Diving equipment

The fundamental item of diving equipment used by divers is the SCUBA equipment, such as the Aqualung or Rebreather. There are other important pieces of equipment that make diving safer, more convenient or more efficient.

Personal Diving Equipment

Scuba life support

• Open-circuit Scuba consisting of diving cylinder(s) and diving regulator(s)
• Rebreather, closed-circuit or semi-closed-circuit Scuba

Alternative life support

• Liquid breathing systems are extremely rare and at an early experimental stage. It is hoped that some day practical systems allow very deep diving.
• Snorkel allows breathing at the surface with the face submerged.
• Standard diving dress - mostly used in professional diving. Merely of historical interest now.
• Surface supplied diving - mostly used in professional diving, except recreational forms like snuba.

Thermal, sting and abrasion protection

• In cold water, a diving suit such as a dry suit or a wet suit
• In very warm water, many types of tough, long, everyday clothing provide protection, as well as purpose made garments such as dive skins and shorty wetsuits
• Diving gloves, neoprene is often used for thermal insulation
• Diving boots, often made of neoprene and rubber
• Safety helmet for scuba diving. Not air-holding. May have a built-in forehead light. Images at [1].

In-water stabilisation and movement

• A backplate is a structural device linking the buoyancy of the wing with the weight of the diving cylinders and harnessed around the diver's body
• Buoyancy compensator, Buoyancy Control Device, BCD or BC - many names for a buoyancy adjusting and life-saving buoyancy device
• Diver Propulsion Vehicle - to increase the range of the diver undwerwater
• Diving weighting system - to counteract the buoyancy of the diving suit and diver to allow descent
• Fins for efficient propulsion

Measurement and navigation

• Compass for underwater navigation
• Decompression tables to avoid decompression sickness
• Depth gauge is used with watch for decompression monitoring on decompression tables
• Distance line is used to navigate back to the start point in poor visibility
• Dive Computer to avoid decompression sickness
• Watch is used with depth gauge for decompression monitoring on decompression tables

Vision and communication

A dive mask offers clear sight and protection.

• Mask allows the diver to see clearly underwater and protects the eyes.
• Full face mask protects the face from dirty or cold water and increases safety by securing the gas supply to the diver's face. If it contains no mouthpiece, the diver can talk allowing the use of communications equipment.
• Diving helmets are often used with surface supplied diving. They provide the same benefits as the full face mask but provide a very secure connection of the gas supply to the diver and additionally protect the head.
• Underwater writing slates and pencils are used to transport pre-dive plans underwater, to record facts whilst underwater and to aid communication with other divers.
• Torchs / flashlights are essential for safety in low visibility or dark environments such as night diving and wreck and cave penetration. They are useful for communication and signalling both underwater and on the surface at night. Divers need artificial light even in shallow and clear water to reveal the red end of the spectrum of light which is adsorbed as it travels through water.
• Hand-held sonar for a diver.

Tools

Gerber River Shorty, a river/diving knife, with serrated edge for cutting lines and straps, and a blunt tip for prying.

• Airlift - a gas "powered" tube that is used in nautical archaeology, which vacuums small objects, sand and mud from the sea bed
• Camera and housing - for underwater photography or underwater videography
• Decompression trapeze consists of one or more horizontal bars, suspended at decompression stops by buoys
• Diving reel to transport a distance line or line for a surface marker buoy
• Diving shot consisting of a weight, line and buoy used to mark the location of a dive site, allowing divers to navigate to and from the surface and to do decompression stops at a safe location
• Dry box to hold objects the diver needs to keep dry at depth (wallet, cell phone)
• Knife to cut lines, nets or to pry or dig. Can also be used for personal protection against underwater predators if needed, however not recommended.
• Lifting bag - to lift heavy objects underwater activated by adding air

Surface detection aids

The purposes of this class of personal equipment are to:

• allow the support boat to monitor and find divers on the surface during or after a dive
• prevent the diver being struck by boat traffic
• mark the diver's position when drift diving or while at the decompression stop
• help rescue services in lifeboats and helicopters to locate the diver

Surface detection aids (with cheapest and most effective towards the top) include:

