life-of-sailing-logo

How Do Sailboats Work Without Wind?

How Do Sailboats Work Without Wind? | Life of Sailing

Last Updated by

Daniel Wade

June 15, 2022

When it comes to sailing, the momentum that's brought about by wind is exactly what propels your sailboat. But what happens when there's no wind and it feels like the sailboat is sitting on the water going nowhere? Well, the sails will become slack and your sailboat will just drift along. So unless you have oars or a motor attached to a propeller, you might not go anywhere.

Although the total absence of wind is physically impossible when out there on the water, it can sometimes happen and you may be wondering what to do with your sailboat as it mainly relies on the wind. Of course, it will feel eerily strange because your sailboat will just drift along given that a sailboat with no wind has no propulsion. So whether the wind is blocked by land or there's just no wind on the water, it's of great importance to know how sailboats work without wind.

When sailing there are those weird times when it may feel like there's no wind to propel your sailboat. In most cases, you'll have two options when there are no winds to propel your boat. You can either choose to row your sailboat, which can be very exhausting or you can resort to the motors if they're attached to your propellers.

But if these options aren't available for you, then you may have to tide over and just float with the tides and wait for the wind to return. In essence, you may have to make a small amount of wind work until a larger amount of wind is available.

In this brief article, we'll highlight how you can get around when there's no wind to propel your sailboat.

Table of contents

Know Various Parts of Your Sailboat

Sailboats are not like cars. You definitely know that you can drive your car without necessarily knowing how the car's piston or engine works. All you have to do is use the ignition to turn on the engine, shift into the required gear, step on the gas pedal and you'll be good to go. Unfortunately, the same cannot be said of a sailboat. Well, you have to play a far more active role in bringing together and harnessing the power that propels the sailboat forward, which in this case, is the wind.

Without having the winds in your sails, the boat will not move forward. Instead, you'll only drift along and get stuck in the neutral. Worst still, you can easily capsize. As such, it's of great importance to have a good grasp of how the wind works in propelling a sailboat and what you can do without it.

When there are forces of the wind on the sails, it's referred to as aerodynamics and can propel the sailboat by lifting it in the same way the winds lift an airplane wing. Generally, the force of the wind that lifts and propels the sailboat often contains sideways force and small forward force and so you need to trim the sails accordingly so that you can experience the least resistance. But what happens when there's no wind? Well, here's what you can do.

You can rely on Hydrodynamics of the Water Flow

As we noted earlier, it's physically impossible to have a total absence of wind while out there on the water. But even if it happens, which is of course very rare, you can rely on the heat from the warm zone to the cold zone, which will definitely create some form of hydrodynamics or flow, which would then create currents to at least propel your sailboat even if not in the same way as the winds.

In terms of relativity, strong winds may not be of great help to you when it comes to propelling your sailboat if it's accompanied by insignificant currents. Similarly strong currents with insignificant winds may not be of much help in propelling a sailboat. However, many modern sailboats are designed in such a way that they can work just fine even when there are strong currents with insignificant winds without a lot of modifications.

The most important thing is to ensure that the sails of your boat are relative to the existing strong currents. For example, if the existing currents have a speed of 15 knots, it would be easier to propel your sailboat using the same exact techniques you'd use when you have the winds or 15 knots. The idea here is the many modern sailboats are designed with hydrodynamic engineering techniques that make them feel as if you have 15 knots winds when the currents are at 15 knots.

The only difference may revolve around the fact that in addition to the normal sailing speed that you're managing, you also have to manage the 15 knots offset in the direction of the currents. This explanation may seem complex from the onset but it's pretty much easy. When there's no wind and you're trying to sail with the current, it means that you're technically trying to sail upwind, so you have to apply the similar techniques that you always use when sailing upwind.

Sailing with the Current

Simply put, sailing upwind means that you're sailing exactly anti-parallel to the wind. This revolves around the wind blowing into the sails and pushing against them. The science behind this is that the wind is faster than a sailboat, which leads to the air getting decelerated by the sails. The sails will push back against the wind so the wind pushes forward on the sails. It's a lot easier to sail upwind because the wind pushes you in the same direction it is going but it may not offer the most interesting way of sailing.

The same can be said when you have to rely on the currents when there are no winds. The only difference is that the currents will push the keel if you're sailing in the direction of the currents.

Sailing against the Current

The problems revolving around sailing without winds may start sneaking up their heads when you're sailing against the currents. You will most likely drift along, remain afloat, or even make negative progress. As such, the best thing is to deal with the situation by tiding over and doing your best to remain afloat until the winds fill up your sails.

You have to remember that it's almost impossible to control the direction of your sailboat by just relying on a single strong current. Generally, a sailboat can only go in a different direction from the direction in which the wind is blowing because it has a second sail, which is the keel under the water. But because you can no longer use the actual sails, you only have the keel and it will be impossible to apply both the aerodynamic forces of the wind and the hydrodynamic forces of the water currents, and your sailboat will most likely remain stagnant or make a negative process if you have to travel against the currents with no winds.

On the contrary, if you're drifting the direction of the very fast currents, you'll get your sailboat moving even when the wind speed over land is zero. Of course, you won't get lots of speed but you'll make some progress.

Relying on Propellers

If your sailboat has motor propellers, then it will be pretty much easy to propel your sailboat even when there are no winds. The propeller works by literally using a portion of the forward energy to propel the sailboat forward while directing the same energy back to the propeller to blow backward. This then creates additional energy and an additional thrust in some form of a domino effect or an amplifying cycle.

So if you anticipate that a time may come that your sailboat might have to work without wind, you can choose to fit your sailboat with a folding or feathering propeller to give you an extra knot when the sails seem not to be the reliable option just because there are no winds. Many modern propellers are designed not just to minimize drag but also in a position perpendicular to the water flow. This is to help them have a neutral cutting edge to the water and can propel the boat ahead.

If your sailboat does not have motor propellers and you do not want to rely on the currents, your remaining option would be to go back to the good old days when muscles were the order of the day. You can do it the way Egyptians and Romans used to do by rowing your boat. This can be quite exhausting but it's good for your body and soul if you have to move forward at all costs.

The idea here is that you have to be your own wind by creating opportunities for yourself. Rowing will be tiresome but it can give you the right momentum that you need when the wind comes back. So if there is no wind, no propellers, and the currents are working against you, rowing could be an ideal alternative.

To this end, it's important to be prepared in the event that there are no winds to propel your sailboat. Knowing what to do in such a situation can be the difference between life and death. And even if you've decided to sail with the water currents, use propellers (if they're already fitted on your boat), or have to row your boat, just don't take your sails down. It won't be long before the wind comes so you should give up just yet.

Related Articles

I've personally had thousands of questions about sailing and sailboats over the years. As I learn and experience sailing, and the community, I share the answers that work and make sense to me, here on Life of Sailing.

by this author

How to Sail

How Do Sailboats Work Without Wind?

Most Recent

What Does "Sailing By The Lee" Mean? | Life of Sailing

What Does "Sailing By The Lee" Mean?

October 3, 2023

The Best Sailing Schools And Programs: Reviews & Ratings | Life of Sailing

The Best Sailing Schools And Programs: Reviews & Ratings

September 26, 2023

Important Legal Info

Lifeofsailing.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon. This site also participates in other affiliate programs and is compensated for referring traffic and business to these companies.

Similar Posts

How To Choose The Right Sailing Instructor | Life of Sailing

How To Choose The Right Sailing Instructor

August 16, 2023

How To Sail From California To Tahiti | Life of Sailing

How To Sail From California To Tahiti

July 4, 2023

How To Tow A Skier Behind A Boat | Life of Sailing

How To Tow A Skier Behind A Boat

May 24, 2023

Popular Posts

Best Liveaboard Catamaran Sailboats | Life of Sailing

Best Liveaboard Catamaran Sailboats

December 28, 2023

Can a Novice Sail Around the World? | Life of Sailing

Can a Novice Sail Around the World?

Elizabeth O'Malley

Best Electric Outboard Motors | Life of Sailing

4 Best Electric Outboard Motors

How Long Did It Take The Vikings To Sail To England? | Life of Sailing

How Long Did It Take The Vikings To Sail To England?

10 Best Sailboat Brands | Life of Sailing

10 Best Sailboat Brands (And Why)

December 20, 2023

7 Best Places To Liveaboard A Sailboat | Life of Sailing

7 Best Places To Liveaboard A Sailboat

Get the best sailing content.

Top Rated Posts

Lifeofsailing.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon. This site also participates in other affiliate programs and is compensated for referring traffic and business to these companies. (866) 342-SAIL

© 2024 Life of Sailing Email: [email protected] Address: 11816 Inwood Rd #3024 Dallas, TX 75244 Disclaimer Privacy Policy

how do sailboats work without wind

How Do Sailboats Work Without Wind?

how do sailboats work without wind

You’ve been watching the weather forecast all week. When you woke this morning and looked outside, the day is as gorgeous as the weather predictors had promised. It looks like a perfect day to be on the water! But what do you do when the air isn’t moving – and there seems to be no wind to fill your sails?

How do sailboats work without wind? If there isn’t enough wind to move your boat in the direction you want to sail, here are six ways you can get yourself sailing:

  • Use your motor.
  • Pump your rudder.
  • Row your boat
  • Use the physics of weight distribution. 
  • Be patient, relax, and enjoy the moment.

People love to debate this topic. Some even begin with, “There’s no such thing as ‘no wind.’” Be that as it may, there will be time when you need to know how to keep your sailboat sailing when there is little to no wind to cruise by.

Six Tips For Sailing Without Wind

  • Use your motor : The first tactic is one of the easiest and most obvious. Granted, you wanted to go sailing today, not boating, but you’ll need to use your motor some to get to a place on the water where you can either:
  • Find some wind, or
  • Use the wind you manufacture with the motion created by the motor to fill your light-weight cruising sail.

2. Pump your rudder : If you move your rudder back and forth, you will create movement which will, once again, manufacture wind your cruising sail can capture.

3 . Use a fan: Some feel that using a fan similar to those used on swamp boats can be helpful. The key to this approach, however, is to point the fan away from the sails.

It seems counterintuitive but blowing the fan into the sails will actually create a circular wind motion that will blow the wind back out of the sails again.

4. Row your boat : This option will only work if you have a smaller sailboat. It’s also exhausting. But… using your oars is an option.

5. Use the physics of weight distribution : If you move everyone to the front of the boat to nudge the bow down and raise the stern some, the water’s current may generate enough wind to make your cruising sail more effective.

6. Be patient, relax, and enjoy the moment: If your overall goal was to be on the water, pop open a beverage, make a snack, and enjoy the time.

You may choose to leave your cruising sail up to catch that elusive breeze when it decides to grace you with its presence. You may also choose to lower your sail and drop anchor. Either way, you have a chance to enjoy the beauty around you.

Now that you’re picturing yourself being the captain of your own destiny on the pristine waters of the world let’s look a little more closely at some sailing terms relating to wind and how they correlate to these options.

Wind by Any Other Name…

Just as you would never refer to a cruise ship as a boat, it’s important to know the correct nautical terms for how the wind blows. Since this article is focused on having no wind, we’ll start there.

1. Becalmed

When you’re on the water, and suddenly your sails deflate, you are becalmed . Merriam-webster.com defines becalmed as “to keep motionless by lack of wind.”

In the sailing race industry, this is a strategy that some opponents use to render the other competitor momentarily ineffective. If one boat passes very closely to another, it may render the original sailboat’s sails useless.

The saying, “ To take the wind out of someone’s sails, ” comes from the use of this strategy.

More often than not, becalmed is used to describe a vessel’s predicament on open water outside of racing circles when there isn’t enough wind to fill the sails and move the sailboat.

2. Easterly and Westerly

It may seem obvious, but these terms are often confused for each other. A wind is an easterly when it is from the east . It follows, then, that a westerly wind is from the west .

3. Offshore and Onshore

These winds follow the same rule as easterly and westerly. If the wind is blowing off of the shore out to sea , it is offshore wind. The shore off which these winds blow are called windward shores.

Conversely, if the wind is blowing from the sea toward the shore , it is onshore wind. The shore onto which the onshore wind is blowing is called the lee shore.

Caution is key when sailing toward a lee shore in an onshore wind as unexpected changes can cause you to run aground. Because of this, it is preferable to sail to a windward shore to allow you better sail management.

4. True Wind and Apparent Wind

When you are standing still on the shore, and you feel an easterly wind blowing, you are experiencing true wind.

As soon as you start moving, however, you are experiencing apparent wind. Apparent Wind is the result of True Wind plus the wind created by motion. When you are on your sailboat, you will only experience apparent wind because if there is true wind, it will cause your boat to move thereby creating apparent wind.

Nautical wind speed. When we’re onshore, we talk about wind in miles per hour. On the water (and in aviation), though, wind is discussed in terms of knots (abbreviated as kn).

One knot is generally the equivalent measure of one statue mile per hour times 1.15.

Knots are used because they correlate directly to the latitude measurement system. To travel one knot, a ship moves one minute of latitude. Navigational directions are given in latitude and longitude, and the knot system ties back to that process.

How Much True Wind Is Needed for My Sailboat to Move?

Some experienced sailors suggest that as little true wind as .02 knots will move your boat forward and that six knots make for near-perfect conditions.

Below is a general rule of thumb of wind-speed breakdowns for various conditions from experienced sailors.

11 Differences of Sailing on a Lake vs. an Ocean

Sailing is sailing – right? Wrong.

Sailing on a lake is very different than sailing on the open ocean. Let’s discuss some of those basic differences.

Note: Lake references exclude The Great Lakes – they are more like ocean sailing than general lake sailing.

1. Navigation Planning

It may seem obvious, but a trip on the lake, or even along the shore, doesn’t usually require an advanced trip plan outside of making sure you have enough gas for your motor, should you have to use it, and having some freshwater and snacks.

Ocean travel, however, means that you need to plan your general route, review wind, weather, and tide forecasts several days out, and stock up.

Most things are digital these days, but there is still value in having up-to-date paper maps displaying general ocean topography and depths.

Even on very large lakes and close to coastlines, the number of boats is significantly more than you would experience on the open ocean. This usually translates to having to be more aware of the boats on the water and making sure you know and adhere to the rules of the water.

3. Wind Gusts

Gusts are a result of wind disruption created by various topography changes on land. That means that wind gusts are more likely to happen on lakes than on the ocean.

4. Waves Sizes

Ocean waves will be much larger than lake waves. This is because the ocean experiences full tides, and there isn’t anything in the open water to keep the wind from creating the waves, whereas the lake is somewhat protected.

5. Wave Frequency

You will probably experience larger waves on the open ocean but will experience more frequent waves in lakes or near the shoreline. The surface wind will create more frequent waves on shallower water than the larger waves created when at sea.

6. Boat Roll

It may seem counterintuitive, but you will experience more boat roll on the ocean than you will on the lake or when shore sailing.

Waves on lakes, and during shore sailing, tend to create a choppy experience. However, there are constant swells deep-sea sailing, which allows for that wonderful lulling experience and sensation.

