Hydrostatics And Stability

Ship Stability And Trim

Iooking back at hull development in the history of- yachting, it is obvious that opinion about the optimum shape of a yacht has - changed many times. This is due in part to the changing rules, but more recently the changes in design trends reflect the increasing knowledge about the physical laws governing the behaviour of sailing yachts. The aim of this book is to present the state of the art in yacht design. While current knowledge does not provide explanations for all phenomena, there is one...

Principles of Yacht Design

Catamaran Design Principles

Fig 10.4 The influence of dead rise on spray and pressure forces The spray from a bottom with deadrise normally increases the frictional resistance, since most of the spray actually goes backwards. Savitsky measured this effect and devised a spray correction to the wetted length to beam ratio. This correction is shown graphically for different deadrise and trim angles in Fig 10.5, which also gives the appropriate formulae for computing the frictional resistance. Forces on a planing hull Fig...

Keel and Rudder Design

Wing Pressure Distribution

Fig 6.2 Pressure distribution around a wing section Most of the wing sections of interest in sailing yacht design are symmetric, as in Fig 6.1, since they have to work equally well on both tacks. At zero angle of attack the pressure distribution along the section looks in principle like the one along a waterline (see Fig 5.9), ie there is high pressure at the nose and tail, and lower pressure in between. However, at non-zero angle of attack (as in Fig 6.1), the flow becomes highly asymmetric....