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東京ひるま農園グループ

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Castor Panfilov
Castor Panfilov

Surf SURF SPEED CHANGER AUGUST 2021 Download



In tow-in surfing (most often, but not exclusively, associated with big wave surfing), a motorized water vehicle such as a personal watercraft, tows the surfer into the wave front, helping the surfer match a large wave's speed, which is generally a higher speed than a self-propelled surfer can produce. Surfing-related sports such as paddle boarding and sea kayaking that are self-propelled by hand paddles do not require waves, and other derivative sports such as kite surfing and windsurfing rely primarily on wind for power, yet all of these platforms may also be used to ride waves. Recently with the use of V-drive boats,[clarification needed] Wakesurfing, in which one surfs on the wake of a boat, has emerged.[citation needed] As of 2023, the Guinness Book of World Records recognized a 26.2 m (86 ft) wave ride by Sebastian Steudtner at Nazaré, Portugal as the largest wave ever surfed.[1]




surf SURF SPEED CHANGER AUGUST 2021 Download



Tube speed is the rate of advance of the break along the length of the wave, and is the speed at which the surfer must move along the wave to keep up with the advance of the tube.[24] Tube speed can be described using the peel angle and wave celerity. Peel angle is the angle between the wave front and the horizontal projection of the point of break over time, which in a regular break is most easily represented by the line of white water left after the break. A break that closes out, or breaks all at once along its length, leaves white water parallel to the wave front, and has a peel angle of 0. This is unsurfable as it would require infinite speed to progress along the face fast enough to keep up with the break. A break which advances along the wave face more slowly will leave a line of new white water at an angle to the line of the wave face.[24][25]


Standup surfing begins when the surfer paddles toward shore in an attempt to match the speed of the wave (the same applies whether the surfer is standup paddling, bodysurfing, boogie-boarding or using some other type of watercraft, such as a waveski or kayak). Once the wave begins to carry the surfer forward, the surfer stands up and proceeds to ride the wave. The basic idea is to position the surfboard so it is just ahead of the breaking part (whitewash) of the wave, in the so-called 'pocket'. It is difficult for beginners to catch the wave at all.


Many popular surfing destinations have surf schools and surf camps that offer lessons. Surf camps for beginners and intermediates are multi-day lessons that focus on surfing fundamentals. They are designed to take new surfers and help them become proficient riders. All-inclusive surf camps offer overnight accommodations, meals, lessons and surfboards. Most surf lessons begin with instruction and a safety briefing on land, followed by instructors helping students into waves on longboards or "softboards". The softboard is considered the ideal surfboard for learning, due to the fact it is safer, and has more paddling speed and stability than shorter boards. Funboards are also a popular shape for beginners as they combine the volume and stability of the longboard with the manageable size of a smaller surfboard.[32] New and inexperienced surfers typically learn to catch waves on softboards around the 210 to 240 cm (7 to 8 ft) funboard size. Due to the softness of the surfboard the chance of getting injured is substantially minimized.


The surf zone is the place of convergence of multiple waves types creating complex wave patterns. A wave suitable for surfing results from maximum speeds of 5 metres per second (16 ft/s). This speed is relative because local onshore winds can cause waves to break.[40] In the surf zone, shallow water waves are carried by global winds to the beach and interact with local winds to make surfing waves.[40][41]


Different onshore and off-shore wind patterns in the surf zone create different types of waves. Onshore winds cause random wave breaking patterns and are more suitable for experienced surfers.[40][41] Light offshore winds create smoother waves, while strong direct offshore winds cause plunging or large barrel waves.[40] Barrel waves are large because the water depth is small when the wave breaks. Thus, the breaker intensity (or force) increases, and the wave speed and height increase.[40] Off-shore winds produce non-surfable conditions by flattening a weak swell. Weak swell is made from surface gravity forces and has long wavelengths.[40][42]


The wave peel angle is one of the main constituents of a potential surfing wave. Wave peel angle measures the distance between the peel-line and the line tangent to the breaking crest line. This angle controls the speed of the wave crest. The speed of the wave is an addition of the propagation velocity vector (Vw) and peel velocity vector (Vp), which results in the overall velocity of the wave (Vs).[40]


Table 1 shows a relationship of smaller peel angles correlating with a higher skill level of the surfer. Smaller wave peel angles increase the velocities of waves. A surfer must know how to react and paddle quickly to match the speed of the wave to catch it. Therefore, more experience is required to catch low peel angle waves. More experienced surfers can handle longer section lengths, increased velocities, and higher wave heights.[40] Different locations offer different types of surfing conditions for each skill level.


