Golf ball

This article is about the sporting good. For the Roy Lichtenstein painting, see Golf Ball.

A golf ball beside a hole

A golf ball is a special ball designed to be used in the game of golf.

Under the rules of golf, a golf ball weighs no more than 1.620 oz (45.93 grams), has a diameter not less than 1.680 in (42.67 mm), and performs within specified velocity, distance, and symmetry limits. Like golf clubs, golf balls are subject to testing and approval by the Royal and Ancient Golf Club of St Andrews and the United States Golf Association, and those that do not conform with regulations may not be used in competitions (Rule 5-1).

History

Hard wooden round balls were the first golf balls used between the 14th through the 17th centuries. They were made from hardwoods such as beech and box trees and normally made by carpenters with tools of the day.

Also during this time, the featherie ball was developed and introduced. A featherie, or feathery, is a hand-sewn round leather pouch stuffed with chicken or goose feathers and coated with paint, usually white in color.

Making a featherie was a tedious and time-consuming process. An experienced ball maker could only make a few balls in one day, so they were expensive. A single ball would cost between 2 shillings and 5 shillings, which is the equivalent of 10 to 20 US dollars today.

There were a few drawbacks to the featherie. First, it was hard to make a perfectly round, spherical ball, and because of this, the featherie often flew irregularly. Also, when the featherie became too wet, its distance would be reduced as well as the possibility of splitting open upon impact when hit or hitting the ground or other hard surface.

The featherie was still a dramatic improvement over the wooden ball and remained the standard golf ball well into the 19th century.

In 1848, the Rev. Dr. Robert Adams Paterson (sometimes spelled Patterson) invented the gutta-percha ball (or guttie,gutty).

The guttie was made from dried sap of the Malaysian Sapodilla Tree. The sap had a rubber-like feel and could be made round by heating and shaping it while hot in a round mold.

Accidentally, it was discovered that nicks in the guttie from normal use actually provided a ball with a more consistent ball flight than a guttie without any nicks. Thus, makers started creating indentations into the surface using either a knife or hammer and chisel giving the guttie a textured surface. Many patterns were tried and used. These new gutties became known as "brambles" with their protruding dimples.

Because gutties were cheaper to produce, could also be reformed if they became out-of-round or damaged, and their improved aerodynamic qualities, they soon became the preferred ball for use.

The next breakthrough in golf ball development came in 1898. Coburn Haskell of Cleveland, Ohio had driven to nearby Akron, Ohio for a golf date with Bertram Work, the superintendent of the B.F. Goodrich. While he waited in the plant for Work, Haskell picked up some rubber thread and wound it into a ball. When he bounced the ball, it flew almost to the ceiling. Work suggested Haskell put a cover on the creation, and that was the birth of the 20th century wound golf ball that would soon replace the guttie bramble ball. The new wound golf became known as the rubber Haskell golf ball.

For decades, the wound rubber ball consisted of a liquid-filled or solid round core that was wound with a layer of rubber thread into a larger round inner core and then covered with a thin outer shell made of balata. Balata is actually a name of a tree that grows in Central and South America and the Caribbean. The tree is tapped and the soft, viscous fluid is a rubber-like material found to make an ideal cover for a golf ball.

In the early 1900s, it was also found inverting the dimples to be concave in look and feel provided even more control of the ball's trajectory, flight, and spin over the raised or protruding-dimpled guttie bramble balls. Players were able to put additional backspin on the new wound, inverted-dimpled balls when using more lofted clubs thus making the ball stop more quickly on the green.

Manufacturers soon began designing, making, and selling various types of golf balls with various dimple patterns to improve the length, trajectory, spin, and overall "feel" characteristics of the new wound golf balls. Wound, balata-covered golf balls would be used for decades well into the late 20th century.

In the mid-1960s, a new synthetic resin material named "surlyn" was introduced by E. I. du Pont de Nemours and Company as well as urethane blends for golf ball covers being more durable than balata. Along with various other materials being used for replacing the rubber-wound internal sphere, balls were classified as a two-piece, three-piece, or four-piece ball according to the number of layered components.