7 . Knowing Your Boat

When you’re sailing on a lake or even shore sailing, you need to understand your boat, but chances are pretty strong that if something goes wrong, someone else will be around to help you or to tow you back to the marina.

When you’re in the middle of the ocean, you need to be prepared to conduct any necessary repairs yourself. In addition to having a thorough understanding of the mechanics of your sailboat, you also need to be prepared with various spare parts recognizing you have limited storage space.

8. On-Boat Amenities

You wouldn’t necessarily have a lake sailboat that would be the same size as the one you’re going to take to the open ocean waters.

Sure, the basics will all be there, but a weekend lake boat may not have a full galley or even a head (restroom). These are necessities, not nice-to-haves for longer ocean trips.

9 . Available Edible Marine Life

When you’re sailing on a lake, you may be able to catch fresh trout, bass, crappie, and catfish.

Deep-sea fishing may yield opportunities for some wonderful tuna, mahi-mahi, mackerel, and even shellfish.

10. Tying Up at the Dock

Lake levels don’t tend to rise and fall, so it is common to tie closer and tighter to the dock.

Because of the fluctuation of water levels with the tides, experienced sailors leave slack in their lines recognizing that water levels will change up and down.

1 1. Safety Precautions

Regardless of where you’re sailing, life jackets should be available for all people on the boat.

On the surface, it may seem that it would be an unnecessary “inconvenience” when you’re on your local lake, but even on the lake, storms can come up quickly – even unexpectedly.

The additional safety item that is an absolute must for ocean sailing is a jackline. The jackline is a line that runs from the bow to the stern of the boat to which the crewmember attaches himself via a clip attached to his safety harness to keep him from falling overboard in harsh conditions.

Learning to Read the Wind

It’s impossible to be an effective sailor if you don’t understand how to interpret wind changes – particularly in direction and speed. These two dynamics affect how you use your sails, and which sails you use.

To be able to accurately read the wind, there are expensive electronic devices available that are or can be incorporated into your boat’s navigation system.

If you are lake sailing in a smaller boat, you may not want to invest in an expensive navigation and weather system. You might want to consider the following options:

  • Flying a small flag . Some say you can even use strands of yarn on the shrouds to help you determine wind direction – make sure that you make your wind direction readings from the windward side, so the sail doesn’t affect the way the flag acts in the wind.
  • Watch how the wind is impacting the water . Are there ripples (cat’s paws) on the water that used to be really smooth? Does the water all of a sudden seem darker than it used to? If it does, it’s because the wind is changing the water’s texture, but it’s farther off than you can see any ripple effects.
  • Use a small hand-held wind meter. A reasonable option is the Kestrel 1000 . Reliable hand-held wind meters can range anywhere from about $100 to about $600. How much you’re going to spend all depends on how techie and gadget addicted you want to be.

Basic Terms You Should Know About Your Sailboat

You’re getting more and more excited about getting out on the water. While you’re looking for a local school so you can get certified and are able to legally sail your boat, here are some general terms you’ll want to know:

  • Lines – Your sailboat doesn’t have ropes – it has lines. As you learn more about your boat, you will learn that there are different lines for various purposes.
  • Knots – In addition to referring to speed, there are also several maritime knots you need to be able to tie effectively. Among the basic sailing knots are the:
  • Bowline Knot – used when controlling the side-to-side motion of the boat while approaching the dock.
  • Cleat Hitch Knot – used when tying to the dock.
  • Weaver’s Knot – used when extending anchor lines and repairing sails.
  • Square Knot – many of us learned this knot as a child. In sailing, it is used to secure ropes together – often when putting a sail cover over a sail.
  • Trucker’s Knot – used to make sure that items on deck are secure.
  • Figure Eight Knot – used to connect two lines together to prevent one from slipping out of sight.
  • Port, Starboard, Bow, and Stern – These are the different areas of your boat. The bow is the front; the stern is the back. Port is the left side when you are facing toward the bow. Starboard is on the right side while you’re facing the bow. The easiest way to keep port and starboard straight is that port has four letters – so does left.
  • Tack and Jibe – Like knot, tack is also used in two different ways. The first means to change direction by turning the bow through the wind. The second usage is the course you’re on in relation to the wind. Jibing, on the other hand, is when you turn the stern of the boat through the wind.
  • Mainsail and Jib – Both are sails. The mainsail is the largest and most important sail attached to the mast and the boom. The jib is forward of the mainsail and doesn’t have a boom.

In Conclusion

As you are learning more about the process of sailing, you will undoubtedly become more and more excited with each step you take toward overall certification.

One of the best pieces of wisdom offered by seasoned sailors is that sailing is a cumulative experience of proficiency and patience. 

how do sailboats work without wind

I am the owner of sailoradvice. I live in Birmingham, UK and love to sail with my wife and three boys throughout the year.

Recent Posts

How To Sail From The Great Lakes To The Ocean

It’s a feat in and of itself to sail to the Great Lakes. Now you want to take it one step further and reach the ocean, notably, the Atlantic Ocean. How do you chart a sailing course to get to the...

Can You Sail from the Great Lakes to the Gulf of Mexico by Boat? 

You have years of boating experience and consider yourself quite an accomplished sailor. Lately, you’ve been interested in challenging yourself and traveling greater distances than ever before. If...

How Do Sailboats Sail into the Wind?

sailboat-100929-02

It seems intuitive that sailboats, powered only by the wind, can travel easily with the wind at their backs, but it may seem impossible that they turn around and come home again, with the wind blowing straight against them.

But this reverse movement is possible because a moving boat's sail is shaped as an airfoil like the wing of a plane. When air moves over a plane's wing, from front to back, wind flowing over the top of the wing has to travel farther than wind flowing under the wing's bottom surface. This creates a pressure difference that lifts the plane.

On a sailboat, wind blowing against the boat at an angle inflates the sail, and it forms a similar foil shape, creating a difference in pressure that pushes the sail perpendicular to the wind direction.

According to "The Physics of Sailing Explained" (Sheridan House Inc, 2003), by Kent State University physics professor Bryon D. Anderson, this force from the sail's foil shape is combined with and balanced by other forces, including those of the boat's keel (the long thin piece that juts down from the bottom of the boat).

Together, the forces of drag, from the water, and the pressure from the wind against the sail itself push the craft forward. It moves at an angle opposite the direction of the wind, called windward in sailing terminology.

According to the American Institute of Physics' Physics Today magazine, the keel is especially important because without its balancing action, a boat would simply drift downwind.

Windward sailing also does not work if a boat is pointed directly opposite the wind direction, according to The Physics of Sailing. Wind has to be moving against the boat at an angle of at least 40 degrees for most vessels. Angling too sharply into the wind causes the forces on the boat to become unbalanced, and moves the boat sideways in the water.

Sign up for the Live Science daily newsletter now

Get the world’s most fascinating discoveries delivered straight to your inbox.

A sailor intending to travel windward toward a point exactly in line with the direction of the wind will have to zig zag back and forth to reach its target. Using this "tacking" technique, and traveling at an angle as close to the wind's direction as possible, sailors can reach a point in any direction, regardless of the direction of wind.

Got a question? Email it to Life's Little Mysteries and we'll try to answer it. Due to the volume of questions, we unfortunately can't reply individually, but we will publish answers to the most intriguing questions, so check back soon.

Iceland volcano: Gigantic plume of toxic gas from latest eruption is moving across Europe, satellite data shows

2,000 earthquakes in 1 day off Canada coast suggest the ocean floor is ripping apart, scientists say

13 billion-year-old 'streams of stars' discovered near Milky Way's center may be earliest building blocks of our galaxy

Most Popular

By Charles Q. Choi March 22, 2024

By Jamie Carter March 22, 2024

By Nicoletta Lanese March 21, 2024

By Harry Baker March 21, 2024

By Orla Loughran Hayes March 21, 2024

By Stephanie Pappas March 21, 2024

By Sneha Khedkar March 21, 2024

  • 2 India's evolutionary past tied to huge migration 50,000 years ago and to now-extinct human relatives
  • 3 Dying SpaceX rocket creates glowing, galaxy-like spiral in the middle of the Northern Lights
  • 4 12 surprising facts about pi to chew on this Pi Day
  • 5 1,900-year-old coins from Jewish revolt against the Romans discovered in the Judaen desert
  • 2 Speck of light spotted by Hubble is one of the most enormous galaxies in the early universe, James Webb telescope reveals
  • 3 8-hour intermittent fasting tied to 90% higher risk of cardiovascular death, early data hint
  • 4 James Webb telescope confirms there is something seriously wrong with our understanding of the universe
  • 5 Beluga whales appear to change the shape of their melon heads to communicate, scientists discover

ASA / American Sailing

  • Find A School
  • Certifications
  • North U Sail Trim
  • Inside Sailing with Peter Isler
  • Docking Made Easy
  • Study Quizzes
  • Bite-sized Lessons
  • Fun Quizzes
  • Sailing Challenge

how do sailboats work without wind

So, You Need Wind to Sail?

By: Zeke Quezada, ASA Learn To Sail

A sailor’s world revolves around the wind and staying aware of the wind’s direction is crucial. When you are just beginning to sail-you may feel so inundated with all of the new information that it’s easy to lose track of the wind direction. If that happens, just relax, take a deep breath and feel the wind on your face and skin. Your ability to accurately sense changes in the wind, its speed and its direction will improve as you learn. This is an important transition that will occur as you become a sailor.

Points of Sail

Points of Sail Diagram

No sailboat can sail directly into the wind;  it is physically impossible because the sail will not “fill.” By harnessing the forces created by air and water flow, a sailboat can sail remarkably “close” to the wind. 

These are the points of sail and your understanding of them will help in your ability to propel the boat in the direction that you choose. They are an important concept for all sailors to understand and the points of sail dictate the direction any boat can sail relative to the wind direction. 

In Irons (into the wind) AKA No Sail Zone – The sector bisected by the wind direction where a sailboat cannot sail. It is about 90 degrees wide.

Close-Hauled – Sailing upwind as close to the wind as possible, also called beating. This point of sail is very narrow, just a few degrees.

how do sailboats work without wind

Close Reach – Sailing at an angle closer than 90 degrees to the wind (but not quite up to close-hauled).

Beam Reach – Sailing at 90 degrees to the wind direction.

Broad Reach – Sailing at any angle between reaching and running.

how do sailboats work without wind

Running – Sailing “downwind” directly away from the wind.

Time to Practice the Points of Sail?

ASA's Sailing Challenge - Harbor Tour

Take a look at the Sailing Challenge App . The Points of Sail module will help you master your knowledge of the subject. The Sailing Challenge app is a cutting-edge gaming app designed as a fun learning aid to help illustrate the principles of sailing in a rich interactive and entertaining format. Available on Windows | Mac | iPads | iPhones .

Related Posts:

feature_2023-10-24_what-to-expect-beginner-sailing-class

  • Learn To Sail
  • Mobile Apps
  • Online Courses
  • Upcoming Courses
  • Sailor Resources
  • ASA Log Book
  • Bite Sized Lessons
  • Knots Made Easy
  • Catamaran Challenge
  • Sailing Vacations
  • Sailing Cruises
  • Charter Resources
  • International Proficiency Certificate
  • Find A Charter
  • All Articles
  • Sailing Tips
  • Sailing Terms
  • Destinations
  • Environmental
  • Initiatives
  • Instructor Resources
  • Become An Instructor
  • Become An ASA School
  • Member / Instructor Login
  • Affiliate Login

Nomadic Sailing

How a Sail Works: Basic Aerodynamics

Sailboat heeling on the water

The more you learn about how a sail works, the more you start to really appreciate the fundamental structure and design used for all sailboats.

It can be truly fascinating that many years ago, adventurers sailed the oceans and seas with what we consider now to be basic aerodynamic and hydrodynamic theory.

When I first heard the words “aerodynamic and hydrodynamic theory” when being introduced to how a sail works in its most fundamental form, I was a bit intimidated.

“Do I need to take a physics 101 course?” However, it turns out it can be explained in very intuitive ways that anyone with a touch of curiosity can learn.

Wherever possible, I’ll include not only intuitive descriptions of the basic aerodynamics of how a sail works, but I’ll also include images to illustrate these points.

There are a lot of fascinating facts to learn, so let’s get to it!

Basic Aerodynamic Theory and Sailing

Combining the world of aerodynamics and sailing is a natural move thanks to the combination of wind and sail.

We all know that sailboats get their forward motion from wind energy, so it’s no wonder a little bit of understanding of aerodynamics is in order. Aerodynamics is a field of study focused on the motion of air when it interacts with a solid object.

The most common image that comes to mind is wind on an airplane or a car in a wind tunnel. As a matter of fact, the sail on a sailboat acts a bit like a wing under specific points of sail as does the keel underneath a sailboat.

People have been using the fundamentals of aerodynamics to sail around the globe for thousands of years.

The ancient Greeks are known to have had at least an intuitive understanding of it an extremely long time ago. However, it wasn’t truly laid out as science until Sir Isaac Newton came along in 1726 with his theory of air resistance.

Fundamental Forces

One of the most important facets to understand when learning about how a sail works under the magnifying glass of aerodynamics is understanding the forces at play.

There are four fundamental forces involved in the combination of aerodynamics and a sailboat and those include the lift, drag, thrust, and weight.

how do sailboats work without wind

From the image above, you can see these forces at play on an airfoil, which is just like a wing on an airplane or similar to the many types of sails on a sailboat. They all have an important role to play in how a sail works when out on the water with a bit of wind about, but the two main aerodynamic forces are lift and drag.

Before we jump into how lift and drag work, let’s take a quick look at thrust and weight since understanding these will give us a better view of the aerodynamics of a sailboat.

As you can imagine, weight is a pretty straight forward force since it’s simply how heavy an object is.

The weight of a sailboat makes a huge difference in how it’s able to accelerate when a more powerful wind kicks in as well as when changing directions while tacking or jibing.

It’s also the opposing force to lift, which is where the keel comes in mighty handy. More on that later.

The thrust force is a reactionary force as it’s the main result of the combination of all the other forces. This is the force that helps propel a sailboat forward while in the water, which is essentially the acceleration of a sailboat cutting through the water.

Combine this forward acceleration with the weight of sailboat and you get Newton’s famous second law of motion F=ma.

Drag and Lift

Now for the more interesting aerodynamic forces at play when looking at how a sail works. As I mentioned before, lift and drag are the two main aerodynamic forces involved in this scientific dance between wind and sail.

Just like the image shows, they are perpendicular forces that play crucial roles in getting a sailboat moving along.

how do sailboats work without wind

If you were to combine the lift and drag force together, you would end up with a force that’s directly trying to tip your sailboat.

What the sail is essentially doing is breaking up the force of the wind into two components that serve different purposes. This decomposition of forces is what makes a sailboat a sailboat.

The drag force is the force parallel to the sail, which is essentially the force that’s altering the direction of the wind and pushing the sailboat sideways.

