which has only been observed by previous researches in the two-dimensional case. The results obtained indicate that the evolution of the wing locomotion is controlled not only by the flapping frequency and amplitude, but also influenced by the system inertia as well as the wing aspect ratio and density ratio. Moreover, initial perturbation effect on wings flexibility plays a role in the evolution development. Subsequently, a comprehensive investigation is carried out on the dynamics response of a three-dimensional flapping wing with two degree of freedoms in lateral and rotational direction under a zero initial velocity condition. Distinguishing from the limited existing studies, present work performs a systematic examination on the effects of wing aspect ratio, inertia, torsional stiffness and pivot point on the dynamics response of a low aspect ratio rectangular wing under an initial zero speed flow field condition. The reduced rotational pitching help with the symmetry breakdown of the flapping wing and results in a forward/backward motion. When the wing reaches its stable periodic state, the induced pitching frequency is identical to its forced flapping frequency. However, depending on various kinematic and dynamic system parameters,(i.e. flapping frequency, density ratio and pitching axis), the lateral induced velocity shows a number of different oscillating frequency. Furthermore, compared with one degree of freedom wing in lateral direction only, the propulsion performance of such a two degree of freedom wing relies very much on the magnitude of torsional stiffness adding on the pivot point, as well as its pitching axis. In all cases examined, thrust force and moment generated by a long span wing is larger than that of a short wing,which is remarkably linked to the strong reverse von Kármán vortex street formed in the wake of a wing. In a separate study, the undulatory motion of fish body is mimicked with a series of linked rigid bodies, i.e. a multi-body system. The connection between two adjacent rigid components can be modelled as the revolute hinge joint, with either a passively induced pitch motion or actively prescribed pitch motion. Emphasis is put on the development for solving the problems of coupling multi-body dynamics with fluid dynamics by implementing Mobile Multi-body System (MMS) algorithm with CFD solver. Verifications are carried out by repeating the previous work, and innovative cases are tested on a prototype with three-linked rigid body system with an active joint and a passive joint. The investigation is made on the flexibility effect of tail on the propulsion performance. It shows there are optimized stiffness and damper coefficients at the passive joint leading the most efficient propulsion and fastest velocity through varying the posture of undulatory trajectory.

Despite continual improvements in the shipping industry related to structural design, operational practices, onboard technology and regulations, accidents still occur that result in sinking or capsize. When this happens to passenger ships, the results are often shocking and devastating with loss of life, sometimes numbering in the thousands. For this reason, the International Maritime Organization (IMO), which regulates the maritime industry, provides guidelines for evacuation analyses for passenger ships [1]. The scope of work presented in this dissertation fills gaps in our understanding of human performance during the evacuation process on passenger ships, particularly as it relates to passengers' alarm response time, the influence of response time distributions on total assembly time predicted by the evacuation model maritimeEXODUS, passenger movement onboard during the assembly process, and methods for validation of evacuation models in general. The research carried-out was experimental in nature and involved a total of 5582 passengers onboard three large passengers ships - a ferry without cabins, a ferry with cabins and a cruise ship. All passengers had paid for their voyage and, prior to boarding, had no knowledge that an experiment was being conducted. The experiment was carried-out as a typical assembly exercise, which started with sounding of an alarm and ended when all passengers had been assembled. Passenger response to the alarm was recorded using digital video cameras and routes to assembly stations and associated times were captured using a novel infrared light detection tracking system. The dataset collected represents the most comprehensive collected to date for passenger response and movement during assembly trials at sea. Analysis of the data has provided important insights into the nature of response time distributions for passengers on ferries and cruise ships. It was found that response time distributions generally took a lognormal shape, which is consistent with response time distributions measured in the built environment. Response time distributions generated from repeat trials on the same ship were statistically similar and could be combined to produce a single distribution for each ship - a powerful result suggesting that if the response times and demographics of a sufficiently large number of people are characterised for a given type of structure, an assembly exercise repeated under similar notification conditions should result in a similar distribution. Another key finding was that response time in cabin areas was not similar to that in public areas on the same ship. In addition, response times for passengers in public areas on ferries was found to be statistically similar, while public space results for the cruise ship were different. This suggests that different response time distributions should be used for different ship types. Passenger movement results have enabled the development of two unique datasets for use in validating ship evacuation models - one validation dataset which is relevant for ferries without cabins and the other for cruise ships. The validation method developed enables a clear, yet objective means by which ship evacuation models can be assessed using the experimental data collected. It is felt that the suggested validation protocol and acceptance criteria developed form a reliable basis for validating ship evacuation simulation tools. This research has resulted in the submission of two information papers to the IMO suggesting credible response time distributions relevant for different ships and different areas onboard, as well as a detailed method for conducting validation of ship evacuation models. The recommendations being made from this work are significant since, if accepted by the IMO for inclusion in the regulations, will influence the design and construction of all new passenger ships worldwide.

This thesis explores the occupational socialisation of Filipino merchant marine officer cadets through their experiences of maritime education and training (MET). The socialisation of the cadets is contextualised within the broad aim of the global and national regulations of MET to develop competent seafarers. In the international seafaring labour market, there is an increasing trend of labour participation of seafarers coming from the ‘new labour supplying countries’ (NLSCs). The Philippines is seen by industry insiders to be one of the top NLSCs for officers. However, the academic literature is silent about the experiences of officer cadets of their education and training especially those coming from NLSCs. Using multi-modal data collection tools such as in-depth interviews, field notes and document analysis, this qualitative study examines the experiences of the current and former cadets under the sponsored cadetship programs (SCPs) in the Philippines in order to analyse first-hand experiences of MET. The key findings of this thesis are: (a) SCPs are officer training platforms developed mainly by shipping companies to meet their sea-based labour needs and intended to comply with the Philippine standards of MET; (b) there are a variety of SCPs from which four models are described in this study; (c) SCPs utilise a ritualistic socialisation of cadets in college campus as key mechanism of training; and (d) there is a diversity of shipboard training experiences of cadets ranging from well-planned training programs to the complete absence of programs. The thesis concludes the following: (a) the quality of training experienced by the cadets is characterised as a highly regulated and reinforced professionalization process intent on producing certificated officers; (b) the SCPs are routes for migrant work for mainly male Filipinos being guaranteed a post-collegiate sea-based employment by their shipping patrons; (c) the socialisation of the cadets is influenced by processes of globalisation embodied in the global standards of MET enforced locally, and the role of international shipping companies in funding the recruitment and training of cadets as well as offering them post-training employment; and (d) in spite of global and local standards of MET, there is no common or shared understanding of the notion of seafaring competence among the trainers, which have affected the way competencies were taught and assessed.

The IMO has recently developed technical and operational measures aimed at enhancing shipping environmental efficiency, i.e. the EEDI and the EEOI, respectively. The purpose of this exploratory research work is to investigate the Life Cycle Assessment (LCA) methodology as a complementary tool to these metrics, capable of not only serving as a widespread accepted environmental performance indicator, but also able to competently highlight energy efficiency. The EEDI and EEOI methodology is reviewed, while also using two case vessels as sample implementation case studies. An LCA model formulation is developed and also applied on the two case studies, utilising them for validation, and additionally for comparing the LCA approach to the IMO regulatory metrics. One of the case vessels comprises the evaluation of a proposed retrofit, in order to emphasise on the different metrics' potential to assess changes in the results, with regards to the retrofit's before and after phases. Results show that aside from the environmental score of CO₂ emissions per unit of work - documented by the current regulatory metrics -, LCA can also offer NOx and SOx scores, along with other hazardous releases. Moreover, LCA - aside from showing compliance to the formulation of both IMO regulatory metrics - is able to present material and energy utilisation throughout different stages within the vessel's lifetime. Lastly, it is demonstrated that LCA can be used in parallel to the regulatory metrics, in order to efficiently emphasise detailed environmental information, pertaining to specific substance release or phase improvement/redesign as required. It is concluded that LCA could serve in aiding to monitor and report maritime transport emissions with an already widely accepted methodology. Furthermore, LCA could be recognised between industry and international stakeholders - including shipping and shipbuilding and repair -, as a common performance marker capable of consistent implementation not only across shipping divisions, but also across different industry sectors.

