Ship steelwork manufacture

Southern, Geoff (1978) Ship steelwork manufacture. PhD thesis, University of Glasgow.

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Abstract

The primary aim of the work described in this thesis was to investigate the manufacture of ship hulls. The British share of the world shipbuilding market has fallen from over 50% to under 50% in the last thirty years, although its output in terms of tonnage has remained fairly stable at about one million tons per year. The increase in world demand during this period has been met by overseas shipyards which use production methods akin to those employed in general manufacturing industries. However British shipbuilders have tended to use more traditional shipbuilding methods, and investment in capital plant and improved management techniques has been relatively low. It was therefore intended that British shipyards should be investigated by a person with knowledge of other manufacturing industries. It became evident at the start of the work that active collaboration with shipyards was essential to achieve meaningful results. Nineteen British shipyards were approached and asked if they wished to participate, :Pour initially agreed, and a further four companies and two consultant organisations joined at a later date. During a preliminary exercise the four collaborating companies were visited for periods of one or two weeks. Design and production personnel were interviewed, and the areas of ship manufacture which might prove most fruitful on investigation were discussed. It was decided that a detailed study of ship hull steelwork manufacture, its management, and the plant and factory layout best suited for it would be most beneficial. These functions would be investigated and recommendations made to collaborating shipyards on how they might be improved. The main feature of the work carried out was the compilation and exploitation of a computer data bank describing the design and production features of ship hull components. It became apparent from initial shipyard discussions that difficulties would be met in directly applying production analysis techniques of general manufacturing industries in shipbuilding. The main reason for this is that there is a relative lack of essential production data. In many shipyards information does not exist on component process routes, component and assembly standard times, and standard costs. In the engineering industry in general an analytical investigation can start with the assumption that this data already exists within the firm. It was thought this problem would only be overcome by collecting information directly from ship steelwork drawings and material lists, and by then using this information to generate production data. The information would also be most economically stored, manipulated, and analysed using a computer. Component and assembly information was collected from drawings and material lists for selected ships and stored in computer data banks. Each data bank described components and assemblies comprising a complete ships hull. They employed descriptive coding systems which were specifically designed to indicate the manufacturing features of components and assemblies. It was thus possible to overcome the lack of production data by directly recording design information. In addition efficient computer storage, manipulation, and analysis packages were found to be readily available. The data banks were directly analysed to quantitatively investigate raw material standardisation. More important, by using the data banks it was possible to indirectly derive manufacturing methods from design drawings, and to use this to publish statistical tables of ship hull components for use in management decision making. Further investigations were made into work scheduling and shop floor layout problems in a specific shipyard. In these investigations the nonexistence of manufacturing process plans and work content estimates was found to be severely restricting. Computer programs were therefore written to generate these directly from the computer data banks for both component production and assembly. The resulting systems are faster in response and inherently more consistent than manual planning methods. They are accurate enough for scheduling, and they are now available for more detailed investigation of schedule work balancing and shop floor layouts.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Additional Information: Adviser: C C Gallagher
Keywords: Naval engineering, Industrial engineering, Operations research
Date of Award: 1978
Depositing User: Enlighten Team
Unique ID: glathesis:1978-73772
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 14 Jun 2019 08:56
Last Modified: 14 Jun 2019 08:56
URI: https://theses.gla.ac.uk/id/eprint/73772

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