Rip currents can be extremely strong and narrow as they extend out of the surf zone into deeper water, reaching speeds from 0.5 m/s (1.6 ft/s) and up to 2.5 m/s (8.2 ft/s),[46][47] which is faster than any human can swim. The water in the jet is sediment rich, bubble rich, and moves rapidly.[46] The rip head of the rip current has long shore movement. Rip currents are common on beaches with mild slopes that experience sizeable and frequent oceanic swell.[47]


When the surfer is at wave speed, the surfer must quickly pop up, stay low, and stay toward the front of the wave to become stable and prevent falling as the wave steepens. The acceleration is less toward the front than toward the back. The physics behind the surfing of the wave involves the horizontal acceleration force (Fsinθ) and the vertical force (Fcosθ=mg). Therefore, the surfer should lean forward to gain speed, and lean on the back foot to brake. Also, to increase the length of the ride of the wave, the surfer should travel parallel to the wave crest.[42]


Clay and Ant broke down exactly why you should not wiggle on a smoothstar or a surf skate. If you look at the gif below taken from the video. You'll see Ant wiggling on a smoothstar, it helps the surf skate move, gain speed and can be fun...


Expected vertical migration speed (effective vertical velocity, Veff, Eq. (2), relative to swimming velocity Vswim) as a function of the turbulence dissipation rate ε [34]. We consider three typical plankters: a copepod, an invertebrate larva, and a dinoflagellate, whose characteristics are given in Table 1. Two strategies are compared: the proposed surfing strategy (red) and bottom-heavy swimmers (blue) orienting upwards due to gravity. In the upper panel, we indicate the range of turbulence intensity for different marine habitats (data from [35]) and the corresponding range of Kolmogorov time τη and Kolmogorov velocity uη, Eq. (6).


"Car surfing" is a term introduced in the mid-1980s to describe a thrill-seeking activity that involves riding on the exterior of a moving motor vehicle while it is being driven by another person (1). Although reports of car-surfing injuries have been published in the United States, no study to date has analyzed these events from a national perspective (2--5). Because traditional public health datasets do not collect morbidity or mortality data on this practice, CDC searched U.S. newspaper reports to provide an initial characterization of car-surfing injuries on a national scale. That analysis identified 58 reports of car-surfing deaths and 41 reports of nonfatal injury from 1990 through August 2008. Most reports of car-surfing injuries came from newspapers in the Midwest and South (75%), and most of the injuries were among males (70%) and persons aged 15--19 years (69%). The first identified newspaper reports about car-surfing injuries were published in the early 1990s, and new reports have been published every year since then. Parents and teens should be aware of the potentially lethal consequences of car surfing, which can occur even at low vehicle speeds, sometimes resulting from unanticipated movements of the vehicle, such as swerving or braking.


Case 2. In August 1996, a male aged 14 years ran and jumped onto the hood of a friend's vehicle to car surf as it was pulling out of a residential driveway in Virginia. Witnesses stated that the vehicle was traveling at a slow speed, estimated at 5 mph, when the car hit a bump in the driveway, causing the boy to slide off of the hood. He fell on his head and had a fatal head injury.


The speed of the vehicle at the time of injury was reported in 21 of 99 cases, 17 of which were fatal. Vehicle speed was less than 30 mph in 11 of the 21 cases (52%), with fatalities occurring at speeds ranging from 5 mph to 80 mph. Alcohol or drugs were mentioned as contributing factors in 11 of 99 cases overall (11%) and six of 58 fatal cases (10%). In 28 of 99 cases, a sudden maneuver or movement of the vehicle was reported, which might have contributed to the car surfer subsequently falling from the vehicle. These maneuvers included turning or swerving the vehicle (16 of 28), braking the vehicle (7 of 28), hitting a bump or dip in the road (3 of 28), and accelerating the vehicle (2 of 28).


Data compiled from newspaper reports suggest that car surfing is most popular among teenaged males, which is consistent with cases of car-surfing injury reported in the medical literature (2--5). The predominance of head injury as the cause of death also is consistent with the medical literature (2--5). The data in this analysis, though subject to substantial limitations, suggest that, from a national perspective, high vehicle speeds are not required for a serious or fatal injury to occur, and that sudden changes in vehicle speed or direction might often be the crucial event that forces the car surfer off of the vehicle, even at low speeds. The data further suggest that many car-surfing injuries are not associated with the use of alcohol or drugs. 041b061a72


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