The reason drag is occurring in the first place is based on the positioning of the sail to the wind. Since we want our sail to catch the wind, it’s only natural this force will be produced.

The lift force is the force perpendicular to the sail and provides the energy that’s pointed fore the sailboat. Since the lift force is pointing forward, we want to ensure our sailboat is able to use as much of that force to produce forward propulsion.

This is exactly the energy our sailboat needs to get moving, so figuring out how to eliminate any other force that impedes it is essential.

Combining the lift and drag forces produces a very strong force that’s exactly perpendicular to the hull of a sailboat.

As you might have already experienced while out on a sailing adventure, the sailboat heels (tips) when the wind starts moving, which is exactly this strong perpendicular force produced by the lift and drag.

Now, you may be wondering “Why doesn’t the sailboat get pushed in this new direction due to this new force?” Well, if we only had the hull and sail to work with while out on the water, we’d definitely be out of luck.

There’s no question we’d just be pushed to the side and never move forward. However, sailboats have a special trick up their sleeves that help transform that energy to a force pointing forward.

Hydrodynamics: The Role of the Keel

An essential part of any monohull sailboat is a keel, which is the long, heavy object that protrudes from the hull and down to the seabed. Keels can come in many types , but they all serve the same purpose regardless of their shape and size.

Hydrodynamics, or fluid dynamics, is similar to aerodynamics in the sense that it describes the flow of fluids and is often used as a way to model how liquids in motion interact with solid objects.

As a matter of fact, one of the most famous math problems that have yet to be solved is exactly addressing this interaction, which is called the Navier-Stokes equations. If you can solve this math problem, the Clay Mathematics Institute will award you with $1 million!

There are a couple of reasons why a sailboat has a keel . A keel converts sideways force on the sailboat by the wind into forward motion and it provides ballast (i.e., keeps the sailboat from tipping).

By canceling out the perpendicular force on the sailboat originally caused by the wind hitting the sail, the only significant leftover force produces forward motion.

We talked about how the sideways force makes the sailboat tip to the side. Well, the keep is made out to be a wing-like object that can not only effectively cut through the water below, but also provide enough surface area to resist being moved.

For example, if you stick your hand in water and keep it stiff while moving it back and forth in the direction of your palm, your hand is producing a lot of resistance to the water.

sailboat wind vector forces

This resisting force by the keel contributes to eliminating that perpendicular force that’s trying to tip the sailboat as hard as it can.

The wind hitting the sail and thus producing that sideways force is being pushed back by this big, heavy object in the water. Since that big, heavy object isn’t easy to push around, a lot of that energy gets canceled out.

When the energy perpendicular to the sailboat is effectively canceled out, the only remaining force is the remnants of the lift force. And since the lift force was pointing parallel to the sailboat as well as the hull, there’s only one way to go: forward!

Once the forward motion starts to occur, the keel starts to act like a wing and helps to stabilize the sailboat as the speed increases.

This is when the keel is able to resist the perpendicular force even more, resulting in the sailboat evening out.

This is exactly why once you pick up a bit of speed after experiencing a gust, your sailboat will tend to flatten instead of stay tipped over so heavily.

Heeling Over

When you’re on a sailboat and you experience the feeling of the sailboat tipping to either the port or starboard side, that’s called heeling .

As your sailboat catches the wind in its sail and works with the keel to produce forward motion, that heeling over will be reduced due to the wing-like nature of the keel.

The combination of the perpendicular force of the wind on the sail and the opposing force by the keel results in these forces canceling out.

However, the keel isn’t able to overpower the force by the wind absolutely which results in the sailboat traveling forward with a little tilt, or heel, to it.

Ideally, you want your sailboat to heel as little as possible because this allows your sailboat to cut through the water easier and to transfer more energy forward.

This is why you see sailboat racing crews leaning on the side of their sailboat that’s heeled over the most. They’re trying to help the keel by adding even more force against the perpendicular wind force.

By leveling out the sailboat, you’ll be able to move through the water far more efficiently. This means that any work in correcting the heeling of your sailboat beyond the work of the keel needs to be done by you and your crew.

Apart from the racing crews that lean intensely on one side of the sailboat, there are other ways to do this as well.

One way to prevent your sailboat from heeling over is to simply move your crew from one side of the sailboat to the other. Just like racing sailors, you’re helping out the keel resist the perpendicular force without having to do any intense harness gymnastics.

A great way to properly keep your sailboat from heeling over is to adjust the sails on your sailboat. Sure, it’s fun to sail around with a little heel because it adds a bit of action to the day, but if you need to contain that action a bit all you need to do is ease out the sails.

By easing out the sails, you’re reducing the surface area of the sail acting on the wind and thus reducing the perpendicular wind force. Be sure to ease it out carefully though so as to avoid luffing.

Another great way to reduce heeling on your sailboat is to reef your sails. By reefing your sails, you’re again reducing the surface area of the sails acting on the wind.

However, in this case the reduction of surface area doesn’t require altering your current point of sail and instead simply remove surface area altogether.

When the winds are high and mighty, and they don’t appear to be letting up, reefing your sails is always a smart move.

How an Airplane Wing Works

We talked a lot about how a sail is a wing-like object, but I always find it important to be able to understand one concept in a number of different ways.

Probably the most common example’s of how aerodynamics works is with wings on an airplane. If you can understand how a sail works as well as a wing on an airplane, you’ll be in a small minority of people who truly understand the basic aerodynamic theory.

As I mentioned before, sails on a sailboat are similar to wings on an airplane. When wind streams across a wing, some air travels above the wing and some below.

The air that travels above the wing travels a longer distance, which means it has to travel at a higher velocity than the air below resulting in a lower pressure environment.

On the other hand, the air that passes below the wing doesn’t have to travel as far as the air on top of the wing, so the air can travel at a lower velocity than the air above resulting in a higher pressure environment.

how do sailboats work without wind

Now, it’s a fact that high-pressure systems always move toward low-pressure systems since this is a transfer of energy from a higher potential to a lower potential.

Think of what happens when you open the bathroom door after taking a hot shower. All that hot air escapes into a cooler environment as fast as possible.

Due to the shape of a wing on an airplane, a pressure differential is created and results in the high pressure wanting to move to the lower pressure.

This resulting pressure dynamic forces the wing to move upward causing whatever else is attached to it to rise up as well. This is how airplanes are able to produce lift and raise themselves off the ground.

Now if you look at this in the eyes of a sailboat, the sail is acting in a similar way. Wind is streaming across the sail head on resulting in some air going on the port side and the starboard side of the sail.

Whichever side of the sail is puffed out will require the air to travel a bit farther than the interior part of the sail.

This is actually where there’s a slight difference between a wing and a sail since both sides of the sail are equal in length.

However, all of the air on the interior doesn’t have to travel the same distance as all of the air on the exterior, which results in the pressure differential we see with wings.

Final Thoughts

We got pretty technical here today, but I hope it was helpful in deepening your understanding of how a sail works as well as how a keel works when it comes to basic aerodynamic and hydrodynamic theory.

Having this knowledge is helpful when adjusting your sails and being conscious of the power of the wind on your sailboat.

With a better fundamental background in how a sailboat operates and how their interconnected parts work together in terms of basic aerodynamics and hydrodynamics, you’re definitely better fit for cruising out on the water.

Get the very best sailing stuff straight to your inbox

Nomadic sailing.

At Nomadic Sailing, we're all about helping the community learn all there is to know about sailing. From learning how to sail to popular and lesser-known destinations to essential sailing gear and more.

Quick Links

Business address.

1200 Fourth Street #1141 Key West, FL 33040 United States

Copyright © 2024 Nomadic Sailing. All rights reserved. Nomadic Sailing is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means to earn fees by linking to Amazon.com and affiliated sites.

Boat Pursuits Logo

How Do Sailboats Work? (The Complete Guide)

how do sailboats work without wind

Ever wondered how a sailboat moves through the water? If so, you’re in the right place! In this article, we’ll explore the science behind sailboats, from what they are to the parts they use to move.

We’ll uncover the basics of how to angle the sails, the role of the rudder, and safety tips that every sailor should know.

Finally, we’ll dive into the many benefits of sailing, from the joy of exploring the open waters to the feeling of accomplishment when you reach your destination.

So, if you’re ready to discover the wonders of sailboats, let’s get started!

Table of Contents

Short Answer

Sailboats use the power of the wind to propel them forward.

The sails are designed to catch the wind, and as the wind passes through the sails, it creates lift which moves the boat forward.

The sails can be adjusted to different angles to maximize the lift and the direction of the boat.

The rudder is used to steer the boat and the keel helps to keep the boat stable in the water.

What is a Sailboat?

A sailboat is a type of boat that uses sails to propel itself through the water.

The sails are usually made of lightweight, durable fabric, such as nylon or polyester, and are attached to a mast which is mounted on the boat.

The sails are designed to catch the wind, which pushes the boat forward.

The sails can be adjusted and angled in order to capture more or less of the wind, allowing for more efficient movement.

The rudder of the boat is a large fin-like structure located at the back of the boat which is used to steer the boat in the desired direction.

With the right skills and understanding of how sailboats work , anyone can enjoy the thrill of sailing.

How Does a Sailboat Work?

how do sailboats work without wind

Sailboats use the power of the wind to move through the water, allowing them to be an efficient and eco-friendly way to explore the open seas.

In order to understand how sailboats work, its important to understand the parts that make up a sailboat and how they interact with the wind.

The most important part of a sailboat is the sail, which is typically made of lightweight and durable fabric.

The sail is held up by a mast attached to the boat, and it is designed to capture the wind and use it to push the boat forward.

The sail is able to capture more wind when it is angled in a certain direction, allowing it to move faster and more efficiently.

In addition to the sail, sailboats also have a rudder that helps steer the boat in a desired direction.

The rudder works in conjunction with the sail to allow for precise maneuvering of the boat in any direction.

The rudder is typically located behind the boat and is made of a solid material like wood or metal.

Another important part of a sailboat is the keel, which is a fin-like structure that is attached to the bottom of the boat.

The keel helps stabilize the boat and keep it upright in the water.

It also helps the boat stay in a straight line when sailing in a straight direction.

Finally, the sailboat must have a rigging system, which is made up of ropes and lines that are used to control the sails.

The rigging system is used to adjust the angle of the sail to capture the most amount of wind and move the boat forward.

With the right knowledge and understanding of how sailboats work, anyone can enjoy the thrill of sailing.

Understanding how to use the sails, the keel, the rudder, and the rigging system together will help you become an expert sailboat captain in no time.

The Parts of the Sailboat

Sailboats are propelled by the force of wind on their sails, and the most important part of the sailboat is the sail itself.

The sails are typically made of lightweight, durable fabric and are held up by a mast attached to the boat.

The angle of the sail is what captures the wind, allowing for more efficient movement.

The rudder of the boat helps steer it in the desired direction, working in conjunction with the sails to allow for precise maneuvering.

In addition to the sail and mast, the sailboat also contains a boom, which helps hold the sail out when the wind is blowing.

The boom is connected to the mast and can be adjusted to control the angle of the sail.

Additionally, the sailboat features a keel, which is a fin-like structure that helps keep the boat stable and upright in the water.

The keel also helps the boat move in a straight line when the wind is blowing.

Lastly, the sailboat features a tiller, which is the handle used to steer the rudder.

These are the key parts of a sailboat that allow it to move through the water.

How to Angle the Sails

how do sailboats work without wind

Angling the sails is an essential part of sailing a boat effectively.

By adjusting the angle of the sails in relation to the wind, you can capture more of the winds power to propel the boat forward.

To angle the sails correctly, the sailor must first identify the direction of the wind.

This can be done by feeling the air on their face, or by looking for telltale signs like rippling water or flags flapping in the wind.

Once the wind direction is known, the sailor must adjust the angle of the sails so that they will catch more of the winds power and propel the boat forward.

The most efficient angle for the sails depends on the type of boat and the strength of the wind, but in general, the sails should be angled so they are at a 45-degree angle to the wind.

This allows the sails to catch the most wind and propel the boat forward with the most efficiency.

It is also important to make sure that the sails are not too close to the boat, as this can cause them to lose their shape and be less effective.

In addition to angling the sails correctly, the sailor must also be aware of the wind speed and direction.

As the wind speed and direction change, the sailor must adjust the angle of the sails in order to stay on course and maintain the most efficient angle for catching the wind.

By making small adjustments to the sails angle, the sailor can keep the boat moving in the desired direction and maintain the most efficient speed.

Sailors must also be aware of how their body weight can affect the angle of the sails.

If the sailor leans too far to one side of the boat, the angle of the sails will be affected.

This can result in the boat veering off course or the sails not catching the wind efficiently.

To prevent this, the sailor must be aware of their body weight and be mindful of how it affects the sails.

By understanding and being aware of how to angle the sails correctly, sailors can ensure that they are using the power of the wind to propel their boat forward efficiently.

With practice and experience, anyone can become a skilled sailor and enjoy the thrill of sailing.

The Role of the Rudder

The role of the rudder on a sailboat is essential for steering and maneuvering the boat in the desired direction.

The rudder is typically located at the stern of the boat and is a flat piece of metal or wood that is connected to the hull and runs along the bottom of the boat.

By changing the angle of the rudder relative to the hull, the boat can be steered in the desired direction.

When the rudder is angled to the left, the boat will turn to the left and when the rudder is angled to the right, the boat will turn to the right.

The rudder is also used to keep the boat on a straight course when sailing in strong winds.

By angling the rudder slightly, it helps to create a drag on one side of the boat and a lift on the other side, allowing for greater control and stability in high winds.

In addition to the rudder, sails can also be angled to help turn the boat in the desired direction.

Together, the sails and the rudder work together to help the sailor steer and maneuver the boat in the desired direction.

Safety Tips for Sailing

how do sailboats work without wind

Sailing is a popular recreational activity, but it can also be dangerous if not practiced safely.

Before setting sail, it is important to be aware of some key safety tips that will help you enjoy your sailing experience without any hiccups.

First, make sure you have the proper safety equipment onboard.

This includes life jackets, flares, a first-aid kit, and a fire extinguisher.

It is also a good idea to carry a radio or GPS device onboard in case of emergency.

Additionally, make sure that the boat has been inspected and is in good working condition before leaving the dock.

It is also important to check the weather before setting sail.

Make sure you are aware of any storms or other hazardous conditions that may be in the forecast.

Make sure to also check the tide and wind conditions before leaving, as these can greatly affect your course and speed.

It is important to wear the proper clothing when sailing.

Choose clothing that is lightweight, breathable, and waterproof.

Make sure to also bring a hat or visor and sunscreen to protect yourself from the sun’s rays.

Additionally, make sure you have plenty of food and water onboard in case of emergency.

Finally, make sure you have a good understanding of the sailing basics, such as sailing terms, the parts of the boat, and how to properly sail.

Knowing these basics, as well as the local rules and regulations, will help ensure a safe and enjoyable sailing experience.

By following these safety tips, you can ensure that your sailing experience is a safe and enjoyable one.

