Surfing is a surface water sport in which the participant is carried by a breaking wave usually on a surfboard to the shore. As well as surfboards surfers make use of kneeboards, body boards, kayaks, surf skis and their own bodies. Derivatives of surfing make use of other elements, such as the wind, these include kitesurfing and windsurfing. Further sub-divisions reflect differences in surfboard design, such as long-boards and short-boards. Additional Tow-in surfing involves motorized craft to tow the surfer onto the wave, this is associated with big wave surfing, where standard paddling is unwise due to the the waves rapid forward motion.History Surfing was first recorded in Hawaii by Lieutenant James King[1], who's task it was to complete the journals of James Cook after his death in 1779. However, by this time surfing had already become an integral part of Hawaiian culture[1] with surfers riding waves lying down or standing on long hardwood boards. Surfing was as much as a part of Hawaiian life as many major sports are part of western life today. It permeated every part of Hawaiian society including religion and myth. Hawaiian Chiefs would demonstrate their leadership by the skills they possessed on the surf.[1] [edit] The Science of Surfing Waves A surfer on a cliff in Santa Cruz, California. A surfer on a cliff in Santa Cruz, California. Several factors influence the shape and quality of breaking waves. These include the bathymetry of the surf break, the direction and size of the swell, the direction and strength of the wind and the ebb and flow of the tide. Swell is generated when wind blows consistently over a large area of open water, called the wind's fetch. The size of a swell is determined by the strength of the wind, the length of its fetch and its duration. So, surf tends to be larger and more prevalent on coastlines exposed to large expanses of ocean traversed by intense low pressure systems. Local wind conditions affect wave quality, since the rideable surface of a wave can become choppy in blustery conditions. Ideal surf conditions include a light to moderate strength "offshore" wind, since this blows into the front of the wave. The factor which most determines wave shape is the topography of the seabed directly behind and immediately beneath the breaking wave. The contours of the reef or sand bank influence wave shape in two respects. Firstly, the steepness of the incline is proportional to the resulting upthrust. When a swell passes over a sudden steep slope, the force of the upthrust causes the top of the wave to be thrown forward, forming a curtain of water which plunges to the wave trough below. Secondly, the alignment of the contours relative to the swell direction determines the duration of the breaking process. When a swell runs along a slope, it continues to peel for as long as that configuration lasts. When swell wraps into a bay or around an island, the breaking wave gradually diminishes in size, as the wave front becomes stretched by diffraction. For specific surf spots, the state of the ocean tide can play a significant role in the quality of waves or hazards of surfing there. Tidal variations vary greatly among the various global surfing regions, and the effect the tide has on specific spots can vary greatly among the spots within each area. Locations such as Bali, Panama, and Ireland experience 2-3 meter tide fluctuations, whereas in Hawaii the difference between high and low tide is typically less than one meter. In order to know a surf break, one must be sensitive to each of these factors. Each break is different, since the underwater topography of one place is unlike any other. At beach breaks, even the sandbanks change shape from week to week, so it takes commitment to get good waves (a skill dubbed "broceanography" by California surfers). That's why surfers have traditionally regarded surfing to be more of a lifestyle than a sport. Of course, you can sometimes be lucky and just turn up when the surf is pumping. But, it is more likely that you will be greeted with the dreaded: "You should have been here yesterday." Nowadays, however, surf forecasting is aided by advances in information technology, whereby mathematical modelling graphically depicts the size and direction of swells moving around the globe. The regularity of swell varies across the globe and throughout the year. During winter, heavy swells are generated in the mid-latitudes, when the north and south polar fronts shift toward the Equator. The predominantly westerly winds generate swells that advance eastward. So, waves tend to be largest on west coasts during the winter months. However, an endless train of mid-latitude cyclones causes the isobars to become undulated, redirecting swells at regular intervals toward the tropics. East coasts also receive heavy winter swells when low pressure cells form in the sub-tropics, where their movement is inhibited by slow moving highs. These lows produce a shorter fetch than polar fronts, however they can still generate heavy swells, since their slower movement increases the duration of a particular wind direction. After all, the variables of fetch and duration both influence how long the wind acts over a wave as it travels, since a wave reaching the end of a fetch is effectively the same as the wind dying off. During summer, heavy swells are generated when cyclones form in the tropics. Tropical cyclones form over warm seas, so their occurrence is influenced by El Niņo & La Niņa cycles. Their movements are unpredictable. They can even move westward, which is unique for a large scale weather system. In 1979, Tropical Cyclone Kerry wandered for 3 weeks across the Coral Sea and into Queensland, before dissipating. The quest for perfect surf has given rise to a field of tourism based on the surfing adventure. Yacht charters and surf camps offer surfers access to the high quality surf found in remote, tropical locations, where tradewinds ensure offshore conditions. Since winter swells are generated by mid-latitude cyclones, their regularity coincides with the passage of these lows. So, the swells arrive in pulses, each lasting for a couple of days, with a couple of days between each swell. Since bigger waves break in a different configuration, a rising swell is yet another variable to consider when assessing how to approach a break. [edit] Wave intensity classification The geometry of tube shape can be represented as a ratio between length and width. A perfectly cylindrical vortex has a ratio of 1:1, while the classic almond-shaped tube is nearer 3:1. When width exceeds length, the tube is described as "square". The geometry of tube shape can be represented as a ratio between length and width. A perfectly cylindrical vortex has a ratio of 1:1, while the classic almond-shaped tube is nearer 3:1. When width exceeds length, the tube is described as "square". Surf breaks can be grouped according to their intensity. There are two variables to consider in determining the intensity of a surf break: the shape of the tube and the angle of the peel line. Tube shape indicates the degree of upthrust, which is roughly proportional to the volume of water being thrown over with the lip. The angle of the peel line reflects the speed of the tube. A fast, "down the line" tube has a peel line with a smaller angle than a slower, "bowly" tube.