Monday, January 13, 2014

Bungee jumping

Bungee jumping

Bungee jumping, sport in which the jumper falls from a high place with a rubber (“bungee”) cord attached both to his or her feet and to the jump site, and, after a period of headfirst free fall, is bounced partway back when the cord rebounds from its maximum stretch. It traces its roots to the “land diving” practiced on Pentecost Island, Vanuatu, in which divers jump off a high tower, their feet connected to it by a vine whose length is calculated to allow the jumper to fall until his hair just brushes the ground below. The Oxford Dangerous Sports Club, inspired by reports of the Pentecost Island divers, made the first Western bungee jumps, and bungee jumping was first offered commercially to the public in New Zealand.

History
The first modern bungee jumps were made on 1 April 1979 from the 250-foot (76 m) Clifton Suspension Bridge in Bristol, by members of the Oxford University Dangerous Sports Club. The jumpers were arrested shortly after, but continued with jumps in the US from the Golden Gate and Royal Gorge bridges, (this last jump sponsored by and televised on the American program That's Incredible) spreading the concept worldwide. By 1982, they were jumping from mobile cranes and hot air balloons.
Organized commercial bungee jumping began with the New Zealander, A J Hackett, who made his first jump from Auckland's Greenhithe Bridge in 1986.During the following years, Hackett performed a number of jumps from bridges and other structures (including the Eiffel Tower), building public interest in the sport, and opening the world's first permanent commercial bungee site, the Kawarau Bridge Bungy at the Kawarau Gorge Suspension Bridge near Queenstown in the South Island of New Zealand. Hackett remains one of the largest commercial operators, with concerns in several countries.
Several million successful jumps have taken place since 1980. This safety record is attributable to bungee operators rigorously conforming to standards and guidelines governing jumps, such as double checking calculations and fittings for every jump. As with any sport, injuries can still occur, and there have been fatalities. A relatively common mistake in fatality cases is to use a cord that is too long. The cord should be substantially shorter than the height of the jumping platform to allow it room to stretch. When the cord becomes taut and then is stretched, the tension in the cord progressively increases. Initially the tension is less than the jumper's weight and the jumper continues to accelerate downwards. At some point, the tension equals the jumper's weight and the acceleration is temporarily zero. With further stretching, the jumper has an increasing upward acceleration and at some point has zero vertical velocity before recoiling upward. See also Potential energy for a discussion of the spring constant and the force required to distort bungee cords and other spring-like objects.
The Bloukrans River Bridge was the first bridge to be 'bungee jumped off' in Africa when Face Adrenalin introduced bungee jumping to the African continent in 1990. Bloukrans Bridge Bungy has been operated commercially by Face Adrenalin since 1997, and is the highest commercial bridge bungy in the world.
In April 2008 a 37-year-old Durban man, Carl Mosca Dionisio, made bungee jumping history when he jumped off a 30 m (100 ft.) tower attached to a bungee cord made entirely of 18,500 condoms.

Most Extreme Bungee Jumping Destinations
·        Victoria Bridge Falls, Zimbabwe
At 364 feet (110.95 meters), Victoria Bridge Falls in Zimbabwe isn't that much higher than the crane in the Catskills, but it does overlook the largest waterfall in the world. Overlooking the thundering water of the Zambezi River, the bridge is 107 years old and the second most visited tourist attraction in Zimbabwe



·        Verzasca Dam, Val Verzasca, Switzerland
721.78 feet (220 meters), it took five years to build the Verzasca Dam, which generates hydroelectric power. Apparently, bungee jumping is permitted off the dam, steel pegs and all. In case you were wondering, you'll be jumping at your own risk, so you better follow the bungee team's instructions




·        Royal Gorge Suspension Bridge, Canon City, Colo.
With spectacular views of the Arkansas River, the Royal Gorge Bridge was built in 1929 specifically with tourists in mind. The gorge is framed by sheer cliffs. The bridge spans 1,260 feet (384.05 meters) and is 956 feet (291 meters) high.







·        Bhote Kosi River Bridge, Nepal
Looking down on the Bhote Kosi River, the 524.93-foot [160-meter] span is Nepal's first bungee jumping site. Built by the Swiss, the bridge, which is nothing more than a narrow steel walkway, is less than three hours outside of Kathmandu.











·      Macau Tower, China
At 764 feet (233 meters), jumping off the Macau Tower is the longest bungee jump in the world. The jump is the size of two-and-a-half football fields. Jumpers accelerate to a top speed of 124.27 miles (220 kilometers) an hour. It's a 4 to 5 second free-fall that then stretches the bungee cord 164.04 feet (50 meters).




