A passive suspension system for a hydrofoil supported catamaran

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dc.contributor.advisorVan Niekerk, J. L.
dc.contributor.advisorMigeotte, G.
dc.contributor.authorKopke, Markusen_ZA
dc.contributor.otherUniversity of Stellenbosch. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering.
dc.date.accessioned2008-06-17T13:12:02Zen_ZA
dc.date.accessioned2010-06-01T08:38:13Z
dc.date.available2008-06-17T13:12:02Zen_ZA
dc.date.available2010-06-01T08:38:13Z
dc.date.issued2008-03en_ZA
dc.descriptionThesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2008.
dc.description.abstractThis study investigates practical passive methods to improve the seakeeping of a Hydrofoil Supported Catamaran (Hysucat). The Hysucat is a hybrid vessel combining hydrofoil efficiency with the stability of catamarans. The seakeeping of the Hysucat was initially investigated experimentally to determine what seakeeping improvements are inherent to the Hysucat design. The results showed that the seakeeping is improved by 5-30%. A passive suspension system for the main hydrofoil of the Hysucat was designed and tested. A concept development strategy was followed for the design of the suspension system as such a system had never been investigated previously. Detailed specifications for the design were developed and concepts that could satisfy the customer and engineering requirements were generated. Numerical simulation models for the Hysucat and the final concepts were derived assuming a simplified 2nd order system to describe the seakeeping dynamics of the demi-hulls. Unknown parameters were determined using parameter estimation techniques. Representative parameter values were calculated from multiple towing tank experiments. Theory describing the motion of a hydrofoil in an orbital velocity wave field was combined with the hull model to simulate the Hysucat as well as the suspension system concepts. The models indicated that the concept where the main hydrofoil was attached to a spring loaded arm, that was free to pivot in response to orbital waves, was the most feasible in damping out vertical transmitted accelerations. Experimental tests indicated that little improvement was achieved with the suspension system at low frequencies. At resonance the suspension system was effective in decreasing the heave of the vessel by up to 27%. The pitch and acceleration response results showed improvements at the higher encounter frequencies of up to 50%. The calm water resistance of the vessel increased by 10% over the Hysucat with rigidly attached hydrofoils; however was still 24% less than the hull without foils.en_ZA
dc.identifier.urihttp://hdl.handle.net/10019.1/1991
dc.language.isoenen_ZA
dc.publisherStellenbosch : University of Stellenbosch
dc.rights.holderUniversity of Stellenbosch
dc.subjectHysucaten_ZA
dc.subjectSeakeepingen_ZA
dc.subjectDissertations -- Mechanical engineeringen
dc.subjectTheses -- Mechanical engineeringen
dc.subjectHydrofoil boats -- Design and constructionen
dc.subjectCatamarans -- Design and constructionen
dc.subjectShips -- Hydrodynamicsen
dc.subject.otherMechanical and Mechatronic Engineeringen_ZA
dc.titleA passive suspension system for a hydrofoil supported catamaranen_ZA
dc.typeThesisen_ZA
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