The aim of this research was to contribute towards energy efficiency in the shipping industry through improved operational practices that reduce fuel consumption, hence exhaust emissions and the amount of carbon dioxide released into the atmosphere. This is in line with meeting global emission reduction targets and the mitigation of Climate Change. A critical review is presented that was undertaken to understand Climate Change as a driver towards energy efficiency within the maritime industry. The regulations are reviewed along with existing operational practices and the enablers and barriers towards improvements. Several field studies that were undertaken to further examine current practices and barriers are described, including a questionnaire identifying the opinions and perceptions of seafarers. Based on conclusions from the review and field studies, a Framework for improving the energy efficiency of ship operations is presented. The proposed Framework identifies that for practical solutions in the industry, human factors must be addressed in parallel with technical advances. The following features of the Framework to enable improvements are identified to be: a) Ship Operational Performance Monitoring for performance feedback distribution and supporting operational strategic decisions and b) updates to existing Operating Procedures. However, it is proposed that these features cannot be achieved on a wide scale without first the development of the following elements: a) Maritime Education and Training on energy efficiency; b) Analysis of ship Operational Profiles; c) A Ship Operational Performance Prediction (SOPP) Model. These three elements were developed and are described in this thesis. The developments described in this thesis were enabled by the collection of operational datasets (namely Ship Reports, also commonly known as Noon Reports) and information for 21 case study ships; including tanker, container and bulk carrier ships. The collection of this data was enabled by field study visits. Regarding the development of Maritime Education and Training on energy efficiency, three course curriculums are proposed. The training material developed for the Energy Resource Management course is then described. The results from the analysis of Operating Profiles for the 21 case study ships are presented. Typical operating practices are identified along with the opportunities for energy efficiency improvements. The Ship Operational Performance Prediction Model was developed using the Ship Report dataset for a case study tanker ship. The model predicts the ship's main engine brake power and fuel consumption with adequate accuracy and allows for assessment of the impacts due to different operating conditions. Specifically, a function to account for time dependent performance changes is developed so that the hull and propeller surface degradation and fouling are taken into consideration. Finally, the utilisation of the developed elements within the proposed Framework to improve energy efficiency is discussed, so that the importance of methods utilising Ship Report operational datasets becomes evident.

The majority of current techniques used for predicting ship motions rely on assumptions from the potential flow theory. However, this approach is not ideal, since potential flow theory ignores important effects such as breaking waves, turbulence and viscosity, which are significant in problems involving high Froude numbers, those involving large amplitude motions, shallow water problems and problems involving multi-hull ships. These effects should therefore be included in seakeeping and resistance calculations. Reynolds-Averaged Navier-Stokes (RANS) approaches are excellent alternatives to potential flow theory, as they can directly account for viscous effects in their calculations. Towing tank tests are used widely around the world, giving very accurate results. However, these may be costly and time-consuming. Towing tank experiments are also hampered by a limited availability of suitable facilities. Computational simulations offer a fast, low cost alternative to towing tank experi ments. Continued technological advances offer ever-increasing computational power, which can be harnessed for viscous flow simulations to solve the Navier-Stokes equations. Computational Fluid Dynamics (CFD) methods are rapidly gaining popularity for naval architecture, ocean and marine engineering applications. The application of CFD techniques to seakeeping problems allow designers to assess the seakeeping performance of a vessel whilst it is still being designed, enabling any necessary corrective action to be taken before the vessel is actually built. This work mainly aims to perform hydrodynamic analyses of mono- and multi-hull ships, and to develop a CFD-based unsteady RANS numerical model to predict the hydrodynamic performance of these ships. This model will cover seakeeping and resistance calculations in both deep and shallow water regions. Firstly, a detailed literature review of the existing numerical methods which have been developed to solve seakeeping problems of ship is performed. This review also looks in detail at the differences between seakeeping analysis techniques; the reasons for these differences are investigated. Following this, unsteady RANS simulations are performed for various seakeeping and resistance applications. In each specific study, the results obtained using a commercial RANS solver are compared to the results obtained using a potential flow theory code and the available towing tank experiments. Finally, the results drawn from each chapter of this thesis are summarised and discussed, and recommendations are made for future research.

The move by the offshore oil & gas industry to deep water has an impact on the selection of mooring system configuration and design method. Methods of analysis need to be re-evaluated as water depth increases. The primary purpose of this thesis is to study the hydrodynamics of deep water moorings and the nonlinear dynamic response of the mooring line, which is representative of a Spar platform and a floating offshore wind turbine (FOWT). Emphasis is placed on the coupling effects between the floating body and mooring line and the nonlinear dynamic response of elastic mooring line. For a Spar platform, this thesis studied the behaviour of a 4-point mooring system in water depths from 300m to 3000m, using an indirect time-domain method. A panel method was applied for the hydrodynamics of the floating structures and a lumped mass and spring method for the dynamic response of the mooring lines. Coupled analysis results for intermediate water depth were compared with experimental data to check the validity of the numerical modelling. The results from coupled low frequency (LF) and fully coupled analysis are compared and discussed. Results from parametric studies are compared to offer guidance to mooring system designers on the suitability of particular approaches. For a floating wind turbine, three water depths-300m 600m and 900m were simulated in the time domain under both operational and shutdown conditions. A fully-coupled analysis was carried out to study the motion response of the FOWT under wave only and wave-plus wind condition. The aerodynamic modelling was based on the blade element momentum theory, while the mooring system global performance was simulated by the indirect time-domain method. By performing a comprehensive parametric study, the effects of the second-order wave drift force and the aerodynamic turbine thrust force on the motion response of the FOWT are studied and discussed. The performance of a polyester mooring line is non-linear and its elongation plays a significant role in the dynamic response of an offshore moored structure. Unlike chain, the tension-elongation relationship and the behaviour of elastic polyester ropes are complex. In this thesis, by applying a new stiffness model of the mooring line, the traditional elastic rod theory is extended to allow for large elongations, which are appropriate for simulating the static and dynamic response of both polyester lines and traditional chains. Galerkin's method was applied to discretise the equation of motion for the rod. One beneficial feature of the present method is that the stiffness matrix is symmetric; in non-linear formulations the element stiffness matrix is often non-symmetric. The static problem was solved by Newton-Raphson iteration whereas a direct integration method was used for the dynamic problem. The mooring line tension based on the enhanced model was validated against the proprietary software OrcaFlex. Results of mooring line top tension predicted by different elongation conditions were compared and discussed. The present method was then used in a time-domain simulation of a Spar-type platform, typical of those used for offshore wind turbines, moored by three taut lines in waves and currents. From a comparison between linear and non-linear formulations, it is seen that a linear spring model under-estimates the mean position when the turbine is operating, but over-estimates the amplitude of the platform response at low frequencies when the turbine has shut down.

In general, for shipping companies or any organisation the important decisions are made to deal with the selection of a particular alterative. This thesis presents a decision support tool for selecting a Ballast Water Treatment System (BWTS) for a given ship. A single decision has to be made between a number of given BWTS alternatives for a VLCC tanker under its voyage in the presence of a single decision maker. The decision support tool was developed using the Analytical Hierarchy Process (AHP) method, in order to help decision makers in shipping companies to select the most feasible BWTS for their ships. The ultimate aim of the developed decision support tool is to aid decision makers in shipping companies to make the right decisions when selecting between numbers of BWTS alternatives for their ships. In order to achieve the aim of this thesis several objectives were identified as follows: (1) To identify the influencing parameters and/or criteria related to both ballast water treatment system and ships parameters; (2) To evaluate the importance of the selected criteria for both BWTS and ship parameters/criteria; (3) To apply an appropriate Multi-Criteria Decision Making (MCDM) technique along with the above points; (4) To validate the develop decision support tool and investigate its applicability in actual case studies. The criteria were identified through the literature review and the semi-structured interviews with twelve senior staff or experts from three different trade shipping companies. The latter was an important step in finalising the new decision support tool, to evaluate the importance of the selection issues in shipping companies, and to evaluate the importance of the criteria used by the developed model. In addition, it helped framing the hierarchy structure of the Analytical Hierarchy Process (AHP) as a new model to support the selection of BWTS for ships. The comparisons between the case study, derived results, sensitivity analysis, robustness test, case study two and the validation interview with two experts from a well-known shipping company have supported the applicability and the validity of the model to help decision makers in shipping companies to select the most feasible BWTS for their ships. The model has also demonstrated its ability to aid decision makers or researchers in understanding the relationships between the different processes and their consequences on their BWTS selection.

The ability to predict the powering performance of twin skeg LNG ship is a complex endeavour requiring appraisal of operating conditions and hydrodynamic analysis to arrive at a suitable stern design solution. Inherently coupled with the stern design process is the design optimization, namely the selection of most suitable geometrical parameters of the propulsor, control surface and their arrangements with respect to the hull. An approach to the stern design may commence with the prediction of general ship stern flow, hence its resistance and self-propulsion capabilities. Almost a century of experience exists regarding how to predict the resistance and powering capabilities of the twin skeg LNG ship. Despite this, improvement in numerical methods is still in high demand. A RANS based numerical approach is presented in this thesis to predict the resistance and powering performance of future twin skeg ships. This is supported by a meshing approach which easily blends the hull-skeg boundary layer to the free surface. Predicting the non-uniform wake in the propeller plane due to the hull-skeg and control surface interaction was identified as one of the main challenges in the stern design and powering assessment. To predict this within acceptable cost a sectorial approach was developed as part of the numerical method which discretizes the propeller plane into a series of radial and circumferential subdivisions. The local axial and tangential inflow conditions at each location can then be considered. This was coupled to a blade element momentum theory propeller code. The two-way coupling was found to be a computationally efficient tool for studying the powering performance of ships. To demonstrate the pertinence of the RANS based numerical approaches developed in this work a series of case studies has been analysed. These include: skeg-rudder-propeller interaction studies, propulsive characteristic of the KCS ship, and the resistance and self-propulsion characteristics of a future twin skeg LNG ship. These highlight the roles of the numerical approaches in the stern design process for future twin skeg ships. The techniques developed in this work enable the designer to predict the powering performance of future twin skeg LNG ships at a cost effective manner in the initial design stage.

