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Container-ships are vessels possessing an internal structure that facilitates the handling of containerised cargo. At each port along the journey of a container-ship, containers destined for that port are unloaded, and some containers destined for subsequent ports are loaded. Determining a viable configuration of containers that facilitates this unloading and loading, in a cost-effective way, constitutes the deepsea container-ship stowage problem. The work of determining a stowage configuration for a container-ship, on leaving a port, is performed by human stowage planners. The success of a configuration requires consideration of many factors. These factors include whether the configuration contravenes ship stability, minimises the physical costs of handling the containers, and takes into account expected container loads at subsequent ports. Further complications arise from the existence of hazardous cargo that must be segregated from other cargo and the ship's crew, and from the need to handle containers of non-standard dimensions. Stowage planners must work under strict time constraints, and are limited in the number of stowage configurations that they can consider. This real-world problem seems to be one that would benefit from automation through the application of artificial intelligence. Although many decision support systems exist that automate the time-consuming calculations for ship stability, little work has been published in the area of full automation of stowage planning. Authors proposing full automation have correctly identified the salient features of the problem, but have allowed the array-like nature of spaces within containerised vessels to entirely dictate their approach to addressing the placements of specific containers to specific locations. To enable the implementation of these approaches, excessively large search spaces are pruned through the removal of important features of the problem, rendering the solutions not commercially viable. By concentrating solely on the specific placements of containers, these authors have not recognised how human planners solve the problem. The author of this thesis approaches the container-ship stowage problem from a knowledge engineer's perspective. In the proposed approach, 'intelligence' is provided through the application of the findings of a knowledge elicitation exercise and a systems analysis of the work of human planners. The assumed heuristics inherent in their use of documents are highlighted. This thesis reports on the results of the analysis of the processes employed by a stowage planner. Explanations are provided of how these results allow the problem to be decomposed into subproblems. An implementation of the approach described would determine good, although not necessarily optimum, solutions to the entire problem in a commercially viable duration of time. Further, this approach allows many more stowage configurations to be considered than would be possible for a human planner. The work contained within this thesis demonstrates the feasibility and benefits of such an implementation. The last chapter contains, in addition to a full and detailed list of conclusions made during the research, a summary of some of those areas that still require further work.

In this thesis consideration is given to a selection of nonlinear dynamic problems in the field of offshore engineering. Hydrodynamic loading on fixed horizontal and vertical tubular members and the dynamic response of articulated towers together with the distribution of shear force and bending moment along the tower are investigated using various wave theories. Effects of nonlinear convective acceleration terms in the calculation of fluid inertia forces and moments are examined and attention is given to integration of wave forces up to the free surface for vertical members. Calculation of fluid loading at the displaced position of the articulated tower and any Mathieu type instabilities that may occur have been considered. The dynamic analysis of a damaged Single Anchor Leg Storage (SALS) system subject to loss of buoyancy in the yoke chamber is studied. The equations of motion of the yoke/riser system are derived assuming large displacements and solved in the time domain. Time histories of the response, variations of the riser tension, velocities of riser top end and the time histories of pivot reactions are given. Natural periods and mode shapes for small displacements of the system are calculated. Two methods of simulating random seas, both represented by a sum of harmonic wave components, are used to simulate second order low frequency (slow drift) force on a tanker in head seas by Pinkster's time domain method. In one method the wave amplitudes are generated randomly from a Rayleigh distribution and in the other they are obtained deterministically via the wave spectrum. Time histories of slow drift force and response together with simulation results with various duration lengths are presented and compared. Estimates of the extreme vessel response and its relation to rms value are compared with the result of a commonly used method of determining peak/rms ratios. The results of these investigations highlight the importance of accurately simulating nonlinear effects in both fixed, floating and compliant offshore structures from the point of view of safe design and operation of such- systems.

This Thesis investigates the methods which are currently available for the dynamic analysis of Offshore Mooring Terminals, with particular regard being paid to Single Point Mooring (SPM) Terminals. Various aspects of the problem are considered in turn, these being the random vibration of non-linear systems, the analysis of catenary mooring lines, buoy dynamics, ship motions, second order (or slow drift) forces and motions, and low frequency motions caused by instabilities. These various aspects are then applied to the dynamic analysis of a Single Buoy Storage (SBS) System and the effect of the method of analysis employed, the system dimensions and the environmental conditions on the computed response is investigated. A Time Domain investigation of the stability of the SBS System in the presence of wind and current alone reveals that the system is only unstable for combinations of wind and current which are unlikely to occur in practise. A static offset position is then assumed and the calculation of the three-dimensional first and second order response to random waves is performed in the Frequency Domain, linear wave theory being used. The first order wave forces are calculated by using strip theory for the tanker and Morison's equation for the buoy. The second order response in surge, sway and yaw is calculated by a reflection coefficient method, these coefficients being obtained from published literature. The non-linear mooring system and the drag forces acting on the buoy are linearised using the equivalent linearisation method, due account being taken of the coupling between the first and second order response. The model developed for the first order response of the system allows the use of a spreading function in the incident wave spectrum. The accuracy of linearisation techniques and the statistics of the second order force and response are also investigated.

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Whilst the issue of open registry shipping has constituted one of the greatest controversies in the shipping industry over the last thirty years, no detailed quantitative work has been carried out on the issue. In this thesis transcendental logarithmic cost functions are estimated for the production functions of open registry bulk ships and those operating under traditional maritime nations. In this way an appropriately unrestricted cost function for the flag dichotomy is estimated and the parameters of the cost functions provide the basis for determining the structure of the production technology of tankers and bulk carriers under the two· flag groupings. Evidence of scale economies and the extent to which they have been exploited by each flag group is provided along with factor substitution patterns, own-price and crossprice factor demand elasticities. It is found that the costs of bulk carriers operating under open registries are lower for all vessel sizes than for those operating under traditional registries. For tankers/open tegistry costs are found to be higher for product tanker services and lower otherwise. The translog estimates reveal that the manning cost element is the greatest contributor to the cost differential between the two groups. Open registry operations are also found to be subject to greater factor substitution flexibility. Statistical analysis of tanker and bulk carrier time charter freight rates over a ten-year period provides empirical evidence for the hypothesis that lower open registry costs are passed on to consumers of shipping services by way of lower freight rates. For this reason, a methodology for measuring this benefit is suggested. It is concluded that whilst this study provides evidence of the possible cost to international trade of phasing out open registries, such cost of itself does not provide an argument for retaining the system. The social and economic rationality of retaining the system will be determined by a wider cose-benefit analysis to which this study has contributed.

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