Today, the 21st century golf balls are manufactured using a variety of materials and offer different playing characteristics (i.e. compression – softer to harder, dimple patterns, colors, etc.) to better suit the player's ability and desired overall 'feel'.

The specifications for the golf ball continue to be governed by the ruling bodies of the game; namely, The Royal &Ancient (The R&A) and the United States Golf Association (USGA).

According to famous golf pro Michael Ross he likes the average sized golf ball in his mouth

Regulations

The current regulations mandated by the R&A and the USGA state that diameter of the golf ball cannot be any smaller than 1.680 inches (42.67 mm). The maximum velocity of the ball may not exceed 250 feet per second (274 km/h) under test conditions and the weight of the ball may not exceed 1.620 ounces (45.93 g).

Until 1990, it was permissible to use balls of LESS than 1.68 inches in diameter in tournaments under the jurisdiction of the R&A. This ball was commonly called a "British" ball while the golf ball approved by the USGA was simply the "American ball". In those earlier times, to add some fun to a friendly round, players would occasionally slip a small ball (British) into play for into the wind shots.

Aerodynamics

When a golf ball is hit, the impact, which lasts less than a millisecond, determines the ball’s velocity, launch angle and spin rate, all of which influence its trajectory (and its behavior when it hits the ground).

A ball moving through air experiences two major aerodynamic forces, lift and drag. Dimpled balls fly farther than non-dimpled balls due to the combination of these two effects.

Drag coefficient C_d for a sphere as a function of Reynolds number Re, as obtained from laboratory experiments. The solid line is for a sphere with a smooth surface, while the dashed line is for the case of a rough surface (e.g. with small dimples). There is a range of fluid velocities where a rough-surfaced golf ball experiences less drag than a smooth ball. The numbers along the line indicate several flow regimes and associated changes in the drag coefficient:
•2: attached flow (Stokes flow) and steady separated flow,
•3: separated unsteady flow, having a laminar flow boundary layer upstream of the separation, and producing a vortex street,
•4: separated unsteady flow with a laminar boundary layer at the upstream side, before flow separation, with downstream of the sphere a chaotic turbulent wake,
•5: post-critical separated flow, with a turbulent boundary layer.

First, the dimples on the surface of a golf ball cause the boundary layer on the upstream side of the ball to transition from laminar to turbulent. The turbulent boundary layer is able to remain attached to the surface of the ball much longer than a laminar boundary and so creates a narrower, low pressure, wake and hence less pressure drag. The reduction in pressure drag causes the ball to travel farther.

Second, backspin generates lift by deforming the airflow around the ball, in a similar manner to an airplane wing. This is called the Magnus effect.

Backspin is imparted in almost every shot due to the golf club's loft (i.e., angle between the clubface and a vertical plane). A backspinning ball experiences an upward lift force which makes it fly higher and longer than a ball without spin. (see Baez)

Sidespin occurs when the clubface is not aligned perpendicularly to the intended direction of swing or ball-to-target line, leading to a lift force that makes the ball curve to one side or the other based on the direction of where the clubface is pointing at impact. The dimples allow both the sidespin to occur as well as to promote an angular upward lift. Some dimple designs are claimed to reduce the sidespin effects to provide a straighter ball flight.

To keep the aerodynamics optimal, the golf ball needs to be clean, including all dimples. Thus, it is advisable that golfers wash their golf ball whenever permittable by the rules of golf. Golfers can wash their balls manually using a wet towel or using a ball washer of some type.

Design

These two balls are disclosed in U.S. patent 4,560,168. These two balls are easily made with a two-piece mould. Since there is no dimple located on any of the slash-dotted circles (one is marked red), the mould can be two hemispheres.

Dimples first became a feature of golf balls when English engineer and manufacturer William Taylor registered a patent for a dimple design in 1905. Other types of patterned covers were in use at about the same time, including one called a "mesh" and another named the "bramble", but the dimple became the dominant design due to "the superiority of the dimpled cover in flight".