Types

Catapult
In "Catapult" (Reverse Bungee or Bungee Rocket) the 'jumper' starts on the ground. The jumper is secured and the cord stretched, then released and shooting the jumper up into the air. This is often achieved using either a crane or a hoist attached to a (semi-)perma structure. This simplifies the action of stretching the cord and later lowering the participant to the ground.

Twin Tower
"Twin Tower" is similar with two oblique cords. There are two towers, each with a cord leading the jumper. When the cords are stretched the jumper is released and shoots straight up.

Trampoline
"Bungy Trampoline" uses, as its name suggests, elements from bungy and trampolining. The participant begins on a trampoline and is fitted into a body harness, which is attached via bungy cords to two high poles on either side of the trampoline. As they begin to jump, the bungy cords are tightened, allowing a higher jump than could normally be made from a trampoline alone.

Running
"Bungee running" involves no jumping as such. It merely consists of, as the name suggests, running along a track (often inflatable) with a bungee cord attached. One often has a velcro-backed marker that marks how far the runner got before the bungee cord pulled back. This activity can often be found at fairs and carnivals and is often most popular with children.

Ramp
Bungee jumping off a ramp. Two rubber cords - the "bungees" - are tied around the participant's waist to a harness. Those bungee cords are linked to steel cables along which they can slide due to stainless pulleys. The participants bicycle, sled or ski before jumping.

Suspended Catch Air Device
SCAD diving is similar to bungee jumping in that participant is dropped from a height, but in this variation there is not a cord; instead the participant falls into a net.

Records

HIGHEST BUNGEE JUMP
Curtis Rivers (UK) performed a bungee jump from a hot air balloon at 4,632 m (15,200 ft.) over Puertollano, Spain, on 5 May 2002 - thus achieving the highest altitude bungee jump.
He jumped using a 10 m (33 ft.) cord, which stretched to 30 m (98 ft.). After bouncing five times he freed himself from the cord and parachuted to the ground. At jump altitude the air was so thin that breathing equipment had to be used.

HIGHEST REVERSE BUNGEE JUMP
The highest height a human was catapulted using a reverse bungee system is 54.25 m (178 ft.) and was achieved by Ben Shephard (UK) on the set of Guinness World Records - Smashed, in London, UK, on 3 October 2008

HIGHEST BUNGEE JUMP FROM A BUILDING
The highest bungee jump from a building is 199 m (652 ft. 10 in) and was achieved by A.J. Hackett (New Zealand) who leaped off a platform at 233 m (764 ft. 5 in) on the Macau Tower, Macau, China, on 17 December 2006.
The key point here, is that the distance between the ground and AJ was 34 m (111 ft. 6 in).

This, naturally, is a lot different to people who claim to have bungeed off the highest building, but have used a short bungee cord, so only fall a few meters.


Ways to Jump

 Body Harness
The most common ways to attach yourself to the cord are by using a body harness or a leg harness. If the only way of connecting yourself to the cord is a body harness you should have at least a sit harness and a shoulder harness, or a full body harness (see the harnesses section). Jumping with just a sit harness is not recommended.
If you are jumping with just a body harness you are afforded quite a bit of freedom to move around, your arms and legs are free to flail around. The cord will be attached to a point close to your belly (your center of gravity), making spins and flips easier. As you jump you can do many flips on the way down if the jumpmaster holds the spare cord and releases it when you jump (this is called 'spotting', the jumpmaster being the spotter).

Leg Harness
The leg harness comes in different styles. Some let you jump with just one leg harnessed, but most with both. You should always have a backup harness when using leg harnesses, usually just a normal climbing sit harness. This is especially important if you are to be brought back up to the jump point since being brought up upside down is uncomfortable.
The leg harness can really give you the feeling of flying and is the best ground rush there is (especially for water touchdowns). While you are rebounding, if you are at the right angle, you can tuck at the top and flip right over for another beautiful swallow dive for your second fall.
It is important when jumping with a leg harness that when the cord becomes tight your body is facing along the line of the cord, otherwise you will get thrown around quite a bit (and maybe even break your ankles).

Arm Harness
It is possible to jump with a harness on your arms; which is usually just a regular leg harness. Your arms are not usually used to support your whole body weight, so this could easily lead to dislocated shoulders etc... Jumping with an arm harness is not recommended.

