The double skinned ‘soft’ sails that are used on these boats may look like a compromise between traditional sails and the solid wings of the previous three America’s Cups, but they are proving to be far more potent.

Capable of creating asymmetric sections shapes that are believed in some cases to change gear automatically with varying boat speeds, double America’s Cup helmsman and North Sails president Ken Read explains why they are much faster upwind than the wings of the previous Cup boats.

Read tells Matt Sheahan why these sails work and how they might affect the rest of us in the future, plus he sets out the options that may be open to the British team in their quest to achieve more speed in time for the Challengers’ Series, the Prada Cup.