Feasibility study of Solitaire's aftship retrofit

A Systems Engineering approach

Master thesis (2019)

Authors

F. Aguilar Tejero Mechanical Engineering

Contributors

A.A. Kana Ship Design, Production and Operations - Mechanical, Maritime and Materials Engineering (supervisor 1)
J.J. Hopman Marine and Transport Technology (supervisor 2)
Marijn Dijk Allseas Engineering (supervisor 1)
Faculty
Mechanical Engineering
Copyright: © 2019 Fernando Aguilar Tejero
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Published Date

20-11-2019

Language

English

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Faculty

Mechanical Engineering

Abstract

Solitaire is a DP positioned pipelay vessel capable of laying pipe up to 3000 meters. Currently, Solitaire is more than 40 years old. Although it has been upgraded multiple times, it has been identified that certain improvement can be achieved by retrofitting just the aft of the vessel. The purpose of the research is to evaluate the feasibility of improving Solitaire by retrofitting it with a new aftship, by exploring the different design possibilities, including the different stinger support configurations. To this end, an analysis of alternatives has been done and the preferred options have been implemented into a concept design. The use of Systems Engineering (SE) has been motivated by the need to establish a clear structure to guide the design due to the complexity of the problem. This methodology allows to keep a good overview of the requirements and constraints involved in the design. An operational analysis was carried out to identify the operational deficiencies of the design. This lead to four main areas of improvement. i.e, Longitudinal strength, Stinger and Stinger handling system (SHS), Resistance and Deck space. By addressing these operational deficiencies, the operational time of the vessel can be improved. Either by reducing the theoretical peak cycle time, decreasing the downtime or a combination of both. Based on the operational analysis a set of requirements has been compiled and a functional definition of the design has been made. With all the insight obtained through the operational analysis, the design requirements and the functional definition; an analysis of alternatives has been carried out. For each of the operational deficiencies, multiple alternatives are analysed. Local optima are found for each of the deficiencies although, if each of these local optima is implemented in the design, the global performance of the vessel is compromised. Therefore, a holistic design is proposed to integrate all the solutions into one preferred concept design. Overall, the findings of the research suggest that the retrofit of the aft is technically and economically feasible. Nevertheless, a design validation needs to be carried out to better quantify the total improvement of the new design.