The Royal National Lifeboat Institution (RNLI) is the charity that aims to save lives at sea. The RNLI D-class is a five metre inflatable lifeboat that is used near the shore in waves and surf. Anecdotal evidence indicates that the D-class has improved performance due to its unique, flexible, fabric structure, and this flexibility is highly likely to affect the vibrations generated by the D-class. The boat motion is experienced by the on-board crew, and the air and water borne noise are heard by the on-board crew and the wildlife. This thesis aims to measure these two types of vibration, predict the perception of these vibrations and measure the effects of hydroelasticity on both the vibration and perception. Three aspects of hydroelasticity were identified within the D-class: hydroelastic slamming, hydroelastic planing surfaces and global hydroelasticity. This gives a new perspective with which to view the effects of hydroelasticity. A four stage full-scale holistic hydroelastic experiment was performed with each stage aiming to trigger one aspect at a time. The four stages were: static tests, flat water trials, drop tests and wave trials. The D-class was fitted with 52 sensors to measure the boat motion, engine thrust, sponson and keel pressures, deck hinge angles, deck panel deflections and the fabric hull deformation. The static trials measured the shape of the D-class under only buoyancy and weight forces. The flat water trials measured the effect of a hydroelastic planing surface on the forward speed and investigated a phenomenon termed the pulsing motion. The drop tests were performed at full-scale and quasi-2D, and they measured the effect of hydroelastic slamming on the peak acceleration and predicted the Whole Body Vibration (WBV). The open-water wave trials investigated the global hydroelasticity. The static tests showed that the shape of the D-class was more dependent on the keel pressure than the sponson pressure. The flat water trials proved that a flexible planing surface decreases the forward speed by 0.44 knots. The pulsing motion surprisingly exhibited the highest forward speed and it is hypothesised that the structure achieved an unstable equilibrium position of minimal potential energy. The full-scale and quasi-2D drop tests demonstrated that hydroelasticity can affect the peak accelerations and WBV, but the trend was inverted when the drop height was varied from 0.5 m to 1 m. It is believed that the keel is the dominant component during the flat water trials and drop tests, and this is coupled with the fabric hull. No statistical difference was found in the wave trials results but this was explained through the drop test results. The predicted WBV from the wave trials does emphasises the need for a new WBV reduction strategy and incorporating an element of hydroelasticity along with other reduction methods could make a significant impact on the WBV. The airborne noise of the D-class was measured using ISO 14509. The airborne noise was above the limits set out by the European directive 2003/44/EC. A method was developed to measure the water borne noise of small High Speed Craft (HSC) in shallow waters. The water borne noise propagation was modelled using an Image source Transmission Loss (ImTL) model. The perception of the air and water borne noise by a harbour seal was predicted and it showed that the D-class is unlikely to cause damage to the auditory system at one metre but will definitely be audible to the seal at 20 m. The horizontal and vertical transmission loss through a shallow water channel was investigated.

It is well known that ageing steel marine structures are susceptible to corrosion in its all manifestations. The most critical areas are cargo and ballast tanks of merchant ships. However, due to the regulations such as the Performance Standard for Protective Coatings, which requires a 15-year target life of coating in ballast tanks, plus the cathodic protection systems, the internal structures within cargo holds have become more problematic but poorly studied. In the underdeck area and bottom plating, the structures are not normally fully protected. Also, the complex structural arrangement may place difficulties in inspection and repair. In extreme cases, it has been reported that the corrosion rate in these areas could be 5 to 7 times higher than a normal value, and has led to catastrophic structural failures. Currently, the classification societies apply both visual and gauging methods for corrosion inspection during ship surveys. However, it is time consuming especially for large vessels and is highly experience dependent. Therefore, to improve the survey efficiency, facilitate economical maintenance decisions, and even extend the structural life, it is essential to investigate the ultimate strength of such aged and corroded steel structures. Based on the identification of existing corrosion issues in cargo tanks of oil tankers and bulk carriers and the state-of-art of corroded marine structural strength assessments, a nonlinear finite element method was adopted to investigate the influences of pitting and grooving corrosion on the structural integrity. Two full-field experimental techniques were used for a complete validation of the numerical models. Based on the repair conditions provided by classification societies, the numerical results showed that 25% locally corroded area of a plate (800 mm × 800 mm × 15 mm) with 3.75 mm remaining thickness may reduce the ultimate strength by up to 20% compared to a uniformly corroded plate. The weld-induced grooving corrosion of a width of 59 mm and a remaining thickness of 3.75 mm would cause up to 26% strength capacity reduction for a stiffened plate (4750 mm × 950 mm × 15 mm). Moreover, it was shown that the corrosion depth had a greater influence on structural performance compared to corrosion area for the same volume/material loss. By combining mechano-electrochemical protocols with the stress and strain results obtained from the modelling, it enables predictions of the ‘hot spot’ locations of mechanically-induced corrosion acceleration. Results showed that the anodic current density inside grooving corrosion damage (24 mm in width and 3.75 mm in depth) was 7 times greater vis-a-vis the unstressed condition for the stiffened plate at its ultimate strength state. The results, which are closely related to the industrial corrosion inspection and repair requirement, will not only benefit the shipping industry, but are also applicable to a whole range of marine structures (offshore platforms and steel bridges).

The Double Estimation Technique (DET) is a comparatively new GNSS tracking loop architecture that mitigates the ambiguity present in pseudoranges from Binary Offset Carrier (BOC) signals. These signals are part of ‘modernised’ GNSS development, and will see extensive use on both existing and in-development constellations. Many techniques have been proposed that either partly or wholly eliminate the problem of ambiguous BOC pseudoranges: proposal and investigation of new techniques is still an active area of research, however many of the techniques described in literature must make a trade-off between ambiguity mitigation and computational complexity. Few of the techniques have been demonstrated on hardware receivers and so knowledge of their effectiveness and practicality is limited. Comparison between the Double Estimator Technique (DET) and the commonly-used alternative Bump-Jumping (BJ) channels’ operation was obtained from a hardware receiver running customised tracking channels and from simulation channels (developed from MathCAD programs supplied by Dr. Stephen Hodgart) designed to closely match the parameters of the hardware receiver. Both DET and BJ channels were compiled for the SGR-ReSI – an FPGA-based receiver developed by SSTL as the first in the new generation of GNSS receivers. These comparison data show that an implementation of DET as described in [Blunt 2007] is not without some limitations, and this work shows how it is possible to produce in the DET a ‘false-lock’ condition that was previously not thought possible due to the two independent estimates. Several updates to the DET tracking architecture are herein proposed and tested, and with these additions, the DET can be made more robust to conditions that can severely disrupt operation of other techniques such as Bump-Jumping.

The mooring of vessels and other floating bodies at sea, such as offshore platforms has necessitated the development of specialised moorings technology. The marine renewable energy (MRE) sector is now at a stage in its development whereby floating devices are adding new challenges to the moorings industries. Floating MRE devices are smaller than, for instance offshore platforms, and are usually targeted for deployment in highly energetic environments. The extreme conditions and the highly dynamic response of an MRE device present challenges in terms of peak loading within the mooring system itself and load transfer to the floating body. Compliant mooring systems provide advantages by reducing the peak loads and fibre ropes are an important asset in achieving such compliance. However, the extent to which existing fibre ropes can safely extend axially to provide compliance is insufficient and is strongly associated to the minimum breaking load (MBL) of the rope. A novel fibre rope mooring tether is presented here that provides advantages over existing ropes. The tether employs a hollow fibre rope containing an elastomeric core, this mechanism de-coupling the extension properties from the strength of the line. The load path is carried through the polyester rope which is terminated conventionally by eye splices, thus minimising any new risks to reliability. Very low axial stiffness is achieved and is shown to be selectable within limits. For comparison, the prototype tether’s MBL of 222 kN is assigned to polyester and Nylon reference ropes. The axial stiifness of these ropes are 590 kN and 463 kN respectively when measured by a secant between the origin and 30% MBL; the novel tether displays an axial stiffness of 72 kN by the same method. This enables the novel tether to achieve more than two and a half times the extension of a comparable Nylon rope in its working range. Numerical modelling of a moored installation demonstrates a threefold reduction in peak load magnitude compared to the existing Nylon rope solution. The tether exhibits two distinct stages of extension, the first having very low axial stiffness. It is demonstrated that the extent of this soft phase can be selected by design and that this might add another useful element of control to moorings design work.

This present thesis investigates the accidental load of ship collision and grounding performances. To achieve this objective the thesis is composed of several main tasks. The main tasks comprise the rupture prediction, validation of material failure, ship grounding analysis and ship collision analysis. To predict material rupture, FLD material failure was used and validated with available experimental and FEA data. The FLD was extended to established material failure scaling laws which consider onset failure at plane strain in relation to mesh sizes. This was accomplished by running mesh convergence studies at different mesh sizes and at different FLD0. The linear material damage evolution is adopted in this case until the convergence results were satisfied. The material damage was used for all of further analysis in ship collision and grounding and employed mild steel and high tensile steel material properties. The ship grounding structure damage was investigated by deploying conical rocks at different locations of the ship's double bottom structure. The analysis focused on vertical penetration and horizontal penetration which contributed to significant damage to the structure. The ship collision analysis was investigated in various types of structures arrangement and diverse ship striking scenarios to penetrate struck ship and collide rigid wall. Furthermore, the prediction of ship collision and grounding were extended by using simplified approaches that were capable to predict ship collision to rigid wall, rigid body striking ship collided with deformable struck ship and deformable collision of striking and struck ship. Finally, this substantial amount of research work achieved the objectives of the study when the results of accidental load were validated and correlate well with experimental, empirical and FEA simulations at more than a satisfactory level.