• Surface Marker Buoy, Decompression buoy, Delayed SMB, safety sausage or blob
• Red or yellow collapsible flag - high visibility, robust, bungeed to cylinder
• Whistle - cheap, will only be heard by people far from engine noise
• Torch/flashlight - if at sea after night fall
• Strobe light - needs long-lasting batteries
• High pressure whistle - expensive but effective
• Orange water dye - increases diver's visibility from search helicopters
• Mirror such as a used Compact Disc - to reflect sunlight or searchlights
• Red pyrotechnic flares - for helicopters and lifeboats
• Emergency position-indicating rescue beacon
• Glow stick - for night diving

Surface equipment

Informal Recreational diving flag

Signal flag A - "I have a diver down - Keep clear"

• Diver down flag is flown warning others that divers are underwater
• Diving air compressor to fill diving cylinders with high pressure air or other gasses
• Boats such as the rigid-hulled inflatable boat
• Echo sounder - a SONAR depth measuring and profiling device used for dive site location
• GPS receiver - for locating dive sites
• Proton magnetometer - for locating ferrous wrecks
• Remotely Operated Underwater Vehicle - for locating dive sites
• Marine VHF radio - for communicating with rescue services and other boats

Illustration

Basic diving equipment

This picture shows some of the basic diving equipment and controls:

• 1) the diving mask
• 2) the demand valve of the diving regulator
• 3) the buoyancy compensator inflation and vent valves
• 4) an alternate buoyancy compensator vent valve
• 5) shoulder straps of the BCD, which can be released by another diver in case of emergency
• 6) a depth gauge - showing 23 metres
• 7) the contents gauge displaying remaining pressure in the diving cylinder - showing 150 bar

Retrieved from "http://en.wikipedia.org/wiki/Diving_equipment"

Categories: Diving equipment | Underwater diving

DIVE SITES

Daily Diving and Snorkelling Trips to many Top Locations

NORTH BALi DIVE SITES

During our diving or snorkeling activities you are always under the guidance of a highly trained professional. So you can be sure to have enjoyable days exploring the amazing underwater world that Bali offers. The most interesting variety of marine life. Combined with stunning views during our trips. Choose from one of these sites. Or ask us what else we can mean for you to make your diving or snorkeling program the way you like it. Your safety is our responsible! Please click here to know who we are?

Lovina Dive BaliLovina Dive BaliLovina Dive Bali

Kerobokan Dive Sites
A new dive sites has been found in north of Bali. We are the only dive operator that offers it magnificent underwater sites. Now most of choices goes to this dive sites. Kerobokan Dive Sites has two points which is one for muck diving and other for shore dive or boat dive. Night dives in this point would be the best.

The place about 5 kilometres to the eastern part of the town, and about 1 kilometre from The Jalan Kerobokan. Nudibranches, Turtles, unique Lion Fish, moraeel, frog fish, seahorses, box fish, etc, easily to finds in here.

For underwater photography lover should not missed this moment and in the afternoon would be the clearest time with visibility about 10 metres. Current is friendly and coral reef lives so healthy.

This place has been commented by several diver who has been done diving in this place. This is a very warm environtment.

We will look forward for your adventure to this place.

Tulamben U.S.S. Liberty Shipwreck
Dive this fascinating WO II Shipwreck. Torpedoed by the Japanese in 1942, this complete coral covered wreck offers many swim-throws. Surrounded by thousands of fish. For all diver levels and people who is willing to snorkel. Regarded as "probably the best dive site in the world" (The Independent) There are many other world class Dive Sites in the Tulamben area!

Bali DiveMenjangan Island National Marine Park
With beautiful reefs that plunge straight down into clear blue waters. Fantastic corals, millions of multi colored tropical fish, rays turtles sharks you name it. There are at least 8 different Dive Sites around the island. You can dive here for days! For all divers levels and a great place to snorkel or even just hang out on the white sandy beaches!

Lovina Reef
It is in north bali. Lovina reef is unfortunately not regarded as an interesting Dive Site. Mostly by people who never dove it. It has some interesting newly formed corals. Even a little wooden shipwreck. Lot's of fish! Lovina reef is better at greater depths and therefore a good place for deep divers. Or beginners to explore the very easy and safe diving environment at shallower depths. Very convenient since you avoid long car trips!

