Sailing Faster than the Wind
For all those of you thinking this is a typo - it’s not. In fact, ask any sailing enthusiast, and they will tell you that one of the most intriguing things that put sailing at the top of the list for adventurers and thrill-seekers (and those who just love being out in open waters) is that you can literally sail faster than the wind speeds.
However, it is important to add here that it depends on the right conditions and the right technique. That being said, the great news is that even a beginner who has never stepped foot on a sailing boat can also learn how to sail faster than the wind with the right training and effort. While many avid boaters cannot explain the physics of this phenomenon or how it’s possible to beginners, it is commonplace amongst many avid sailors.
To find out just how this is possible, we need to take a look at the experts. For those who follow America’s Cup, you will know that the sailboats there are tremendously sleek and fast. For instance, catamarans such as the AC72 can travel at speeds three times that of the wind, given the right conditions.
In fact, with the right conditions, boats can record speeds of up to 44 knots when the wind speed that’s blowing the sails is just south of 15 knots. So, how does this happen if the wind is the only thing that is powering these boats? To the layman, it may seem like these sailboats are defying the laws of physics. But this isn’t the case at all.
Conservation of Energy
In physics, one often hears the term “conservation of energy.” While there is no way for us to create energy when it comes to speed, a parallel theorem exists for the conservation of speed, which is applied to sailing faster than the wind. In other words, the sails in sailboats might not be able to create their own energy, but using the right technique, the sails are able to harness more than one kind of wind out there.
This is something that’s often difficult for beginners to grasp, but the technique works similar to how jet airplanes harness airflow in order to fly faster.
True Wind vs. Apparent Wind
The type of wind you feel when you start moving is known as “apparent wind” and is exactly the type of wind that sailors and boat enthusiasts harness when they want to sail faster than the wind.
To differentiate between the two, the wind that one feels when they are standing still is called “true wind,” and the wind that one feels while they are in motion is apparent wind. Harnessing both kinds of winds is key to getting the sailboat to sail faster than the wind speed.
So, how do true wind and apparent wind work when it comes to pushing sailboats forward? The short answer is that the sails of the boat need both of these winds to go faster, but both aren’t necessarily performing the same function when it comes to pushing a sailboat forward.
For instance, the true wind helps push the sailboat forwards, as in, when the sails of the boat are perpendicular to true wind and are being pushed from the back. But while true wind helps push the sailboat’s sails forwards, the apparent wind is dragging or pulling the sailboat forward as well.
It should be noted that the sails of a sailboat cannot take full advantage of the force of apparent wind, especially when the wind is hitting flat against the sail. This is why experienced sailors tend to drive their sailboat at a specific angle, and it is not until the boat is traveling at the angle of true wind that the force of both these types of wind kick in and push the sailboat even faster.
Achieving Lift
So, the sailboat is not capturing wind from just one angle; it is harnessing the power of two opposing winds. One that is pushing the sailboat forward and the other that is dragging it forward, which produces lift. This is why sailboats seem like they are in the air during a race because they are traveling incredibly fast.
This is the same lift that one feels when they are driving a car. The next time you are driving a car, stick one of your hands out the side with the palm facing the ground. Now, slowly raise your palm towards the wind, and you will find that your whole arm lifts automatically. This is what the force of lift does in airplanes – and now, you know that this happens in sailboats as well.
Lift is the force that is generated whenever apparent wind bends around the outsides of a sail. This is important to understand because this is where all the magic happens. Since the wind hitting the inside of the sail is moving a lot slower than the wind around the sail, this creates a significant pressure difference, which is what creates the lift that is so important for planes and sailboats to pick speed.
This is why the push and drag that sailors experience when angling the sailboat to catch the true and apparent winds is quite similar to what passengers feel under their feet whenever a plane starts to take off from the runway.
However, while a passenger in a commercial airplane may not have much control over what to do about it, the push and pull sailors sense is what allows them to act accordingly. This can only be achieved through time and a lot of practice. So, the next time you see a catamaran’s hulls raised off the waters, you know that the sailors who are maneuvering the boat are harnessing both true and apparent wind to their advantage.
Foiling
But that’s not the only trick up a sailor’s sleeve. Those looking to achieve incredible speeds often use a technique that is known as “foiling.” This is a technique that pushes both of the hulls off the water, which makes the sailboat appear like it is in the air. This is one of the techniques that can be used in smaller sailboats effectively. With just the rudder and the board used to anchor the sailboat, foiling allows the sailboat to reach even higher speeds since there is no drag force that’s slowing down the boat.
The fundamental principle of sailing is pretty straightforward: the sails are used to catch the wind, which is then sent down to the hull and helps move the sailboat forward. While that’s how the sails of a sailboat are supposed to work, if you want to sail faster than the wind, you will need to try out the techniques mentioned above and hone your skills with a lot of practice. So, can sailboats sail faster than the wind? Absolutely!
