Zenith El Primero Chronomaster Grande Date Bracelet (03.2160.4047/01.M2160)

To achieve this feat, the multi-hull sailboat is equipped with hydrofoils (or underwater wings) that lift the hulls of the boat out of the water as speed increases. The hulls leave the water entirely at a speed of 10 knots (18.52 km/h), which reduces hydrodynamic drag considerably. The hydrofoils are thus the only parts left in contact with the water, and the trimaran flies, between air and water, at up to two times the speed of the wind propelling the boat. Although the operating principle is relatively simple to understand, the technology and computer models developed to apply it are extremely sophisticated. New, optimized carbon and titanium composite materials were needed to endure the enormous forces exerted on the boat's structure. Propelling a machine such as the Hydroptere at more than 100 km/h meant developing a boat that could withstand forces of up to 20 tons per square meter. By way of comparison, the pressure exerted on a hydrofoil is two times greater than that exerted on a fighter jet.

Setting new records
Alain Thebault's flying trimaran is currently the fastest sailing craft on the planet over a distance of one nautical mile. The boat's record average speed of 50.17 knots (92.91 km/h) is over 8 knots faster than its nearest competitors' speeds. The goal of breaking the legendary 50-knot barrier - the equivalent of breaking the sound barrier in aeronautics - has been achieved and largely surpassed by Alain Thebault.
World speed records
Nautical mile: 50.17 knots - 92.91 km/h
Maximum speed: 56.30 knots - 104.27 km/h

In the world of sailing, the mythical 50-knot barrier was long considered the equivalent of the sound barrier in aeronautics. Yet, at a speed of 56.3 knots (104.27 km/h) - 6.3 knots over this legendary limit - Alain Thebault's Hydroptere was able to shatter existing speed records thanks to a truly extraordinary performance. While setting these records, the Hydroptere clocked up a speed twice that of the wind blowing over the water, without using any other means of propulsion other than the wind itself. A perfect laboratory for high-tech experimentation, the Hydroptere incorporates numerous new technical developments. This is what prompted the watchmaking Manufacture Zenith, a pioneer in high-frequency movements, to climb aboard the flying sailboat.

Alain Thebault and Jean-Frederic Dufour, CEO of Zenith, have recently entered into a partnership agreement that unites these two innovative leaders. Both men enjoy rising to technical challenges and are leaders in their respective fields: fluid kinematics for one, and the finest division of time for the other. A genuine meeting between two bold spirits…
Louis Bleriot
Faster than Louis Bleriot's plane
In 1909, Louis Bleriot crossed the English Channel in exactly 37 minutes, a feat which made him famous around the world. Nearly 100 years later, the Hydroptere has made the same crossing in 34 minutes and 24 seconds, i.e. over 2 minutes faster than the Bleriot XI, the flying machine built by the French engineer and aviator.

A telling sign of the times, the Hydroptere was propelled by wind power alone, a clean and renewable energy source, as it set its new record. And, as with the historic flight of 1909, this new crossing has opened the door to a wealth of incredible possibilities. We can now imagine being able to navigate the high seas without releasing a single gram of CO2 into the atmosphere, at speeds that bring the French and English coasts within just 35 minutes of each other.
Two Zenith precision instruments were onboard the Bleriot XI: an altimeter and the pilot's invaluable wristwatch. On Louis Bleriot company stationery, the owner wrote: "I am very satisfied with the Zenith watch that I routinely wear, and I cannot recommend it enough to those who are truly concerned with real precision." One hundred years later, Zenith watches still have the same sense of timing; today, they support a project that is ushering in new means of transportation for the next century that are fast, comfortable and, above all, clean.

