Everything from Stem to Stern That You Need to Know About Getting in the Wind

How Do Sails Work?

A wise man once said, “A bad day sailing is 100 times better than a good day at work.” For those who have known the water at her worst and best, the words couldn’t be truer. The sea or lake is the muse and temptress of all who venture in this sport. Its elegance belies its demands. That may make you ask, how do sails work?

The simplicity of sails puts it on the brink of genius. How could something so basic power something so great as the tall ships that the likes of Christopher Columbus rode to traverse the seas and discover a nation?

History of Sailing

You could almost say that sailing is a part of the collective DNA. Water, of course, is the primordial draw. It also represented a massive obstacle to exploring more of the planet. Merely observing nature will provide all the necessary clues. Watch birds fly or leafs floating in the breeze. The concepts of aerodynamics and upwinding become evident.

The early history of sailing remains murky. However, the Greeks had it well in hand by 1200 BC. The Egyptians likely figured it out a couple of thousand years before that. Fast-forward to the Renaissance with its reign of tall ships that opened up trade routes and the arrival of European settlers to the United States.

Sailing has continued to evolve from their early roles in exploration and discovery. Participants see as a recreational activity with 1,300 yacht clubs in the country. The demographics are different too, with sailors more likely to have over $2 million in assets and a $50,000 ride. It has become more of a gentleman’s sport than a vital transportation mode.

Today, about 742,000 Americans have fallen under its spell, not including the ones along for the ride. It’s no wonder that recreational boating has sailed to its 10-year high. Cruising is the primary activity with racing not too far behind the pack. The technology has also changed and impacted the mechanics of sailing. The concept has remained the same, with improvements in the design and materials.

Anatomy of a Sailboat

The typical design provides the info you need to know about how sails work. Variations to the basic plan act on the specifics of speed and maneuverability. Most crafts have eight components. First, there is the hull which is the body of the boat with the keel, rudder, and tiller. Then, you have the business end, which includes the mast, boom, jib, and mainsail.

A sailor uses the tiller to maneuver the rudder and direct the movement in the water. The keel keeps the craft from tipping over and capsizing. The mast is the foundation for the boom on the bottom of the mainsail, running parallel to the hull. The jib is the power backup. Another component, the spinnaker, provides additional support when heading downwind.

The design means that the pilot has to take a more active role in the control of the vessel. The engine in a powerboat takes on that job of many of the functions of the additional components of a sailboat. It helps to explain the differences in boat prices too.

Sail Construction

The first sails were square-riggers.  The sail consists of cloth sail, bound by two horizontal wooden poles or spars. One laid across the top and the other along the bottom. The mast was in the center.

The square or rectangle shape created the elements necessary to harness the aerodynamics of the wind to move the vessel forward—and only forward. That was their drawback. They worked fine for this purpose as long as that was the direction you needed to go. Otherwise, you had to row. Nevertheless, it served history well for centuries.

Shipbuilding continued to improve, focusing primarily on the hull and its components. Soon, builders started making boats sleeker to cut through the water quicker and more efficiently. That meant a change in the shape of the mainsail to the triangular form you see today to complement the innovations.

Back in the day, sailors relied on natural fabrics like cotton, flax, and hemp. However, these materials had their issues too. They couldn’t handle the strong forces of the wind for long before becoming frayed or tearing. They were also heavy. Bring on the tensile sails made of polyester, nylon, Kevlar, and Dacron.

These synthetic fibers are stronger and bring other advantages to the forefront, such as heat resistance. Their superiority is evident when you consider that some have other more demanding applications, such as tires and hull construction.

Laminated sailcloth offers added reinforcement in all directions. They are lightweight without compromising on durability. There are even carbon fiber options for the ultimate in strength for activities like racing.

How Sailing Works

You first need to understand the wind and its function in sailing. There are two kinds when on the water. There is the true wind, which is what you experience when you walk outside. Apparent wind is what is rushing past you as you race across the water plus the true wind. It’s the power behind the sail.

Physics and Sailing

Several physics principles come together to make sailing possible. First, there is the aerodynamics of the wind. Then, you have the hydrodynamics of the water. Then, there’s that question of staying afloat. The sailboat must keep its density less than the water while displacing enough to equal its weight to stay above the water. Thus, there is the hollow hull and the elongated shape of a sailboat that ticks off both boxes.

Moving forward involves the wind catching the sails from behind and creating lift. It’s not unlike the forces you see in action with a kite. That’s the easy part when you are upwind of the breeze. Going into it is another story. That’s where tacking comes into play.


Instead of letting the wind push you lazily along, it’s now pulling your boat forward. To control your direction and the angle that the wind hits the sails, it’s necessary to use a zigzagging track called tacking or up winding. The water is creating a sideways thrust at the same time. The wind then counters both actions and moves forward.

The sailor will then tack the opposite way to stay on course. At the same time, the sails are creating drag. The newer materials help reduce it because of their slicker surfaces.

The keel has a ballast which is a weight designed to keep the boat from tipping or heeling. It also takes on the role of displacing water and helps right the craft. Controlling the combined forces of the water and wind along with the angle of the boat is what makes sailing so challenging.

The magic number is 30 degrees before you end up in the drink. Telltales help sailors stay on an even keel. They are strands of colored material attached to the luff or leading edge of the mainsail and the jib.

When tacking correctly, they should stream upwind or to the back or aft of the boat. Telltales also are an indicator of how to adjust or trim the sails.


The water, of course, isn’t staying still while all of this is happening. That makes knowing about the direction in which it is moving essential. If it’s going the same way you are, you’re in luck with a boost of power and speed. However, it also puts an uncontrollable factor into the mix with little room for error.