Be sure to always practice good safety habits and use common sense when out on the water.

With the proper preparation and knowledge, sailing can be a fun and enjoyable experience.

The Benefits of Sailing

Sailing is an activity that can provide countless benefits to those who take part in it.

Not only can it be great fun, but it can also be a great way to relax and get away from the hustle and bustle of everyday life.

Sailing can also increase physical and mental wellbeing, as it provides an opportunity to be out in nature and enjoy the fresh air.

Additionally, sailing can help improve coordination, balance, and focus, as well as provide a unique way to explore the world.

It can also be a great way to build self-confidence, as mastering the art of sailing requires skill and determination.

Finally, sailing can be a great form of exercise, as it can help improve endurance, strength, and flexibility.

All these benefits make sailing a great activity for anyone looking to enjoy the outdoors and have a memorable experience.

Final Thoughts

Sailboats are a fantastic way to enjoy the outdoors and even take part in competitive sailing events.

With the right knowledge of how sailboats work, anyone can get out on the water and enjoy the thrill of sailing.

From understanding the parts of a sailboat to how the sails and rudder work together, sailing is a skill that can be easily learned.

With all the benefits of sailing, it’s an activity that’s sure to bring plenty of fun and memories.

So, what are you waiting for? Get out on the water and experience the magic of sailing!

James Frami

At the age of 15, he and four other friends from his neighborhood constructed their first boat. He has been sailing for almost 30 years and has a wealth of knowledge that he wants to share with others.

Recent Posts

Does Your Boat License Expire? Here's What You Need to Know

Are you a boat owner looking to stay up-to-date on your license requirements? If so, youve come to the right place! In this article, well cover everything you need to know about boat license...

How to Put Skins on Your Boat in Sea of Thieves? (Complete Guide)

There is a unique sense of pride and accomplishment when you show off a boat you customized to your exact specifications. With Sea of Thieves, you can customize your boat to make it look like your...

Better Sailing

How Does Sailing Work? The Physics of Sailing

How Does Sailing Work? The Physics of Sailing

Sailing, with its graceful boats skimming across the water powered solely by the wind, is a captivating and ancient mode of transportation and recreation. While it might seem like magic, the principles behind sailing are firmly grounded in physics. The interplay between the wind, the water, and the structure of the sailboat creates an intricate dance of forces that propels the vessel forward. In this article, we will delve into the physics of sailing to uncover the mechanics behind this age-old practice.

The Role of the Wind: Lift and Drag

At the heart of sailing lies the wind – a dynamic force that fills the sails and provides the energy needed to move the boat. The interaction between the wind and the sail is based on the principles of lift and drag, which are also fundamental to aviation and other fluid dynamics.

When wind flows over the curved surface of a sail, it creates an area of lower pressure on the windward side and an area of higher pressure on the leeward side. This pressure difference generates lift, much like an airplane wing. The sail’s shape and angle in relation to the wind determine the amount of lift generated. By adjusting the sail’s angle, sailors can control the lift and subsequently the boat’s direction.

Drag, on the other hand, is the resistance the sail experiences due to the friction between the air molecules and the sail’s surface. While drag can’t be entirely eliminated, modern sail designs aim to minimize it to ensure the boat moves efficiently through the water.

>>Also Read: How Fast Can a Sailboat Go?

The Concept of Apparent Wind

In a straightforward scenario, a sailboat would travel directly downwind with the wind pushing the sails from behind. However, sailing often involves moving at angles to the wind, a concept that introduces the notion of apparent wind.

Apparent wind is the combination of the true wind – the wind blowing over the Earth’s surface – and the wind generated by the boat’s motion through the water. As the boat sails at an angle to the true wind, the wind experienced by the boat appears to come from a different direction and at a higher speed than the true wind. This apparent wind is crucial for maintaining lift on the sails, even when sailing against the true wind direction.

The Physics of Sailing

Points of Sail: Navigating the Wind Angles

To understand how sailboats maneuver, it’s essential to grasp the concept of points of sail. These are specific angles at which a boat can sail relative to the wind direction. The main points of sail are:

  • Close-hauled:  Sailing as closely as possible into the wind. This requires the sails to be trimmed in tightly, and the boat moves forward at an angle against the wind.
  • Close reach:  Sailing diagonally to the wind, between close-hauled and a beam reach.
  • Beam reach:  Sailing perpendicular to the wind. This is often the fastest point of sail as the boat can fully capture the wind’s energy.
  • Broad reach:  Sailing diagonally away from the wind, between a beam reach and running.
  • Running:  Sailing directly downwind, with the wind coming from behind the boat.

By adjusting the angle of the sails and the boat’s course, sailors can optimize their speed and direction according to the prevailing wind conditions.

>>Also Read: Points of Sail Explained

Balancing Forces: The Keel and Centerboard

While the wind provides the forward propulsion, the boat’s stability and ability to maintain a straight course are maintained through the use of a keel or centerboard, depending on the type of sailboat.

The keel is a heavy, fin-like structure located beneath the boat’s hull. It serves two main purposes: counteracting the force of the wind pushing the boat sideways (referred to as leeway) and providing ballast to keep the boat upright. The keel’s shape generates lift in the water that counters the lateral force of the wind, allowing the boat to sail closer to the wind without being pushed sideways.

For boats with a centerboard, which is a retractable fin located in the center of the boat, the principle is similar. By adjusting the centerboard’s depth, sailors can control the boat’s lateral resistance and stability.

>>Also Read: How do Sailboats Move Without Wind?

Tacking and Jibing: Changing Course with the Wind

Sailing isn’t just about going in a straight line – sailboats can change direction by tacking and jibing.

Tacking involves turning the boat’s bow through the wind so that the wind changes from one side of the boat to the other. This maneuver allows the boat to change direction while maintaining forward momentum. During a tack, the sails are let out to spill the wind’s energy, the bow crosses through the wind, and then the sails are trimmed in again on the new tack.

Jibing, on the other hand, is a maneuver where the stern of the boat crosses through the wind. This is often used when sailing downwind. Jibing requires careful coordination, as the sails can swing abruptly from one side to the other, potentially causing powerful forces.

How do sails work in the wind

Sail Shape and Rigging: Aerodynamics of Sailing

The shape of the sail and the configuration of the rigging also play a vital role in the physics of sailing. Modern sail designs use a combination of materials and engineering to create sails that are both efficient and durable.

The angle at which the sail is set, known as the angle of attack, determines the amount of lift and drag produced. Sails are typically designed with a curved shape, known as camber, which allows for better lift generation and minimizes drag. Adjustable controls such as the cunningham, outhaul, and boom vang enable sailors to modify the shape of the sail according to wind conditions.

The mast, rigging, and other structural elements of the sailboat are designed to distribute forces evenly and provide stability. The tension in the rigging affects the shape of the mast, which, in turn, affects the shape of the sail. Balancing these factors ensures optimal sail performance and boat stability.

>>Also Read: Most Common Sailing Terms

How Does Sailing Work? The Physics of Sailing – In Conclusion

Sailing is a captivating interplay of physics and nature, where the wind’s energy is harnessed to propel a boat gracefully across the water. By understanding the principles of lift, drag, apparent wind, and the mechanics of sail shape and rigging, sailors can navigate the seas with precision and finesse. From the ancient mariners who first ventured out onto the open waters to the modern sailors competing in high-tech races, the physics of sailing remains a timeless and essential art.

Peter

Peter is the editor of Better Sailing. He has sailed for countless hours and has maintained his own boats and sailboats for years. After years of trial and error, he decided to start this website to share the knowledge.

Related Posts

Atlantic vs Pacific: Which is More Dangerous for Sailing?

Atlantic vs Pacific: Which is More Dangerous for Sailing?

Why Do Sailboats Lean?

Why Do Sailboats Lean?

How Does a Boat Sail Upwind? Unveiling the Mechanics of Against the Wind Sailing

How Does a Boat Sail Upwind? Unveiling the Mechanics of Against the Wind Sailing

Best Sailing Certifications – Which Sailing Certification is Better?

Best Sailing Certifications – Which Sailing Certification is Better?

  • Buyer's Guide
  • Destinations
  • Maintenance
  • Sailing Info

Hit enter to search or ESC to close.

How Do Sails Actually Work: Full Beginners Guide

The sails are your boat's primary driving force. Your boat is designed to sail , and with good wind it will be faster and more comfortable than using the engine. Engines on sailboats are called "auxiliary" for a reason, almost every sailor hates to use them once they get the hang of sailing. But it won't happen if you don't learn to trim the sails, and to trim them you have to understand them.

But how does a bunch of cloth - your sails - get so much motive power and force? How do sails actually work?

The short answer is that upwind sails generate lift which acts against forces on the keel in the water to pull the boat forward, and downwind sails capture as much wind force as they can to push the boat downwind.

how do sailboats work without wind

On this page:

How sailing requires some math, understanding the physics of sailing, putting math and physics together under sail, why is it easier to sail downward, applying your knowledge of sails.

But the detailed answer for sailing upwind is more complex, so come join us for a deep dive into the reason sailboats work and can sail up, down, and across the wind. It's going to get a little into math and a little physics, but we'll keep it on a practical level where you can get the concepts with little hard stuff. And downwind sails are much easier to explain.

how do sailboats work without wind

To understand sails and sailing, understand the forces which apply to a boat and how they combine to make forward motion. To represent forces, motion, and velocity, we need to use vectors .

We'll do our best to keep this simple, and you will not need a calculator. The important takeaway is how we add forces together to figure a net force or motion .

What is a Vector?

A vector is a number with both a magnitude (a number or size) and a direction. Traveling at 60 miles per hour down the highway is a speed—the car's speed is 60 mph no matter where it’s headed. It has no direction component. But traveling west at 60 mph is a velocity , which is a speed and a direction (west).

You represent the speed easily with a number: "60." But how do you show its velocity headed west? Just as easily, with a vector.

Draw a six-inch line running east/west, then put an arrow on the west end. If we set our scale to one inch = 10mph, then we have our scalar measurement (6") and our orientation - west, or 270°. This arrow is the velocity vector of a car moving at 60mph headed west.

You can represent anything with an orientation and a scalar measurement this way. Whether it's the force and direction a pool cue applies to a ball, the force a hammerhead puts on a nail or the speed and direction of the wind, you can show it with vectors.

Calculating the sailing vector (with pictures)

So what is the point of drawing arrows to describe things? If we can describe forces with vectors, then we can add and subtract the vectors to see how the forces add and subtract, too.

Adding vectors is simple. To add two vectors, put the arrow end of the first vector at the beginning of the second vector. Then, with a straight edge, draw a line from the start of the first vector to the end of the second and put an arrow on the end where it meets the second vector. That new line you just drew is the sum of the vectors.

That's all there is to it. But what does it mean? Let's do a couple of thought exercises to show how it works.

Picture a bicyclist riding north along a road at 20 mph with no wind. The bicyclist feels a 20 mph north wind in her face, right? You can draw that as a line 20 units long pointing directly at the rider's face. The exact units on paper don't matter. That they're consistent is all that counts, so "one square of graph paper = one unit" and "one unit equals one mph" is just fine.

Now picture a 10 mph north wind from straight in front of the rider. What does it feel like to the rider?

That 10 mph wind is added to the 20 mph wind, and it feels like the rider is moving into a 30mph wind. You don't need vectors to see this, it's simple math, and you know how this feels. Just like you know a 10 mph south wind from straight behind the rider will make the total wind feel like just 10 mph.

But what about if there's a 10 mph wind from the east - 90 degrees from the rider's right? What does the wind force feel like in her face now?

  • Draw your 20-unit north wind line in the rider's face.
  • From the end of the first line, draw a 10-unit east wind.
  • With a straightedge, draw a line from the beginning of the north wind vector to the arrow on the east wind vector.
  • That line is what the rider feels in her face from the combined wind of her motion on the bike and the 10 mph east wind.
  • You can measure the exact angle of the new vector with a protractor or compass and measure the length in units to get the wind strength. You'd get a wind that felt like 22.4 mph from 26.6° to the rider’s right.

how do sailboats work without wind

Vector A, the north wind (0°) 20 mph long, and B is the east wind (90°) at 10 mph

how do sailboats work without wind

The line is drawn to add them together.

how do sailboats work without wind

The new vector for the wind force.

how do sailboats work without wind

To explore this further, check out the tool used to make these graphics , where you can create your own vectors and add them together. Just remember it's made by mathematicians, not sailors, so North (0°) is to the right instead of up!

Applying vectors when sailing

You don't need to understand how to measure vectors or even do the math to get all the numbers. All you need to understand is how to add the forces together with the arrows.

Lay them head-to-tail and draw the new line. And that's enough for you to see how the combined forces will look without using a calculator.

Vectors are an important part of understanding sailing. When you learn to navigate, you'll use vectors to calculate the current set and drift or the course to a waypoint (though they won't call it that!). From our examples, you see how they apply to understand apparent wind. You don't need to draw lines on paper all the time, but understanding how forces, currents, and wind affect each other will make you a better sailor.

Now that we know how to measure and add forces, we can talk about the forces on a boat that create upwind motion. There are a few basic physics principles that describe and explain these forces and how they apply to a sailboat. If you never took physics back in the day (or you remember as well as most of us do years later...) don't sweat. We'll keep it relatable.

What is the Bernoulli Effect?

Standing near a chimney, you can feel flue drafts that suck the heat right out of the room if you leave it open, or see them suck smoke up the chimney. And if you've ever flown, did you ever look out the window at what the wing was doing during the flight? Ever wonder how the wings get that big jet plane off the ground?

The answer lies in the work of Daniel Bernoulli, an 18th-century Swiss mathematician. Bernoulli's Principle states that a moving fluid is associated with a decrease in static pressure. The faster the flow, the lower the pressure near it.

At lower speeds, the air is effectively fluid, and the same rules apply. So wind moving over a chimney opening creates a low-pressure spot at the top of the chimney, which draws air up the chimney even when there is no fire. On a windy day, this force is powerful enough to rattle the flue cover when it's closed.

How the sail generates lift

How does this get a plane in the air? And by extension, how does it get power to a sail? Because the same principle applies and upwind sails are very similar to airplane wings.

An airplane wing is a curved surface. As air flows over a curved surface, the air on the outside of the curve has a longer path to travel than air on the inside before it meets again at the back of the wing. Both sides of the wing are moving through the air at the same speed, so the air over the top of the curve must move faster than the air on the bottom.

The faster a fluid moves, the lower the pressure. So the faster air on top of the wing has lower pressure than the bottom, which leads to a lifting force from the higher pressure under the wing. The curve of a wing causes the lifting force towards the top of the wing. The same thing applies to upwind sails - the curve in the sail generates "lift" towards the outside of the sail.

If you want to feel this yourself, the next time you're a passenger in a car, roll down the window and put your hand. Flatten your hand with your palm down parallel to the ground. Then, slowly curve your hand and feel the lifting force!

