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INTRO TO SCUBA DIVING
You've always wanted to take the scuba diving plunge, your friends are always talking about it and your best mate keeps raving about his amazing dive trip to the Sipadan. But, how do you start this adventure? Who's out there to baptize you into the sport and who's around to help you side step any aquatic snags?
The skill of being able to dive, survive and actually enjoy the underwater experience can be a life-long learning curve. It can also be incredibly rewarding!
To allow you a wee taste of the sport, diving agencies have designed the Try Dive, Resort Dive or Discover Scuba Dive. These courses are usually over one or two days and teach you a few diving skills needed to safely introduce you to the underwater world. During these early diving days you will be shackled to your instructor by virtual elastic bungee and kept at a limited depth.
Your first venture below the surface is one you'll never forget. Your body submerges like a submarine on a mission; the water and air bubbles disorientate you as the light intensity decreases. The little gremlin, the dive instructor has planted in your mind, seems to be on automatic replay and all you hear is "breath, slow down, relax". You soon come to realize that these are not easy things to achieve. There is so much to look at! You will be amazed at how the buzz of spotting your first moray eel jutting it's pointed snake-like head out of a rock crevice can over-ride your nervous system ambushing your air intake for a good 30 seconds.
To enjoy your diving experiences and make sure you remain safe, it is strongly recommended you complete a certified diving course. These courses are designed to teach you to survive while breathing underwater, understand and know how to use your dive equipment and protect and respect the marine environment.
The general pecking order of dive training gets going with the 4-5 day Open-water course; Specialties, Advanced Diver, Rescue Diver, Dive Master, Assistant Instructor, Dive Instructor and Master Scuba Trainer courses follow this.
Dive training is organized by a number of international certification agencies, the following are some of the most prominent associations: the British Sub Aqua Club (BSAC), the Confederation Mondiale des Activities Subaquatiques (CMAS), the Professional Association of Diving Instructors (PADI), Scuba Schools International (SSI) and the National Association of Underwater Instructors (NAUI).
These dive courses not only provide you with the skills to survive underwater, but you are also awarded with a certification or C-Card. The C-card is important proof of your qualification and reputable diving centres will need to sight this before signing you up on their dive trips.
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THE HISTORY OF DIVING
For thousands of years man has shown an inborn need to explore, conquer and experience the unknown. Decades before the first weighted boot was stamped upon the moon divers had been delving into the gravity defying depths below the ocean waves.
When Did It All Start?
Although there is no official record of the first underwater adventure historians guess it's some 5000 years before the three wise men trundled into Bethlehem. Early Persian records tell of a diver being sent into the ocean depths to salvage sunken treasure in the fifth century BC.
To increase stamina and lung capacity many salvaging divers were trained from a young age. The deeper these divers could go the more they got paid, so with the aid of a flat rock and a rope around the waist they could drop down to 30 meters.
Breathing Underwater
Using reeds to breath while submerged was one of the first primitive air supply systems adopted for warfare. It wasn't until the end of the 16th Century that the open-ended diving bell was produced. This contraption allowed trapped air to be compressed within it when dropped vertically into the water giving divers a small reservoir of air to draw from.
In 1823 inventors revolutionized diving by converting a smoke apparatus used by firemen into the "Deane's Patent Diving Dress" - a heavy suit for protection and leaded helmet with viewing ports and a hose for surface air. As the exhaust air was released through the open bottom of the helmet divers had to remain upright or risk drowning. In 1840 an added exhaust valve made the suit a precursor for today's standard deep-sea surface-air-supplied diving dress.
SCUBA
SCUBA, - Self Contained Underwater Breathing Apparatus, was developed with the increase in technology enabling demand regulators to be invented, air to be compressed, and tanks to be designed light enough to be carried by divers while containing pressurized air. During WW2 French naval officer, Jacques-Yves Cousteau and French engineer, Emile Gagnan, developed the open-circuit SCUBA system and aqualung - the blueprints for the safe and efficient scuba systems of today.
HISTORY
With the massive increase in technology and the modernizing of dive equipment over the past 50 years, diving has become more accessible not only for salvaging and hunting but also as a sport. Every day new marine species, terrain and ecosystems are being discovered and explored. The next decade of diving is shaping up to be another milestone in diving and marine history.
Men and women have practiced breath-hold diving for centuries. Indirect evidence comes from thousand-year-old undersea artifacts found on land (e.g., mother-of-pearl ornaments), and depictions of divers in ancient drawings. In ancient Greece breath-hold divers are known to have hunted for sponges and engaged in military exploits. Of the latter, the story of Scyllis (sometimes spelled Scyllias; about 500 B.C.) is perhaps the most famous. As told by the 5th century B.C. historian Herodotus (and quoted in numerous modern texts),
During a naval campaign the Greek Scyllis was taken aboard ship as prisoner by the Persian King Xerxes I. When Scyllis learned that Xerxes was to attack a Greek flotilla, he seized a knife and jumped overboard. The Persians could not find him in the water and presumed he had drowned. Scyllis surfaced at night and made his way among all the ships in Xerxes's fleet, cutting each ship loose from its moorings; he used a hollow reed as snorkel to remain unobserved. Then he swam nine miles (15 kilometers) to rejoin the Greeks off Cape Artemisium.
The desire to go under water has probably always existed: to hunt for food, uncover artifacts, repair ships (or sink them!), and perhaps just to observe marine life. Until humans found a way to breathe underwater, however, each dive was necessarily short and frantic.
How to stay under water longer? Breathing through a hollow reed allows the body to be submerged, but it must have become apparent right away that reeds more than two feet long do not work well; difficulty inhaling against water pressure effectively limits snorkel length. Breathing from an air-filled bag brought under water was also tried, but it failed due to rebreathing of carbon dioxide.
