The modern racing yacht is awash with onboard instruments and electronics giving enormous amounts of data. But few people fully understand how to get the most out of all the information at their fingertips, let alone make it useful for the team to enable them to win races. But ace navigators, Mark Chisnell and Gilberto Pastorella, do - both have worked with professional sailing programmes all over the world - from America's Cup to Maxi, ORC / IRC...