Offshore Supply Vessel Design Studies with Application of Expert Systems

Mainal, Mohd. Ramzan (1993) Offshore Supply Vessel Design Studies with Application of Expert Systems. PhD thesis, University of Glasgow.

Abstract

This thesis deals in depth with the design, operational and economic characteristics of offshore supply vessels, including pure supply and anchor handling/tug/supply types. The design characteristics investigated in this thesis include the main dimensions, hullform, stability, group weights, capacity and powering. The hullform of the offshore supply vessel is developed using the initial sketch technique where the vessel is divided into four boundary curves, that is, stem profile, parallel middle body and stem profile. The operational characteristics examine the seakeeping and manoeuvring behaviour, and the modelling of the supply operation of offshore supply vessels. The seakeeping characteristics are analysed using strip theory, while the manoeuvring characteristics are based on established empirical formulae. The modelling of the supply operation simulates the operating pattern of such vessels supplying materials to drilling platforms. Economic studies incorporated in this thesis served as a base for economic evaluation of each design. The required freight rate is used as a measure of merit for the owner operating the vessel, while the minimum charter rate is used if the owner is to charter the vessel. The computer is used as the principal tool in this thesis and a digital computer program algorithm has been developed to carry out the task. The computer program is written using expert system programming. Instead of using one of the languages used in expert system programming such as Lisp or Prolog, a well known commercial expert system shell, Leonardo, is used. The programs have been carefully written so that the user can interact with the system, the interaction can be merely to request continuation of the calculation or discuss the next step, with the system giving guidance, advice and stimulation. In general, three major programs have been developed. They are a. an iterative design program for offshore supply vessels, b. an interactive optimisation design program which involves mathematical optimisation procedures, and c. an operational modelling program for the offshore supply vessels. This thesis also considers methods of incorporating uncertainties in the preliminary design of offshore supply vessels. Apart from reviewing the existing methods of incorporating uncertainties in ship design studies, two methods are examined, Certainty Theory and Bayes' Rule. A program is written to incorporate uncertainties in the selection of main engine and propulsion units for the offshore supply vessels.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Adviser: R M Cameron
• Keywords: Naval engineering
• Date of Award: 1993
• Depositing User: Enlighten Team
• Unique ID: glathesis:1993-74749
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 27 Sep 2019 16:40
• Last Modified: 27 Sep 2019 16:40
• URI: https://theses.gla.ac.uk/id/eprint/74749