A methodology for the assessment of global wave load combinations on a container ship is developed taking into account load modelling uncertainties such as the sea state, the speed with and direction in which the ship travels etc. Data from wave statistics are used to determine the sea state which is required for specifying the sea spectrum associated with a given sea state. The sea spectrum together with the response amplitude operators (RAOs) of the ship are used to determine the stochastic responses of the ship in waves. This load combination methodology employs stochastic analysis in conjunction with cross-spectral analysis to determine a given wave-induced load that is associated with a principal wave-induced load which have been determined a priori via common spectral methods. All the global wave-induced loads are assumed to be random variables that are Gaussian distributions with zero means and variances obtained from their respective zeroth spectral moments. The peaks of the responses are modelled as Rayleigh distributions and the combination of any two responses modelled by a copula function which is a bivariate Rayleigh distribution with parameters such as the zeroth spectral moments of the responses concerned and their interactions in form of a correlation parameter obtained via a cross-spectral analysis of the given responses. Load combinations are obtained with respect to any given design extreme global wave-induced load as the principal load whose effects may be a source for concern at the design stage of the ship. The results were compared to results obtained from existing methods of load combinations. A Spearman’s rank correlation test shows a very good covariation between the compared methods. Nonlinear finite element modelling and analyses on the midship section of a 10,000 TEU container ship are used to assess its ultimate strength under combined loads such as the vertical bending moment, horizontal bending moment and torsional moment. The primary loads that act on an actual ship hull girder are of different modes corresponding to the six degrees of freedom hence it is more realistic to consider the ii E. Alfred Mohammed effects of loads in other modes other than the dominant vertical bending moment in the determination of the longitudinal strength of the hull girder. Torsional moment is particularly important because it can be a serious problem for container ships which have wide open hatches and hence low torsional rigidity. A three-compartment finite element model for the container ship OL185 is developed from the transverse section detail of the ship. A progressive collapse analyses are performed on it using the Abaqus finite element code to determine the ultimate strength of the container ship under combined vertical bending, horizontal bending and torsional moments. These provide a basis for load interaction and combination studies via interaction relationships featuring the relevant load combinations. Finally, the interaction relationships are used to show the hull girder safety margin via a comparison with a predetermined global wave-induced load combination for the midship section of OL185 container ship obtained using the cross-spectral probabilistic methodology.

The phenomenon of low cycle fatigue (LCF) is characterised by high stress range, close to or above yield, and relatively low number of cycles to failure, typically below 104. In the case of tankers and Floating, Production, Storage and Offloading units (FPSO), nominal stress amplitudes lower than the yield stress may result in plastic strains due to the high stress concentrations that are typical in many of the hulls’ structural details. FPSOs are more susceptible to damage due to LCF compared to tankers, cargo and other ocean going ships. The main reasons are; the unique structure of FPSO in terms of the presence of internal turret and topsides load which affects the structural response of FPSO to dynamic and quasi-static loads, the frequent loading and unloading patterns of FPSO (i.e. unlike oil tankers which are either in full load or ballast condition) which causes the FPSO to experience the maximum hogging and sagging still water bending moment every single cycle and the condition of the sea at which the FPSO is operating (site specific environment) where even benign condition may subject the FPSO to extremely diverse wave induced loads. An increasing number of FPSOs are being used in the oil and gas industry due to the practical advantages they offer as compared to fixed installations, however, many FPSO show signs of cracks at critical locations in the first five years of service. It is believed that this is primarily due to LCF. It is therefore imperative to address LCF at the design stage. Finite Element Analysis (FEA) has been used to demonstrate that extremely high stress levels, exceeding three times the yield stress of the material, may occur at some critical locations during FPSO operations. Due to this ‘new’ form of damage in ship structures classification societies, shipyards and other organizations are addressing the issue of LCF by issuing various guidance notes and recommended practices in order to assess the damage due to LCF. This research contains a very extensive and useful literature review of the state-of-theart in LCF assessment methods available in literature and various class societies. Representative operational loading conditions (most onerous) have been presented for LCF Assessment of FPSO. LCF tests of typical longitudinal attachment were performed. This important structural element is seldom tested compared to the transverse attachment or cruciform. Experimental and numerical results compare well. A novel method of predicting LCF life has been proposed and a new S-N curve is proposed to be used for LCF assessment.

With world shipping and other maritime based industries tending to operate assets requiring a large capital investment representing over half the total operating cost of the vessel, considering life extension at the end of a structure’s design life can postpone further capital investment and reduce the yearly operating costs of a particular asset for the owner. Despite this experience the concept of asset life extension for continued use once design life is exceeded is one which has been covered in very limited detail in the academic community. In more recent years the concept of asset life extension has become important to a growing number of maritime industries and as such has become an industry lead area for investigation, with the lead being taken by the Health and Safety Executive in the UK and other regulatory bodies abroad. The work presented here describes the investigations into life extension assessment of assets, with a special focus on the Severn class lifeboat fleet owned by the RNLI, who wish to assess the potential for life extension of this fleet to enable the continued use of a successful asset and offset a £120 million replacement program. The vessels themselves are a monolithic stiffened composite construction with a design life of 25 years. A methodology is devised which uses material static and fatigue data, environmental conditions and structural response data to determine the expected useful life of a composite structure. This methodology is then applied to the Severn class fleet by conducting experiments to determine the fatigue life of the materials through coupon tests, understanding the environmental conditions and the errors involved in predicting them and carrying out measurements of the structural response of a Severn class lifeboat whilst in service. Combining these variables using Monte Carlo simulations and the Miner’s rule allows an estimate of the useful life of the asset to be made.

This PhD thesis presents the development of a practical computational tool named Large Amplitude RESponse (LARes), based on 3D quasi-non-linear time-domain technique, to predict ship motions and loads in large amplitude waves which can be accessible to ship designers. Firstly, a linear 3-D Green source panel code (LARes L1) was developed to perform linear time-domain analysis ship motion and internal load simulations based on the frequency-domain hydrodynamic coefficients which were calculated in the linear PRECAL software. Linear simulations are validated with the linear time-domain PRETTI software results using rectangular barge geometry. The motions, internal loads, global and sectional hydrodynamic forces were agreed well with the linear PRETTI model results in zero and forward speed simulations. Then, non-linear time-domain panel code (LARes L2) was developed in order to predict ship motions and loads in large amplitude waves using the Froude-Krylov nonlinearity level. At each time step, the exact wetted area of the ship surface under the wave profile was calculated and fed in the time-domain motion and load equations while the diffraction and radiation forces were kept as linear. The present program achieved good agreement with the non-linear PRETTI model results both for the barge and S175 container geometries at zero and forward speed conditions in small amplitude waves. Moreover, the S175 container ship results are compared with the available experimental data and agreed well with the experimental results in forward speed case. It has been observed that PRETTI code is over-estimating motion and load responses especially around the resonant frequency due to the surge motion influence in the memory forces evaluations. In the Froude-Krylov nonlinear level predictions, it has been observed that PRETTI diverges from the experimental results when the wave steepness is higher than 0.08 due to the linear radiation and diffraction forces. Based on the same framework, a more advanced nonlinear time-domain panel code (LARes L3) was developed in order to investigate the effects of quasi-non-linear diffraction and radiation forces in large amplitude ship simulations. A new mesh generator was introduced in order to cut and correct the original panels under the still water level in the updated position of the ship after displacements and rotations. The quasi-non-linear diffraction and radiation forces were calculated at the pre-defined position cases and stored in a database. In order to lower the computational cost multi-dimensional integration and interpolation codes were generated. The S-175 containership was tested in 120 different position cases and resulting hydrodynamic coefficients and forces were stored in the database. The results of the LARes L3 model were compared with the available experimental data using the S-175 containership in forward speed. The computed motion responses showed a good agreement with the experimental data. Moreover, three of the developed models are compared with the experiments and their performances were investigated with respect to the increasing wave slope. In addition to that, the effect of the wave length and ship speed in large amplitude waves are investigated in detail. Non-linear behaviors of the codes were compared with the experimental results which showed a good agreement. Finally, the Vertical Shear Force (VSF) and Vertical Bending Moment (VBM) responses were investigated in large amplitude motions. It was observed that, in the validation section, numerical model peak amplitudes showed well agreement with the experimental results, but they were observed to be shifted to the higher frequencies compared to the experimental results. The reason for that was attributed to the longitudinal mass distribution on the ship in the experimental setup which had not been provided in detail in the published experimental results.