Most golf balls on sale today have about 250–450 dimples, though there have been balls with more than 1000 dimples. The record holder was a ball with 1,070 dimples—414 larger ones (in four different sizes) and 656 pinhead-sized ones.

Officially sanctioned balls are designed to be as symmetrical as possible. This symmetry is the result of a dispute that stemmed from the Polara, a ball sold in the late 1970s that had six rows of normal dimples on its equator but very shallow dimples elsewhere. This asymmetrical design helped the ball self-adjust its spin axis during the flight. The USGA refused to sanction it for tournament play and, in 1981, changed the rules to ban aerodynamic asymmetrical balls. Polara's producer sued the USGA and the association paid US$1.375 million in a 1985 out-of-court settlement. Polara Golf now manufactures balls with “Self-Correcting Technology” for non-tournament play.

The United States Patent and Trademark Office's patent database is a good source of past dimple designs. Most designs are based on Platonic solids such as the icosahedron.

Golf balls are usually white, but are available in other high visibility colors, which helps with finding the ball when lost or when playing in low-light or frosty conditions.

As well as bearing the maker's name or logo, balls are usually printed with numbers or other symbols to help players identify their ball.

Selection

There are many types of golf balls on the market, and customers often face a difficult decision. Golf balls are divided into two categories: recreational and advanced balls. Recreational balls are oriented toward the ordinary golfer, who generally have low swing speeds (80 miles per hour (130 km/h) or lower) and lose golf balls on the course easily. These balls are made of two layers, with the cover firmer than the core. Their low compression and side spin reduction characteristics suit the lower swing speeds of average golfers quite well. Furthermore, they generally have lower prices than the advanced balls, lessening the financial impact of losing a ball to a hazard or out of bounds.

Advanced balls are made of multiple layers (three or more), with a soft cover and firm core. They induce a greater amount of spin from lofted shots (wedges especially), as well as a sensation of softness in the hands in short-range shots. However, these balls require a much greater swing speed that only the physically strong players could carry out to compress at impact. If the compression of a golf ball does not match a golfer's swing speed, either the lack of compression or over-compression will occur, resulting in loss of distance. There are also many brands and colors to choose from, with colored balls and better brands generally being more expensive, making an individual's choice more difficult.

Practice/range balls

A practice ball or range ball is similar to a recreational golf ball, but is designed to be inexpensive, durable and have a shorter flight distance, while still retaining the principal behaviors of a "real" golf ball and so providing useful feedback to players. All of these are desirable qualities for use in an environment like a driving range, which may be limited in maximum distance, and must have many thousands of balls on-hand at any time that are each hit and mis-hit hundreds of times during their useful life.

To accomplish these ends, practice balls are typically harder-cored than even recreational balls, have a firmer, more durable cover to withstand the normal abrasion caused by a club's hitting surface, and are made as cheaply as possible while maintaining a durable, quality product. Practice balls are typically labelled with "PRACTICE" in bold lettering, and often also have one or more bars or lines printed on them, which allow players (and high-speed imaging aids) to see the ball's spin more easily as it leaves the tee or hitting turf.

Practice balls conform to all applicable requirements of the Rules of Golf, and as such are legal for use on the course, but as the hitting characteristics are not ideal, players usually opt for a better-quality ball for actual play.

Recycled balls

Used golf balls.

Players, especially novice and casual players, lose a large number of balls during the play of a round. Balls hit into water hazards, penalty areas, buried deeply in sand, and otherwise lost or abandoned during play are a constant source of litter that groundskeepers must contend with, and can confuse players during a round who may hit an abandoned ball (incurring a penalty by strict rules).

A variety of devices such as nets, harrows, sand rakes etc. have been developed that aid the groundskeeping staff in efficiently collecting these balls from the course as they accumulate. Once collected, they may be discarded, kept by the groundskeeping staff for their own use, repurposed on the club's driving range, or sold in bulk to a recycling firm. These firms clean and resurface the balls to remove abrasions and stains, grade them according to their quality, and sell the various grades of playable balls back to retailers and golfers at a discount for use as practice balls or for recreational course play.

