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File:Sailing at sunset.jpg

Sailing at sunset

Sailing is the skillful art of controlling the motion of a sailing ship or smaller boat, across a body of water. Sailing vessels are propelled by the force of the wind on sails. Today, for most people, sailing is recreation, an activity pursued for the joy of being on the water and pursuing the mastery of the skills needed to maneuver a sailboat in varying sea and wind conditions. Recreational sailing can be further divided into Racing, Cruising and "Daysailing."

Introduction

A sailboat or sailing ship moves forward due to the action of the wind on its sails. Since at least the dawn of history this vital technology has afforded mankind greater mobility and capacity for fishing, trade and warfare. From moving the stones of the great pyramids from Aswan to Giza to allowing man to migrate throughout Polynesia to Nelson's defeat of the French Navy at Trafalgar, mankind's history has been intertwined with this seemingly simple technology (although it is not quite as simple as it seems).

The physics of sailing

Downwind Sailing is easy to understand when the wind is pushing the sails and the boat downwind. European sailing technology relied on downwind sailing through much of its history, limiting the efficiency of sail-borne travel and commerce. Basically the wind pushes the sail and the boat moves. This allows sailing directly away from the wind, and by changing the angle of the sail to the wind, sailing about 80 degrees to either side of directly downwind. The angles "closer to the wind" are made more effective by a keel, or fin attached to the bottom of the hull to counter-act side-slipping. Unfortunately, you couldn't go in a direction, if the wind wasn't blowing behind you.

Upwind It is more difficult to understand how upwind sailing works, although it was mastered by the Egyptians and Polynesians early in their history. All modern sailing uses upwind sailing technology, including the large cruse ships recently built with auxillary hard surface "sails".

When sailing upwind the angle of the sail (or its "trim") is adjusted so that slightly more wind pressure hits the upwind or "windward" side of the sail than the downwind or "leeward" side. The sail is cut and trimed so that this increased pressure pushes the sail into a shape that resembles an airplane wing - a flat windward side and a curved shape to leeward. Then as the wind flows around the mast and on either side of the sail, Bernoulli's principle acts to create a vaccuum on the leeward side of the sail, "pulling" the sail and the boat through the water.

The keel or centerboard is much more critical to upwind sailing, as much of the force created is tipping or "heeling" the boat over, as opposed to pulling it forward. In a balance of forces and flows probably too complicated to describe here, the keel forms a hydrofoil that counteracts the heeling of the boat and translates some of the heeling force into forward motion. The understanding and use of this effect explains the transition from "full keels" that ran along all or much of the bottom of the boat to the modern "fin keels" that are relatively deep and narrow.

A boat moves forward with a resultant force proportional to the dot product of the forward vector of the boat and the force vector of the sail on the boat. The force of the sail on the boat is parallel to the average normal vector of the sail and is proportional to the dot product of the relative wind vector and the average normal vector of the sail. This proportionality is most obvious because depending on the angle of incidence of the wind on the sail, the effective area of the sail varies. So, a positive value for a resultant force on the boat requires that the angle of the sail be bound between the forward direction of the boat and the upwind source.

When sailing downwind, a boat catches up to the wind, so the wind cannot push as hard on the sails. When sailing at an angle to the wind, however, although the boat may move fast, it is not catching up to the wind, so the wind continues to push the boat faster. Of course, eventually the boat cannot move faster because of the water, but not before speeding along much faster than if it had been sailing directly downwind.

The force on a sail is actually proportional to the relative velocity of the wind to the sail. Many factors complicate these generalities, however, such as the drag of the wind on the sails, the drag of moving through the water, the loss of wind force due to the boat heeling to a side so that the sails are pushed down and not just across the water.The force of the wind is used to create motion by using one or more sails. When sailing downwind (away from the wind source) the vessel's motion is derived from the simple force of the wind pushing the sail. When sailing upwind (towards the wind source) the movement of air over the sails acts in the same way as air moving over an aircraft's wing. Air flowing over the sail generates lift. This pulls the sail (and the boat) ahead, but also pushes it downwind rather strongly. The downwind, or leeward, component is offset by an underwater hydrofoil in the form of a Centerboard, Daggerboard or Sideboards in Dinghies and a keel in Keel Boats. The shape of the hydrofoil resists lateral movement from the Center of Lateral Resistance and counters the lateral force exerted from the sail's Center of Effort converting it into forward motion. Without this hydrofoil, sailing upwind would be impossible.

