You may have heard of the term “foiling” or “hydrofoiling” in relation to water sports and wondered what the heck that even means? Luckily for you, I know all about foiling and I can quickly explain what it is, and even try to explain how it works.
Foiling is the act of riding a hydrofoil through a body of water. The rider isn’t physically touching the hydrofoil as they ride it, though. The hydrofoil is attached to a board that hovers above the water which the rider uses as a platform to control the foil during their “flight”.
When trying to explain foiling, a photo is worth 1000 words!
In the above photo you can see the basic components than enable foiling. You have a kiteboard with footstraps with the rider will stand on, and then the hydrofoil extends down into the water.
Once the rider picks up a bit of speed from their kite, sail, or propeller, the hydrofoil will create lift as it moves through the water, raising the board out of the water. At this point, the rider is truly riding on the hydrofoil itself!
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The above photo shows windfoilers racing through the water. You can see that the sailors can control how high they are in the air by adjusting the angle of their foil.
Why is Foiling a Thing? Why Do People Hydrofoil?
Up until this point you’re probably confused why anyone would ever strap these long hydrofoils to a board. Why not just do the same watersport without the foil?
The answer is that hydrofoils give you insanely more efficient movement through the water. When foiling, the entire board is out of the water which means there’s no drag or friction on it slowing you down.
The end result is the sailor is able to maintain speeds in much less wind or energy than they would even be able to do without a foil.
Foiling has a bright future because it can be a massive efficiency boost for anything that travels on water.
Types of Foiling
There’s a wide variety of different types of foiling, though they all use very similar designs the same way all airplanes use very similar designs for their wings. The biggest difference is the design of the board the foil is attached to as well as the method the sailor uses to power their movement.
The namesake for this site, windfoiling is windsurfing with a foil. Windfoiling is rapidly increasing in popularity because it allows windsurfers to get out on the water with much less wind than they would be able to without a foil. Many consider windfoiling to be the future of the sport – which is why it’s a new Olympic discipline for 2024.
Wingfoiling is like a hybrid between windsurfing and regular surfing. Riders ride a surf foil board, but hold a large inflatable wing with their hands which they can manipulate to take advantage of the wind as desired.
As you may have guessed by now, kitefoiling is the act of foiling while kitesurfing.
An eFoil is an electric-powered foilboard. These are typically relatively small boards with a hydrofoil attached, and then there is a battery-powered propeller attached to the mast of the foil.
An eFoil will cost you anywhere from $5,000-13,000 today – quite expensive, but very fun! This is a growing market that I think we’ll see a lot of new entrants into and it should be fun to watch the market grow.
eFoils are a breakthrough that’s enabled by the foil because if you tried to just have an electric surfboard, the drag of the board on the water would be too great to get up to higher speeds and the batteries would drain quickly. An eFoil can get up to 25-30 mph.
Wakefoiling is a bit unique in the uses for the foil because wakeboarders don’t really need the efficiency gains as much as other sports since they’re being towed by a boat or jetski.
Adding a foil to the wakeboard can enable some pretty big jumps, though and it lets a rider cruise in the wake of the boat without being towed for an extended period of time. Pretty cool!
That’s right, you can even foil on a large standup paddleboard, but only when you’re actually riding waves. If you’re just paddling out on a lake or river, you’re not likely to get enough speed to really get up on the foil. For that reason, SUPfoil is typically done in the ocean.
Surf foiling is surfing with a foil. The foil actually makes a huge difference to surfers, because you no longer need decent sized waves to catch a ride. Small, crumbly waves that you could never surf without a foil become perfect swells for surf foiling.
The other epic thing about surf foiling is it allows you to “pump” the foil to extend your ride – even for miles! Less time waiting for a wave, more time surfing.
Finally, foiling is done in many sailing races today (but with much larger foils). These foils can get the entire hull of a boat up out of the water, giving massive speed advantages over any boat that has to cut through the chop of the water.
How Does Foiling Work?
I’ve read a lot of explanations of “how hydrofoils work” on the internet and I’ll be honest – these things are magic and very difficult to explain.
My basic, simple explanation is that as water flows over the top of the front wing of the hydrofoil, it is accelerated off the back of the wing at a downward angle, creating an upward lift.
This is why the design of the front-wing is so important to how the hydrofoil performs. Large front-wings with more surface area will generate more lift at lower speeds, getting you up out of the water sooner.
Smaller front-wings don’t generate as much lift at lower speeds, but they have higher top-speeds.
Have a better way to explain how foiling works? Please share it in the comments!