That’s why anyone sailing on ocean waters must know the timing of currents and tides. Nautical charts provide accurate information to plan trips in keeping with these factors. On smaller bodies of water, you can use the Beaufort Wind Scale to give you an indication of the speed, and thus, the impact on the wave action.

Whitecaps are a sure sign of more challenging sailing experience. They start to become a reckoning factor at 11 knots or nautical mile. It equals 1.15 mph. Higher speeds can also affect docking or mooring.

Types of Sailboats

Researching the different kinds of vessels will give you a clue about the range of sailboat prices. There are three primary kinds of sailboats based on their design. Each one has an effect on the sailing experience in different ways. They include

● Keel      

● Hull       

● Mainsail and mast configuration


These include familiar types of sailboats that you may first picture. They may have one or more along with different designs for various purposes. The keel may run the entire length of the hull. Others have a centerboard that the sailor can control. The latter is an excellent option for high-performance watercraft and racing.

Bilge keel sailboats are ideal if you live in an area that experiences tidal shifts in the water. These vessels can stand up when the tide goes out, leaving it off the mud or sand to protect the underside. As you may expect, they are more difficult to handle with the added weight on the hull.


These sailboats rely on their form and number of hulls to provide the stability and speed of a keel. They’re named based on the number they have. A monohull, as the name implies, has only one. A catamaran has two, whereas the trimaran has three.

This pattern makes them wider for added stability. They may include a cabin on-deck or within the hulls. These sailboats are expensive and will have you busting out that boat payment calculator to see if they’re an option. These sailboats are fast and are ideal for day cruising.

Mainsail and Mast Configuration

These boats get their name from the number and placement of these components. The simplest is the cat or catboat. It has only one mainsail which is located in the front or bow of the craft. The next step up is the sloop. It has two sails on one mast.The cutter is similar to the sloop. Only its mast is located farther back in the boat so that you can have two headsails or jibs on the rig. The ketch has two masts with one positioned toward the bow and a second mizzen mast in the aft region. A schooner takes it to the next level with two or more masts.

Specs and Performance

The specs of a sailboat can provide valuable clues about its performance, speed, and stability. They relate back to the physics of sailing and the impacts of different measurements. The most significant factors are

● Weight

● Length

● Ballast

The displacement/length (D/L) ratio, for example, gives an indication of a boat’s speed based on its weight relative to its length at the waterline. A small figure means that it’s lighter and therefore, faster. However, it also means you have to pay closer attention to what you stow on board because of its effect on performance.

Wind becomes a more significant factor, especially when upwinding. You may find yourself reefing or reducing the sail’s surface area if things get lively on the water. You may have trouble handling the boat too. The figures can range anywhere from 100 for a lightweight craft to 400 or more for a heavy sailboat.

Another essential number is the angle of vanishing stability (AVS). It measures how far before you tip the boat. However, it also gives you an idea about how fast the vessel will recover. A high figure makes for a safer ride, but you’ll give up some maneuverability with the added weight.

The number over 90 tells you how far below the horizon that the vessel can roll. If it’s 120, that means 30 degrees below it. Another thing to bear in mind is how quickly you’re vertical again, which is typically within two minutes. That’s a long time when you’re underwater.

The sail area/displacement ratio calculates the sail’s power in relation to the weight of the sailboat. The higher the number, the wilder the ride. If you want a cruising vessel, a lower number is better, though adding extra pounds onboard can tame it so some degree.

You’ll get more out of your sailboat’s performance—at a price. You’ll also have a tougher time managing her. Anything over 20 puts you in that category.The number of crew members is another vital factor when considering performance. Heeling requires quick action and strength. The wind constantly changes too, especially if you’re cruising closer to shore where it can swirl around structure or blow harder through channels.

Benefits of Sailing

The primary benefits of this sport lie with the means of transportation. It is quiet, which adds to the experience of connecting with nature and the water. Some groove on the rush of the challenge of meeting the wind head-on and maneuvering through it. It’s undoubtedly part of the reason that some get into racing. It’s different than riding a personal watercraft with the added skill involved.

Some may argue that an engine gets in the way of your relationship with the water. You control everything, well, almost everything. She still has the final say. After all, that’s one reason that sailboats have the right-of-way because of the lack of control they have when relying on wind power. That also speaks to another significant advantage they have over power boats. Sailboats use less fuel.

Even if you’re using an auxiliary motor, it’s nowhere near the same as a 350-horsepower motor. Sailors like to brag about the minimal amount of fuel they use. While you’ll save on gas, you’ll likely pay more for the rig outright because of the components when compared to used outboard motors. You can think of it as the initial cost of a renewable energy source versus a fossil fuel source.

Cons of Sailing

Sailing is not without its downsides, which are essential to consider when making a move to a wind-powered vessel. First, there is a learning curve. You don’t just drop into the cockpit and go sailing. It requires physical and mental engagement. If you’re looking for a more leisurely, hands-off experience, you may not find it here.

You may also have some issues with navigation because of the masts, especially if you have to go through channels with limited clearance. You also have more maintenance with the sails and ensuring that they are in good shape and free from rips. Also, there is the fact that the best sailing times are not necessarily the ideal boating days because of the wind. It’s breezy, and spray.

Sailing is one of the best ways to connect with the water. Purists can enjoy the fact that it connects with nature in a way that no other form of boating can. Boaters that are far from the water in a floating bridge can’t feel the same connection or excitement when your sailboat threatens to capsize. The sport can challenge you like no other with an opponent or friend who’ll make sure that it’s never boring.