Preliminary design of a monohull racing sailing yacht

Abstract

The preliminary design of a racing sailing yacht is obtained through the use of a design spiral, from which a number of tasks must be completed iteratively until a satisfactory result is reached. A sailing yacht preliminary design can be rather tricky to generate as the yacht must deal with both the hydrodynamic forces acting upon the hull and also the aerodynamic forces acting on the yacht, mainly from the sails. The design begins with the selection and subsequent formation of the yacht hull which will be used to calculate, estimate, and assess other calculations and simulations required such as the resistance estimation and velocity performance (VPP). After numerous iterations of design the overall length for the racing sailing yacht was selected to be 11.2 m. The hull form was chosen to be a displacement hull and was created from scratch until ideal values for hydrostatic parameters such as the block coefficient (CB) and prismatic coefficient (CP) were obtained, and a lines plan of the yacht hull was also generated. The resistance acting on the hull was also estimated, both analytically and through software, by using the yacht hull formed and comparing to the standard series data known as the Delft Systematic Yacht Hull Series (DSYHS). The installed power for the yacht was also estimated by using the results obtained from the estimation for resistance. The Maxsurf software package by Bentley was used to obtain results for the resistance and installed power, the dynamic stability, and the velocity prediction (VPP), and the results were closely compared and analysed against the results gathered from the analytical calculations. The total displacement on the yacht was also approximated by estimating the mass of each component onboard the yacht, from which the centre of gravity of the yacht was also found. The stability regulations (the BN ES ISO 12217-2: 2015 and the Malta Commercial Yacht Code) regarding the yacht were also consulted in order to make sure that no criteria were failed or up to standard. Estimations for the mast and boom dimensions, and the sail area were also carried out and used to help accurately predict how the yacht would perform at different wind speeds within the velocity prediction program (VPP). The results obtained were highly satisfactory for the design requirements initially specified and were well within the necessary ranges. The results yielded that the stability criteria required were passed, the estimations for masses, the mast and boom, and the sail area were adequate, and the yacht performed very well at different wind speeds.