Amed
Amed is considered as one of the best dive sites on Bali. Unfortunately it lost a lot of corals due to Al Nino in 1997. Since than the reef has recovered at high speed. It's definitely worth diving here. Especially to see the big fish on Bali. Great drop offs. It takes a boat trip from Amed beach to reach the better dive sites.

Night Diving
Night diving is maybe the reason why many divers dive! It's sounds a bit scary but it's so relaxing. Adventures Night Dives is the best in Tulamben and Lovina reef.
Switch on your torch, stay with your buddy and descend to the magnificent Tropical Marine Night Life! So challenge your self with us.

Secret Bay where under photographers can make nice pictures:

in front of the docking area of Gilimanuk Harbor. Be prepared - you are diving on fine black and gray volcanic sand and rubble and not on a coral reef! This place is a great place for the rare and unusual. This so called muck diving is one of favorite pastimes since we like macro-photography best. Here you find frogfish (where we found species on one dive: A. hispidus, A. striates, A. maculates and A. nummifer), special nudibranchs, ghost pipefish, the rare picturesque dragonet and gobies, several species of sand eels, stonefish and devilfish, mimic octopus and even the Ambon scorpion fish (Pteroidichthys amboinensis), crabs and shrimps and many other critters that like to live on sand. Probably just so some under water photographers can make nice pictures!

See around the pieces of half rotten wood, among the sponges and especially under the garbage (inside the metal drums for example) and in the metal structures put up in several places. These objects act like a small oasis where animals can hide, so they are a good place to find camouflaged animals such as the frogfish or seahorses. We noticed that there are seasonal changes at the Secret Bay dive sites. On one visit a place would be just full with certain nudibranchs on the sea grass, another year only a few could to be found. See the Map of Dive site

Puri Jati (PJ)
Puri Jati is on the north coast of Bali not far from Lovina, Great for Diving, Underwater photographers, Night diving, Sharks, muck diving, Mandarin fish, pelagic, reef, coral reef, Shark Dive Bali, Padang Bai 2 hours 15 minutes, Sharks, Bali Diving, Indonesia Diving, Tulamben is 1 hours drive, Secret Bay only 1.5 hours, add Nusa Penida & Manta Point along with Pemuteran makes a Bali Dive Safari. Absolute Scuba Diving Center offers a comfortable and luxurious accommodations.

Dive BaliPuri Jati (PJ) is a dive site with dark volcanic sand and some seaweed and soft coral similar to Seraya, Gilimanuk or Lembeh. PJ Puri Jati is a good place to see small rand rare animals like frogfishes (for example A. striates), dragonets, seahorses, nudibranchs, ambon scorpion fishes and devil fishes, flying gurnard, the mimic octopus and other rare species of octopus.

Puri Jati lies close to the Zen Resort Bali, which is a boutique hotel in the serene and natural environment of un spoilt North Bali and over looking the Sea of Bali at Puri Jati. The 15 Ocean view sunset and sunrise villas are surround by vineyards and rice terraces and located just 300 meters from the beach.

BALI EAST SOUTH DIVE

Bali's hidden secret below the waves offers you but another reason to visit this magical paradise and unlike many of the other top dive destinations in the world when you have finished your days diving there is still plenty to do and enjoy during a dive vacation to Bali.

Diving in South Bali/ Nusa Penida -- The Mola Mola, and we know as Oceanic Sunfish, doing their seasonal migrations to Nusa Penida islands. The best time of the year to see these huge creatures is between July and October although they can be seen occasionally outside these times. Our guides are well rehearsed in locating these creatures that tend to congregate around a few sites, namely Blue Corner, Crystal Bay and Toyapakeh.

Manta Rays were easily to find in here. Unpredictable current will welcomes you in this area, but believe that we are professionals and we recommended for experienced diver but nothing to worry since there are some spots or number of beautiful sites for all level of divers.

Crystal Bay is named because of its fantastic underwater visibility. The sites consist of a fantastic little bay in shallow water that offers excellent opportunities for photography, before sliding down into deep drop offs. Superb coral is only matched by the equally superb marine life.

Toyapakeh means "salty Water" has to be the best of all Nusa Penida's dive sites. Actually the site breaks into two with wall and Toyapakeh. Both these sites are encrusted with corals and fish. The intensity of the fish life is something to be witnessed. Large pelagic are often seen here just lurking in the blue.

