Recent Advances in Experimental Downwind Sail Aerodynamics

Souppez, Jean-Baptiste R. G. (Warsash School of Maritime Science and Engineering, Solent University) | Arredondo-Galeana, Abel (University of Edinburgh) | Viola, Ignazio Maria (University of Edinburgh)

OnePetro 

While sailing downwind has benefited from millennia of evolution, the very first instance of a highly cambered and dedicated downwind sail, termed spinnaker, did not occur until 1865, as reported by King (1981), and was not popularized until the 1970s and 1980s; primarily thanks to the development of symmetric spinnakers for the America's Cup. Asymmetric spinnakers were then introduced in the 1980s in the 18ft fleet in Sydney, before being popularised on offshore racing yachts in the 1990s. These new sails were promptly adopted in many significant sailing events; firstly in offshore races such as the Vendée Globe and the Whitbread 60, and later in the America's Cup (Fallow, 1996; Richards et al, 2001; Viola & Flay, 2009). The significant advances made in terms of spinnaker design and analysis during this particular decade can be related to the greater part that downwind legs took in the 1995 America's Cup (Fallow, 1996), thus motivating further research and development. The 1990s also coincide with a fast increase in accessible computational power, allowing advanced numerical methods to be used in sail design (Hedges, 1993; Hedges et al, 1996), particularly for downwind sails.