Argentine Santi Lange, the 2004 bronze medalist, previous world champion and a yacht designer, put the effective operating range for the sail at six-nine knots of wind.

Lovell confirmed as much. "It's got to be below nine knots of wind to work." This is an exceptionally narrow band and would represent a brave choice as the past two Test Events run in Aug 2007 and 2006 have shown that there can be days when the wind blows 15 knots as well as only two knots.

But Booth is also unhappy that the slot allocated by officials for measuring in his boat is earlier than some of his rivals. It is on Aug 10 with the Tornado competition starting on the 14th, which is a significant delay if you want the most up-to-date weather forecast to determine your sail selection.

By contrast, the American measurement slot is Aug 13. Once measured-in, sailors are not normally permitted to swap sails.