The lifting force of the sails also acts to lean the boat over to one side, which is called heeling. Heeling is counteracted by ballast, either in the form of dense material located deep in the bilge or externally in the keel, usually lead or iron, or for smaller, centerboard boats, by the wieght of the crew.

In ancient times ships used following or rear-quarter winds. Therefore, they had to either row or wait in port or at sea for the right wind directions.

Basic sailing techniques

The article Points of sail defines several terms that identify a sailboat's movement relative to the wind direction.

Steering and turning

When steering a sailboat, the method for changing direction depends on the direction of the wind. Thus, all direction changes or turns are described by one of the following terms:

Heading up (or luffing up) means steering so the wind is closer to coming from directly in front (or "on the bow"). Heading closer to the wind requires trimming the sails, pulling them towards the vessel's center. Heading up so the wind is nearly or directly ahead causes sails to luff, to flutter without achieving lift. If the boat loses maneuverability because of this, it is said to be in irons. Tacking (or coming about), one of the basic turning techniques, requires heading up and through the wind so it then comes across the opposite side of the boat, and the boat sails away on the opposite tack.
Heading down, bearing away, and falling off mean steering so the wind comes from closer to the vessel's aft. This requires easing sails, letting them out away from the vessel's center. Jibing is the turning maneuver in which the boat heads down past the point where the wind crosses the vessel's stern, which causes the sails and boom to swing to the opposite side, before the boat sails off on the opposite tack. The sail crosses with significant speed and misjudged jibing can easily capsize a boat especially in strong winds

Trim

An important aspect of sailing is keeping the boat in "trim". To achieve this a useful mnemonic (memory aid) is the phrase:

Can This Boat Sail Correctly?

This helps the crew to remember these essential points;

Course to Steer - Turn the boat using the wheel or tiller to the desired course to steer. See points of sail. This may be a definite bearing (e.g steer 270 degrees), or towards a landmark, or at a desired angle to the apparent wind direction.
Trim - This is the fore and aft balance of the boat. The aim is to adjust the moveable ballast (the crew!) forwards or backwards to achieve an 'even keel'. On an upwind course in a small boat, the crew typically sit forward, when 'running' it is more efficient for the crew to sit to the rear of the boat. The position of the crew matters less as the size (and weight) of the boat increases.
Balance - This is the port and starboard balance. The aim, once again is to adjust weight 'inboard' or 'outboard' to prevent excessive heeling.
Sail - Trimming sails is a large topic. Simply put however, a sail should be pulled in until it fills with wind, but no further than the point where the front edge of the sail (the luff) is exactly in line with the wind.
Centreboard - If a moveable centreboard is fitted, then it should be lowered when sailing "close to the wind" but can be raised up on downwind courses to reduce drag. The centreboard prevents lateral motion and allows the boat to sail upwind. A boat with no centreboard will instead have a heavy permanent keel built into the bottom of the hull, which serves the same purpose.

Running

Sailing the boat within roughly 30 degrees either side of dead downwind is called a run. This is the easiest point of sail in terms of comfort, but it can also be the most dangerous. When sailing upwind, it's easy to stop the boat by heading into the wind; a sailor has no such easy out when running. Severe rolling is more likely as there is less rolling resistance provided by the sails, which are eased out. And loss of attention by the helmsman could lead the boat to jibe accidentally, causing injury to the boat or crew. (A preventer can be rigged to prevent an accidental jibe.) Alternately, if there is a sudden increase in wind strength, the boat can round up very suddenly and heel excessively, often leading to a capsize in smaller boats. This is called broaching.

Reaching

When the boat is traveling approximately perpendicular to the wind, this is called reaching. A 'close' reach is somewhat toward the wind, and 'broad' reach is a little bit away from the wind (a 'beam' reach is with the wind precisely at right angles to the boat). For most modern sailboats, reaching is the fastest way to travel.

Sailing upwind

File:Beating an upwind course.png

Using a series of close hauled legs to beat a course upwind

A basic rule of sailing is that it is not possible to sail directly into the wind. Generally speaking, a boat can sail 45 degrees off the wind. When a boat is sailing this close to the wind, it is close-hauled or beating (beating to weather).