In this research, mathematical formulations for the dynamics of raising sunken vessels using buoyant systems are developed in a form which is suitable for integrating control techniques to ensure both hydrodynamic and structural stability for a safe and stable salvaging operation based on both rigid body modeling and flexible body modeling concepts. Due to the coupled nature of salvage dynamics and for integrating controller techniques, the mathematical modeling is carried out as two subsystems. In the primary model, the salvage dynamics is formulated in such a way that the variation in additional buoyancy due to flow rate of filling gas inside the lift bags is the controlling force with respect to hydrostatic force due to weight, buoyancy and suction break out, hydrodynamic forces and uncertainty arises due to any external disturbances. In the secondary model, the purging of gas through the valves is taken as the control parameter by accounting the excess buoyancy available after suction break out and to the variation in pressure difference between gas inside lift bag and surrounding sea water pressure for a stable ascent. According to the simplified two-degree-of-freedom equations of rigid-body vessel motion, a state space model is developed for integrating the primary controller. Initially a proportional derivative (PD) controller is selected as the primary controller for regulating the flow rate of filling gas inside the lift bags according to the buoyancy requirement and extended to other classic controllers like proportional integral and derivative (PID) controller and sliding mode controller (SMC) for improving the performance. Numerical simulations are carried out in MATLAB & SIMULINK by solving the standard State Dependent Ricatti Equation in a body-fixed coordinate reference frame. Preliminary results in terms of coordinate positions or trajectories, linear and angular velocity components of the raising body are evaluated based on an experimental pontoon model. A number of case studies are carried out for different target depths with the developed linear state space model including sensitivity analysis such as change in hydrodynamic coefficients, breakout lift force and the effect of external disturbances and uncertainty. SMC is found to be the optimum choice among these conventional controllers by satisfying the Lyapunov stability condition even for higher water depths with system robustness and capability to handle parameter variations, external disturbances and uncertainty. The tuning effort and chattering were found to be the two major draw backs of conventional sliding mode controller (CSMC), which is improved by integrating it with artificial intelligence such as fuzzy logic controller to bring together the advantages of both controllers to become fuzzy sliding mode controllers (FSMCs). In FSMCs, the performance of the CSMC is improved by dynamically computing the sliding surface slope by a FLC and adaptively computing the controller gain by another FLC. FLCs are designed using MATLAB's fuzzy logic interface based on Mamdani's implification method the combined models will be developed in SIMULINK. A two input fuzzy sliding mode controller (TIFSMC) is designed first and later simplified to single input fuzzy sliding mode controller (SIFSMC), for reducing the tuning effort and computational time. With the development of SIFSMC, the tuning process becomes standardized and hassle free and hence the well known chattering problem associated with SMCs is avoided. The comparative performance of the fuzzy sliding mode controllers over CSMC has been investigated by performing numerical simulations on the pontoon model. It is found that both FSMCs show 30% of improvement in the tracking performance when compared to the CSMC, while maintaining its robustness. It is also noted that FSMCs are less sensitive to external disturbances and uncertainties in comparison with CSMC. The responses obtained by the SIFSMC are the same as those obtained by the TIFSMC, with the former involving a much less tuning effort and computational time. Simulation studies reveals the fact that for complicated non linear underwater operations like marine salvage involving uncertainty and external disturbances, a closed loop control system is mandatory and an adaptive controller like SIFSMC is the optimum choice as the primary controller for regulating the gas flow rate. Purge valve modeling is carried out according to the excess buoyancy available after suction breakout and to the variation in pressure difference between gas inside the lift bags and surrounding sea water for a stable ascent.

Working at sea has traditionally been perceived by society as an arduous but rewarding occupation. Competitive markets, minimal manning and an increase in the prevalence of technology have led to the profession of a seafarer evolving from being focused on skills of a physical nature to those requiring an increased cognitive approach. This has resulted in human performance and wellbeing becoming more significant in securing the health and safety of the individual, and the safety and efficiency of the system. The impact of noise on human performance and wellbeing is an area which has not been appropriately addressed in the maritime domain but has been attributed in literature to hearing loss, fatigue, performance reduction, stress and ultimately accidents. In this thesis, through a review of literature, an assessment of noise exposure levels of crew on board ships, an experimental study measuring performance in relation to noise and the collection and analysis of real human response data from ships; statistical models for predicting human response to noise on board ships have been developed. Then, through utilisation of the human response models a new human oriented noise criteria and design methodology is proposed. In this body of research the main findings include: the strong suggestion that health is at risk due to noise on board ships; evidence that human performance is being affected by background noise levels and; the establishment of a statistically significant relationship which predicts noise in relation to performance. It is envisaged that this research will be utilised by ship designers in estimating the human response to noise at the design stage. Overall, this research has made a significant contribution in addressing the effects of noise on human performance and wellbeing in the maritime domain. In future research it is anticipated that the findings of this research can be combined with the other factors affecting human response on board ships.

Sustainable and efficient provision of shipboard energy is an obvious challenge for the merchant marine industry. Various initiatives have been made to find alternatives to replace the currently used combustion engine for ship power and propulsion. In recent years, fuel cell technology, as has been widely advertised as a clean and efficient means of power generation, is drawing much attention from the marine industry. Among various types of fuel cells, the Solid Oxide Fuel Cell (SOFC) tops others in terms of energy conversion efficiency as it can be fed with both hydrogen rich fuels and traditional fossil fuels after being chemically reformed. These features make it most promising to meet the large power demands of seagoing ships. However, due to the comprehensive and hazardous working environment, shipboard installation of SOFC power systems is not available. Can the SOFC be a viable proposition for commercial shipping and how will it behave under severe seagoing circumstances? These questions need to be addressed before commercialising SOFC marine power systems. In the thesis, simulation methods are used to predict the performance of marine SOFC systems at both static and dynamic working loads. A mathematical model is developed for describing the thermodynamic nature of a tubular SOFC concerning the thermal equilibrium of the system. Electric-chemical reactions are reflected in the stack modelling. Reforming reactions of the fuel are included in the model. Auxiliary subcomponents within the SOFC power system are modelled based on their own mechanisms and working principles. The whole simulation system is composed by combining subcomponent models via reasonable control strategies to function the system's purpose. SOFC power system models are developed to represent different working scenarios which may possibly occur onboard ship. The dynamic responses of simulation systems are examined. Thermal flow transfer influence, manifold volume influence and controller 's influence are also taken into account in the dynamic modelling process. As concluded from the simulation outcomes, the sample SOFC system, while running alone, could satisfy the demand of dynamic load change for both propulsion and auxiliary power. However, the electric output of the SOFC system would be greatly smoothed if paralleled with a battery. In addition, risk and safety issues regarding SOFC onboard installation are examined from both design and operating perspectives. Relevant ship rules and regulations for verifications of system installation and maintenance are reviewed in detail. Conceptual design of marine SOFC application are also proposed at the last stage.

This thesis presents the development and application of a numerical method that associates the Rankine source method with double Doppler shift to predict the hydrodynamic interactions between two ships travelling or stationary in shallow waters. Firstly, a 3-D Rankine source panel method was developed to predict the hydrodynamic properties of a single ship travelling with a wide range of forward speeds. Double Doppler shift was taken into consideration in the boundary condition of the control surface. A Wigley III hull travelling with different forward speeds was considered to validate this radiation condition. Comparing with the experimental data, both the hydrodynamic coefficients and motion responses were well predicted by the present method. Then, the method for single ship was extended to ship-to-ship without forward speed problem. Comparing the present calculations of the hydrodynamic coefficients, wave excitation forces and motion responses with the experimental data, as well as with the numerical results from Green function method, a very good agreement was achieved which illustrated that the present program was a useful tool to predict the hydrodynamic behaviours of two ships arranged side by side without forward speed. The effects of mooring and fender system were also discussed based on the linear assumption. Based on the same framework, the 3-D Rankine source panel method associated with double Doppler shift was applied to ship-to-ship interaction with forward speed problem. The validations were established through two pairs of models. The computed dynamic responses of both models in heave and pitch motions showed a good agreement with the published experimental results. However, the prediction of the roll motion was full of challenges due to the inviscid assumption in the potential flow theory. The comparison between the present and Sommerfeld radiation condition was made at τ< 0.25, while the comparison between the present and upstream radiation treatment was made at τ> 0.25. It was shown that the present treatment could obtain a better wave pattern without reflections from the truncated control surface, which confirmed the effectiveness of the present radiation condition as a wave-pattern prediction tool for the ships travelling with a wide range of forward speed. After the validations of the present method, the parametric study about the forward speed and configurations was carried out in order to develop recommendations for ship designers and operators for maximum speed and distance between two ships in given environmental conditions for safe operation. The analytical expression of the semi-wedge angle based on double Doppler shift theory was derived to obtain the wake and quiescent region of the free surface. Based on the semi-wedge angle, the analytical formulation was established to obtain the optimal transvers distance between two travelling ships.

This research looks at moisture uptake and its effects on the flexural properties of glass reinforced epoxy, linseed oil and castor oil composites. Water uptake damages the material through chemical, physical and mechanical ageing. At the same time there is a need to reduce the environmental effects of the maritime industry and using composites from renewable resources could be a viable solution. While the conventional composites like glass/epoxy are trusted as a structural material in harsh humid conditions, there is very little known about more sustainable composite materials. As resins have a greater environmental impact when manufactured, and no information on their long term performance is available, this research looks at the flexural performance of glass reinforced castor and linseed oil resins over 2 years of ageing in comparison with glass/epoxy. As a result of accelerated ageing it has been shown that the degradation of all three composites is significant, ranging between 18{87% over the 2 year testing period. The moisture equilibrium content in glass/epoxy was 2.11%, glass/castor oil 3.62% and glass/linseed oil 2.87%. While the moisture uptake of glass/epoxy follows an expected trend, the moisture uptake of plant oil based resin composites does not and differs from conventional models. After 2 years of ageing the properties of glass/castor oil are comparable with glass/epoxy. The degradation of properties in glass/linseed oil is the greatest. MicroCT and AE techniques were used to look at the failure modes in glass/epoxy and glass/linseed oil specimens showing changes in the failure mode of glass/linseed oil only after 3 days of ageing. The failure modes of glass/epoxy were found to be mainly fibre dominated and most of the damage occurred on the tensile side of the specimens while the failure in glass/linseed oil was largely dominated by compressive damage. For the first time the failure mechanisms of glass/linseed oil have been proposed.