Manta Point One of Penida's most popular sites. A beautiful boat ride along the coast line of Nusa Penida brings you to Manta Point. Manta sightings here are very common with some very large animals being seen. This site is very open to the elements so sometimes it is not possible to dive this site.

Blue Corner was a famous Bali dive sites. This site was flowed with currents and stretched down to some unpredictable depths. You will be amazed at the marine life when you do diving in a right time. You will see Mola Mola in season since they love to plays around in here! Marble rays, Eagle rays, nurse sharks, dogtooth tuna, easily to find. This site recommended for experienced divers only to do this trip. Ready for it??

The deep of Blue lagoon has nice shallow reefs that are perfect for underwater photography dives and night dives. They have huge coral bommies that start in around 7 meters of water. The fish life is amazing naturally and healthy. The large Napoleon Wrasse that lives here, you will have reef shark, nudibranches, stonefish, morays, blue ribbon eels, rays, squid and octopus, Leaf Scorpion fish and many more. So don't miss this moment and get you camera for amazing photography also try the night dives.

You will welcome by Great walls, the canyon, combined with strong currents. The currents bring in a lot of fresh water so you can normally expect excellent visibility, also Conditions here are very changeable so a good guide is essential with superb marine life makes this a dive dedicated for experienced divers only. Tepekong Island with its steep coral walls and cold waters dropping occasionally as low as 19 °C! Make sure you're armed with a full wetsuit when diving these islands. Amazing that just further up the coast you can be languishing in a balmy 28°C but here the cold up welling of nutrient rich water from the deep can really put a chill in the water. By a short boat ride from Padang Bay brings you to Gili tepekong. These excellent drift dives you can expect to see all kinds of pelagics such as grey reef sharks, eagle rays, barracuda, and many other spectacular fish which Tepekong offers and of course some of the most impressive diving in underwater Bali for sure, the vast amount of sea fans offers some superb underwater scenery. Clouds of angelfish and chromes can be seen amongst the schools of other fish. It is common to see Napoleon wrasse here, as well as black rays, leopard sharks, and white tip reef sharks. This site really only goes down to around 18m so there is plenty of time to explore this beautiful site.

So, what you waiting for, let check our rates and reserve now.

DIVING AND SNORKELING

Daily Diving and Snorkelling Trips to many Top Locations

Lovina Dive BaliDuring our diving or snorkelling activities you are always under the guidance of a highly trained professional. So you can be sure to have enjoyable days exploring the amazing underwater world that Bali offers. The most interesting variety of marine life. Combined with stunning views during our trips. Choose from one of these sites. Or ask us what else we can mean for you to make your diving or snorkelling programme the way you like it. Your safety is our business!

Tulamben U.S.S. Liberty Shipwreck
Dive this fascinating WO II Shipwreck. Torpedoed by the Japanese in 1942, this complete coral covered wreck offers many swim-threws. Surrounded by thousands of fish. For all diver levels and snorkelers. Regarded as “probably the best dive site in the world” (The Independent) There are many other world class Dive Sites in the Tulamben area!

Menjangan Island National Marine Park
With beautiful reefs that plunge straight down into clear blue waters. Fantastic corals, millions of multi coloured tropical fish, rays turtles sharks you name it. There are at least 8 different Dive Sites around the island. You can dive here for days! For all divers levels and a great place to snorkel or even just hang out on the white sandy beaches!

Bali Lovina DiveLovina Reef
Lovina reef is unfortunately not regarded as an interesting Dive Site. Mostly by people who never dove it. It has some interesting newly formed corals. Even a little wooden shipwreck. Lot’s of fish! Lovina reef is better at greater depths and therefore a good place for deep divers. Or beginners to explore the very easy and safe diving environment at shallower depths. Very convenient since you avoid long car trips!

Amed
Amed is considered as one of the best dive sites on Bali. Unfortunately it lost a lot of corals due to Al Nino in 1997. Since than the reef has recovered at high speed. It’s definitely worth diving here. Especially to see the bigger fish on Bali. Great drop offs. It takes a boat trip from Amed beach to reach the better dive sites.

Night Diving
Night diving is maybe the reason why many divers dive! It’s sounds a bit scary but it’s so relaxing. Adventures Night Dives are the best in Tulamben and Lovina reef.
Switch on your torch, stay with your buddy and descend to the magnificent Tropical Marine Night Life!