Since a boat cannot sail directly into the wind, but the destination is often upwind, one can only get there by sailing close-hauled with the wind coming from the port side (the boat is on port tack), then tacking (turning the boat through the eye of the wind) and sailing with the wind coming from the starboard side (the boat is on starboard tack). By this method, it is possible to reach that destination directly upwind. The heavier the wind, the rougher the seas, thus boat movement can be more uncomfortable. This can feel like the boat is beating its hull into the waves, hence the term beating.

How close a boat can sail to the wind depends on the boat's design, sail trim, the sea state and the wind speed, since what the boat "sees" is the apparent wind, i.e., the vector sum of the actual wind and the boat's own velocity. The apparent wind speed is what the anemometer on top of the mast shows. A good analogy to this would be walking through an indoor room and feeling the "wind" on your face. The faster you walk, the more wind your feel. The apparent wind angle while sailing close hauled will be less than the true wind angle. A good, modern sloop can sail within 25 degrees of the apparent wind. An America's Cup racing sloop can sail within 16 degrees, under the right conditions. Those figures might translate into 45 degrees and 36 degrees relative to the actual wind, depending on boat speed.

Reducing sail

An important safety aspect of sailing is to adjust the amount of sail to suit the wind conditions. As the wind speed increases the crew should progressively reduce the amount of sail. On a small boat with only jib and mainsail this is done by furling the jib and by partially lowering the mainsail, a process called 'reefing the main'.

Reefing means reducing the area of a sail without actually changing it for a smaller sail. Ideally reefing does not only result in a reduced sail area but also in a lower center of effort from the sails, reducing the heeling moment and keeping the boat more upright.

There are three common methods of reefing the mainsail:

Slab reefing, which involves lowering the sail by about one-quarter to one-third of its luff length and tightening the lower part of the sail using an outhaul or a pre-loaded reef line through a cringle at the new clew, and hook through a cringle at the new tack.
In-mast (or on-mast) roller-reefing. This method rolls the sail up around a vertical foil either inside a slot in the mast, or affixed to the outside of the mast. It requires a mainsail with either no battens, or newly-developed vertical battens.
In-boom roller-reefing, with a horizontal foil inside the boom. This method allows for standard- or full-length horizontal battens.

Mainsail furling systems have become increasingly popular on cruising yachts as they can be operated shorthanded and from the cockpit in most cases, however, the sail can become jammed in the mast or boom slot if not operated correctly. Mainsail furling is almost never used while racing because it results in a less efficient sail profile. The classical slab-reefing method is the most widely used. Mainsail furling has an additional disadvantage in that its complicated gear may somewhat increase weight aloft. However, as the size of the boat increases, the benefits of mainsail roller furling increase dramatically.

Sail trimming

As noted above, sail trimming is a large subject. Basic control of the mainsail consists of setting the sail so that it is at an optimum angle to the wind, (i.e. no flapping at the front, and tell tales flowing evenly off the rear of the sail).

Two or more sails are frequently combined to maximise the smooth flow of air. The sails are adjusted to create a smooth laminar flow over the sail surfaces. This is called the "slot effect". The combined sails fit into an imaginary aerofoil outline, so that the most forward sails are more in line with the wind, whereas the more aft sails are more in line with the course followed. The combined efficiency of this sail plan is greater than the sum of each sail used in isolation.

More detailed aspects include specific control of the sail's shape, e.g.:

reefing, or reducing the sail area in stronger wind
altering sail shape to make it flatter in high winds
raking the mast when going upwind (to tilt the sail towards the rear, this being more stable)
providing sail twist to cope with gusty conditions

Heeling

When a boat rolls over to one side under wind pressure, it's called 'heeling'. As a sailing boat heels over beyond a certain angle, it begins to sail less efficiently. Several forces can counteract this movement.