How the sailor controls lift

If you've watched the wing while a plane takes off or lands, you've seen the pilot adjusting the flaps and the overall shape of the wing. A modern plane wing changes shape from a low-flat profile to a shorter, thicker shape. This different shape changes the amount of lift the wing gives, and the thicker shape has more lift, which helps at takeoff and landing.

The pilot is trimming the wing like a sailor trims a sail.

In a curved surface like an airplane wing (or sail), the chord is the curve's height. The fuller the curve, the longer the chord. And the faster the wind has to travel over the outside to meet the inside wind, which leads to more lift. But it also creates more drag, so once a plane is off the ground and getting closer to cruising speed, the pilot flattens out the wing to reduce drag for higher speed.

For airplanes, this makes taking off and landing easier since the plane can get off the ground and land at lower speeds. For sails, it gives more power for acceleration from low speed or through waves and chop.

What is Newton's Third Law of Motion?

"For every action, there's an equal and opposite reaction."

If you push against a wall, the wall pushes back with the same force. If it didn't, the wall would fall over. A rocket blasts hot gasses from burning fuel out of the bottom, and the rocket moves forward from the reaction force. A car's tires push against the road, the road pushes back, and the car moves forward.

When wind hits a boat's sails, it will either flop over and capsize or skitter sideways through the water unless it has a keel or other appendage under the water . A mono-hulled boat without a keel, centerboard, daggerboard, or other underwater stabilizers can not sail upwind.

So the keel acts as a counterpoise to the forces on the sails to keep the boat upright, but it also pushes against the water. This pushing against the water and the sails is an action, and there's an equal and opposite reaction. This force works against the sail lift to move the boat.

Sailing upwind, you've got a combination of lifting force from the sails, reactive force from the keel against the water, and other forces, like friction and drag from the water. These forces have their own vector arrows.

For simplicity, we will ignore friction and drag, since they're the only forces pushing against the boat in one direction as it moves through the water. While they increase with speed, we can assume the other forces are large enough to overcome them. And you don't want to make me explain adding four or five vectors together at once...

Friction and drag are very important to boat performance. We've simplified them out of the equation to make the force diagrams clearer. Faster boats have less drag from hull form and smooth bottoms, but all the drag and friction vectors point straight back against the boat's forward motion so they only slow the boat down, not change its direction.

In the diagram below, you can see vectors for the lifting force from the sails and the side force of the keep pushing against the water.

how do sailboats work without wind

Now, add them.

You don't have to do it on paper, as long as you can see that those vectors, when added together, result in a vector that nets a forward motion of the hull through the water. There's your answer.

Any yacht designer will tell you there's much more to getting the correct forward vector. And this is true. The shape of the hull, the smoothness of the bottom, and a few other factors will affect the final forward forces on the boat.

But at its core, the lift vector from the sails added to the keel vector ends up in the boat being pulled forward.

how do sailboats work without wind

What makes a boat sail downwind is much simpler than the mashup of force vectors we had to work through for upwind sailing. It's quite simple really - the sails fill with wind and pull on the boat to push/drag it downwind.

When you're not going against the wind, the physics is a lot simpler.

Not that you can't look more closely at the forces involved to maximize your speeds and find the best way to sail downwind. But we're not asking how to trim for speed, we're asking how the boat moves. And heading downwind, your full sails catch as much wind as possible to put as much propulsive force onto the hull as possible.

If you've gotten this far, you may wonder "now what?" The next step is to apply that knowledge to sail your boat. Now that you know you can change sail shapes for speed and power and why that works, check out our complete guide to trimming sails so you can trim better and sail faster.

Leave a comment

Own your first boat within a year on any budget.

A sailboat doesn't have to be expensive if you know what you're doing. If you want to learn how to make your sailing dream reality within a year, leave your email and I'll send you free updates . I don't like spam - I will only send helpful content.

Ready to Own Your First Boat?

Just tell us the best email address to send your tips to:

Sail Outfitter

The Perfect Gear for Any Sailing Adventure

How Sailboats Work

How Sailboats Work: The Evolution of the Sailboat 

Sailboats are mainly powered by the wind and are simple but incredible vessels that once opened up new pathways for exploration and international trade. Many believe that the sailboat shaped the modern world. If you don’t know how sailboats work, you’d be surprised to learn how simplistic the design really is and just how much it has changed over the years.  

While no one really knows exactly when the first boat was built, the remains of sailboats have been found that date back to ancient Egypt.  

Key Takeaway: Learning how sailboats work will not only make you a better sailor overall, but it can help you to get the most out of your next trip and can teach you how to navigate the waters and take advantage of certain types of wind and water conditions.

Read on to learn about the anatomy of the sailboat and how to sail like a pro.

Table of Contents

Sailboats Over the Centuries  

Over the centuries, sailboats have steadily developed, offering faster speeds and improved maneuverability, easier handling, and a more durable design.  

Sailboats range in capability and size, but each type of sailboat is linked by basic elements. Whether the vessel is large or small, sailboats of the past and present both feature the same movement and flotation abilities.  

The basic sailboat consists of eight important parts:  

The shell of the boat is called the hull and it contains all of the internal components. The shape of the hull balances the boat and reduces drag, which is caused by friction. In the stern of the boat, you’ll find the tiller, which is attached to the rudder. If the rudder of the sailboat is the tire then the tiller is the boat’s steering wheel. In order to maneuver a boat, you’ll pull the tiller to one side, causing the rudder to change direction.  

sailboats over the centuries

The keel and the sails work as the sailboat’s engine. The larger sail is called the mainsail and it catches most of the wind power that’s necessary to propel the boat. The vertical side of the mainsail attaches to the mast, which is a long pole. The horizontal size of the mainsail attaches to the boom, which is a massive pole that runs parallel to the deck. A sailor can rotate the boom three hundred and sixty degrees from the mast in order to allow the sail to capture as much wind as possible. When the boom is pivoted perpendicular to the wind, the sail will push outward. It will also go slack when it’s swung parallel to the wind. This type of freedom of movement will allow the sailor to catch the wind in any direction it blows. The small triangular fixed sail that provides added power to the mainsail is called the jib. The slim, long plank known as the keel, juts from the bottom of the hull, providing a balancing force underwater that prevents the boat from tipping over. In smaller boats, a daggerboard or centerboard has the same task as the keel and prevents the boat from tipping over, however, the daggerboard can be lowered or raised into the water in order to allow the boat to move through shallow waters.  

To learn more, you can click here to read our article on how to make sail.  

How the Sailboat Floats  

According to Archimedes ’ principle, in order for a boat to float it must first displace an amount of water that’s equal to its weight. As the boat’s weight pushes down, displacing the water underneath it, an upward force that’s equal to that is what holds the boat up.  

In order to displace the right amount of water to keep the boat afloat, the boat must have a density that’s less than water. Because of this, the hull of a sailboat is always hollow. A boat’s average density is less than water, whether the boat is made out of fiberglass or wood.  

The boat’s surface area is also what helps to keep it afloat. A large surface space will give the boat a better chance of displacing enough water to offset the boat’s weight.  

Taking Advantage of the Wind

As you know by now, a sailboat needs a certain amount of wind to move. Stronger winds means an increase in your sailboat’s speed. If you understand the anatomy of the sailboat, how it works, and how to use the sails in order to trap wind, you can make better time and reach your destination on schedule.

Reading the Wind

When sailing, you must learn how to determine the direction of the wind in order to take advantage of it. There are actually some basic tools that can help you determine the direction of the wind, such as telltales. This tool is just a length of nylon that’s tied to the backstay and shrouds. At the top of the mast should be a masthead fly, complete with a wind arrow.

Using your sails to locate wind is another option. An experienced sailor can also look at the surface of the water to determine the wind’s direction, but this technique can take years of practice.

To increase a sailboat’s speed you must first pick a distant point to aim for. Next, try a little experimenting by heading up and bearing off, gradually, as you adjust the sails. Steering in this manner will take a little practice.

The most relaxing point of sail is called running with the wind. Since the wind isn’t blowing across the sailboat, there will be no sideways force. As the sailor bears off from the beam reach to a run, they will need to ease out the sheets in order to allow the sails to grab as much wind as possible.

Centerboard for Stabilization

If the sailboat has a centerboard, the sailor will need to have it raised when they’re running. When running straight with the wind, the centerboard isn’t needed to keep the boat from moving sideways, however, a little board can help minimize any type of side to side rocking. If your sailboat doesn’t have a centerboard, in high wind conditions, stabilizing the boat and preventing any side to size movement can be almost impossible.

Beginners often struggle with steering the sailboat in high and low wind conditions and it’s true that it can be very challenging. Sailing is more of an art form, and like any art form, learning how to master it will take time, skill, and proper guidance.

How They Glide Through the Water  

Glide Through the Water

Your first few times in a sailboat will be exhilarating and challenging. With a little practice and a few tricks up your sleeve, you should be able to get the hang of steering the boat in no time. However, if you’re planning on taking your sailboat for an extended sailing adventure, you’ll have a lot to learn, including how to properly position the boat in order to grab more wind and increase your speed.

When you’re traveling downwind with the wind at your back you’ll let the mainsail loose, keeping it perpendicular to the wind in order to harness the most energy. The wind will press directly into the sails. This is what naturally propels the boat forward.  

But plotting a course upwind can be much harder. It’s actually impossible to sail directly upwind. Either the wind will stall the boat if the sails are slack and pulled in, or the wind will push the boat backward.  

While the wind pushes the sailboat when going downwind, the opposite will happen when traveling upwind. When sailing upwind the boat is actually being pulled instead of pushed by the wind. The forward pull is referred to as lift. When steering upwind, you’ll have to make a zigzagging path which is known as tacking. When tacking, the wind won’t approach head on and will instead come at the boat from an angle. When the sailor uses tacking, the sails work like an engine, harnessing the power of the wind. But because the boat is moving in an angled position, the wind ends up pushing the sailboat sideways. As the boat is pushed to one side, the flat, long keel pivots upward and creates a sideways force in the opposite direction due to the amount of water that’s displaced as it moves. These opposing forces work to cancel each other out.  

The Modern Sailboat  

Today’s sailboats are sleeker, lighter, and faster. They’re also much wider, which works to increase the boat’s stability.  

The keels are also sleeker and longer, which allows for a quicker, closer tack. Their large surface area tends to displace more water, allowing for a tighter tack. These modern sailboats simply slice through the water, without the worry of drag. Designers have also honed the hull in order to reduce pull using newer materials such as fiberglass.  

Due to their innovative modern designs, some boats can exceed the speed of wind.  

But while many of the components on these vessels have been remade and improved upon, the basic elements of how sailboats work still remains the same.  

If you’d like to learn more about the art of sailing and the type of gear you’ll need, click here to read our epic buyer’s guide on sailing pants.

How Modern Sailboats Work: The Evolution of the Sailboat

  • Sailing Pants
  • Sailing Shoes
  • Uncategorized

Sail Outfitter

  • Privacy Overview
  • Strictly Necessary Cookies

This website uses cookies so that we can provide you with the best user experience possible. Cookie information is stored in your browser and performs functions such as recognising you when you return to our website and helping our team to understand which sections of the website you find most interesting and useful.

Strictly Necessary Cookie should be enabled at all times so that we can save your preferences for cookie settings.

If you disable this cookie, we will not be able to save your preferences. This means that every time you visit this website you will need to enable or disable cookies again.

Boat Reviews

  • Aquila Boat Reviews
  • Aspen Boat Reviews
  • Avalon Boat Reviews
  • Aviara Boat Reviews
  • Axopar Boat Reviews
  • Barletta Boat Reviews
  • Bayliner Boat Reviews
  • Centurion Boat Reviews
  • Charger Boat Reviews
  • Cruiser Yachts Reviews
  • Formula Boat Reviews
  • Fountaine Pajot Reviews
  • Freeman Boatworks Reviews
  • Galeon Luxury Yachts Reviews
  • Intrepid Boat Reviews
  • Jupiter Marine Reviews
  • Manitou Boat Reviews
  • Native Watercraft Reviews
  • Phenom Yacht Reviews
  • Pursuit Boat Reviews
  • Sailfish Boat Reviews
  • Sea Ray Boat Reviews
  • Sea-Doo Watercraft Reviews
  • SeaVee Boat Reviews
  • Solace Boat Reviews
  • Windy Boat Reviews
  • X Shore Boat Reviews
  • Yamaha Boat Reviews
  • Boats Specs
  • Marine Pros
  • Boat Insurance
  • Boat Warranties
  • Boat Transport
  • Boat Towing
  • Marine Forecasts

BoatingWorld

Your Ultimate Boating Resource

BoatingWorld

2024 Pursuit OS 445: An Overview

Boat safety 101: exploring the serenity and adventure of boating, the moment of truth – 6 signs you need a new boat, is it possible to wakesurf on a pontoon boat, 2024 aquila 47 molokai review, 2024 sea-doo switch 13 sport review, 2024 aspen c120 review, what happens to a sailboat if there is no wind.

As any sailor will tell you, sailboats cannot move without wind. It’s what powers their movement, maneuvers, and ultimately the sailor’s success. But?

The answer is simple: the sailboat stops. Without wind, there’s no way to move the sails, which in turn powers the boat’s movement. With no wind, the boat will be adrift, at the mercy of the currents and tides.

However, just because there’s no wind doesn’t mean a sailor’s adventure is over. A sailboat that’s found itself becalmed can still maneuver, albeit not very fast or efficiently.

One option is for sailors to use their motor to move the boat. However, the motor can be a bit of a last resort for sailors since it’s not their preferred method of travel. Most sailboats have small motors that are only used rarely when winds and currents aren’t cooperating.

Another option is to use oars to row the boat, possibly to shore or another location with better wind. However, this method can be time-consuming and requires a lot of effort from the sailors.

Sailors can also try to catch any slight breeze by using their sails. While a sailboat needs a certain amount of wind to move efficiently, sometimes a gentle breeze can be enough to get it started in the right direction. Sailors can also drop anchor and wait for the wind to pick up.

Finally, sailors can adjust their sails or rigging to try to capture any light breezes that do arise. By angling the sails just right, sailors can catch and use whatever little bit of wind there is to move their boat, at least temporarily.

If there’s no wind, a sailboat can still maneuver, but not very well. Motor, oars, and adjusting the sails are viable options to move the sailboat to a more favorable location. While it might not be the most exciting voyage, becalming can be an excellent refresher, and a chance for the sailors to workshop new skills.

Related Questions

What type of wood is used for pier pilings, what is the difference between a dock and a floating pier, what is the proper technique for pulling a beginner wakeboarder, what does ‘no wake’ mean on a lake, what is the difference between wash and wake, is wakesurfing possible in the sea, why don’t wooden piers rot, what size wakeboard is needed, how to achieve more pop on a wakeboard, does wake surfing translate to ocean surfing, latest posts, the top 9 reasons to maintain a meticulous boat log, don't miss, our newsletter.

Get the latest boating tips, fishing resources and featured products in your email from BoatingWorld.com!