DIVING COURSES

LOVINA DIVE Bali offers the full range of PADI courses. All the academics of our courses are held in our purposely designed, fully equipped, air-conditioned scuba school.

Introductory Dives
Under the supervision of a PADI Professional in pool-like ocean conditions, Menjangan Island, Tulamben shipwreck or Lovina reef, you will be introduced to scuba diving. During your adventure, you'll master some basic concepts and scuba skills and head off to experience open water adventure. No previous experience needed! Minimum age 12 years. Full day program making 2 dives.
Safe and Fun! Maximum two divers per divemaster/instructor.

PADI Open Water Diver Course
Entry level certification course
The PADI Open Water Course is a 3 to 5 day course that will permit you to dive anywhere in the world with or without the assistance of a qualified professional.

This course is of the same structure whether you take it in England, Japan, Thailand or Bali. Only the quality of the diving and that of the instruction will vary.

PADI Advanced Open Water Diver Course
For more adventure and experience! In only 2 or 3 days you complete 5 Adventure training dives. 2 Dives are mandatory, the Deep and Navigation Dive. Than together with your instructor you choose three more elective Adventure Dives. Like; Multilevel, Wheel/Computer, Under Water Naturalist, Drift, Wreck, Peak Performance Buoyancy and many other adventure dives. If you don’t have the time you can also “collect” adventure dives on different locations during your holidays. Completing 5 Adventure dives and the Knowledge reviews in your Adventures in Diving book, and completing the required training exercises, this will lead to your certification as an ADVANCED OPEN WATER DIVER! A worldwide respected Diver rating, that proves your advanced diving skills. We dive 3 dives sites during your course. Lovina Menjangan Island and Tulamben Shipwreck!
You learn by doing. No long classes!

EXCEPTIONS

Diving BaliAlthough diving is a very safe sport, there are some people who cannot be taught to dive because of a pre-existing medical condition. Examples of such conditions are asthma, diabetes, epilepsy, pregnancy, and heart disorders. We are very sorry about this, but safety is our main concern

All Courses include: qualified PADI instructor, equipment, PADI manual, logbook, lunches, PADI insurance, transportation, and certification upon completion. There are no hidden costs or extra charges. Please contact us for any information.

United States diving

Divers can compete in several venues, which may each have age and experience limitations.

Summer diving

In the United States, summer diving is usually limited to one meter diving at community or country club pools. Some pools organize to form intra-pool competitions. These competitions are usually designed to accommodate all school-age children. One of the largest and oldest competitions in the United States is found in the Northern Virginia area where 47 pools compete against each other every summer (with over 380 divers in NVSL's "Cracker Jack" meet).

High school diving

In the United States scholastic diving at the high school level is usually limited to one meter diving (But some schools use 3 meter springboards.). Scores from those one meter dives contribute to the swim team's overall score.

Club diving

In the United States, pre-college divers interested in three meter or tower diving should consider a club sanctioned by USA Diving or AAU Diving. There is a group called Future Championship. Top club divers are usually called "junior Olympic", or JO divers. JO divers compete for spots on national teams. Divers over the age of 19 years of age cannot compete in these events as a JO diver.

USA Diving sanctions one East-West one and three meter event in the winter time with an Eastern champion and Western champion determined. In the summer USA Diving sanctions a national event with tower competitions offered.

AAU Diving sanctions one national event per year in the summer. AAU competes on the one, three, and tower to determine the All-American team.

College diving

The University of Houston's CRWC Natatorium is home to the United States' largest collegiate swimming pool

In the United States scholastic diving at the college level requires one and three meter diving. Scores from the one and three meter competition contribute to the swim team's overall meet score. College divers interested in tower diving may compete in the NCAA separate from swim team events. NCAA Divisions II and III do not usually compete platform; if a diver wishes to compete platform in college, he or she must attend a Division I school. Each of the different divisions also has different rules on number of dives in each competition. Division II schools compete with 10 dives in competition whereas Division III schools compete with 11. Division I schools only compete with 6 dives in competition.

A number of colleges and universities offer scholarships to men and women who have competitive diving skills. These scholarships are usually offered to divers with age-group or club diving experience.