Swallow Dive
By far the best way to jump - just take a nice leap away from the platform, arms stretched out wide and soar like a bird down towards the earth. By the time the cord starts to stretch you should be pointing straight down and the deceleration should be very smooth.
If you are jumping with just a body harness connected at the front you will need to rotate even more in the air so that when the cord becomes taut you will be facing upwards.

Back Dive
Slightly harder than a swallow dive to get right since many people that try it lean back a little, but end up falling feet first. You must really throw yourself into it so that at the bottom of the fall you are pointing towards the ground.
If you are jumping with just a body harness connected at the front you will need to either just drop backwards or rotate even more in the air so that when the cord becomes taut you will be facing upwards again.

Railing Jump
This is most common when jumping off bridges with a railing. Instead of climbing over the railing, you climb onto the railing. Two people stand behind you with their arms up and hands in a fist: By holding onto them you can balance right on the edge of the railing and then jump from there.

Top of Cage
Like a railing jump, but when you jump from a cage below a crane, climb on top of the cage and jump from the top. It really doesn't buy you that much more and the chances of accidents are high.

Bat Drop
You maneuver yourself so you are hanging upside down with your toes (or someone else) holding you to the jumping platform, then you just drop like a rock straight down.

Elevator (aka Pile Driver on Mil. Spec cord)
Like an inverted bat drop; just jump from the platform with your feet pointing down. When you get to the end of the cord, you will be flipped the right way round. With an all rubber (Euro/Kiwi) cord this is bearable; with Mil. Spec it will almost certainly hurt a lot (hence the Pile Driver name), and you could even break your ankles).

Pogo
When you jump with ankle harnesses, it's possible to end up so that you are standing on your ankle harnesses, holding onto the cord at the end of your jump. Most jumpmasters don't like you touching their cord, so make sure they know you're going to do this. Plus grabbing the cord is always dangerous, if you're lucky, you'll end up with rope burns on your hands. If you're unlucky, you could easily break your arms, wrists or fingers.

Thrown
Instead of jumping, why not get a gang of friends to throw you from the bridge! Check out these photos from Over the Edge Bungee in Idaho, or these from Icarus Bungee.

Water Touchdown
Many sites are so confident that they can judge how much the cord will stretch that they offer water touchdowns. You jump as normal, but at the bottom you will go into the water. This is best attempted over DEEP water (see this disaster).
The way you jump affects how much the cord will stretch, and whether there is a spotter (someone dropping the cord beside you). If you jump far away from the bridge you will drop less than if you were to jump straight down.

Cutaway
You can be facing forwards or backwards to feel the rush of a cutaway. A piece of webbing is tied to the platform and then to your waist so that you are leaning out at 45 degrees from the platform (you can be facing either up or down at this point). Make sure you are looking straight up or down and NOT at the webbing. The webbing is then slowly cut; eventually it will break, sending you plummeting to the ground. However you won't quite know when it will happen.

Tandem
Two jumpers jump at the same time. This is actually pretty dangerous since it's very easy to bang heads at the bottom or just get tangled up in each other. Plus the weight of two people are not the 'norm' that clubs are used to dealing with so there can always be errors made when selecting cords and harnessing.
There is also the chance of one person jumping and the other not, but since you're attached the 'chicken' will just get dragged down (and then bang heads at the bottom). This was well documented on video from MTV's Real World.

Sandbagging
This is EXTREMELY DANGEROUS, and you really shouldn't try it, but I'll explain it here. You jump holding a heavy weight; once you get to the bottom of the drop, you let go of the weight. All of the extra elastic energy the weight put into the cord is now transferred to you, making you fly MUCH higher than the place you jumped from.
It's important to consider that you will fly back toward what you jumped from, which is usually pretty solid. Hence, you could fly back into the platform at great speed! If you jump from the opposite side of a bridge (opposite to the side the cord is attached) you may bounce back above the bridge (if you are lucky).
You need to account for your weight and the weight of the sandbag when working out what cord to use. Since subsequent rebounds will be just you (on a cord designed for a heavier weight), they will be pretty harsh. Plus, you must make sure you can hold onto the sandbag until the end of your first drop.

Some people actually use another person as the 'sandbag'. Dropping the sandbag/person early or late has even more serious consequences in this scenario. As demonstrated on an MTV show where they couldn't hold on the whole way and the sandbag guy dropped early (Bungeed without the cord) and broke his ribs and arm.

1 comment:

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