Eco-Savvy Sailing: Expert Tips for Reducing Fuel Costs and Enhancing Your Boating Experience

Sea safety blueprint: constructing the perfect float plan for your boating adventures, 10 essential tips for fishing near private property, the benefits of using a drift sock: guidance for anglers, lure fishing: secrets for imitating live bait and attracting fish, explore the untapped depths of america’s best bass fishing spots, tackle your catch-and-release adventures with these 6 tips, outboard motor maintenance: tips for keeping your engine in top shape, the essential boat tool kit: tools every boater needs, diy boat building: 8 tips and tricks for building your own vessel, the art of miniature maritime craftsmanship: ship in a bottle, antifouling paints: a guide to keeping your boat shipshape, beginner’s guide to standup paddle boarding: tips and techniques, boating for fitness: how to stay active on the water, kayak safety: how to stay safe on the water, anchoring in a kayak or canoe: how to secure your small boat, 2024 yamaha 222xd review, 2024 sailfish 316 dc review, 2023 seavee 340z review, 2023 centurion fi23 review, gear reviews, megabass oneten max lbo jerkbait review, fortress anchors fx-7 anchoring system review, fortress anchors fx-11 anchoring system review, fortress anchors commando anchor kit review, fortress anchors aluminum anchors review, stay in touch.

To be updated with all the latest news, offers and special announcements.

  • Privacy Policy
  • Pontoon Boats
  • Personal Watercraft
  • nauticalknowhow
  • Nautical Knots
  • Tools and Calculators

How Do Sailboats Work?

Ian Fortey

To a casual observer, a sailboat makes perfect sense. Wind pushes the boat forward on the water. The boat goes in the direction of the wind. The true physics of sailing a boat are definitely more complicated. How do you sail against the wind? Why does the sailboat move forward if wind hits the sails from the side? How do you sail perpendicular to the wind? How does a sailboat move faster than the wind?

There’s a lot to understand about how sailboats work . Much of it is not obvious at first. You need to understand your boat design and drag force. Also point of sail and beam reach. The direction of the wind is just one piece of the puzzle. Once you understand it all, sailing becomes much easier.

Let’s take a look at the physics of sails and wind, and how they work together. Understanding these forces is key for any sailor who wants to master sailing. At least in the true “wind in your sails” sense of the word.

How Does a Sailboat Sail?

how do sailboats work without wind

The physics of how a sailboat sails does depend on wind direction. Sailing your boat downwind with the wind at your back is easy to understand. Wind fills the sails and pushes the boat forward on the water. At angles, it takes more of an understanding of physics to explain.

Sails on a boat work like the wings of an airplane. Both create aerodynamic lift to move an object. In the case of a boat, even when wind comes from the side, it moves the boat forward.

If you viewed a sailboat from above, it would resemble the wing of an airplane. The difference would just be that it seems to be on its end.

Air hits your sails and makes lift. Some of the force is lost thanks to friction. Some of that force pushes your boat forward. The rest would push the sailboat sideways if it could. But it can’t, and this is where the aerodynamics of your sail meet the hydrodynamics of the keel.

Because the boat has a keel or centerboard, it can move forward. This part of your sailboat extends under the water. It balances the boat and keeps it running straight. Without a keel, your sailboat would drift wherever the wind pushes it. However, the keel acts with the sails to make forward motion. There will be a small amount of sideways motion as well. This is how your sailboat is able to sail.

As your hull and keel resist sideways motion, that force is translated into motion. When you are sailing upwind, the wind needs to travel smoothly front the front of the sail to the back. If it doesn’t, you won’t be moving far. This can be hard for new sailors to master.

The Orange Seed Test

A fun example of how to understand the forward motion is to get a seed from an orange. These are roughly the same shape as a boat’s keel. Put the seed on a smooth table and then squish it with your thumb. The seed will squirt out from under your thumb in a forward direction. The same basic principle applies to your sailboat. Force applied to it redirects as forward motion.

What Does Point of Sail Mean On a Sailboat?

how do sailboats work without wind

The sails on your sailboat can be rigged at different angles. This is essential for catching and making use of wind. These angles are called point of sail. You need to alter the angle as you sail when the wind changes. Otherwise you will lose that forward motion that you want.

Adjusting the sails is called trimming them. You do this by adjusting the tension of the line, called a sheet, attached to the sail. When you pull the sheet in, it moves the sail towards the center of the boat. When you let the tension out, or sheet it, it lets the sail out.

It can be hard to master trimming the sails. The wind is rarely cooperative. It may come in at constantly changing angles. You will need to adjust accordingly. This is a learning process, and no one is an expert sailor their first time out.

Trimming Sails Upwind

It can be hard to trim the sails when you are sailing upwind. The angle of the sail needs to be just right to allow proper airflow. If you have sheeted too far out or in, it will not work. You will not get that wing shape you want, and you will stall out in the water.

The easiest way to trim your sails upwind is by trial and error. Sheet your sails out until they flap loosely. This flapping is called luff. Then sheet the sail back in slowly. Watch the shape and tension of the sail. When it smooths out and curves there is no more luff. This is where you want it to be.

How to Turn Upwind

Turning upwind is called heading up. Sometimes it is called bearing up or pointing up. If you push the tiller towards the sail and away from yourself, you are turning upwind. The sails need to be trimmed along with the turning. The angle of the wind is going to change. If the sails are not sheeted, you will lose the wind.

Trimming Sails Perpendicular to the Wind

Treat winds perpendicular the same as upwind. The process of trimming the sails will be the same. Smooth out the luff and proceed on course once you have that wing shape.

Trimming Sails Downwind

Despite what you may think, trimming sails downwind can be hard. The sails will naturally parachute or balloon in the wind. To control them takes work. You need to try to get the sail perpendicular to the wind. This will expose the maximum surface of the sail. Thus, you get the most lift. Again, this is a trial and error process to get it right.

How to Turn Downwind

Turning downwind is also called falling off. This is also called bearing away or pointing down. You do this by turning the tiller towards yourself and away from the sail. Like turning upwind, the sail needs to be adjusted. You will have to sheet out to maintain your course.

What is Tacking?

how do sailboats work without wind

When you want to sail into the wind, you need to engage in what is called tacking. A sailboat cannot head directly into the wind on a straight course. This puts you in the No Go Zone. The angles we mentioned earlier, or points of sail, can be divided on different tacks. There are port tacks and starboard tacks. They divide around the boat very similar to how a clock looks. Tack, then, has two different meanings. An angle relates to the wind and also the directional corrections you make into the wind.

You need to be about 45 degrees off the wind in any direction to keep sailing. In the No Go Zone, your boat is dead in the water. You will need to engage in a maneuver calling tacking to get out of it. This involves sailing in a zig zag pattern. The direction of the wind will shift from one side of the boat to the other. This allows you to keep moving towards the wind. It will keep you on course, it just may take more time.

How Do You Tack?

Learning how to tack is a process. It’s not always simple. Try the following steps to tack into the wind.

  • Turn towards the wind by pushing the tiller towards the sail. Do this in a slow and controlled manner.
  • As the boat turns, step across the board without letting go of the tiller or the main sheet.
  • The sail will tack when it switches sides. When this happens, sit down on the new side of the boat, opposite the sail.
  • Center the boat again so that you’re on a straight course.
  • You’ll need to switch hands here. But don’t let go of the mainsheet or the tiller. Run the hand holding the sheet along the mainsheet until you have the tiller. Then let go of the tiller with your other hand.
  • Now you can grab the sheet with your free hand, having successfully switched.
  • Trim your sail as necessary. You have just tacked in one direction. If you need to keep heading into the wind, you will need to tack back by repeating the process in reverse. This can continue as long as necessary to get you where you want to go. The end result is a zig zag through the water.

How Do You Control Speed in a Sailboat?

how do sailboats work without wind

When the wind really picks up, a sailboat can move extremely fast. Sailboats can go from 4 miles per hour to nearly 20 miles per hour. So how do you stop that when you need to?

If your boat is travelling upwind and needs to stop, sheet your sails. Let them luff briefly, which will disrupt the speed of your boat. You can sheet back in again when you are ready.

Downwind is harder. There is little resistance from the water on your boat in this direction. You can sheet your sails in to slow the boat down somewhat. However, your momentum will still carry you for some time.

You can point the bow of a boat upwind to stop. Alternately, you can point the boat perpendicular to the wind and luff the sails. Downwind, however, you have no options to stop a boat.

How Do Some Boats Sail Faster Than the Wind?

how do sailboats work without wind

This has to do with a phenomenon called apparent wind. Apparent wind is the wind you feel on your face as you move forward. True wind is the wind that is blowing naturally.

If you can imagine riding your bicycle on a day when there is no wind whatsoever, you still feel wind on your face (apparent wind) and it gets stronger as you go faster. That is because your forward motion is creating its own wind. If you were to ride your bike on a day when there was a 5 mile per hour wind behind you and you were pedaling at 5 miles per hour, the two winds (true and apparent) would cancel each other and you would not feel any wind at all.

Boats that are able to sail faster than the true wind are “creating their own wind”. Generally these are fast catamarans and iceboats, although some racing monohulls may be able to achieve this. The apparent wind is the wind that the boat sails in. Usually, you can sail faster at 70 degrees to 80 degrees off the apparent wind (called a “close reach”) than you can with the wind directly behind you.

This is because you can trim the sails so that the wind flows over them to create a lift, much like an airplane wing, that propels the boat. As you can see, there is a positive force against the inside of the sail, and a negative force pulling the outside of the sail. (You can try this by holding your hand out of the window of a moving car (With your parent’s permission, please!). Rotate your hand to feel how the wind pushes and pulls on it at different angles.)

Under optimum conditions, the apparent wind is greater than the true wind. Let’s say you are on a fast catamaran and sailing in a true wind of 10 knots. By moving very fast through the water you may be able to create an apparent wind of 20 knots which may allow you to sail at 12 to 13 knots, which is faster than the true wind. (Friction will keep you from moving as fast as the apparent wind.)

' src=

My grandfather first took me fishing when I was too young to actually hold up a rod on my own. As an avid camper, hiker, and nature enthusiast I'm always looking for a new adventure.

Categories : Boats

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Save my name, email, and website in this browser for the next time I comment.

More in Boats

how do sailboats work without wind

What Is A Gunwale?

Best Snorkeling in Maui

131 of the Best Hawaiian Boat Names

how do sailboats work without wind

167 Patriotic Boat Names

how do sailboats work without wind

The 138 Best Boat Names for Dog Lovers

how do sailboats work without wind

The People’s Poncho Review and Ratings 

how do sailboats work without wind

Oru Lake Kayak Review

how do sailboats work without wind

About Boatsafe

Established in 1998, BoatSafe is your independent guide into the world of boating, fishing, and watersports. We provide expert insights and detailed guides to help you find products tailored to your needs and budget.

Contact Boatsafe

  • Address: 4021 West Walnut Street. Rogers, AR 72756
  • Phone:  (479)339-4795
  • Email: [email protected]

Site Navigation

  • How We Test
  • Corrections Policy
  • Privacy Policy
  • Terms & Conditions
  • Editorial Policy
  • Affiliate Disclosure

Our Reviews

Boat Safe BBB Business Review

All content is © Copyright 2024. All rights reserved.

How Sailboats Work.

How Sails Work: Understanding the Basics

how do sailboats work without wind

Table of Contents

Sailing is all about physics and geometry but don’t worry, it’s not too hard to learn. Once the theory is down, it’s all a matter of practice. Let’s look at what sails are and how they work.

Book a sailboat rental & set out on your next expedition

Aerodynamics, hydrodynamics & modern sails

Sails work like airplane wings, except they’re vertical rather than horizontal. As the wind hits the front of a curved sail, it splits, passing on both the downwind (leeward) side and upwind (windward) side.

The leeward wind travels farther due to the curvature of the sail and creates a low-pressure area while the windward wind travels a shorter distance and reaches the aft end faster – together, they create aerodynamic lift that “pulls” the boat forward .

The keel or centerboard in the water below the hull prevents the boat from being pushed sideways. With the lift of the sails and the lateral push or hydrodynamics of the keel, the boat is propelled forward. Where the wind concentrates force in the sails is called the center of effort, while the keel below is called the center of lateral resistance.

Most modern sailboats have a forward (or headsail) and a mainsail. The headsail may be called a genoa, jib, or staysail (different sizes) and is attached at the top of the mast and leads down at an angle to the bow . It’s controlled by lines called sheets. The mainsail is supported by the mast and is attached at the bottom to a lateral spar called the boom.

Sailboat sail.

Parts of a sail

Sails come in various shapes, but for our purposes, we will focus on modern, triangular sails. The top of the sail is called the head , and the bottom is the foot. The forward end of the foot is the tack, and the aft end is the clew. The forward edge of the sail is the luff, and the aft end is the leach.

Telltales or short strands of yarn are often attached near the leading edge of a sail to help with sail trim. The shape of the sail is ideal when the strands on both sides are streaming back at the same level, which indicates that wind is moving evenly along both sides of the sail.

READ MORE: Parts of a Sailboat

Points of sail

A boat cannot sail directly into the wind– instead, it sails at an angle to the true breeze. Close hauled is roughly 45 degrees off the wind, close reach is 60 degrees, beam reach is at 90 degrees, and a broad reach is approximately 150 degrees off the wind.

When moving directly or dead downwind, a boat is said to be running, and when the bow is pointed into the wind, that’s called being in irons. A boat cannot sail in irons and can be hard to control when running. When sails begin to luff at the leading edge, the boat is trying to sail too close to the wind and will stall.

Sailing crew.

Tacking and jibing (gybing)

A boat changes direction by either tacking or jibing. Sailing upwind, a boat tacks when the bow passes through the eye of the wind until the boat is sailing on the opposite side or “tack” creating a zig-zag course. When sailing downwind, the boat jibes when passing the stern through the wind.

Turning upwind is called heading up and turning away, or downwind is falling off. When the wind passes over the starboard rail first, you’re on a starboard tack and vice versa.

Pro Tip: You can learn how to sail without owning a sailboat. Find a sailboat rental near you , then book! You can save that boat listing and book again to continue practicing.

Sail shape & angle

Boats sail in true wind (the wind that is actually blowing at a given speed and angle) by they’re actually responding to the apparent wind (the angle and speed of the breeze that is felt once the boat is moving). The wind always changes speed and angle, so sails must be adjusted or trimmed in response to the boat to maintain optimal speed.

When sailing upwind, the sails are sheeted in (made flatter by pulling in the sheet lines) to create better foils and greater lift or pull. When sailing downwind, sails are usually loosened or let out to create a “belly” and adjusted to be as perpendicular to the angle of the wind as possible.

Sheeting in (bringing the sails closer to the centerline) enables the boat to point higher (sail closer to the true wind) while easing out (loosening the aft end of the sail) creates more power when the wind is aft like around the beam or broad reach.

A boat is more likely to heel when sheeted in and sailing upwind. Excessive healing doesn’t mean the boat is traveling faster. In fact, it may just be getting overpowered and becoming less efficient than if the sails were trimmed properly.

Sailboat at sea.