The buoyancy of that part of the hull which is being submerged tends to bring the boat upright.
Raising the centreboard can paradoxically increase leeway, and therefore reduce heeling.
A weighted keel, which can in larger boats be canted from side to side, provides additional force to right the boat.
The crew may move onto the high (upwind) side of the boat, called hiking, changing the centre of gravity significantly in a small boat. They can trapeze where the boat is designed for this (see Dinghy sailing).
The underwater shape of the hull relative to the sails can be designed to make the boat tend to turn upwind when it heels excessively: this reduces the force on the sails, and allows the boat to right itself. This is known as rounding up.
The boat can be turned upwind to produce the same effect.
Wind can be spilled from the sails by 'sheeting out', i.e. loosening the sail.
The sail shape can be altered to reduce its efficiency e.g. tightening the downhaul (see list of nautical terms)
Lastly, as the boat rolls farther over, wind spills from the top of the sail.

Most of the above effects can be used to right a heeling boat and to keep the boat sailing efficiently: if however the boat heels beyond a certain point of stability, it can capsize. A boat is said to have capsized when the tip of the mast is in the water.

Sailing safety

First and foremost:

Stay on the boat
Wear a life vest
Learn to swim
Learn how to recover someone who has fallen overboard

Sailing requires respect for the risks of being on the water. All sailors therefore should be sensibly prepared. Most jurisdictions have certain minimum regulations that must be met as to equipment. When engaged in publicly organized activities they may be required to take additional precautions, as detailed by the authority which regulates the training or racing.

Safety measures may include:

Appropriate floatation aids, including life preservers
Provision of a safety boat for rescue purposes
Appropriate first-aid and firefighting equipment
Carry a knife suitable for cutting rigging or netting in an emergency
Install jacklines and use them to secure the crew to the vessel.
Ensure visibility, use the required running lights and mount at least one radar reflector.

Man Overboard

Aside from what may be required by law or a sailing organization, real safety on the water comes from an informed awareness of risks involved and the exercise of reasonable steps to avoid dangers. A Man overboard situation is likely to be life threatening for any of several related reasons since the most likely cause is rough waters and weather conditions. These degrade the ability to maneuver easily, result in vastly different rates of drift caused by both wind and current to the boat and the unwilling swimmer, and in rough weather the reduced visibility makes fast and sure immediate action to be paramount as it is easy to lose sight of the swimming person. In many waters, including inland Lakes, hypothermia can be a major threat to life, so quick recovery of unwilling swimmers can be life-saving. This requires practice and situational awareness.

For sailing: Understanding and practice of man overboard procedures such as the Figure 8 or Quick turn and/or the LifeSling technique.
for power boats: (Or sailboats maneuvering under (auxiliary engine) power, not sails) Understanding and practice of man overboard procedures such as the Anderson turn, the Williamson turn, and the Scharnow turn is also helpful.

Rules of the road

Also, know the 'rules of the road':

Port tack gives way to Starboard tack (when the paths of two boats on opposite tacks cross, the boat with its port side to windward must give way)
Windward gives way to the leeward, or downwind boat (if on the same tack)
Overtaking boat gives way if above do not apply
Non-Commercial Powerboats usually give way to sailboats (but be careful in shipping lanes, and use common sense)
It is everybody's responsibility to avoid a collision, and avoiding action must be taken if these rules are ignored.

Sailing hulls and hull shapes

Sailing boats can have one, two, or three hulls. Boats with one hull are known as monohulls, while those with two or more are known as multihulls. Multihulls can be further subdivided into catamarans (two hulls), and trimarans (three hulls). A sailing boat is turned by a rudder which itself is controlled by a tiller or a wheel. Smaller sailing boats often have a stabilising, raisable, underwater fin called a centreboard (or daggerboard); larger sailing boats have a fixed (or sometimes canting) keel. As a general rule, the former are called dinghies, the latter yachts. However, up until the adoption of the Racing Rules of Sailing, any vessel racing under sail was considered a yacht, be it a multi-masted ship-rigged vessel (such as a sailing frigate), a sailboard (more commonly referred to as a windsurfer) or remote-controlled boat, or anything in between. (see Dinghy sailing)

Multihulls use flotation and/or weight positioned away from the centre line of the sailboat to counter the force of the wind. This is in contrast to heavy ballast that can make up to 1/3 of the weight of a monohulled sailboat. In the case of a standard catamaran there are two similarly sized and shaped narrow hulls connected by beams which are sometimes overlaid by a deck superstructure. Another catamaran variation is the proa. In the case of trimarans, which have an unballasted centre hull similar to a monohull, two relatively smaller amas are situated parallel to the centre hull to resist the sideways force of the wind. The advantage of multihulled sailboats is that they do not suffer the performance penalty of having to carry heavy ballast, and their relatively smaller hulls reduce the amount of drag caused by friction and inertia when moving through the water.