Steady ship motion in calm water is a classical problem in ship hydrodynamics. Potential flow modelling is a common method to predict the wave resistance of ships. In its conventional form the flow is assumed to be free from damping due to the inviscid assumption of potential flow. It has been argued by the founding fathers of ship resistance predictions that damping plays an important role in determining the wave resistance. Despite this viscosity is often omitted from present wave resistance prediction methods. It is known that damping plays an important role in the formation of the wave pattern and it is therefore of interest to determine the effect on the resistance prediction by including a damping factor in a previously undampened model. In this study, the problem is modelled using Kelvin sources with a translating speed. The fluid flow is modelled using a linearised free surface condition but an exact body condition on the hull. Rayleigh damping is introduced in the model to emulate viscous damping. To calculate the source influences, a new dissipative 3D Green function is derived. The image source part of Green function is separated into the near field and far field disturbance to achieve fast convergence of the integrals. The method is evaluated using thin ship theory to determine the wave pattern behind and the wave profile along a Wigley hull. A panel method is used to determine the wave and residual resistance for submerged ellipsoids and spheres. The results are validated and compared to existing numerical and experimental data from other sources. The results show that it may be possible to capture the residual resistance by including damping in a potential flow model but that more evaluations are needed.

This thesis looks at the use of wood in boatbuilding in the Red Sea from classical antiquity until present times. It draws on primary sources and archaeological evidence from the Graeco-Roman period extending from the 8th century BC to the eve of Islam in the 7th century AD, and from the medieval Islamic period stretching from the 7th century AD to the 15th century AD. In doing so, it seeks to shed the light on timber trade and the timber exploitation processes; and examine how these were interlinked with the geopolitics and socio-economics of the time. It then portrays the Red Sea areas not only as wood importers from a wide array of regions such as the Mediterranean, East Africa, and South Asia, but also as beneficiaries of local wood resources for their boatbuilding needs. In that respect, it stresses that little attention has been given to the exploitation of local woods in favour of a greater reliance on Indian timber, and more specifically on teak. Thus, it suggests the need to consider other timber species than teak which were equally suitable for shipwrightry, as well as other western Indian Ocean wood providers. To illuminate and colour past interpretations of the subject, in addition to document a vanishing craftsmanship, this thesis has drawn on ethnographic research in Egypt, Sudan, Eritrea, Djibouti, Saudi Arabia and Yemen. The ethnographic enquiry focused on the types of timber used in boatbuilding in the Red Sea and their vernacular names, the timber exploitation processes, and the factors and variables that come play in the metamorphosis of a tree into a boat part. Finally, by interlinking diverse pathways of enquiry drawing on primary sources, archaeology and ethnography, this thesis aims to provide the field of maritime culture and maritime archaeology a deeper understanding of wooden boatbuilding in the Red Sea.

This dissertation examines ancient anchoring practice in the Mediterranean through ca. 1500 CE, as well as the history and technological developments of iron anchors, which are among the most important tools inherited from the ancient world. The methodology employed is holistic in synthesizing archaeological finds, textual, and iconographic evidence, and includes statistical and geographical analysis based on a substantial catalogue of ancient anchor finds. An experimental project is also included where anchor reconstructions were used in the sea and their utility tested. Mooring is one of the least studied aspects of everyday life for the people of the ancient Mediterranean. It has been elucidated that in most circumstances beaching would not have been a practical option, even for warships and the smallest cargo vessels. Rather, vessels were equipped with specialized gear for mooring off or near undeveloped shores. This included ship's boats enabling access to the shore. Lower draft vessels, particularly galleys, could approach unbuilt shores and employ mooring stakes and cables, and the ship's landing-ladder would be deployed into shallow water. Where available, however, ships would benefit from built quays which facilitated goods transport. The iron stock-anchor displays the greatest longevity of any anchoring tool, evinced as early as the 5th c. BCE, and appears to have achieved dominance over wooden types by the 3rd c. CE. From its conception the iron-stock anchor undergoes a broad range of gradual changes to its form and features. The earliest known finds take a 'V' form in the bulk-arms and gradually develop through rounded to 'T' and 'Y' forms in the Byzantine Period. The stocks evolve from removable iron types, to permanent forms entirely of wood. Reintroduction of upward-oriented arm designs from northern Europe around the 13th c. CE, and incorporation of hydraulic mechanized smithing developments, heralded a revolution of anchoring technology. Larger, stronger and more efficient anchors were being produced to standardized dimensions and quality, promoting larger ships, and ultimately resulting in novel characteristics of navigation.

Floating production storage and offloading systems, otherwise known as FPSOs in the oil and gas industry, are high risk structures because of their exposure to hazardous and flammable hydrocarbons which they carry and in some situations, because of their vulnerability to terrorist attack especially in their areas of operation. These structures have been widely used for the development of offshore oil and gas fields all over the world, especially in most part of Africa, because of their attractive features such as large work area and storage capacity, relative lower cost of construction and good stability. They are either converted from existing tankers or bulk carriers or purposely built. However the recent wave of terrorism across the Nigerian Niger Delta has necessitated the study for the need for offshore structures especially FPSO to be protected from the activities of terrorist. One of the worst case scenarios that is likely to occur on an FPSO is an attack by terrorist resulting in an above water external air blast on the side plate of a midship section of an FPSO. The resulting damage effects that would be caused by this form of attack can be devastating in terms of loss of revenue to a nation, loss of life, assets and degradation to the local environment. This was tragically demonstrated in the North Sea with the loss of the Piper Alpha Platform mentioned by (lees, 1996), albeit initiated by an accidental internal blast, unrelated to terrorist activities. At present, most design methods on the midshipsection structural members of a merchant vessel are based on working stress design concepts that are safe and suitable for normal pre-commissioning and operating conditions and which emphasize the minimum acceptable requirement for the classification society. However, design under extreme air blast loading especially those typical of terrorist/Militant attack, whose magnitude would be far higher than ordinary operating load, are desirable. In order to make it a major design consideration, this study addressed this issue on minimizing the effects of blast overpressure through the evaluation of the 3 types of T stiffeners and 3 L stiffeners to local structural response of such blast pressure on the side shell of the midshipsection of a typical FPSO code named FPSO Nigeria. The Nigerian Niger Delta accounts for over 95% of Nigerian oil and foreign reserve earning, and has been a source of attack and insurgence by militant of the Niger Delta. The objective of this study is to examine an above water air blast pressure attack to the side plate of a midshipsection of an FPSO code named FPSO Nigeria. This blast pressure is converted to an equivalent amount of TNT explosive typical to that which may be used by the militants of the Nigeria Niger delta or other parts of the world and to v KAZEEM SHITTU-An Investigation Of The Response OF AN FPSOVStructure To External Blast: A Case Study Of FPSOV Operating In The Niger Delta recommend ways by which an FPSO operating in this area could be made more resilient to terrorist attack to a larger extent or at least to minimize terrorist caused damage to the barest minimum by the selection of the best of the 3 types of T and L stiffeners considered. Additionally, blast resistant anti-ballistic material was recommended and a cost benefit analysis carried out in order to justify the need and the importance of using such blast resistance anti-ballistic materials. In order to achieve the aim of the thesis, the study commenced with the investigation of the displacement and stresses of plates and stiffened plates using Abaqus software code and compared the results of displacement and stresses generated from Abaqus with that of classical theory in order to validate the accuracy of the Software code by considering different plate thickness and boundary conditions, frequency extraction analysis were generated for plates and stiffened plates in order to obtain frequencies at which resonance could occur and to prevent such. The results generated from Abaqus software code were found to correlates with those generated from classical theory. Actual FPSO Nigeria stiffened panel were then considered and subjected to non-linear blast analysis under different boundary conditions where effects of mesh refinement were considered in details. The mid ship section of the above water side of the FPSO Nigeria was then subjected to blast pressure attack considering the different type of stiffeners with a view to determine the best stiffener configuration and to determine the rupture strain consequently an anti-ballistic blast resistant material was recommended as an aftermath of Cost Benefit analysis was carried out to validate the need for such anti-ballistic blast resistance material on the above water side of FPSOs operating in the Nigeria Niger Delta and the cost savings to nigerian Government was highlighted vis a vis the loss that would have been incurred by the Government should such attack occurs. The research concentrates mainly on developing an appropriate methodology and an illustrating the behavior of typical ship structures to high rate transient air blast loading effects, rather than undertaking a specific detail design study as such. Consequently the research has made modest contribution to knowledge by the determination of all of the above including the cost benefit analysis carried out.

