In the transition from deterministic to probabilistic approaches to assessing the damage survivability of passenger ships this PhD study seeks to draw attention to the key need in regard to loss prevention - the need to address damage survivability by taking full account of vessel dynamics in realistic environments. The thesis begins by critically reviewing the development of subdivision and damage stability requirements, emphasising the inherent weaknesses in the existing approaches to assessing damage survivability. The approach adopted in this thesis is then described. This is based on real time simulation of the dynamic behaviour of the damaged vessel in realistic wind and wave conditions. The mathematical model comprises coupled sway-heave-roll motions in beam seas while taking into consideration progressive flooding as well as water accumulation. A series of comprehensive model experiments have been specifically designed and undertaken to investigate the nature and magnitude of couplings in the above modes of motion in upright and inclined conditions. The damage survivability of the vessel is examined by considering a number of damage scenarios, chosen on the basis of maximising the danger of potential capsize (or sinkage) while taking into account actual accident records. The practical applicability of the proposed procedure is demonstrated by means of a parametric investigation aimed at identifying the effect of a number of key parameters on the damage survivability of a modern car/passenger ferry. These include: wave height; wave length; wind speed; flooding; water accumulation; location and extent of flooding; loading. The results of the investigation are presented and discussed. On the basis of these results boundary stability curves are proposed as a substitute for existing still-water damage stability criteria. These curves involve relationships between design and environmental parameters and inherent stability-related parameters.

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This research addresses the problem of coordinating multiple autonomous underwater vehicle (AUV) operations. An intelligent mission executive has been created that uses multi-agent technology to control and coordinate multiple AUVs in communication deficient environments. By incorporating real time vehicle prediction, blackboardbased hierarchical mission plans and mission optimisation in conjunction with a simple broadcast communication system this system aims to handle the limitations inherent in underwater operations and intelligently control multiple vehicles. In this research efficiency is evaluated and then compared to the current state of the art in multiple AUV control. The research is then validated in real AUV coordination trials. Results will show that compared to the state of the art the control system developed and implemented in this research coordinates multiple vehicles more efficiently and is able to function in a range of poor communication environments. These findings are supported by in water validation trials with heterogeneous AUVs. This thesis will first present an in depth state of the art of the related research topics including multi-agent systems, collaborative robotics and autonomous underwater vehicles. The development and functionality of this research will then be explained followed by a detailed description of the experiments. Results are then presented both for the simulated and real world trials followed by a discussion of the findings.

Characterisation of a tidal stream site before device deployment is important for the marine tidal industry, in order to optimise the device design and accurately predict its performance during operation. Understanding the short-term uctuations in tidal stream velocity, resulting from turbulence and wave-current interactions, is essential for proper evaluation of the transient performance of a tidal stream turbine. Several aerodynamic models have been proposed for the design of tidal stream turbines and energy production calculation, most of which have proved to predict accurately mean quantities within the ow regime. Unfortunately, these models cannot accurately predict the instantaneous ow variation and resulting forces within the ow regime acting on tidal stream systems which is of central importance to the tidal energy industry. The reasons for this may not be unconnected to the signi cant differences between wind and tidal turbines. Given the uncertainties which exist in the assumptions of resource modelling and the need for an accurate energy capture assessment at a speci c site, accurate on-site measurements that can predict the ow velocity (and its directional component) at a given location, are needed. This thesis is devoted to characterisation of ow in a typical tidal stream site (the Fall of Warness, of the European Marine Energy Center (EMEC), Orkney) through measured data. The high-frequency Acoustic Doppler Current Pro ler (ADCP) surveys were conducted at different locations within this site by EMEC. This dataset allows for the rst time a statistical and thorough analysis of the vertical turbulence structure at the EMEC's tidal stream test site. Detailed analyses of the directional components of the wave elds using a non-phase-locked method and in uences of seabed and tidal stream on wave elds, were performed. The bulk turbulence parameters within the tidal streams were estimated using the variance method. The results suggest a signi - cant effect of directionality and short-term uctuations in stream velocity resulting from turbulence and wave-current interactions, on the hydrodynamics in a typical tidal energy test site. The results from this study can be used to validate and improve/develop proposed hydrodynamic models and can play a vital role in tidal energy resource planning.

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