Types of sails and layouts

A traditional modern yacht is technically called a "Bermuda sloop" (sometimes a "Bermudan sloop"). A sloop is any boat that has only a single mast. The Bermuda designation refers to the fact that the sail which has its forward edge (the "luff") against the mast (the main sail) is a sail roughly triangular in shape. Addionally, Bermuda sloops only have a single sail behind the mast. Other types of sloops are gaff-rigged sloops and lateen sloops. Gaff-rigged sloops have quadrilateral mainsails with a gaff (a small boom) at their upper edge (the "head" of the sail). Gaff-rigged vessels may also have another sail, called a topsail, above the gaff. Lateen sloops have triangular sails with the upper edge attached to a gaff, and the lower edge attached to the boom, and the boom and gaff are attached to each other via some type of hinge. It is also possible for a sloop to be square rigged (having large square sails like a Napoleonic Wars-era ship of the line). Note that a "sloop of war," in the naval sense, may well have more than one mast, and is not properly a sloop by the modern meaning.

If a boat has two masts, it may be either a schooner, a ketch, or a yawl, if it is rigged fore-and-aft on all masts. A schooner may have any number of masts provided the second from the front is the tallest (called the "main mast"). In both a ketch and a yawl, the foremost mast is tallest, and thus the main mast, while the rear mast is shorter, and called the mizzen mast. The difference between a ketch and a yawl is that in a ketch, the mizzen mast is forward of the rudderpost (the axis of rotation for the rudder), while a yawl has its mizzen mast behind the rudderpost. In modern parlance, a brigantine is a vessel whose forward mast is rigged with square sails, while her after mast is rigged fore-and-aft. A brig is a vessel with two masts both rigged square.

As one gets into three or more masts the number of combinations rises and one gets barques, barquentines, and full-rigged ships.

A spinnaker is a large, full sail that is only used when sailing off wind either reaching or downwind, to catch the maximum amount of wind.

Sailing terminology

Sailors use many traditional nautical terms for the parts of or directions on a vessel; starboard (right), port (left), forward or fore (front), aft (rearward), bow (forward part of the hull), stern (aft part of the hull), beam (the widest part). Vertical spars are masts, horizontal spars are booms (if they can hit you), gaffs (if they're too high to reach) or poles (if they can't hit you).

Rope and lines

Rope is the term used only for raw material; once a section of rope is designated for a particular purpose on a vessel, it generally is called a line, as in outhaul line or dock line. A very thick line is considered a cable. Lines that are attached to sails to control their shapes are called sheets, as in mainsheet (line that controls the mainsail) or spinnaker sheets.

Lines (generally steel cables) that support masts are stationary and are collectively known as a vessel's standing rigging, and individually as shrouds or stays (the stay running forward from a mast to the bow is called the forestay or headstay).

Moveable lines that control sails or other equipment are known collectively as a vessel's running rigging. Lines that raise sails are called halyards while those that strike them are called downhauls or cunninghams. Lines that adjust (trim) the sails are called sheets. These are often referred to using the name of the sail they control (such as main sheet, or jib sheet). Sail trim may also be controlled with smaller lines attached to the forward section of a boom; such a line is called a vang, or a kicker in the United Kingdom.

Lines used to tie a boat up when alongside are called docklines, docking cables or mooring warps.

Some lines are referred to as ropes: A bell rope (to ring the bell), a bolt rope (attached to the edge of a sail for extra strength), a foot rope (on old square riggers for the sailors to stand on while reefing or furling the sails), and a tiller rope (to temporarily hold the tiller and keep the boat on course). A rode is what keeps an anchor attached to the boat when the anchor is in use. It may be chain, rope, or a combination of the two.

Other terms

Walls are called 'bulkheads' or 'ceilings', while the surfaces referred to as 'ceilings' on land are called 'overheads'. Floors are called 'soles' or 'decks'. The toilet is traditionally called the 'head', the kitchen is the 'galley'. Lines are rarely tied off, they are almost always 'made fast' or 'belayed.' Sails in different sail plans have unchanging names, however. For the naming of sails, see sail-plan.