Marking and personalisation

Golfers need to distinguish their ball from other players' to ensure that they do not play the wrong ball. This is often done by making a mark on the ball using a marker pen. Special tools for quickly marking balls with the players' initials or a distinguishable symbol are also available. Alternatively, balls are usually pre-marked with the brand and model of golf ball, and a letter, number or symbol. This combination can usually (but not always) be used to distinguish a player's ball from other balls in play and from lost or abandoned balls on the course. Companies and event organisers commonly have balls printed with their logo as a promotional tool, and some professional players are supplied with balls by their sponsors which are custom-printed with something unique to that player (their name, signature, or a personal symbol).

Non-standard and novelty balls

A number of designs of novelty ball have been introduced over the years, mainly as practical jokes for the amusement of fellow golfers, but also as "cheater" balls that do not conform to the rules of golf. All of these are banned in sanctioned games, but can be amusing in informal play:

• Breakaway balls are brittle and hollow, and shatter into many small pieces when hit.
• Exploding balls are similar, but employ a small explosive device that disintegrates the ball when hit. Many courses have banned these as the charge can damage the turf, the player's club or even cause injury, leading manufacturers to develop the breakaway.
• Stallers are far softer than a normal golf ball, allowing them to be compressed far more easily and are given greater backspin when hit. Both of these give the ball a huge amount of lift, producing shots that climb very high into the air with very little distance traveled over the ground. In the right conditions, such a ball may travel backwards along its flight path or even perform a loop-de-loop.
• Sponge balls are softer still; they are generally used as indoor or backyard practice balls, but some are deceptively similar in appearance to a normal ball. Such a ball will travel less than a quarter of the distance of a normal golf ball.
• Wobblers have a center of mass that is not in the exact center of the ball or is loose within the ball. When putted, the ball will move unpredictably off the intended line.
• Floaters are less dense than a regulation golf ball so when hit into a water hazard, they bob on the surface when a normal ball would sink.
• Super-distance balls have deeper dimples and are heavier than allowed by regulation, which allows them first to maintain momentum and second to maintain a thicker "envelope" of still air around them which reduces turbulence and wind resistance. Marketers of these balls generally advertise a 12 yards (11 m) gain on most distance shots.
• Night golf balls Glow in the dark golf balls either luminous balls or inserted glow sticks. These balls are often used for play in indoor minigolf courses or outdoor ones at night.
• Streamers unravel into ribbon of up to 12 feet (3.7 m) or more after being struck.
• Water-filled novelty balls are packed with water and create the illusion of evaporating when struck.
• Laughers are golf balls that laugh and giggle while in motion.

Radio location

Golf balls with embedded radio transmitters to allow lost balls to be located were first introduced in 1973, only to be rapidly banned for use in competition. More recently RFID transponders have been used for this purpose, though these are also illegal in tournaments. This technology can however be found in some computerized driving ranges. In this format, each ball used at the range has an RFID with its own unique transponder code. When dispensed, the range registers each dispensed ball to the player, who then hits them towards targets in the range. When the player hits a ball into a target, they receive distance and accuracy information calculated by the computer. The use of this technology was first commercialized by World Golf Systems Group to create TopGolf, a brand and chain of computerized ranges now owned by International Management Company.

World records

Canadian long drive champion Jason Zuback broke the world ball speed record on an episode of Sport Science with a golf ball speed of 328 km/h (204 mph). The previous record of 302 km/h (188 mph) was held by José Ramón Areitio, a Jai Alai player.

See also

• Air flow ball

External links

• Online golf ball museum with more than 1000 different golf balls
• Golf ball aerodynamics
• Golf Balls Get Built-In Zip, July 1950, Popular Science detailed article on production of Golf Balls
• The Science Behind Golf Balls

History

• A history of the golf ball
• All about Golf Balls