The NCAA limits the number of years a college student can represent any school in competitions. The limit is four years, but could be less under certain circumstances.

Master Diving

In the United States divers who continue diving past their college years can compete in Master Diving programs. Master diving programs are frequently offered by college or club programs.

Masters' Diving events are normally conducted in age-groups of 5 or 10 years, and attract competitors of a wide range of ages and experience (many, indeed, are newcomers to the sport); the oldest competitor in a Masters' Diving Championship was Viola Krahn, who at the age of 101 was the first person in any sport, male or female, anywhere in the world, to compete in an age-group of 100+ years in a nationally organized competition.

British diving

In Britain, diving competitions on all boards run throughout the year. National Masters' Championships are held two or three times per year.

Canadian diving

In Canada, elite competitive diving is regulated by DPC (Diving Plongeon Canada). The main competitive season runs from roughly February to July, although some competitions may be held in January or December, and many divers (particularly international level athletes) will train and compete year round.

Most provincial level competitions consist of events for 6 different age groups (Groups A, B, C, D, E, and Open) for both genders on each of the three board levels. These age groups roughly correspond to those standardized by FINA, with the addition of a youngest age group for divers 9 and under, Group E, which does not compete nationally (although divers of this age may choose to compete Group D). The age group Open is so called because divers of any age, including over 18, may compete in these events, so long as their dives meet a minimum standard of difficulty.

Divers can qualify to compete at the age group national championships, or junior national championships, in their age groups as assigned by FINA up to the age of 18. This competition is held annually in July. Qualification is based on achieving minimum scores at earlier competitions in the season determined by DPC according to the results of the preceding year's national competition.

Divers older than 18, or advanced divers of younger ages, can qualify for the senior national championships, which are held twice each year, once roughly in March and once in June or July. Once again, qualification is based on achieving minimum scores at earlier competitions; in this case, within the 12 months preceding the national championships.

Mechanics of diving

At the moment of take-off, two critical aspects of the dive are determined, and cannot subsequently be altered during the execution. One is the trajectory of the dive, and the other is the magnitude of the angular momentum.

The speed of rotation - and therefore the total amount of rotation - may be varied from moment to moment by changing the shape of the body, in accordance with the law of conservation of angular momentum.

The center of mass of the diver follows a parabolic path in free-fall under the influence of gravity (ignoring the effects of air resistance, which are negligible at the speeds involved).

Trajectory

Since the parabola is symmetrical, the travel away from the board as the diver passes it is twice the amount of the forward travel at the peak of the flight. Excessive forward distance to the entry point is penalized when scoring a dive, but obviously an adequate clearance from the diving board is essential on safety grounds.

The greatest possible height that can be achieved is desirable for several reasons:

• The height attained is itself one of the factors that the judges will reward.
• A greater height gives a longer flight time and therefore longer to execute the moves.
• For any given clearance when passing the board, the forward travel distance to the entry point will be less for a higher trajectory.

Control of rotation

The magnitude of angular momentum remains constant throughout the dive, but since

angular momentum = rotational velocity × moment of inertia,

and the moment of inertia is larger when the body has an increased radius, the speed of rotation may be increased by moving the body into a compact shape, and reduced by opening out into a straight position.

Since the tucked shape is the most compact, it gives the most control over rotational speed, and dives in this position are easier to perform. Dives in the straight position are hardest, since there is almost no scope for altering the speed, so the angular momentum must be created at take-off with a very high degree of accuracy. (A small amount of control is available by moving the position of the arms and by a slight hollowing of the back).

Notice that the opening of the body for the entry does not stop the rotation, but merely slows it down. The vertical entry achieved by expert divers is largely an illusion created by starting the entry slightly short of vertical, so that the legs are vertical as they disappear beneath the surface. A small amount of additional tuning is available by 'entry save' techniques, whereby underwater movements of the upper body and arms against the viscosity of the water affect the position of the legs.

Twisting

A twisting dive performed from a 1 meter springboard.

Dives with multiple twists and somersaults are some of the most spectacular movements, as well as the most challenging to perform.

The rules state that twisting 'must not be generated manifestly on take-off'. Consequently, divers must use some of the somersaulting angular momentum to generate twisting movements. The physics of twisting can be explained by looking at the components of the angular momentum vector.