In high winds, shorten or reef sails so the boat doesn’t become overpowered and potentially dangerous. Reefing is done at the tack and clue or the forward and aft parts of the foot of the sail. There may be 1-3 pre-rigged reefing points controlled by reefing lines, so the sails can be made as small as necessary to keep the boat from heeling too far.

Easy to learn

Trimming sails takes time to master; let sails out until they luff or flap, and then sheet in until you feel the boat pick up speed. Smaller boats react quickly to each adjustment and are better for new sailors to learn on than large boats that take a minute to speed up or slow down. Once you’ve mastered the theory, you may spend years perfecting your sailing skills.

Boatsetter is a unique boat-sharing platform that gives everyone— whether you own a boat or you’re just renting — the chance to experience life on the water. You can list a boat , book a boat , or make money as a captain .

List. Rent. Earn— Only at Boatsetter

Zuzana-Prochazka

Zuzana Prochazka is an award-winning freelance journalist and photographer with regular contributions to more than a dozen sailing and powerboating magazines and online publications including Southern Boating, SEA, Latitudes & Attitudes and SAIL. She is SAIL magazines Charter Editor and the Executive Director of Boating Writers International. Zuzana serves as judge for SAIL’s Best Boats awards and for Europe’s Best of Boats in Berlin. 

A USCG 100 Ton Master, Zuzana founded and manages a flotilla charter organization called Zescapes that takes guests adventure sailing at destinations worldwide. 

Zuzana has lived in Europe, Africa and the United States and has traveled extensively in South America, the islands of the South Pacific and Mexico. 

Browse by experience

how do sailboats work without wind

Explore articles

puerto rico boat rentals

Peer-to-peer Boat Rental Trend Spreads To Puerto Rico

how do sailboats work without wind

Video - Former Miami Dolphin, Jason Taylor shares his top boating tips

St. Petersburg Water Activities.

St. Petersburg Water Activities

using a trolling motor

Using a Trolling Motor: Sizes, Types & How to Operate

RetireFearless

How Do Sailboats Work Without Wind?

A sailboat depends on the wind to get you moving across the water surface. But what happens when there is no wind? How do sailboats work without wind?

Michael Moris

March 16, 2023

This article may contain affiliate links where we earn a commission from qualifying purchases.

When the wind stops, your sails will become slack, and you might feel stranded out in the water and seem to get nowhere. You will have to depend on other forces to take you in the direction you are looking to go.

When there is no wind, you can propel your boat using ocean currents if you know their pattern. Otherwise, an engine connected to a propeller is the most efficient way to power your boat. You can also resort to rowing, but that can be exhausting and put a lot of strain on your body.

It is extremely rare for the wind to stop completely when you are out in open waters, but it is possible. Such a scenario will feel awkward, and you will be drifting along if you have no other forms of propulsion.

Experienced sailors believe that it is possible to propel your boat against the wind by keeping it at a certain angle. But if there is no wind, you cannot propel your boat against ocean currents unless you have an engine or are rowing. If you get stuck in a no-wind zone, it is best to wait for a few minutes, and the wind will start blowing again.

how do sailboats work without wind

Table of Contents

‍ How Do Sailboats Work Without Wind?

As you are well aware, the wind is crucial for a sailboat. If in a rare scenario, the wind stops, you might find yourself at the mercy of the water currents, which will take you in the direction they are flowing. But there are some ways to navigate your boat in the correct direction even without wind.

As the wind slows down, you may struggle to maintain speed. But there are some techniques you can use to keep your boat moving. These techniques are challenging and fun to try. They have a lot of resemblance to what you may have learned when maneuvering a dinghy as a newbie.

Understanding Your Sailboat

Sailboats are much different than cars. You can use your car throughout your life without ever knowing the engine components. All you need to do is turn the key in the ignition, or for modern cars, depress the brake pedal and push a button, and you can be well on your way.

However, sailboats work differently. Unlike cars, you have to understand and know how your sailboat works if you wish to make the most of it. You need to ensure that you have the most wind in your sails to move your sailboat efficiently.

If there is no wind in the sails, your sailboat will not be propelled forward. You can think of it as being stuck in neutral, and any force from the environment will throw you around. In worst cases, your sailboat can even capsize.

Sailboats rely on the wind to push them and lift them up. Most sailboats are designed to move with the wind pushing along the side of the boat and a little wind pushing the boat forward. The idea is to reduce the drag and keep your boat moving in the direction you want to go.

Now, if there is no wind, here is what you can do.

Put Hydrodynamics to Use

Even in the rare case when the wind is absent from the ocean, you can rely on water forces to propel your boat. Like air, water also moves from one place to another. These movements are known as currents. These currents have more than enough power to carry your boat along.

Strong winds with weak currents work pretty well to propel your boat. Strong currents with weak winds work similarly. They can propel your boat well, not as well as wind, but they do the job.

Even a knot of a tide can make a significant difference in your direction. The tide can give you sufficient propulsion if you are drifting in light or no wind. But how can you use tidal energy?

There are tidal maps and atlases available that predict and inform how tides will move during different times of the day. This is not to say that they are 100% accurate. But for the most part, they will give you a good idea of how the tides are moving.

If you find yourself stuck on an opposing side, the best technique is to go as close to the shoreline as possible. This is because the power of tides reduces significantly in shallow water. But if the tides are in the direction you want to go, it is best to stay in deeper water to make the most of the tides.

The Tidal Winds

As tidal streams move through the ocean, they also produce apparent winds. Imagine you have a current of ten knots. You will not feel any wind, but your vessel will drift with the tide at the speed of knots.

When your boat drifts along with the tides, you will move through the air. This will give you an impression of wind because your speed will be three knots relative to the air. You may not be able to use this “wind” for propulsion, but you can use it to set your direction and control your sailboat.

If you are lucky enough to get some light true wind, you can use it with tidal winds to enjoy good sailing. Maintaining the tide and the lee bow is essential if you attempt to get maximum control using tidal winds.

How To Sail With The Current?

When you are sailing upwind, you are going perfectly against the wind. Your objective here is to keep your boat at a 45-degree angle to the wind, as this will give you maximum propulsion if you are going against the wind.

When you are sailing with the current, you can use the tidal winds to control the direction of your boat. But controlling a boat when currents are propelling it can be tricky.

Can You Sail Against The Current?

But if your intended direction is opposite to the current, you will have difficulty navigating along. You will veer over to the sides, come to a standstill, or move further away from your target destination. Your best bet in such a case would be to wait out the quiet period until you get some wind in your sails.

A sailboat can go against the wind thanks to its keel , a flat blade that allows you to control the direction of the boat. But when there is no wind, your sails are of no use, and it is impossible to apply forces against the water currents using only the keel.

Other Methods

Although wind coming to a standstill is not common, it is best to have alternate propulsion methods on board. Here are a few of them.

Using The Propellers

If your sailboat is equipped with an engine and a propeller, you can quickly start the engines and be well on your way to your destination in no time. If you frequently sail in areas that tend to lose their wind, you can choose to have your boat equipped with a retractable propeller. Most modern propellers are designed to keep drag to a minimum, but it is best if you can remove the propeller from the water (if conveniently possible) when you are relying on sail power.

Row, Row, Row Your Boat

If your boat is not equipped with a propeller, it will be time to put your muscles to the test and resort to rowing. You may have to use different methods depending on the size of the boat, and it can be extremely strenuous and exhausting, but the exercise is good for your body.

One of the significant benefits of rowing is that it will give you some momentum, which will pay off if the wind starts blowing suddenly. The key here is to be prepared for works-case scenarios and know what you are doing.

Wait it Out

On warm and hot days, winds usually begin to blow during the afternoon and become still at dusk. This happens due to the changes in atmospheric temperatures.

As the weather turns cooler, the sea breeze will start and change direction during the late afternoon. Sea breezes are stronger near the shore, but they continue to show their effects up to ten miles on the water.

A Few Tips To Sail in Little or No Wind

Lose some weight.

No, we are not talking about you; we are referring to the boat. If the weather prediction shows that wind will be slow, or there are chances of it stopping altogether, consider leaving behind any heavy items such as coolers or additional equipment. A lighter boat is far easier to move than a fully loaded or packed boat.

Move to The Center

When propulsion power goes low, it will be best if you move towards the center of the boat. This causes the stern to rise out of the water, reducing aerodynamic drag. You can use a tiller adjustment to control the rudder if you are captaining the boat.

Raise the Centerboard

The centerboard of your boat is essential for maintaining direction. It also helps prevent the boat from capsizing. But if there is low or no wind, you can raise the centerboard, significantly reducing the drag.

A little trial and error will determine how far you can raise the centerboard without adversely affecting your boat’s performance. You can raise the centerboard halfway or to 75% height if there is no wind. However, you must immediately drop the centerboard back down as soon as the wind starts to blow.

Adjust the Sail

When there is no wind, the sails will be slacked. Sails work in a similar way to the wings on an airplane. But instead of the lift, the wind power translates to lateral motion. If you have everyone sitting on one side of the boat, it will tilt to that side. This can cause the sail to drop down to one side.

You can use this dropping of the sail to your benefit. You can push the sail further out of the edges of the boat and have it act like an airfoil to use any slight wind that comes its way. The sails need to have a sense of orientation when in the air.

Recent Articles

What Size Sailboat Can One Person Handle? | Retire Fearless

What Size Sailboat Can One Person Handle?

How To Tie A Sailboat To A Mooring Ball Ring | Retire Fearless

How To Tie A Sailboat To A Mooring Ball Ring

What Is The Ideal Wind Speed When Sailing? | Retire Fearless

What Is The Ideal Wind Speed When Sailing?

How To Use a Sailboat Winch | Retire Fearless

How To Use a Sailboat Winch

Things You Need To Liveaboard a Sailboat | Retire Fearless

Things You Need To Liveaboard a Sailboat

Types of Sailboat Keels | Retire Fearless

Types of Sailboat Keels

I'm Michael Moris. I've been sailing my whole life, and it has taken me to places I never imagined. From the Caribbean to Europe, from New Zealand to South America - there's nowhere that hasn't felt like home when you're on a boat!

twitter-icon

Trending Articles

How Far Is Havana From Miami By Boat? | Retire Fearless

How Far Is Havana From Miami By Boat?

Yachting Vs Sailing | Retire Fearless

Yachting Vs Sailing

Who Is Sailing Doodles? | Retire Fearless

Who Is Sailing Doodles?

Subscribe To Our Newsletter

Thank you! You're signed up for our free newsletter!

Oops! Something went wrong while submitting the form

About Our Team

We are a publishing team of licensed Nursing Home Administrators, Nurses, Assisted Living Directors, Health Professionals, Gardeners, and individuals with vast experience with senior living and activities.

Nichole Lindemier

©2024 Retire Fearless. All rights reserved.

We can be reached via email at [email protected]

Retirefearless.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon. This site also participates in other affiliate programs such as CJ, ClickBank and more, and is compensated for referring traffic and business to these companies.

Facebook Pinterest

MIT BLOSSOMS

  • Video Introduction to BLOSSOMS
  • Teaching Duet Pedagogy
  • Terms of Use
  • Video Library
  • BLOSSOMS Around the World
  • Video Introduction
  • BLOSSOMS-related Videos
  • Create Your Video
  • Tips for the Video Producer of a BLOSSOMS lesson
  • Accompanying Animations
  • Quick Video Tours

An Introduction to the Physics of Sailing

  • BLOSSOMS in the News
  • BLOSSOMS Newsletters
  • Archived BLOSSOMS Newsletters
  • STEM Pals Newsletter
  • BLOSSOMS Newsletter Sign Up
  • PBL Questions
  • MIT Resources
  • Biology Resources
  • Engineering Resources
  • Math Resources
  • Physics Resources
  • Science Resources
  • Science & Math Resources

An Introduction to the Physics of Sailing English

Video downloads.

  • English - MPEG 4 (mp4)

Video Transcripts

  • Written Transcript (PDF)
  • Written Transcript (MS Word)

how do sailboats work without wind

This lesson is CPALMS Vetted and Approved

Instructors.

Emma Ferris Masters of Mechanical Engineering at MIT Officer, The United States Navy

Lesson Feedback

Introduction.

The goal of this lesson is to explain how sailboats work by exploring basic physics principles. At the end of this lesson, students will be able to identify the forces acting on a sailboat and explain how the combination of these forces results in the forward motion of a sailboat. Students should be familiar with vectors and be able to use them to represent forces and moments, and also should be familiar with using free body diagrams to represent forces and moments. A basic understanding of fluid flow and/or resistance might be helpful, but not necessary. This lesson and the follow-on assessment will each take about one hour to complete. Students only need pen/pencil and paper to complete the activities in the lesson, although an optional activity where students make their own sailboats would require additional materials. The classroom activity challenges are centered around small-group discussions based on the questions posed before each break. Free body diagrams, or another conceptual representation of his or her answer, should support each student’s solution to the questions posed in the video. Instructions for the option of having students design their own sailboats as part of this lesson can be found here: https://tryengineering.org/teacher/sail-away/

Attention : It has been pointed out to us that certain experts disagree with the explanation for the generation of lift presented in this video lesson.  For this reason, we would like to refer teachers to the following articles which present an alternative explanation: 

http://www.gentrysailing.com/pdf-theory/How-a-Sail-Gives-Lift.pdf

https://www.northsails.com/sailing/en/art-science-sails/gentry

Instructor Biography

Emma started sailing at a young age and eventually taught sailing and sailed competitively in college at the United States Naval Academy.. Her passion for sailing and the ocean led her to study Naval Architecture (ship design) as an undergraduate, and she went on to pursue a Masters in Mechanical Engineering at MIT, with a focus on Ocean Engineering. She currently serves as an officer in the United States Navy.

For Teachers

  • Teacher Guide (PDF)
  • Teacher Guide (MS Word)
  • Sail Simulator Tutorial (PDF)
  • Sail Simulator Tutorial (MS Word)

Additional Online Resources

The Physics Classroom: Drawing Free-Body Diagrams This site, sponsored by the Physics Classroom, provides instructions on drawing free body diagrams, as well as practice situations for applying those instructions.

The Physics Classroom: Vectors and Direction Also sponsored by the Physics Classroom, this site provides an introduction to the fundamentals of vectors and directions.

The Physics Classroom: Relative Velocity and Riverboat Problems Again from the Physics Classroom, this is a discussion of vectors and relative velocity.

The Physics Classroom: Addition of Forces Again from the same hosting site, here you will find an introduction to forces and vectors in two dimensions and the addition of those forces.

University of Cambridge: How wings really work Developed by the University of Cambridge in England, this short video demonstrates how lift is created by air flowing over a wing.

Live Science: What Is Fluid Dynamics? This article by Live Science is an introduction to Fluid Dynamics.

Real World Physics Problems: The Physics of Sailing Sponsored by Real World Physics Problems, this site provides a comprehensive overview of the physics of sailing.

YouTube: The Physics of Sailing This is an excellent video on sailing produced by KQED in San Francisco.

