Water speed record
For true connoisseurs of their own time, the choice of yacht will focus exclusively on the highest quality, best and fastest option. Therefore, we can assume that there will someday be buyers for the fast yacht put up for sale, despite its cost of $25 million. After all, this particular yacht is the fastest yacht in the world! Today there is a very wide variety of beautiful and super-fast ships, but this model, built by WALLY, was able to prove its fame by setting a world speed record.
Yacht equipment
The ultra-modern vessel captivates with its minimalist design and sweeping appearance. Built in 2003, the Wally Power 118 reaches speeds of up to 60 maritime knots(111 km/h), which are inaccessible to most existing yachts. The yacht is equipped with three helicopter (gas) turbines, where their total power reaches 16,800 hp. The yacht's pointed stern cuts through waves at speeds of over 40 knots, even when sailing in the roughest waters.
Complete sound insulation
The hull of this vessel is designed so that even when moving at the highest speeds, vibrations and sounds cannot penetrate inside, and this allows vacationers to feel comfortable. The interior design of the vessel was designed by Carl Pickering, a famous designer from Lazzarini & Pickering. Karl focused on functionality and modernity, so the design turned out to be a bit of a mixed style: hi-tech, minimalism and loft. Sharp corners, metal, wood, rectangular windows and light shades of upholstery material - all this significantly helped to complement the technological and comfortable look of the yacht.
Amenities of the “yacht of the future”
The yacht is able to take on board from 6 to 12 passengers and 6 crew members, with a yacht length of 36 meters and a width of 9 meters at the base.
Wally Power 118 has already received the nickname “yacht of the future” and also won the top prize at the MYDA (Millennium Yacht Design Award). The star ship managed to appear in one of the most popular films of recent years.
Vacation on a yacht is not a cheap pleasure. Everyone dreams of having an island of salvation where they can sail away from everyday problems and just relax. But such a hobby, in addition to big material costs and time, requires considerable skills. You won't get far without knowing how a yacht works. Sailors are quite inventive people. They came up with their own name for each element. Therefore, you must also become familiar with the special terminology. You can find a lot in this article useful information on the structure of the yacht and other important points.
Characteristics
Swimming equipment must be different from each other. Yacht classes are determined depending on what characteristics they have. They may differ significantly from each other. The most significant characteristics can be considered:
- Length. The ship's performance depends on it. The longer it is, the faster it can move. This is especially true for sports yachts.
- Width. This factor affects speed and stability. The wider the vessel, the calmer it behaves on the water and the slower it moves (due to the high water resistance). Wide yachts are usually made for sailing on the sea and ocean, as high waves can occur in such places.
- draft. Yachts with a shallow draft maneuver worse. They also have less stability - the ability to resist roll and return to their previous position.
- Side height. It is important for those vessels that go to sea. The higher the board, the larger the waves it can withstand.
- Displacement. Yachts with a higher rating are better able to cope with unpleasant weather conditions, but due to their severity they are less maneuverable.
- Windage. Affects movement speed. The higher it is, the more energy the ship receives from the wind, so it moves faster.
Classification by presence of sail
Yachts differ from each other in several ways. The main thing is the presence or absence of a sail. If it is not there, then such a yacht moves due to the engine and is called a motor yacht. There is something else in between. Such a yacht has a sail, but in case of emergency it can use additional engine power.
By purpose
They are divided into racing and cruising. The first type is intended for sports competitions. They must correspond certain standards. Their main characteristics are windage and weight. The maximum possible speed depends on this. This yacht has nothing superfluous. Therefore, you can hardly call it comfortable. Racing models are only needed to cover distances at maximum speed.
Cruising yachts are a completely different matter. They are designed for walking with great comfort. They are equipped with everything necessary for have a good rest. Cruising yachts can accommodate quite a lot of people. You can live on it for more than one day. Modern ships equipped with a powerful engine can reach good speed. So you can also ride in a breeze on such models.
For long periods world travels Racing-cruising yachts are best suited. They have minimum set so that you can survive at sea. Plus they are quite fast. It is on such yachts that the Volvo Ocean Race, the famous round-the-world race, is held.
By seaworthiness
They are also classified according to where the ships sail. There are sea and river yachts. They differ from each other in design. Swimming equipment designed for movement in the sea must be more resistant to external influences, as there are strong storms there. Therefore, their design is usually wider and the draft is greater than that of freshwater yachts. The latter do not require such good stability.
