In 2012, the race to create the fastest sailboat (or fastest sail-powered watercraft) was on. Ultimately, Vestas Sailrocket II, an inclined-rig hydrofoil designed in Britain, claimed the new speed sailing record with such a significant leap that the competition cooled for some years.
Now, a Swiss team and a French team (SP80 and Syroco) are hoping to set a new world speed sailing record and become the fastest sailboat in the world.
Competitions will take place in 2022. Both teams believe they can smash previous records with their remarkable kiteboats – targeting top speeds of 80 knots (92 mph/148 km/h). If this speed is achieved, it will be very impressive indeed.
The current world speed sailing record was set by an Australian man named Paul Larsen, who recorded an outrageous 65.37 knots (75.23 mph/121.06 km/h) aboard the Vestas Sailrocket II. The video below shows the exciting record run.
However, Larsen was utilizing a sail on a mast, and these two teams are using kites instead. The teams are confident that kites are better than sails because when generating a lot of power from a sail connected to a mast attached to the hull of a boat, the boat can roll over. The higher the power, the greater chances of a roll. That means even a massive catamaran design can tip over.
In addition, kites are far more difficult to control, a key challenge for both contenders. But, on the plus side, the roll can be taken entirely out of the equation, allowing kiteboats to harness significantly more power. Below are the competing designs:
Unlike many fast sailboats that “fly” out of the water on hydrofoils, the SP80 boat from Switzerland’s EPFL University stays in contact with the water. Here are two reasons for that:
- First, the team will take it up to dangerously high speeds, where flipping over is possible if the wind gets beneath it and lifts the front.
- Secondly, the cavitation phenomenon – water turning into vapor as it passes quickly over the foils – creates so much drag and instability that hydrofoiling boats are relatively limited to roughly 100 km/h (62 mph).
Therefore, it will be an 8 m (26.2 ft) long trimaran, shaped like a futuristic high-speed VTOL aircraft, with its two outriggers giving it a “wingspan” of 6 m (19.7 ft) for stability.
The SP80’s large kite is attached to the rear of the boat, and there’s an integrated curved foil in the water to balance against the high power generated by the kite. For this, the team used a triangular “ventilating” shape designed to carve an air pocket into the water behind it as it glides through the sea at high speed, eliminating the instability of cavitation caused by a regular foil shape.
These will perform poorly at slower speeds but are proven excellent in high-speed motorboats capable of racing up to 350 km/h (217 mph). Unlike regular foils, they impose no theoretical speed limit on the vessel. Getting the SP80 up and running could involve the team launching the kite from a motorboat or a floating platform.
The EPFL team explains the SP80 in the video below.
The Speedcraft from France’s Syroco is entirely different. It’s a “weightless boat” that looks like a speared fish flying over the water. One side of that spear is a thin wing leading down to a submerged hydrofoil and the other, directly opposite, are the cords leading to the kite. The hydrofoil performs steering duties and opposes the pull of the kite, holding itself in the water.
While the design looks simple, it has its challenges. For example, as speeds increase, the hydrofoil will pull hard against the kite, creating high pressure on one side of the foil and low pressure on the other. When the pressure gets low enough, the water around it will vaporize, causing the cavitation phenomenon – the speed limiter on all previous hydrofoils.
Surprisingly, Syroco is counting on it. “We won’t even try to avoid cavitation. Instead, we will work to make it steady. We need to achieve a super cavitating regime,” explained the team. The idea is to produce a similar pressure field near the foil’s surface, which will form a stable vapor pocket that doesn’t close and create vibrations and shocks until well behind the foil.
To achieve this, the team turned to computational fluid dynamics simulations. They took a standard cavitation foil designed by NASA in the 1950s and modified it into 400 different designs. Each was subsequently run through roughly nine hours of simulations on a unique HPC system with 9,216 processing cores. The result was a design that the team is confident will perform 50% better than the original. From here, the team aims to optimize the geometry to improve performance by another 50%.
The Syroco team describes the Speedcraft in the video below.
Preparing For The Challenge
Both teams have completed their prototypes and have already run tests on the water. They are currently building and perfecting their final boats. Both plans to smash the world speed sailing record in 2022 – but Syroco is aiming for mid-year, while the SP80 team is targeting the end of the year.
Both designs are impressive, highly innovative, with great crews and substantial resources backing them. This is very exciting! Who do you think will win?
If you are interested in hydrofoil boats, you may want to watch high-speed hydrofoiling racers competing in the first E1 series, scheduled in 2023. E1 is like Formula E, but with boats, and it’s described as an electrified version of the F1H20 powerboat racing series.