Sailing terms have entered popular language in many ways. "Broken up" was the fate of a ship that hit a "rocky point" or was simply no longer wanted. "Poop" refers to the aftermost deck of a ship, taken from "puppis" the Latin word for "stern". "Pooped" refers to a wave breaking over the stern and filling the cockpit with water. "In the doldrums" referred to being becalmed, windless, especially in the narrow band of hot windless water "the doldrums", near the equator. "Adrift" meant literally that a ship's anchor had come loose, and the ship was out of control near land and therefore in serious danger. "Keel-hauled and hung out to dry." was the rather nasty process of attaching a sailor to a rope, and drawing him under the sailboat while underway, and then hanging him from a yard-arm (under his shoulders usually, not by his neck), where officers and crew could mock him. This was a particularly unpleasant punishment; apart from the risk of drowning, the sailor would be lacerated by the barnacles on the ship's hull.

Knots

Knots are one of the most important things that you need to learn before you start sailing. That being said, you will only need to learn a few knots and one in particular that is vital. The bowline is the absolute must have, essential knot. You could even get away with knowing only this knot. If you also know how to tie a clove hitch and a round turn and two half hitches you will be able to easily cope with all of the knot requirements on a boat. A competent grasp of knot-tying, however, will include mastery of the:

Even the most experienced sailors can forget their knots if they are not performed on a regular basis, that is why it is important to work on them all the time. If you are on a boat and you forget how to tie an important knot you can damage the boat or get hurt; you can also become very embarrassed when you’re asking someone how to tie a simple knot.

http://www.tollesburysc.co.uk/Knots/Knots_gallery.htm (Here are some of the most important knots for beginners to learn)

Sailing regulations

There are three very basic rules for avoiding a collision at sea:

Port gives way to starboard.
The more maneuverable vessel gives way to the less maneuverable vessel. It is generally assumed that this means that power gives way to sail, but this is not normally the case. It is always prudent for a small sailing vessel to stay out of the way of large ships by making an early and obvious turn out of the way.
If a collision is imminent both vessels must take immediate avoiding action even if they have the right of way according to normal rules. This means that if you have the right of way and a collision appears imminent that you must take avoiding action. Not to do so, if you have the opportunity, may make you the guilty party at an inquiry.

This first point means that boats that are on a possible collision course with boats approaching on their starboard bow give way. On sailing boats this extended to boats that have their sails set for a breeze coming from the left hand side of the boat (port) must give way to boats that have their sails set for a breeze coming from the right side of the boat (starboard). If both boats have their sails set on the same side of the boat, then the boat closer to where the wind is coming from (the windward boat) must give way to the leeward boat.

However there are many other rules besides and sailors are expected to know the essentials of boating safety which include;

The "rules of the road" or International Regulations for Preventing Collisions at Sea (COLREGS) set forth by the International Maritime Organization are particularly relevant to sailors because of their limited maneuverability compared to powered vessels.
The IALA International Association of Lighthouse Authorities standards for lateral marks, lights, signals, and buoyage and various rules designed to support safe navigation.
The SOLAS (Safety of Life at Sea) regulations place the obligations for safety on the owners and operators of any boat. These regulations specify the safety equipment needed and emergency procedures to be used.
When racing, all sailing vessels are expected to follow the Racing Rules of Sailing promulgated by the International Sailing Federation as well as any prescriptions (additional rules) given by the national governing body. When a boat that is racing encounters one that is not, the racing boat must comply with the International Regulations for Preventing Collisions at Sea with respect to the non-racing boat.

Sailboat racing

File:U.S. sailing team2.jpg

U.S. Sailing team at the World Military Games Sailing Competition, December 2003

Sailboat racing ranges from single person dinghy racing to large boats with 10 or 20 crew and from small boats costing a few hundred dollars to multi-million dollar Americas Cup or Sydney to Hobart Yacht Race campaigns. The costs of participating in the high end large boat competitions make this type of sailing one of the most expensive sports in the world. However, there are relatively inexpensive ways to get involved in sailboat racing, such as at community sailing clubs, and in some relatively inexpensive dinghy and small catamaran classes. Additionally many high schools and colleges offer sailboat racing programs through the Inter-Scholastic Sailing Association and the Intercollegiate Sailing Association. Under these conditions, sailboat racing can be comparable to or less expensive than sports such as golf and skiing. Sailboat racing is one of the few sports in which people of all ages can regularly compete with and against each other.