In this thesis, an approach into the applicability of Large Eddy Simulation (LES) and Detached Eddy Simulation (DES) for the prediction of forces and flow around marine bodies at high Reynolds number is presented. The main aim of the thesis was to investigate and assess the use of LES and DES based computational fluid dynamics applications as a tool for hydrodynamic prediction. A methodology for addressing the problem was followed based on mathematical models and numerical solutions translated into a three-dimensional commercial Computational Fluid Dynamics (CFD) code. Meshing strategy involved the use of adapted unstructured meshes with local refinement around key areas of the bodies. The CFD models based on LES and DES are validated against experimental measurements for three different bodies: a NACA 0012 section trefoil, a 6:1 prolate spheroid at angles of incidence and an assymetric America's Cup yacht keel. Quantitative comparisons included predictions of values of global force coefficients around the geometrics, pressure and friction coefficients on the surface, and wake analysis. Qualitative observation focused on flow generation near the bodies such as separation, velocity vectors. However, it is necessary to examine the problem further to have full confidence in their capabilities when applied to yacht hydrodynamics and more challenging flows.

Marine renewable energy sources are crucial alternatives for a sustainable development. The idea of generating electrical power from water waves has been realized for many years. In fact, waves are now considered as an ideal renewable energy source since a Wave Energy Converter (WEC) has no fuel cost and provides cleanly a high power density that is available most of the time. The third generation of WECs is intended to be installed offshore. This allows the device to harvest the great energy content of waves found in deep water and minimise the environmental impacts of the device. On the other hand, moving WECs to offshore locations will increase the initial and maintenance costs. So many types of device may be suggested for wave power extraction that the task of selecting a particular one is made complicated. Therefore modelling of different WECs allows the comparison between them and the selection of the optimum choice. Recent studies showed that the SparBuoy Oscillat ing Water Column (OWC) has the advantage of being simple, axi-symmetrical, and equally efficient at capturing energy from all directions, but its efficiency (capture factor) is affected significantly by the incident wave periods variation due to the dynamic coupling of the water column and the floating structure. The proper modelling of the device allows the optimization of the geometries and the Power Take-Off (PTO) mechanism in order to maximise the power absorbed. The main objective of this research is to develop experimentally validated numerical wave power prediction tool for offshore SparBuoy OWC WEC. The numerical tool should be able to predict the spar motions and the water column oscillations inside the structure, in addition to the estimation of the pneumatic power absorber and the evaluation of the device performance. Three uncoupled linear second order differential equations have been used to predict the spar surge, heave and pitch motions, where wave forces have been calculated. Three uncoupled linear second order differential equations have been used to predict the spar surge, heave and pitch motions, where wave forces ha ve been calculatedanalytically in frequency domain in inertia and diffraction regimes. Mooring system has been involved in surge motion only using static and quasi-static modelling approaches. Finite element multi-static model have been developed using OrcaFlex to validate the analytical results. Single Degree of Freedom (DOF) mechanical oscillation model has been presented to simulate the water column oscillations inside captive cylindrical OWC where PTO damping and stiffness due to air compressibility inside the pneumatic chamber have been taken into account linearly. Later on, nonlinearity due to large waves has been investigated. Linearized frequency domain model based on classical perturbation theory and nonlinear model where wave forces are calculated in time domain have been proposed. Furthermore, nonlinearity due to damping forces has been considered. First, iterative procedure has been used to optimise the linear and quadratic damping coefficients in frequency domain. Then, another model has been provided where equivalent viscous damping coefficients are calculated in time domain by taking into consideration the instant oscillation amplitude. Finally the nonlinear effects due to air compressibility inside the OWC chamber has been considered in a time domain model which include the water column oscillations amplitudes. Two different dynamic models have been implemented to describe floating OWC and will be referred to in the text as simplified 2DOF model and Szumko model. Both models considered two translational modes of motions in heave direction. Simplified 2DOF model has been solved analytically in frequency domain due to its simplicity, while numerical solutions in time domain have been provided for both models using Matlab. Different approaches have been adopted to modify both models in order to obtain a satisfactory agreement between the predicted and measured results. A floating platform consists of four similar SparBuoy OWC WECs rigidly attached together by trusses where spars are located at the corners have been tested experimentally. Numerical model has been developed to predict the platform motions. Finally the experimentalresults have been compared to those obtained from the modelling of single SparBuoy OWC.

Smart Materials have been investigated for decades and widely used in the automotive and aeronautics industries to measure and control noise and vibration. This study covered ship structure vibration and Smart Materials were employed for the purpose of ship vibration attenuation. One specific Smart Material, piezoelectric material, was the focus of the study. Although previous research has been conducted on vibration mitigation employing piezoelectric shunt systems, this study identified the need for specific applications regarding ship vibration mitigation. Passive piezoelectric shunt damping systems for ships were described and investigated in this study. Computational methods were used to investigate structural vibration of a cantilever beam, a Liquid Natural Gas (LNG) carrier and a bulb keel. The Finite Element Method (FEM) was used to calculate the vibration and vibration treatment with the passive piezoelectric shunt damping system. The numerical results of the passive piezoelectric shunt system bonded to the cantilever beam were compared to experimental results obtained from a previous study. The FEM delivered results, which showed a high degree of similarity in comparison to the experimental results. Both experimental and numerical studies validate the theory that piezoelectric material, connected to an electrical circuit, can be successfully used to achieve vibration reduction. Significant vibration attenuation was found in the numerical simulation of the LNG vessel. The simulation of the bulb keel also provided promising outcome regarding substantial vibration reduction by means of piezoelectric shunt system.

In modern marine structural design, the fatigue life and fracture prediction of local connection details of the vessel is necessary. The traditional empirical rules or numerical work has considerably advanced the qualitative and quantitative understanding of fatigue and fracture analysis. Compared with the existing methods, this thesis explores a novel geometric methodology to evaluate the stress intensity and stress concentration factors (SIF and SCF). The background and special theory was developed to give: 1. A better understanding of the singularities that commonly occur in sharp corners in ship connection details; 2. A quicker method for fatigue life estimation than present methods based on finite element analysis and/or detail classes. 3. A prediction of the stress fields so that more appropriate and reliable finite element meshes can be selected When dealing with the influence of each connection detail, a "Length Scale" estimated from the dimensions of the connection detail. This Length Scale can be converted into a Hot Spot Stress Concentration Factor for SN based fatigue calculations or used with (often simply added to) the real crack length to determine, in conjunction with a constant Y value (commonly 1.1) a Stress Intensity Factor for linear elastic fracture mechanics crack growth calculations. The method is useful both for assessment of existing structures and for design application. The thesis includes a comparison of the results from the application of this new methodology and existing fatigue analysis guidance. Within the thesis the methodology is described together with relevant conclusions.

A finite element model that is capable of simulating the thermo-mechanical welding process was developed by using full thermal-elasto-plastic computational analysis and validated by comparison with experimental data. It shows that distortions predicted by the finite element model agree well with measured data from previous literature and that the numerically obtained residual stress distribution is compared and agreed by both ANSYS and VrWeld software. After that, a simple method for predicting butt-welding residual stresses based on force and moment equilibrium was derived in this section. The results calculated from this simple method were a good match with the FE results. Then the author performed detailed analysis for the distribution of transverse and longitudinal residual stresses of 2D butt welding process by using 3D elements, which illustrated how the butt-welding residual stresses were distributed and accumulated during the welding process and how the boundary conditions affect the final results. A detailed parametric study for butt welding residual stresses based on 2D butt-welding by using 3D element was demonstrated. The factors carried out in the parametric study involved cut-off temperature effect, welding power effect, welding velocity effect, plate length effect and plate width effect. Lastly, the author also presented a simulation and an optimization of welding sequences for residual stress and distortion of a typical, fatigue sensitive, ship's side shell connection detail under different welding sequences.

The main aim of this work is to help the shipbuilder to effectively assess a ships' structural design for its vibratory behaviour. For that purpose state of the art structural modelling techniques are reviewed for the validity of their basic principles, accuracy, practicality and required computation time when applied on typical marine structures. Full finite element modelling has been applied on a part of the structure of an LNG carrier on board which the author has taken vibration and noise measurements. Also fixed interface (Craig-Bampton) and free interface (Rubin's method) component mode synthesis sub structuring techniques have been applied. The aim of the analysis is to evaluate the effectiveness of finite element modelling through evaluation with measurement results, evaluate the accuracy of the sub structuring modelling techniques and to identify short comings of any of the tested methods. Two alternative component synthesis modelling sub structuring techniques are proposed in order to reduce required computation time; Zoet's method and the Rubin Zoet method. The Zoet method is tested using a section of the LNG carrier's structural model. The method is evaluated for accuracy (comparing obtained results with the results obtained through the full harmonic finite element analysis) and required computation time through comparison with the required computation time for: - full harmonic analysis - the classical modal reduction and mode superposition technique - the classical Rubin free interface component mode synthesis - and Rubin's method with interface reduction according to the IRS method (see section 6.5.3) - the Rubin-Zoet technique.

