DURING the European Grand Prix in Valencia on June 26th, Lewis Hamilton discovered that his tyres were overheating. It was not, however, a whiff of burning rubber that gave it away. Instead, the news came from the pits, where a clutch of engineers spend the entire race glued to a bank of monitors replete with numbers and graphs streaming in from their teams' cars. Every second, sensors on the vehicles take hundreds of different measurements—the engine, suspension, or the drivers' well-being—and relay them to the pits. Besides highlighting problems, the data let team strategists advise Mr Hamilton and his rivals on tactics and on how to optimise vehicle settings with the help of the dozen or more switches on the steering wheel.

Such data logging and telemetry has made what used to be more of an art into an exact science. As a result drivers are able to shave fractions of a second off their lap times. These, aggregated over a typical race's 50 or so laps, can make the difference between winning and losing. Now the technology, pioneered in motor racing, is being applied in another discipline where split seconds provide an edge: sailing.

Leading the way is Cosworth, a British company best known for making racing engines, but which also provides many of the F1 teams with their data-acquisition and analysis equipment. Their marine systems work in much the same way as they do on racing cars. But instead of measuring cornering forces and suspension movement they look at wind speed, yaw, rudder angles and sundry other factors that affect the performance of a racing yacht or dinghy. Some sailing teams training for the Olympics have adopted the technology, as have several competitors in the Americas Cup, sailing's most prestigious event.

As with motor racing, so too with sailing, a reliable gauge is needed to ensure successful manoeuvres are repeated time after time. Changing wind and water conditions make this all the more important. The heart of Cosworth's Pi Garda system sits in, literally, a black box. It logs data from sensors inside it, such as accelerometers to measure g-forces and a satellite positioning system. It also takes information from sensors which measure how the boat is behaving on the water, as well as standard marine instruments, such as a wind wand on the mast determining wind speed and direction.

Some sensors are copied straight from the racetrack. A small laser sensor, for instance, is mounted underneath a racing car's chassis to reflect a beam off the track surface in order to calculate the down force being exerted on the vehicle. It is accurate to within 0.03mm. The same sensor is used on a boat to shine a beam off the tiller bar and use the reflection to measure the angle of the rudder. Other sensors are more bespoke. For instance, strain gauges calculate the stretch in the wires or ropes in the rigging and sails.

The information can be displayed to the crew on the yacht, transmitted to coaches on a chase boat, or to a support team on shore. This allows accurate predictions of when the yacht will get to the next buoy, how many tacks it will require to get there and how best to tackle the necessary turns, says Simon Holloway of Cosworth's marine division. An identical system might ease the pressure on the solitary round-the-world yachtsmen, he adds.

In some competitions, including the Olympics, such equipment is not allowed during the event itself. Nevertheless, it remains a valuable training aid. Smaller, self-contained systems have also been developed for enthusiastic amateurs, even windsurfers. This echoes what has happened to motor-racing telemetry. Many modern cars now employ devices first used in F1 to let the driver know how the vehicle is faring. It remains to be seen whether the Cambridge punt gets a similar makeover.