By case type
Standard models are monohulls. But besides them there are also catamarans and trimarans. The latter have their own qualities that help during long voyages.
Yacht design
The main part of every watercraft is the hull. It is divided into 3 parts:
- Nasal.
- Midship.
- Stern.
One of the important parts of the hull is the keel. There is always a bulb at its end. This is a special thickening where the main weight of the keel is located. It is needed to keep the center of gravity as low as possible. This makes the ship more stable. The larger and heavier the keel, the better the yacht copes with external influences. You should never forget about it, because it can run aground.
Also under water, in addition to the keel, there is also a rudder blade. This is an important element of the yacht’s structure, because it is used to control it. The steering wheel itself is connected to the balancer and the rudder head. Through them, force is transmitted to the rudder blade, and the yacht turns.
Upper body
The first thing people pay attention to is called the deck of the yacht. This is a horizontal surface that delimits the upper and inner space. There may be several of them. Their task is to divide the space inside the yacht. There are several types: living, battery, cargo deck. Each can be intended for different purposes.
The upper deck must completely cover the entire upper part of the yacht. It serves as a waterproof barrier. It is important for the strength of the ship. There are many important elements of the yacht on the deck. You should also familiarize yourself with them.
At the very beginning is the bow rail. This is one of the fencing elements present on the yacht. This is a rigid structure made of metal. From it along the entire body there are rails. This is also a fencing element. But only they are made of iron cable. During a storm, insurance is usually attached to them. It all ends with a stern rail.
There are hatches on the deck. They lead inside the yacht. Through them you can get to the lower deck. At strong wind and in the waves they are sealed, so water cannot get inside.
The large superstructure that can be immediately noticed is called the deckhouse. There are various instruments that make up the ship's control and navigation system. For good review there are portholes installed.
The deck is easy upper part ship. And the place where people walk is called flood. It is usually made of wood or metal. Often it is covered with a special non-slip coating.
One of the most important places in the upper part of the hull is the cockpit. People get here as soon as they climb the ladder on board. This is where the passengers and crew are. The helmsman's post along with the steering wheel is also located there.
Sailing weapons
Thanks to this device, the yacht can move only with the help of the wind and without the help of a motor. There are a lot of little things and other nuances here. The design of a sailing yacht is quite complex. Therefore, you need to understand it thoroughly. This system consists of several parts:
- Sails.
- Spar.
- Rigging.
The Bermuda type is usually used. This is when two triangular sails are attached to the front and back. They are called jib and mainsail. The main element of a sailing yacht is the spar. This is a system that together creates the frame and mounting base for the sails. One of the parts of the spar is the mast. It also includes sheets, spreaders, booms and more. The top of the mast is called the top. The lower one, in turn, spurs. It ends at the keel of the ship and rests on the steps.
Rigging is all the gear that is attached to the spar. Thanks to them, the sails are controlled. Among them there are moving and standing elements (which are simply fixed).
Motor yachts
This type of boat does not have sailing equipment. They move using the energy of engines. This type of yacht is the most expensive. It is intended for the elite. And this is not just like that. Motor yachts have some of their own positive aspects which make them more attractive.
The first thing I would like to note is speed. Still, the power of the engine is much greater than that of the wind. Therefore, such models will be faster. If you need to quickly cover a long distance on the water or just ride with the breeze, then motorized vessels will be preferable. Modern yachts can reach speeds of up to 40 nautical miles per hour. Pretty good if you consider that it is approximately 70 kilometers per hour.
Motor yachts are rented or purchased by VIPs. Therefore, most often they go along with professional staff, which guarantees quality service and safety on the yacht.
Another advantage is comfort, which is unique to this class. Yachts with engines most often have special stabilizers that prevent the vessel from swaying so much. This means that the pitching will not be so noticeable.
Mega yachts
Man has always strived for more. Yachts are no exception. With their desire, engineers were able to create mega-yachts. Every year such vessels are awarded the Neptune Prize. To get into it, they must be at least 30 meters in length.
The largest yacht bears the proud name “Azzam”. It has a length of 180 meters. Its cost is $609 million. Despite her colossal size, she can travel at speeds of up to 30 knots. And this is a lot for such a giant.