Zenith, the pioneering spirit
The Zenith brand has often broken new ground in unexplored territories, quickly overcoming obstacles deemed insurmountable by other watch Manufactures. As a pioneer in high frequency, Zenith invented the most accurate automatic movement in the world: the El Primero chronograph caliber. While most precision chronographs only beat at 8 vibrations per second, the El Primero caliber beats at 10 vibrations per second, i.e. 25% faster - the equivalent of breaking the sound barrier in aeronautics. Zenith's ability to create new ideas then pursue them - before anyone else - with new technical developments is what fascinated the French sailor. Alain Thebault, the new Zenith brand ambassador, sports an El Primero Striking 10th on his wrist, the model that made tenths of a second "visible" with each vibration of its mechanism.

The special edition El Primero Stratos Thebault
Built to withstand great stress, this model's black case is crafted from Alchron, a high-strength aluminum alloy. This material was designed and developed especially for watchmaking; its magnetic permeability is 50 times lower than that of any steel. Alchron is especially resistant to corrosion and boasts very impressive mechanical properties: its Vickers hardness number is 210 HV. In addition, before being used to bring the Stratos Thebault watch to life, the Alchron alloy was subjected to a wide range of tests: its corrosion-resistance was tested in saline mists that mimicked tropical climates and human perspiration, while its shock-resistance was tested using a pendulum-impact testing machine, comprising a hammer-like steel pendulum fixed on the end of a swinging arm that drops down and hits the case at full force. It goes without saying that the true goal of these tests is to provide the high-precision El Primero caliber with the best high-strength alloy technology available. Only 500 of these special edition El Primero Stratos Thebault chronographs will be produced. This edition revives one of the unique features of the original El Primero model from 1969: three different colors are used to distinguish the three counters on the dial, a now-iconic characteristic of El Primero models.

Zenith timepieces have participated in some of mankind's greatest adventures: the discovery of the North and South Poles by the explorer Roald Amundsen, Mahatma Gandhi's peaceful struggle for Indian independence, the beginnings of ecology through the work of the "Prince Savant" Albert 1st of Monaco, Louis Bleriot's crossing of the English Channel, John F. Kennedy's political actions, Dr. Jean-Louis etienne's first solo flight over the North Pole in a hot-air balloon and, from this moment on, the design of sailing craft featuring revolutionary technology and awe-inspiring performances.

How to fly on water

Technical explanations and images
Water-resistance
Contrary to what one might think, the speed of a sailboat is restricted more by hull friction in the water than by the speed of the wind. In addition, a highly hindering phenomenon called cavitation appears once a certain speed is reached. Cavitation is caused by small vapor bubbles (cavities) that form and implode all within a few milliseconds. This is where the hydraulic analogy of the sound barrier comes from, since cavitation keeps a sailboat's speed below 50 knots (92.60 km/h), whereas speeds of up to 180 km/h can be attained by land sailors on the beach!
The famous hydrofoils
The underwater wings that enable the Hydroptere to take flight

To counteract the effects of cavitation and water-resistance, the Hydroptere lifts up into the air once it reaches a certain speed and sails with its hulls out of the water. The hydrofoils, acting as submerged wings, make it possible to elevate the entire structure in this way. They function according to the same principle of lift that enables the wings of an airplane to lift it off the ground. As a hydrofoil passes through the water, it generates a difference in pressure between the bottom of the wing (lower surface) and the top of the wing (upper surface). This difference in pressure translates, physically, into a force exerted upwards. The faster the speed at which the hydrofoil travels, the greater the lift.

Sailing at the confluence of air and water
Once a certain speed has been reached, the lift generated by the hydrofoils becomes greater than the weight of the boat, which causes the boat to rise up out of the water. The boat is now flying! There comes a point, however, when the boat must stop rising before it truly begins to fly and inevitably capsizes. The geometry of the hydrofoils equipping the Hydroptere has been designed to restrict lift at a pre-determined height, thus ensuring that the boat stops rising and stabilizes just above the water's surface. By removing water friction from the hulls, reducing cavitation and minimizing the drag caused by wake turbulence, this technique significantly increases the boat's speed and enables it to break the 50-knot barrier.