Comparative evaluation of a hydrofoil-assisted trimaran

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dc.contributor.advisorMigeotte, G.
dc.contributor.advisorHarms, T. M.
dc.contributor.authorMoolman, Rynoen_ZA
dc.contributor.otherUniversity of Stellenbosch. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering.
dc.date.accessioned2008-07-22T08:05:09Zen_ZA
dc.date.accessioned2010-06-01T08:38:39Z
dc.date.available2008-07-22T08:05:09Zen_ZA
dc.date.available2010-06-01T08:38:39Z
dc.date.issued2005-12en_ZA
dc.descriptionThesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2005.
dc.description.abstractThis work is concerned with the design and hydrodynamic aspects of a hydrofoil-assisted trimaran. A design and configuration of a trimaran is evaluated and the performance of a hydrofoil-assisted trimaran is effectively compared to the performance of a hydrofoil-assisted catamaran with similar overall displacement and same speed. The performance of the trimaran with different outrigger clearances are also evaluated and compared. The hydrodynamic aspects focuses mainly on the performance and to a lesser extend on the sea-keeping and stability of a hydrofoil-assisted trimaran. The results were determined by means of experimental testing, theoretical analysis and numerical analysis. The project was initiated as a result of the success of the hydrofoil-assisted catamarans and due to the fact that there does not exist a hydrofoil-assisted trimaran (to the author’s knowledge) where the main focus of the foils is to significantly reduce the resistance. A brief history, recent developments and associated advantages regarding trimarans are discussed. A complete theoretical model is presented to evaluate the lift and drag of the hydrofoils, as well as, the resistance of the trimaran. The data so obtained is then used to compare the reliability and feasibility of the numerical and experimental predicted values. The design of the trimaran and hydrofoil system is explained, together with the problems associated with the final design of the trimaran. The design of a trimaran is much more complicated than a catamaran due to more design variables being associated with trimarans. The selection of the trimaran configuration is done in a logical manner considering stability and hydrodynamics. However, the hydrofoil-assisted trimaran is closely adapted to the main dimensions of the comparable hydrofoil-assisted catamaran. An in-depth discussion of the testing technique used and the problems that are associated with towing tank testing will facilitate similar tests in the future. The scaling method of Froude was modified to account for the different sized hulls. The numerical methods are explained, with emphasis on accuracy, limitations, feasibility and the time required to complete a calculation. The results are presented in an order suggested by the experimental and numerical work carried out. The resistance, trim and rise/sinkage results are presented with speed for both the trimaran and catamaran with and without the addition of foils. The addition of the foils supplies results based on the amount of lift the foils carry and therefore can easily clarify the significant resistance advantage the foils offer the trimaran and the catamaran evaluated in this project. The final design and results of the evaluated trimaran are discussed. It is concluded that the catamaran with similar displacement and speed is still superior to the trimaran, with and without foils in both cases. The addition of foils to the trimaran does decrease the resistance significantly. The conclusions regarding these results are presented, together with recommendations for future work.en_ZA
dc.identifier.urihttp://hdl.handle.net/10019.1/2005
dc.language.isoenen_ZA
dc.publisherStellenbosch : University of Stellenbosch
dc.rights.holderUniversity of Stellenbosch
dc.subjectDissertations -- Mechanical engineeringen
dc.subjectTheses -- Mechanical engineeringen
dc.subjectHydrofoil boats -- Design and constructionen
dc.subjectTrimarans -- Design and constructionen
dc.subject.otherMechanical and Mechatronic Engineeringen_ZA
dc.titleComparative evaluation of a hydrofoil-assisted trimaranen_ZA
dc.typeThesisen_ZA
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