Before Azzam was created, the Eclipse yacht of the famous entrepreneur Roman Abramovich was 162.5 meters in size. It cost the owner almost 800 million dollars. This is one of the most expensive yachts in the world.
Dubai ranks third on the list. Its length is 160 meters and its price is $350 million.
According to the rules determined by the World Sailing Speed Record Council (WSSRC), there is a whole series“tests”, and each of them has its own record holders, its own distances and chronological framework. The three most prestigious records are the average speed of a 500-meter passage, the average speed of a nautical mile, and the average speed of a 24-hour passage. The last nomination differs from the first two, like the run of a stayer from the run of a sprinter. Boats for long passages are equipped with cabins, storage for supplies and traditional system rigging.
Of course, the speed record for a sailing ship depends on many factors, both subject to human influence and random ones. Finding the right “windy balance”—so that the wind is as strong as possible, but does not raise “impassable” waves—is quite difficult. There are only one or two bays suitable for these purposes on the entire planet. Paul Larsen, creator and pilot of Vestas Sailrocket 2, set his records near the port of Walvis Bay in Namibia. But his story was preceded by another, no less interesting.
The main task facing the Vestas Sailrocket 2 designers was to develop an ideal aerodynamic profile. To start, the boat needs wind blowing at an angle of 90° to the line of motion. When moving, the wind flows coming off the boat’s hull are directed onto the sail, combining with the “natural” wind and further accelerating Vestas Sailrocket 2. That is, the faster it moves, the more energy it receives.
Adventures of a Frenchman
Six years ago, in October 2007, Popular Mechanics wrote about the futuristic trimaran l’Hydropt?re, built by the Frenchman Alain Thébault. At that time, “Hydropter” had just appeared in the field of view of journalists and aroused skepticism rather than admiration. But years passed, and Tebo established on his “ the ugly duckling» five world records (four in the nautical mile and one in the 500m), which seemed unbreakable until Larsen came along with his Vestas Sailrocket 2.
L" Hydropt?re is a hydrofoil sailing trimaran. The 6.4 m long wings are fixed at an angle of 45° to the hull and create a very significant lifting force: with a fairly modest wind (about 6.5 m/s), the trimaran is already lifted off surface of the water. If the ship hits a serious wave, gas shock absorbers are activated, “letting go” of the wing, which can move up to 60 cm, taking the energy of the impact.
A nautical mile is a very respectable distance, 1852 m, requiring a record-breaking vehicle sufficient stability. The short 500-meter course opens up the widest field for… kitesurfing. Since the International Sailing Federation officially included kitesurfing as a sailing discipline, athletes who have tamed kites have set six (!) short-distance speed records. However, both l‘Hydroptere and Vestas Sailrocket 2 different times became record holders in this category.
Tebo set his first record back in April 2007 - he covered a nautical mile at an average speed of 41.69 knots (77.21 km/h). It is interesting that the four previous records in this competition were set not on yachts, but on sailing windsurfing boards (the famous Danish windsurfer Bjorn Dunckerbeck, who set three world records for the nautical mile, was especially noteworthy). Subsequently, Tebo improved his performance three times and brought it to 50.17 knots (92.91 km/h) by the fall of 2009, thus becoming the first to exceed the fifty-hundred mark at this distance.
All your eggs in one basket
The main goal that Australian Paul Larsen set for himself was to become a world record holder in both disciplines. Funding for such a project, given the proper quality of the idea, is not so difficult to find - in Larsen’s case, the sponsor was the Danish company Vestas, the world’s largest manufacturer of wind generators. Larsen and a team of engineers set to work - and by 2008 (note that at that time Tebo was also still in its “formation” stage, that is, the French and Australian projects were developing in parallel) the Vestas Sailrocket catamaran was completed. On December 3, 2008, near Walvis Bay, Namibia, Larsen went on his first record swim and had a chance of success. Alas, the lift force exceeded the design one, the sailboat took off, somersaulted in the air and crashed. Larsen was lucky - he did not receive a scratch.
Short-lived record
Interesting story occurred in 2010 in the Namibian port of Lüderitz, where a team of kite surfers set a world record for average speed over 500 meters. Frenchman Sebastien Catellan has just become the world record holder, showing a result of 55.49 knots (102.76 km/h) and becoming the first person in the world to “sail” on a sail of 55 knots. 14 minutes later, his colleague, American Robert Douglas, flew a mile from average speed 55.65 knots (103.06 km/h), breaking the record. Thus Catellan was "on top of the world" in less than a quarter of an hour. To Catellan’s credit, it should be noted that he became a world record holder for the second time.