Most sailboat racing is done in sheltered coastal or inland waters. However, in terms of endurance and risk to life, ocean races such as the Volvo Ocean Race, the solo VELUX 5 Oceans Race, and the non-stop solo Vendée Globe, rate as some of the most extreme and dangerous sporting events. Not only do participants compete for days with little rest, but an unexpected storm, a single equipment failure, or collision with an ice floe could result in the sailboat being disabled or sunk hundreds or thousands of miles from search and rescue.

The sport of Sailboat racing is governed by the International Sailing Federation (ISAF), and the rules under which competitors race are the Racing Rules of Sailing, which can be found on the ISAF web site.

Sailing traditions and etiquette

There are many more esoteric, etiquette rules, traditions, and customs that will demonstrate to others advanced knowledge of boating protocol. Fenders should be pulled up outside ports, a boat should fly the flag of its nation of registry, the flag of a host country should be flown from the starboard yardarm, flags are to be taken down at night, boats are to be referred to as female, a boat should not be named twice, bananas are bad luck aboard sailing vessels, nothing should be deposited into the head (toilet to landlubbers) that has not been digested at least once, etc.

International Sailing Federation Classifications of Competition Sailing

ISAF Classes

Olympic Classes

 470
 49ER
 FINN
 LASER
 LASER RADIAL
 NEIL PRYDE RS:X
 STAR
 TORNADO
 YNGLING

International Centreboard Boat Class Associations

 14 FOOT DINGHY
 29ER
 420
 470
 49ER
 505
 CADET
 CONTENDER
 ENTERPRISE
 EUROPE
 FINN
 FIREBALL
 FLYING DUTCHMAN
 FLYING JUNIOR
 LASER
 Laser 4.7
 LASER II
 LASER RADIAL
 LIGHTNING
 MIRROR
 MOTH
 OK DINGHY
 OPTIMIST
 SNIPE
 SPLASH
 SUNFISH
 TOPPER
 VAURIEN
 ZOOM 8

International Keelboat Class Associations

 11 METRE
 12 METRE
 2.4 METRE
 5.5 METRE
 6 METRE
 8 METRE
 ACCESS 2.3
 DRAGON
 ETCHELLS
 FLYING FIFTEEN
 H-BOAT
 J/22
 J/24
 MELGES 24
 OPEN 60 MONOHULL
 SOLING
 STAR
 TEMPEST
 YNGLING

International Multihull Class Associations

 A-CATAMARAN
 DART 18
 FORMULA 18
 HOBIE 14
 HOBIE 16
 HOBIE 17
 HOBIE 18
 HOBIE TIGER
 TORNADO

International Windsurfing Class Associations

 FORMULA WINDSURFING
 FUNBOARD
 MISTRAL
 MISTRAL JUNIOR
 RACEBOARD

Recognized Class Associations

 60 MULTIHULL
 ACCESS 303
 B14
 BYTE
 FARR 40
 FORMULA EXPERIENCE
 HOBIE DRAGOON
 J/80
 MICRO
 MUMM 30
 NACRA F18
 NEIL PRYDE RS:X
 OPEN 50 MONOHULL
 PLATU 25
 RS FEVA
 SONAR
 SWAN 45
 TASAR
 TECHNO 293
 TOPCAT K1
 X99

Classic Yacht Classes

 GP14
 IOD
 SHARK

Template:Keelboats Worldwide

Types

catamaran = two symmetric hulls
proa = two asymmetric hulls, reverse-shunting (interchangeable bow/stern)
trimaran = three hulls
quadrimaran = four hulls
pentamaran = five hulls

Pre-modern Austronesian

Pre-modern Western

Tessarakonteres and Thalamegos (3rd century BC)
Simon & Jude or Invention I (1662)
Invention II (1662)
Experiment (1664)
St. Michael the Archangel (1684)
Experiment (1786)
Taurus (1790s)