National Sailing Hall of Fame: Introducing STEM Sailing Best Practices This site, sponsored by the National Sailing Hall of Fame, introduces two hands-on activities students can do to study the science of sailing.

how do sailboats work without wind

  • Repeated Customers
  • Booking Request

How do sailboats sail upwind?

Yachts aren’t blown along – they are ‘sucked along’.

The sail creates a low pressure zone in front of the sail and a high pressure zone behind the sail.

The boat moves into the low pressure zone and is sucked forward.

This is very like the idea of an  aeroplane wing , which is curved in a similar way to a sailboat’s sail as you can see below.

How do airplanes fly

In airplane wings, the pressure on the top of the wing is less than the pressure on the bottom of the wing, because  the air moves faster on the top , so this difference in pressure creates a force on the wing that lifts the wing up into the air.

The curve on the sail makes the air travel a longer distance over the top of the wing and a shorter distance behind it.

The longer distance the air flows, the lower the pressure, and this is why the aircraft climbs into the sky.

How do sailboats sail upwind

Below the level of the water on the boat, the sailboat’s shape helps force the boat to go straight forward as opposed to in the direction of the wind.

In addition you have the keel that is shaped like a wing, and has a lot of weight to stop the yacht from falling over when pushed sideways by the wind.

forces on sails

With the sails being unable to push the boat sideways or onto its side, the sails drive the boat forward.

Yacht Charter Greece Guide for 2023

Six innovative ways to float skyscraper-sized wind turbines

how do sailboats work without wind

Career Development Fellow in Engineering, University of Oxford

Disclosure statement

Emma C. Edwards has received funding through the Cornwall FLOW Accelerator, funded through the European Regional Development Fund. Her other research has been funded by the US Office of Naval Research and the UK Research & Innovation council.

University of Oxford provides funding as a member of The Conversation UK.

View all partners

Offshore wind turbine and installation boat

Yes, you read that right – float. You may have seen a wind turbine in the sea before, but chances are you were looking at a “fixed” turbine – that is, one that sits on top of a foundation drilled into the seabed. For the new frontier of offshore wind power, the focus is on floating wind turbines. In this case, the turbines are supported by floating structures that bob and sway in response to waves and wind and are moored with chains and anchored to the seafloor.

This is becoming the focus of the sector for the simple reason that most wind blows above deep water, where building fixed platforms would be too expensive or simply impossible. Designing these new floating platforms is a true engineering challenge, and is a focus of my academic research .

These wind turbines are enormous, reaching up to 240m tall – about the size of a skyscraper. Since they are so tall, strong winds far above the sea surface tend to make the turbine want to tilt, so platform designs focus on minimising this tilt while still being cost-competitive with other forms of energy.

There are more than 100 ideas for platform designs, but we can broadly group them into the following six categories:

Rendering of spar turbine design

Spars are narrow, deep platforms with weight added to the bottom to counteract the wind force (this is called “ballast”). They are usually relatively easy to make because they normally consist of just one cylinder.

However, they can extend 100 metres or more underwater, which means they can’t be deployed in normal docks which are not deep enough. Specialist installation procedures are required to install the turbine once the platform has been towed into deep water.

Floating wind turbine barge from above

Barges are wide, shallow platforms that use buoyancy far from the centre of the structure to counteract the wind force on the tower. As they usually extend less than 10 metres underwater, they do not need any specialist deep-water docks or installation vessels.

However, they can be difficult to make because the platform is usually a single, large unit with a complex shape.

3. Tension-leg platform

Diagram of floating wind turbine

Tension-leg platforms, or TLPs, use taut mooring lines to connect the platform to the seabed and stop the turbine from tilting in the wind.

These platforms are usually smaller and lighter than the other types, which makes them easier to fit at a standard port. Also, their seabed “footprint” is small due to the taut lines.

However, the platforms are usually not stable until attached to their mooring lines, meaning that a special towing and installation solution is required.

4. Semi-submersible

Semi-submersibles consist of three, four or five connected vertical cylinders, with the turbine in the middle or above one of the columns. The platform utilises buoyancy far from the centre (similar to the barge) and ballast at the base of each column (similar to the spar).

Image of floating wind turbine

Like barges, semi-submersibles do not require specialist tow-out equipment and work for a wide range of water depths. Manufacturing is again a challenge.

5. Combination-type

The four categories above are the more “traditional” platforms, influenced by their predecessors in the oil and gas industry. Since the 1960s, floating platforms have meant huge oil rigs can access deeper water sites (the deepest is over 2,000m). Most of these oil rigs in deep water are either semi-submersibles, anchored to the seabed with chains, or TLPs, connected to the seabed with taut cables.

Floating oil platform from above

More recently, there has been a trend towards platforms more specialised to floating wind. Specifically, some use a combination of the stability mechanisms, taking advantages from each of the previous designs.

Diagram of floating wind turbine

For example, “lowerable ballast” platforms look like traditional semi-submersible or barge platforms, but with a weight hanging from from taut cables.

During turbine installation at the port and tow-out, the weight is raised, so that a traditional (non-deep) dock can be used and no specialist equipment is needed. At the site of installation, the weight is lowered and the platform gets extra stability from a low centre of mass.

Other designs use the benefits of stability from taut mooring lines (similar to a TLP) but are designed to be stable during tow-out and so don’t need a special installation vessel. For example, the picture below shows the X1 Wind platform:

Diagram of floating wind turbine

The taut mooring lines are attached to a single column, which is installed initially. The rest of the platform, which is self-stable, is then towed out and connected to the pre-installed column with the taut mooring lines. The platform uses the extra stability from the mooring lines but without the tow-out instability typical of TLPs.

6. Hybrid platforms

Floating wind turbine

These platforms add another type of renewable energy, most commonly a wave energy converter. This increases the overall amount of energy generated, and reduces costs as power cables, maintenance and other infrastructure can be shared.

A wave energy converter also reduces platform motion, which in turn increases the power performance from the turbine.

Room for improvement

Four floating offshore wind farms have already been built, the largest of which was opened in 2023 off the coast of Norway . Two of these farms use the Hywind spar design and two use the WindFloat semi-submersible .

There have been 18 other platform designs to reach at-sea testing, including at least one of each of the categories described above. Some have plans to build floating farms in the next few years, and additional early-stage designs have plans to deploy their own prototype devices in the near future.

Interestingly, platforms are actually diverging in design. After many years, wind turbines have mostly converged on the three-bladed design that you see today, but there has been no such convergence yet on a consensus “best” floating platform. This suggests significant improvements are still possible, especially in terms of reducing motion and decreasing cost.

Imagine weekly climate newsletter

Don’t have time to read about climate change as much as you’d like? Get a weekly roundup in your inbox instead. Every Wednesday, The Conversation’s environment editor writes Imagine, a short email that goes a little deeper into just one climate issue. Join the 30,000+ readers who’ve subscribed so far.

  • Renewable energy
  • Offshore wind

how do sailboats work without wind

School of Social Sciences – Public Policy and International Relations opportunities

how do sailboats work without wind

Partner, Senior Talent Acquisition

how do sailboats work without wind

Deputy Editor - Technology

how do sailboats work without wind

Sydney Horizon Educators (Identified)

how do sailboats work without wind

Deputy Vice-Chancellor (Academic and Student Life)

IMAGES

  1. How Do Sailboats Work Without Wind?

    how do sailboats work without wind

  2. How do Sailboats Move without Wind?

    how do sailboats work without wind

  3. How Do Sailboats Work Without Wind?

    how do sailboats work without wind

  4. How Do Sails Actually Work: Full Beginners Guide

    how do sailboats work without wind

  5. How Sailboats Work

    how do sailboats work without wind

  6. What Physics Are Involved In The Working Of Sailboats? » Science ABC

    how do sailboats work without wind

VIDEO

  1. DIY Wind Vane Self Steering for Sailboats

  2. Getting ready to set sail this summer

  3. Do Sailboats Have BRAKES?

  4. Sailboat Racing Tips: Light Wind Lake Sailing

  5. How much it really costs to live on a sailing boat ⛵️ #sailing #shorts

  6. Boat Work!

COMMENTS

  1. How Do Sailboats Work Without Wind?

    Without having the winds in your sails, the boat will not move forward. Instead, you'll only drift along and get stuck in the neutral. Worst still, you can easily capsize. As such, it's of great importance to have a good grasp of how the wind works in propelling a sailboat and what you can do without it. When there are forces of the wind on the ...

  2. How do Sailboats Move without Wind?

    So, yes, it is possible for a sailboat to move in the total absence of the wind. The solutions include using your motor, propellers, use weight distribution, row the boat, and rely on tidal winds and sea breezes. Moreover, if you carry lightweight sheets and sails and shape a proper course the odds will be in your favor.

  3. How Do Sailboats Work Without Wind?

    2. Pump your rudder: If you move your rudder back and forth, you will create movement which will, once again, manufacture wind your cruising sail can capture.. 3.Use a fan: Some feel that using a fan similar to those used on swamp boats can be helpful.The key to this approach, however, is to point the fan away from the sails

  4. How Do Sailboats Sail into the Wind?

    Windward sailing also does not work if a boat is pointed directly opposite the wind direction, according to The Physics of Sailing. Wind has to be moving against the boat at an angle of at least ...

  5. How to Sail in Little or Without Wind

    Lighten The Weight Of The Boat. With little or no wind, unneeded items like coolers and extra gear let the boat sit lower in the water, let the rudder sit lower in the water, and put more drag on the boat. In addition, it takes more wind to get a heavier boat moving. In light air, you want a light boat.

  6. How Do Sailboats Work Without Wind? (Discover The Answers)

    Exploring Alternative Methods of Propelling a Sailboat Without Wind. Sailing without wind is possible through the use of a variety of auxiliary power sources. There are several ways to propel a sailboat without relying on the wind, including motors, oars, and even sails specifically designed to capture small amounts of wind. Using a motor is ...

  7. How Do Sailboats Go Against the Wind? (ft. a Great Lakes Schooner)

    Welcome to the Alliance! To try and understand more about how sailboats work, I boarded a three-masted schooner and recruited the help of my expert husband.S...

  8. Know how: Sailing 101

    Know how: Sailing 101. To begin You don't need to know much about how a piston engine works in order to drive a car. You get in, turn on the engine, shift into gear, step on the gas, and off you go. In a sailboat, though, you play a far more active role in harnessing the energy that propels you forward. You can get.

  9. So, You Need Wind to Sail?

    This point of sail is very narrow, just a few degrees. Close Reach - Sailing at an angle closer than 90 degrees to the wind (but not quite up to close-hauled). Beam Reach - Sailing at 90 degrees to the wind direction. Broad Reach - Sailing at any angle between reaching and running. Running - Sailing "downwind" directly away from the ...

  10. How a Sail Works: Basic Aerodynamics

    As your sailboat catches the wind in its sail and works with the keel to produce forward motion, that heeling over will be reduced due to the wing-like nature of the keel. The combination of the perpendicular force of the wind on the sail and the opposing force by the keel results in these forces canceling out.

  11. How Do Sailboats Work? (The Complete Guide)

    Sailboats use the power of the wind to propel them forward. The sails are designed to catch the wind, and as the wind passes through the sails, it creates lift which moves the boat forward. The sails can be adjusted to different angles to maximize the lift and the direction of the boat. The rudder is used to steer the boat and the keel helps to ...

  12. How Does Sailing Work? The Physics of Sailing

    Broad reach: Sailing diagonally away from the wind, between a beam reach and running. Running: Sailing directly downwind, with the wind coming from behind the boat. By adjusting the angle of the sails and the boat's course, sailors can optimize their speed and direction according to the prevailing wind conditions.

  13. How Do Sails Actually Work: Full Beginners Guide

    Just as easily, with a vector. Draw a six-inch line running east/west, then put an arrow on the west end. If we set our scale to one inch = 10mph, then we have our scalar measurement (6") and our orientation - west, or 270°. This arrow is the velocity vector of a car moving at 60mph headed west.

  14. How Sailboats Work: The Evolution of the Sailboat

    In the stern of the boat, you'll find the tiller, which is attached to the rudder. If the rudder of the sailboat is the tire then the tiller is the boat's steering wheel. In order to maneuver a boat, you'll pull the tiller to one side, causing the rudder to change direction. The keel and the sails work as the sailboat's engine.

  15. What happens to a sailboat if there is no wind?

    Without wind, there's no way to move the sails, which in turn powers the boat's movement. With no wind, the boat will be adrift, at the mercy of the currents and tides. However, just because there's no wind doesn't mean a sailor's adventure is over. A sailboat that's found itself becalmed can still maneuver, albeit not very fast or ...

  16. How Do Sailboats Work?

    Wind fills the sails and pushes the boat forward on the water. At angles, it takes more of an understanding of physics to explain. Sails on a boat work like the wings of an airplane. Both create aerodynamic lift to move an object. In the case of a boat, even when wind comes from the side, it moves the boat forward.

  17. How Sails Work: Understanding the Basics

    Tacking and jibing (gybing) A boat changes direction by either tacking or jibing. Sailing upwind, a boat tacks when the bow passes through the eye of the wind until the boat is sailing on the opposite side or "tack" creating a zig-zag course. When sailing downwind, the boat jibes when passing the stern through the wind.

  18. How Do Sailboats Work Without Wind?

    Sailboats rely on the wind to push them and lift them up. Most sailboats are designed to move with the wind pushing along the side of the boat and a little wind pushing the boat forward. The idea is to reduce the drag and keep your boat moving in the direction you want to go. Now, if there is no wind, here is what you can do.

  19. How to move a SAILING BOAT with no engine and no wind Episode ...

    This episode we help out another cruising family tow their 49 tonne sailing boat 3 nautical miles from a marina to a boat yard. We also show you some more of...

  20. An Introduction to the Physics of Sailing

    Introduction. The goal of this lesson is to explain how sailboats work by exploring basic physics principles. At the end of this lesson, students will be able to identify the forces acting on a sailboat and explain how the combination of these forces results in the forward motion of a sailboat. Students should be familiar with vectors and be ...

  21. How Sails Work or How Sailboats Sail into the Wind

    Traditional sailboats can only sail with the wind behind them. But modern sailboats have sail designs that enable them to sail in any direction regardless of...

  22. How do sails work in the wind; physics of sailing aerodynamics

    The sail creates a low pressure zone in front of the sail and a high pressure zone behind the sail. The boat moves into the low pressure zone and is sucked forward. This is very like the idea of an aeroplane wing, which is curved in a similar way to a sailboat's sail as you can see below. In airplane wings, the pressure on the top of the wing ...

  23. The World's Strangest Boats: Sailboats Without Sails

    In 1920, German engineer Anton Flettner proposed a revolutionary idea to change the basic foundation upon which sailboats were built. Flettner created a unique sailboat which used large rotating ...

  24. Six innovative ways to float skyscraper-sized wind turbines

    Damping Pool, by French firm BW Ideol. BW Ideol/ V. Joncheray. Barges are wide, shallow platforms that use buoyancy far from the centre of the structure to counteract the wind force on the tower.