The finalization of the catamaran took four long years. The laws for building record-breaking sailboats are defined quite clearly: above the water there is a streamlined cockpit and a rigid sail, under water there are wings. Therefore, the main difference between the second generation of the Larsen “car” both from its predecessor and from competitors such as the “Hydropter” is a different configuration of the hydrofoils. The new Vestas Sailrocket 2 turned out to be very light (275 kg) and quite long (12.2 m), and this time no errors were found.
As a result, on November 16, 2012, Paul Larsen broke Thabo's nautical mile record, showing a result of 55.32 knots (102.44 km/h), and two days later surpassed the 500-meter result of kitesurfer Robert Douglas, racing the distance at a speed of 59.38 knot (109.97 km/h).
The French l'Hydroptere is much more massive than its competitor Vestas Sailrocket 2 (length - 18 m versus 12.2; total sail area - 560 m2 versus only 22), and the crew can accommodate from 5 to 11 people (versus a maximum two).
Larsen did not stop there - on November 18 he improved the mile record, raising the bar to 59.37 knots (109.94 km/h), and on November 24 he finally broke away from his pursuers in the 500-meter race - 65.45 knots (121.06 km /h). Thus, in both nominations Larsen “brought” 10 knots to his closest pursuers. Considering that such records are usually broken by 1-2 knots maximum, the Australian’s achievements are amazing.
Past and future
Since 1972, the 500-meter speed record has been set 24 times, and the first seven times it was set by the same person - Briton Tim Coleman, first on the Crossbow catamaran, then on the Crossbow II. In addition to Coleman's two boats, only three full-fledged vessels became record holders: are these the Hydropt described above? re and Vestas Sailrocket 2, as well as Yellow Pages Endeavor, whose record stood from 1993 to 2004. Seven world records have been set in windsurfing, and another six in kitesurfing.
Speed records for the nautical mile have been recorded relatively recently, since 2003. They were set ten times, four of them by windsurfers. It is difficult to say how long Larsen's records will last. The configuration of his Vestas Sailrocket 2 is known to everyone - it would not be surprising if a number of clones appeared in the coming years. True, with his achievements, the Australian seemed to have knocked out windsurfers and kitesurfers, who had physically exhausted the speed capabilities of their equipment, from the record race.
Vestas Sailrocket 2's 500-meter record is very high compared to all pursuers and therefore has every chance to last at least ten years. We should not forget that for all the genius of the ship’s design, the role lucky coincidence The circumstances and weather conditions during the swim can hardly be downplayed. To break a record, you need to try very, very hard - subject to incredible luck.
On the other hand, if anyone can set a new record, it will most likely be Larsen, since he has a “head start” - a ready-made technical scheme is very high level. If he improves his “car”, he will be able to gradually exceed his achievements - time after time, at least by half a knot, setting new and new world records.
The trimaran Banque Populaire V is designed for long passages - this is immediately evident from its dimensions: length - more than 23 m, displacement - 23 tons. The windage of the record trimaran exceeds 1300 m 2.
Third indicator
A few words still need to be said about the fastest daytime crossings. The last three records in this category were set during swims for the fastest crossing of the Atlantic. Today, in both of these categories, the Frenchman Pascal Bidegorry excels on the trimaran Banque Populaire V - on August 1, 2009, he managed to overcome 1681 km in 24 hours (!). In total, Bidegorry's team crossed the Atlantic in 3 days, 15 hours, 25 minutes and 48 seconds.
As already mentioned, ships for long passages are seriously different in design from cars for one-time instant speed races. For example, Banque Populaire V had a crew of 11 people and, accordingly, all the supplies and premises necessary for their three-day journey. By the way, in 2011, the trimaran was taken over by another captain, Loic Peyron, and a year later, under his command, Banque Populaire V set a new record for high-speed circumnavigation, circumnavigating the entire planet in 45 days, 13 hours, 42 minutes and 53 seconds.
The record race never stops. Nobody knows where the upper limit of speed is, and therefore for many years a person will have something to strive for. You give 70, 80, 90 knots per hour; perhaps someday sailing ships will overcome the 100 knot limit. And at such speeds, they can return to the oceans again, competing with their diesel counterparts.