19th century

Jersey (1812)
York (1813)
Nassau (1814)
Steam Battery (1815)
Double Trouble (1820)
Castaliâ (1874)
Amaryllis (1876)
Calais-Douvres or Express (1877)
Duplex (1877)
Duster (1877)
John Gilpin (1877)
Original (early 19th century)
Tarantella (1877)
Teaser (1878)
Zarifa (1878)
Proa #1 (1898)

1900s

Proa #2 (1903)
Proa #3 (1903)
Proa #4 (1908)
Kommuna (1912), original name Volkhov

1930s

Kaimiloa
Kaimiloa-Wakea

1940s

1950s

1960s

1970s

1980s

1990s

2000s

2010s

2020s

Brands

Unsorted

External links

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 '''Downwind'''
-Sailing is easy to understand when the wind is pushing the sails and the boat [[downwind]].  European sailing technology relied on downwind sailing through much of its history, limiting the efficiency of sail-borne travel and commerce.  Basically the wind pushes the sail and the boat moves.  This allows sailing directly away from the wind, and by changing the angle of the sail to the wind, sailing about 80 to 85 degrees to either side of directly downwind.  The angles "closer to the wind" are made more effective by a [[keel]], or fin attached to the bottom of the hull of the boat to counter-act side-slipping.
+Sailing is easy to understand when the wind is pushing the sails and the boat [[downwind]].  European sailing technology relied on downwind sailing through much of its history, limiting the efficiency of sail-borne travel and commerce.  Basically the wind pushes the sail and the boat moves.  This allows sailing directly away from the wind, and by changing the angle of the sail to the wind, sailing about 80 degrees to either side of directly downwind.  The angles "closer to the wind" are made more effective by a [[keel]], or fin attached to the bottom of the hull to counter-act side-slipping.  Unfortunately, you couldn't go in a direction, if the wind wasn't blowing behind you.
+'''Upwind'''
+It is more difficult to understand how [[upwind]] sailing works, although it was mastered by the Egyptians and Polynesians early in their history.  All modern sailing uses upwind sailing technology, including the large cruse ships recently built with auxillary hard surface "sails".
+When sailing upwind the angle of the sail (or its "trim") is adjusted so that slightly more wind pressure hits the upwind or "windward" side of the sail than the downwind or "leeward" side.  The sail is cut and trimed so that this increased pressure pushes the sail into a shape that resembles an airplane wing - a flat windward side and a curved shape to leeward.  Then as the wind flows around the mast and on either side of the sail, [[Bernoulli's principle]] acts to create a vaccuum on the leeward side of the sail, "pulling" the sail and the boat through the water.
+The keel or centerboard is much more critical to upwind sailing, as much of the force created is tipping or "heeling" the boat over, as opposed to pulling it forward.  In a balance of forces and flows probably too complicated to describe here, the keel forms a hydrofoil that counteracts the heeling of the boat and translates some of the heeling force into forward motion.  The understanding and use of this effect explains the transition from "full keels" that ran along all or much of the bottom of the boat to the modern "fin keels" that are relatively deep and narrow.
-It is more difficult to understand how [[upwind]] sailing works.  In general, the [[keel]] of a boat keeps it from side-sliping. This allows a boat to sail downwind but at an [[angle]]. The wind that blows on a sail is deflected off the sail, and that wind pushes against the sail too. The result is that the sail is not just pushed straight downwind, no matter which way it faces; but rather, it is pushed in the direction that it bows. This lets a boat pointed [[upwind]], though at an angle and not straight upwind, to move forward as long as the sail is able to bow forward. If the sail is pointed just as the boat, then the boat will only be pushed sideways, yet if the sail is pointed into the wind, then it will not catch the wind at all. So, the sail must be pointed somewhere between.
 * A boat moves forward with a resultant [[force]] proportional to the [[dot product]] of the forward vector of the boat and the force vector of the sail on the boat. The force of the sail on the boat is parallel to the average normal vector of the sail and is proportional to the dot product of the relative wind vector and the average normal vector of the sail. This proportionality is most obvious because depending on the angle of incidence of the wind on the sail, the effective area of the sail varies. So, a positive value for a resultant force on the boat requires that the angle of the sail be bound between the forward direction of the boat and the upwind source.