As the diver leaves the board, the total angular momentum vector is horizontal, pointing directly to the left for a forward dive for example. For twisting rotation to exist, it is necessary to tilt the body sideways after takeoff, so that there is now a small component of this horizontal angular momentum vector along the body's long axis. The tilt can be seen in the photo.

The tilting is done by the arms, which are outstretched to the sides just before the twist. When one arm is moved up and the other is moved down (like turning a big steering wheel), the body reacts by tilting to the side, which then begins the twisting rotation. At the completion of the required number of twist rotations, the arm motion is reversed (the steering wheel is turned back), which removes the body's tilt and stops the twisting rotation.

An alternative explanation is that the moving arms have precession torque on them which set the body into twisting rotation. Moving the arms back produces opposite torque which stop the twisting rotation.

Entry

The rules state that the body should be vertical, or nearly so, for entry. The arms must be beside the body for feet-first dives and extended forwards in line for "head-first" dives. It used to be common for the hands to be interlocked with the fingers extended towards the water, but a different technique has become favoured during the last few decades. Now the usual practice is for one hand to grasp the other with palms down to strike the water with a flat surface (the so-called "rip entry"). This creates a vacuum between the hands, arms and head which with a vertical entry will pull down and under any splash until deep enough to have minimal effect on the surface of the water. Once a diver is completely under the water they may choose to roll or scoop in the same direction their dive was rotating to pull the splash away from the channel which they have just created.

Dive groups

A male diver performs a reverse from a 1 meter springboard in the tuck position

There are six "groups" into which dives are classified: Forward, Back, Inward, Reverse, Twist, and Armstand. The latter applies only to Platform competitions, whereas the other five apply to both Springboard and Platform.

• In the Forward Group (Group 1), the diver takes off facing forward and rotates forward
• In the Back Group (2), the diver takes off with their back to the water and rotates backward
• In the Reverse Group (3), the diver takes off facing forward and rotates backward
• In the Inward Group (4), the diver takes off with their back to the water and rotates forward
• Any dive incorporating an axial twisting movement is in the Twist group (5).
• Any dive commencing from a handstand is in the Armstand group (6).(only on platform)

Diving

Diving refers to the sport of performing acrobatics whilst jumping or falling into water from a platform or springboard of a certain height. Diving is an internationally-recognized sport that is part of the Olympic Games. In addition, unstructured and non-competitive diving is a common recreational pastime in places where swimming is popular.

While not a particularly popular participant sport, diving is one of the more popular Olympic sports with spectators. Successful competitors possess many of the same characteristics as gymnasts and dancers, including strength, flexibility, kinaesthetic judgment and air awareness.

Diving tower at the 2008 Euros

In the recent past, the success and prominence of Greg Louganis led to American strength internationally. More recently, the greatest diving nation has been China, which came to prominence several decades ago when the sport was revolutionized by national coach Liang Boxi and after intense study of the dominant Louganis. China has lost few world titles since. Other powers are generally those which import Chinese coaches, including Australia and Canada.

Competitive diving

Competitive Springboard Diving

Competitive Platform Diving

Most diving competitions consist of three disciplines: 1m and 3m springboards, and the platform. Competitive athletes are divided by gender, and often by age groups as well. In platform events, competitors are allowed to perform their dives on either the five, seven and a half (generally just called seven) or ten meter towers. In major diving meets, including the Olympic Games and the World Championships, platform diving is from the 10 meter height.

Divers must perform a set number of dives according to various established requirements, including somersaults and twists in various directions and from different starting positions. Divers are judged on whether and how well they completed all aspects of the dive, the conformance of their body to the requirements of the nominated dive, and the amount of splash created by their entry to the water. Theoretically, a score out of ten is supposed to be broken down into three points for the takeoff, three for the flight, and three for the entry, with one more available to give the judges flexibility.

The raw score is multiplied by a difficulty factor, derived from the number and combination of movements attempted. The diver with the highest total score after a sequence of dives is declared the winner.

Synchronized diving

Synchronized diving was adopted as an Olympic sport in 2000. In this event, two divers form a team and attempt to perform dives simultaneously. The dives are usually identical; however, sometimes the dives may be opposites, in what is called a pinwheel. In these events, synchronicity is valued as highly as technical skill.