The nautical mile has long been the basic unit of measurement for distances at sea. The arc length of one minute at the average latitude of the earth's meridian is taken to be equal to a nautical mile.
The speed of a ship is measured in knots. One knot is equivalent to one nautical mile per hour (1.852 km/h). The term “knot” arose in the 16th century during the time of the sailing fleet, when the speed of the ship began to be determined by a sector lag. The lag consisted of a wooden sector bound with iron, a durable lagline and a winding eye. Laglin was divided into sections of 50.67 feet using knots. The spacing between knots was adjusted so that a knot corresponded to a speed of one nautical mile per hour. By counting the number of knots that went into the water from the stern of the ship in half a minute, the speed was determined.
Factors that determine speed
The speed of a sailing ship depends on various factors: its design, wind strength, the way the sails and rigging are adjusted for different sailing conditions, the crew’s ability to control the ship on different courses.
The movement of the yacht comes from the interaction of the wind with the sail. The air flow, which has kinetic energy, moves the sailing ship. The sail can move the yacht only if it is at a certain angle to the air flow and deflects it. The angle of the sails to the wind is important condition receiving maximum effect in their work. A correctly selected angle creates the maximum pressure difference between the air flows on both sides of the sail. Verification tool correct settings“sorcerers” serve as sails. Fixed on both sides of the sail, they stretch along the air currents. When a vortex is formed, the “wizards” on this side of the sail deviate from the smooth flow path.
A yacht cannot sail against a headwind. Most sailing ships are unable to maintain a course at an angle of less than 45° to the wind. Angles of 45° on both sides of the wind direction form a “dead zone”. When approaching it, the “sorcerers” on the sails begin to shake, indicating a loss of speed by the yacht. In a headwind, yachts tack – zigzag maneuvers.
The theoretical speed to which a displacement yacht can be accelerated is determined by the formula: the square root of the waterline length in feet multiplied by 1.34.
There is a distinction between true wind and apparent wind. Apparent wind represents the geometric sum of the speeds of the true wind and the wind caused by the yacht's progress.
A jibe (with a tailwind) is not the fastest course. On a jibe course, the force with which the wind presses on the sail depends on the speed of the yacht. Maximum speed on this course there is always less wind speed. The wind presses with the greatest force on the sail of a stationary yacht. As speed increases, the pressure on the sail decreases and becomes minimal when the yacht's speed reaches its maximum value. The force with which the wind presses on the sail is proportional to the square of the speed of the apparent wind, and the speed of the apparent wind on a gybe course is the difference between the speed of the true wind and the speed of the yacht.
Gulfwind heading (at an angle of 90º to the wind) sailing yachts able to move faster than the wind. On this course, the force with which the wind pushes on the sails is less dependent on the speed of the yacht.
All yachts, without exception, increase speed in planing mode. When entering planing, the resistance to movement decreases sharply. The lighter the yacht, the earlier it goes on planing. For fast sailing, the stability of the yacht on the chosen course is very important.
The contours of the hull at and below the waterline are important. The hull of the yacht should provide as little resistance as possible to the flow of water so as not to reduce the speed of the vessel. The greatest resistance to movement occurs at the waterline. Reducing shape resistance largely depends on the care of the vessel, the smoothness of its surface, the ratio of length, width and streamlining of the sides and underwater parts - the keel and rudder. Once a year, the yacht must be lifted out of the water for...
The speed of a yacht largely depends on the crew’s ability to steer the vessel in different conditions swimming. Incorrect distribution of the crew's weight reduces speed and impairs the yacht's handling.
Only practical sailing experience, knowledge of the basic theory of aerodynamics and elementary meteorology help improve the skills and means of controlling the performance of a yacht on different courses.
Speed records under sail
The America's Cup, first held in 1851, is considered a well-known and authoritative competition for the speed of sailing yachts. The competition got its name from the name of the ship that won the first English regatta among a dozen sailing ships. The schooner reached a maximum speed of 17 knots.
The title itself fast sailboat The planets are held by the trimaran Hydroptere. Created by a group of French engineers, the vessel shows the promise of sailing vehicles on the water. At a speed of 12 knots, the Hydroptere lifts out of the water and emerges on hydrofoils. The more a sailboat picks up speed, the higher it rises above the surface of the water. The maximum speed that the Hydroptere can achieve while remaining stable is 50 knots. The maximum speed reached by the ship was 61 knots.