Ship weather routing was first developed for determining the minimum time of a voyage. However, after 90's, driven by the increasing oil price and the environmental considerations, most shipping companies have began to show more and more interest in minimising fuel consumption in a route, in the meantime, maintaining a certain time schedule which is specified in the chartering contract of a merchant vessel. This topic is the focus of this thesis. A novel three dimensional dynamic programming method (3DDP) has been developed in this research to determine the optimised ship course and its corresponding engine power for minimum fuel consumption. During the optimisation process, Kwon's method as a new empirical formula is used to calculate ship speed in different weather conditions and an IMO guideline is applied to ensure ship safety during a voyage. In addition to the 3DDP method developed, three multi-objective evolutionary algorithms (MOEAs) are also proposed to treat we ather routing as a multi-objective and constrained optimisation problem. Based on ship hydrodynamic knowledge and optimisation algorithms an Intelligent Tool for Energy Efficient and low environment impact Shipping (ITEES) has been developed. ITEES is established by using the object-oriented software development theory, consisting of several independent functional modules. The OPeNDAP as an advanced communication technique is employed by ITEES for downloading deterministic weather forecast at no cost. Case studies are given in Chapter 8 of this thesis to evaluate the performance of the 3DDP method in a comparison with other different optimisation algorithms under different weather conditions. A 54,000 DWT container ship is used as the case ship. The case studies have demonstrated that, in medium sea condition, different route optimisation methods offer the similar results that the shortest route with a constant engine power brings the lowest fuel consumption. However, the results of different route optimisation methods vary significantly in rough sea states. Optimised results are not only just for fuel saving but also, most importantly, for ensuring ship safety during a voyage. Among the optimisation algorithms evaluated by the research, the 3DDP used in ITEES is able to give a better performance for fuel saving than other methods. In addition, it has the characteristics of using straight forward theory and less parameter settings compared with MOEAs that make the ITEES programme easy and convenient for operators to use.

This thesis aims to develop a decision support system for inspection and maintenance planning of ship hull structures considering the effects of repair activities performed during the different periodical inspection events through the service life of a ship. Because of the severe environmental conditions in which ships operate, their structure is continually subjected to fatigue and corrosion degradation and as a result of that their strength is reduced. Corrosion and fatigue cracking represent the most aggressive types of structural damage faced by ship structures, either of which, if not properly repaired or adjusted, can potentially lead to leakage, pollution, fire, critical failures or unanticipated out of service time and economic costs. For an economic design to be achieved, the ship structures need to be maintained during their life. Building a ship with enough safety margins so that repairs would not be required during its life would be uneconomical and not technically feasible. From the viewpoint of survey and inspection of ship hull structures, improvements in inspection planning, safety and reduction of maintenance costs are the most needed. These issues are addressed in the newly developed decision support system described in this thesis. Inspection planning may be based on experience (determined by Class Society guidelines), which generally treat all ships with the same inspection program or based on a risk-based maintenance planning program. In the first case, only some of the knowledge that could be used to predict structural problems, in the case of ship-to-ship variation (construction or use), is gained from the data gathered, while in the second case, risk based maintenance methods can deal with any individual structural component or with overall ship structural integrity. To bridge the gap between these two approaches, this thesis combines the knowledge gained from currently used practice in ship inspection and maintenance and from risk-based methods which have already been proven as a good practice in several industrial applications. The newly developed decision support system is employed to calibrate the results of prediction models based on the collected data. To assist in the prediction of structural degradation of ships, a new structural connections catalogue, an inspection oriented ship defects database and a calibration methodology for structural degradation prediction models are developed. The new system is designed to improve risk-based ship inspection and maintenance planning programs. Application of the newly developed system will benefit inspection companies, class surveyors, ship managers and ship designers by providing a mechanism for the calibration of risk based inspection planning activities. The decision support system developed in this thesis is inherently adaptable and can be applied to many other applications that require a cost effective maintenace, e.g. renewable energy devices, offshore platforms, machinery systems, large structures such as bridges and other transport systems.

An ocean going vessel, sailing in severe seas, experiences motions and loads that are largely affected by nonlinear phenomena. These effects deviate the responses from the linear prediction, modifying their magnitudes, symmetry and frequency characteristics. The change of the actual wetted geometry due to motions and large ambient waves elevation and the occurrence of impulsive phenomena, such as bottom impact, are some of the main sources of nonlinearities. Current state-of-art in seakeeping, applied to ship design, is based on the assumption of small amplitude motions and linearity between the excitation and the response. These techniques have been proved, during the years, to be reliable for small and moderate sea states, but they are not effective in large amplitude waves. The understanding and prediction of the behaviour of the vessel in rough seas is of crucial importance for its design, and therefore there is a need for better methods and practices. Application of nonlinear seakeeping methods in a every-day design situations is limited. The complexity and the computational cost of some methodologies, together with the absence of standardised procedures, are the main causes for the reduced use of such a methodologies. The work presented in this thesis aims to develop a practical nonlinear seakeeping approach that can be used in a design content to model wave induced motions and loads in large amplitude waves. The wave-body interaction problem is solved using a time domain nonlinear two dimensional approach, that considers the actual wetted hull portion and the relative velocity between the structure and the waves. The vessel is modelled as a flexible body to allow structural dynamics. The proposed formulation takes into account impulsive phenomena due to water impact, on both the bottom and the flare of the hull, using a combination of analytical and empirical techniques. The proposed methodology is applied to the S-175 and the Wils II 13,000 TEU container ships. The validation of the proposed method, conducted in both small and large amplitude regular waves, shows the capability of the technique to correctly predict the behaviour of the vessel also when linear methodologies fail. The analysis demonstrates the importance and the reliability of hydroelastic methods for the prediction of wave induced loads, especially when whipping is relevant. A procedure, which applies the proposed methodology for the evaluation of maximum expected values of wave induced motions and loads is presented. Long term analyses are conducted, using both linear and nonlinear method, to study the e ect of nonlinearities. The comparison between linear and nonlinear approaches shows an increase of maximum load responses when nonlinear hydroelasticity is applied. This study highlights also the dependency of the results on the selection of the return period and operational velocity profile of the vessel.

This thesis explores the history of the sea-going Marine Engineer in comparative perspective from the 1830's. It addresses the development and character of marine engineering and the status of those practicing it at sea in Britain, France and Germany from a disparate and temporary labour force of skilled craftsmen, into an identifiable occupation, and arguably a new profession. It aims to investigate the history of the sea- going marine engineer by exploring those four generic and interdependent themes which are key in occupational development; the function of the occupation, the prerequisites required of those wishing to be engaged in the occupation, the rewards available to the practitioners of the occupation, and the attempts at collective action by the members. By investigating how these themes have progressed from 1830, the thesis aims to construct an overall portrait of the development of the occupation, the status of those engaged in it, and the identity of the occupation and its members which was forged and emerged as a result in each national context. Firstly the thesis will examine the adoption and growth of steam in each of the national fleets, and the subsequent developments and application of both propulsive and auxiliary plant under the charge of the engineer at sea. In investigating the prerequisites of the occupation the thesis will explore the introduction of licensing for engineers at sea imposed upon the marine industry by civil authority in the mid-nineteenth century and the subsequent advent of formal education and training for engineers at sea, as well as the character this assumed. Thirdly the thesis will explore the changing level of monetary and material reward available to the marine engineer in exchange for his services, as well as his social position aboard ship. Finally, the thesis will examine the rise, development and significance of organisation by marine engineers in professional societies and trade unions, looking at the formation and work of these bodies and what they tell us about the aspirations of the members and development of the occupation. Ultimately the thesis will hope to make comment on the development of the market for marine engineers, and on their status as both officers at sea and professional engineers by 1914. This is in essence an occupational history in comparative context. The process by which the sea-going 'engine-man' became the Marine Engineer in Britain, the Mecanicien de la Marine Marchande became the Officier Mecanicien and aspired to become the Ingenieur Mecanicien in France, and the Seemaschinisten became the Schiffsingenieure in Germany contributes to wider literature on the rise of engineers in society since the industrialisation of Britain and Europe in the nineteenth century, and the development and status of technological professionals.

Interest in situation awareness (SA) originated in the 1980s primarily in aviation psychology and has since expanded to other areas where people interact with and control dynamic environments from nuclear power stations to driving cars. SA is important for those in control of dynamic systems, particularly those rich in information and is a precursor to decision making. SA is a psychological construct that is not directly observable, with no agreement regarding an operational definition. This research extends the field of interest to that of ships' officers who act as cargo control room operators and are responsible for the loading and discharging of bulk flammable, noxious and polluting liquids such as oil, chemicals and liquefied gases on tankers. It investigates the relationship between operators' SA and their task focus and operators' SA and their experience. The SAGAT methodology was adapted and a detailed task analysis resulted in a battery of probe questions which were administered in a high fidelity liquid cargo simulator to determine operator SA. It was hypothesised that SA for tasks which are the main focus of attention would be greatest and that operators with greater experience would achieve greater SA than those with less. Unexpectedly the results suggest that operators achieved tasks with limited SA. No relationship was established between SA and experience which may impact on methods of risk assessment used within the tanker chartering industry. Original contributions from the research outcomes show that marine control room operators experiencing high cognitive workloads achieved task goals while attending to a small number of key parameters. There was a divergence between the SA achieved by operators and the ideal SA defined by subject matter experts. Subjects did prepare themselves to answer probe questions in a simulated environment contrary to claims from other researchers.