The Americas Cup begins in Bermuda on the 28th May. It promises to be the most watched sailing regatta in history with a whole new audience coming to watch these carbon flying catamarans blasting around the Great Sound at speeds of upwards of 50 knots.

While most of the audiences just won’t understand how these amazing machines work and just look it in awe, there are a number of people who whinge that it has no bearing on ordinary sailing. Those detractors, who are often old men with decades of sailing experience are very wrong indeed.

Let’s look at two design features of Americas Cup boats that are coming to the mainstream – foils on accessible racing dinghies and the wing sail on commercial and potentially, cruising boats.

Foils and wing sails 101

The reason that the Americas Cup boats can do at speeds approaching double the wind speed you feel on your face (known as ‘true wind speed’) is that firstly they get rid of most of the friction between the hulls and the water by flying on tiny carbon fibre foils, and secondly they have ultra-efficient wing sails.

The foil is essentially a wing that is under water.

As the boat gathers speed it generates lift and eventually carries the boat out of the water. In doing so you go from having the friction of 50ft of hull in contact with the water to something under 3ft of foil in contact with the water. Water being incredibly viscous this means that suddenly the boat is freed from its aquatic chains and go much more quickly.

Wing sails on the Americas Cup boats are rigid and very similar to that of aircraft wings. Yes, they even have trim tabs to optimise the air flow over them. All fore and aft sails suck you through the air rather than push.

This is because they create a low pressure area of air directly in front of the mast and the higher air pressure behind forces the mast into the low pressure area. This is the same idea as wings on aircraft generating lift.

Fabric sails are not very efficient. While the fabrics used on top racing yachts are space age (many of them are carbon fibre and carbon film) so they don’t stretch, the design is far less efficient than that of a wing sail. The problem with going over to a rigid wing sail is that in bigger winds you can’t take sail in (‘reefing’) as you would on a fabric sail. This could be extremely dangerous sailing in European waters let alone on long oceanic passages, thousands of miles from home – until recently.

Let’s look at how these two technologies are feeding down to the real world of ordinary Joe’s sailing.

The Nacra F20, foiling catamaran


At around the same time as the last Americas Cup a company called Nacra launched its first foiling catamaran, the F20. While very much a rich man’s toy, this would begin a rush for companies to develop an accessible foiling boat that is accessible to ordinary sailors. Nacra would go on to develop the full foiling Olympic class catamaran (another elite toy) but also a range of other craft that are for someone who enjoys racing and wants to race at a far higher speed.

The Moth Mk2 has been around for years. While exciting to watch you have to be an elite sailor to even get it moving. One sailing journalist who had hundreds of thousands of sailing miles under his belt spent a day trying to get a Moth Mk2 onto its foils and, nearly killing himself with exhaustion in the process, managed around 30 seconds!

One of the lead designers of the Moth Mk2 looked into developing a fully foiling monohull that anyone can get foiling. This led to the Waszp class dinghy. This is an easy to use and relatively cheap full foiling dinghy that most people with a reasonable amount of sailing experience can launch, sail well and enjoy. It has rig configurations to allow for 40 kilo kids to sail as well as 100 kilo pie addicts, and is designed around making foiling accessible and fun. Priced at around $11,600 including delivery, this falls into the fast amateur racer’s bracket rather than the embarrassingly expensive rich boy’s toy bracket as you might expect.

While Nacra and Waszp have both taken the limelight there are a number of other classes in development that go along the same principles. You can even buy a foiling kit for a Laser dinghy for just under $3600. That puts foiling right in the price bracket of someone who’s interested in seeing what life is like while flying free but hasn’t got $10,000 to spare for a new boat.

The wing sail

While foiling boats have been in development or on the water for the last four or so years, the wing sail has just arrived. While foils are essentially about reducing the friction between the hull and the water, the wing sail is about increasing the efficiency of airflow and maximising the energy you can get from the wind. Fabric sails are a lot less efficient than wing sails, but in bigger winds you haven’t been able to reef a wing sail until recently.

Top French yacht designers VPLP have developed a fully reefing, fabric wing sail. It has the advantages of being the correct shape of a solid wing yet can be reefed for bigger winds. The potential to be reefed has moved the wing sail from being a space age Americas Cup and elite racing anomaly to being something that is accessible to a whole range of other uses.

This is very much at proof of concept phase at the moment. A boat (Arkema 3 Mini 6.50 prototype) is being prepared for the Mini Transat race, where 6.5 metre racing boats set out with a solo sailor, 4500 miles from France to the Caribbean later this year. While it wouldn’t be the first wing sail boat to cross an ocean, it will be the first one to cross the Atlantic in full racing conditions.

There are commercial applications to the new wing sail design too. VPLP have been looking into putting fabric wing sails on to cargo ships. In the face of international pressures to reduce their carbon emissions shipping companies are looking at new ways forward, and a return to the Age of Sail is one of them.

The idea would be for these giant ships to have several masts carrying fabric wing sails that can be set, reefed and furled automatically using computers and on board machinery.

VPLP say that these systems have been computer modelled and it is estimated that a set of wing sails could reduce fuel use by up to 42%. Considering a typical container ship will burn upwards of 120 tonnes of fuel oil a day, reducing this to 80 tonnes a day would immediately bring massive cost savings to running these vessels and could potentially slash global carbon emissions in logistics by millions of tonnes a year.

Will we see anything like this at Kavas Yachting?

The sailing world was extremely excited about the Gunboat G4 when the prototype full foiling cruising catamaran started sailing. The idea of being able to take a shower on a luxury yacht while it was foiling at 40 knots was mind blowing. Sadly this was a case of Icarus flying too close to the sun: at a 2015 Caribbean yacht regatta the prototype lost control and capsized, at least temporarily ending the dream of foiling cruising cats for the moment. Gunboat filed for bankruptcy soon after and foiling has returned to the fast amateur once again.

the Gunboat G4

The wing sail concept is more likely to reach our fleet of cruising catamarans in the next 10 years than any foiling system! This is because sailing a wing sail is so much easier than a fabric sail. In theory you will only have to adjust trim tabs to set the sail, and even racing won’t have to use any great muscle power to adjust the trim of the sails. If anything the idea of the wing sail is more likely to take off in the cruising market than the foiling system.

Technology these days moves at speeds that make Americas Cup boats look like Optimist dinghies. In ten years the world will be different. Kavas Yachting update our fleets regularly, and in 2027 we may just be bringing to you the technology you really only see on the Americas Cup boats today. Given the gush of technology from the rich boys’ toys you will flying around the Great Sound in Bermuda to the real world, we can be almost certain that these technologies will be open to the general sailor in the next decade.

Richard Shrubb