WIND DRIVING FORCE
The NASA website has published very interesting materials about various factors influencing the formation of lift by an aircraft wing. There are also interactive graphical models that demonstrate that lift can also be generated by a symmetrical wing due to flow deflection.
The sail, being at an angle to the air flow, deflects it (Fig. 1d). Coming through the “upper”, leeward side of the sail, air flow travels a longer path and, in accordance with the principle of continuity of flow, moves faster than on the windward, “lower” side. The result is that the pressure on the leeward side of the sail is less than on the windward side.
When sailing on a jibe, when the sail is set perpendicular to the direction of the wind, the degree of increase in pressure on the windward side is greater than the degree of decrease in pressure on the leeward side, in other words, the wind pushes the yacht more than it pulls. As the yacht turns sharper into the wind, this ratio will change. Thus, if the wind is blowing perpendicular to the yacht's course, increasing the pressure on the sail on the windward side has less effect on speed than decreasing the pressure on the leeward side. In other words, the sail pulls the yacht more than it pushes.
The movement of the yacht occurs due to the fact that the wind interacts with the sail. Analysis of this interaction leads to unexpected results for many beginners. It turns out that the maximum speed is achieved not at all when the wind blows directly from behind, and the wish for a “fair wind” carries a completely unexpected meaning.
Both the sail and the keel, when interacting with the flow of air or water, respectively, create lift, therefore, to optimize their operation, wing theory can be applied.
WIND DRIVING FORCE
The air flow has kinetic energy and, interacting with the sails, is capable of moving the yacht. The work of both the sail and the airplane wing is described by Bernoulli's law, according to which an increase in flow speed leads to a decrease in pressure. When moving in the air, the wing divides the flow. Part of it goes around the wing from above, part from below. An airplane wing is designed so that the air flow over the top of the wing moves faster than the air flow under the bottom of the wing. The result is that the pressure above the wing is much lower than below. The pressure difference is the lifting force of the wing (Fig. 1a). Thanks to its complex shape, the wing is able to generate lift even when cutting through a flow that moves parallel to the plane of the wing.
The sail can move the yacht only if it is at a certain angle to the flow and deflects it. It remains debatable how much of the lift is due to the Bernoulli effect and how much is the result of flow deflection. According to classical theory wing lift arises solely as a result of the difference in flow velocities above and below the asymmetrical wing. At the same time, it is well known that a symmetrical wing is capable of creating lift if installed at a certain angle to the flow (Fig. 1b). In both cases, the angle between the line connecting the front and rear points of the wing and the direction of the flow is called the angle of attack.
Lift increases with increasing angle of attack, but this relationship only works at small values of this angle. As soon as the angle of attack exceeds a certain critical level and the flow stalls, numerous vortices are formed on the upper surface of the wing, and the lift force decreases sharply (Fig. 1c).
Yachtsmen know that gybe is not the fastest course. If the wind of the same strength blows at an angle of 90 degrees to the heading, the yacht moves much faster. On a jibe course, the force with which the wind presses on the sail depends on the speed of the yacht. With maximum force, the wind presses on the sail of a yacht standing motionless (Fig. 2a). As speed increases, the pressure on the sail drops and becomes minimal when the yacht reaches maximum speed (Fig. 2b). The maximum speed on a gybe course is always less than the wind speed. There are several reasons for this: firstly, friction; during any movement, some part of the energy is spent on overcoming various forces that impede movement. But the main thing is that the force with which the wind presses on the sail is proportional to the square of the speed of the apparent wind, and the speed of the apparent wind on a gybe course is equal to the difference between the speed of the true wind and the speed of the yacht.
With a gulfwind course (at 90º to the wind), sailing yachts are able to move faster than the wind. In this article, we will not discuss the features of the apparent wind; we will only note that on a gulfwind course, the force with which the wind presses on the sails depends to a lesser extent on the speed of the yacht (Fig. 2c).
The main factor that prevents an increase in speed is friction. Therefore, sailboats with little resistance to movement are able to reach speeds much higher than the speed of the wind, but not on a gybe course. For example, a boat, due to the fact that skates have negligible sliding resistance, is capable of accelerating to a speed of 150 km/h with a wind speed of 50 km/h or even less.
The Physics of Sailing Explained: An Introduction
ISBN 1574091700, 9781574091700