In the 16th century people began to use diving bells supplied with air from the surface, probably the first effective means of staying under water for any length of time. The bell was held stationary a few feet from the surface, its bottom open to water and its top portion containing air compressed by the water pressure. A diver standing upright would have his head in the air. He could leave the bell for a minute or two to collect sponges or explore the bottom, then return for a short while until air in the bell was no longer breathable.
In 16th century England and France, full diving suits made of leather were used to depths of 60 feet. Air was pumped down from the surface with the aid of manual pumps. Soon helmets were made of metal to withstand even greater water pressure and divers went deeper. By the 1830s the surface-supplied air helmet was perfected well enough to allow extensive salvage work.
Starting in the 19th century, two main avenues of investigation - one scientific, the other technologic - greatly accelerated underwater exploration. Scientific research was advanced by the work of Paul Bert and John Scott Haldane, from France and Scotland, respectively. Their studies helped explain effects of water pressure on the body, and also define safe limits for compressed air diving. At the same time, improvements in technology - compressed air pumps, carbon dioxide scrubbers, regulators, etc., - made it possible for people to stay under water for long periods.
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WHAT IS DIVING?
The word "diving " conjures up a number of different meanings, most of which have the action involving descending.
Diving, for our purposes, basically means spending time underwater.
There are several types of diving. The most common forms of recreation diving are snorkeling or free diving and SCUBA diving.
Snorkeling
Snorkeling, as the name suggests, is when a diver is using a mask, snorkel and fins to swim around, mainly on the surface, looking down to see what is under the water. Occasionally snorkeler dive down for closer investigation of the underwater world.
Free Diving
Snorkeling is sometimes referred to as free diving. Generally this term is used when divers/snorkellers dive down holding their breath and spending quite long periods underwater.
Common free diving activities include spear fishing, photography (with no bubbles it's easier to get closer to your subject) and various competitions.
SCUBA Diving
SCUBA stands for Self Contained Underwater Breathing Apparatus. It is a system originally designed by Jacques Cousteau in which high-pressure air is stored in tanks and reduced to a breathable pressure - that of the surrounding (ambient) water pressure. The main components of SCUBA are:
Tank - stores high pressure air for use underwater.
Regulator - breaks down the air pressure to a breathable level and delivers air from the tank to your mouth.
Instruments - indicate your tank pressure, depth, dive time, and sometimes body nitrogen levels, remaining allowable safe dive time, safety or decompression stops required, surface intervals, and the list goes on!
Another component usually needed is a BCD - Buoyancy Control Device (funnily enough, used to control your buoyancy).
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SCUBA DIVING EQUIPMENT
Scuba Diving is made possible thanks to specialized, state of the art equipment. All Diving comes in a wide variety of colors, having bright colors underwater helps buddy recognition as well as looking cool and stylish..
The Mask
The mask is your window into the underwater world, it allows you to by creating an air space in front of your eyes, which also covers your nose so you can equalize the mask air space. The Mask should make an airtight fit against the face, you can check to see if the mask fits by putting your face up to the mask and gently breathing in through your nose. If it fits the air will be not be able to breach the mask The mask will then be stuck against your face caused by you breathing in through your nose and creating a vacuum.
All faces are different and as a result there are many different shaped masks, if you have trouble finding the right mask, just ask for help at your local dive store, they will be more than pleased to find the mask best suited for you. Unless you know what kind of mask fits, you should go to your nearest shop and try some on before buying online. Diving is largely a visual activity, and the importance of having the proper mask cannot be over-emphasized. As a result masks are left out of the beginners Scuba Package, why? Because we wont supply you with something that doesn’t suit your personal needs. We can sort you out with a snorkel though…if you have tried and found the right mask then by all means feel free to buy it from us!
Tips when buying a mask
Tempered-glass lens plate. If broken, tempered glass is less likely to shatter into harmful shards.
Comfortable 100% silicone skirts for a positive feather edge seal
Low volume masks can be more desirable to the beginner as they are easier to clear if it floods, mask clearing is one of the first skills you will learn in the pool on the Open Water Diver Course
An easy to adjust strap
A wide field of vision, such as the Oceanic Trend 3 mask You can buy some masks which have a purge valve, a purge valve is a one-way valve used for clearing masks using the pressure change created by your out breath within the mask air space. The purge valve will be found on the bottom of the mask, if not correctly maintained the salt chrysalises and can cause the valve to leak, as the valve cannot seal itself due to the salt. Most divers prefer not to use the purge valve simply as mask clearing is so easy to learn anyway and becomes effortless very quickly anyway.
Preparing Your New Mask
New masks come with an oily protective coating that must be scrubbed off, I use a toothbrush and toothpaste to lightly rub away the film, don’t forget to scrub both side of the lens. If you don’t remove the film of silicone then the mask will fog up upon use, thus spoiling your valuable dive time, so don’t forget.
The Snorkel
he Snorkel is a standard piece of diving equipment without you to breathe at the surface without having to lift your head from the water, they come in a vast range of colors and styles but all do the same thing.
Fins
Fins allow you to propel yourself through the water with far less effort than just your hands and feet, they become an extension of the diver and allows them to glide through the inner space that can only be found underwater. Fins come in two basic styles (1). Adjustable strap (2). Full foot
Divers more commonly use adjustable fins as they can be worn with thermal protection such as wetsuits, semi-dry suit or dry suits. The Buoyancy Compensator Device (BCD)
The BCD is basically an expandable bladder that can be inflated or deflated to control your buoyancy. The BCD can be orally inflated or mechanically inflated with air from your tank that fixes on to the back of the BCD. Some tanks use integrated weight systems, which eliminates the need for a weight belt. All BCD’s will have pockets and fixing points for your alternate air source and submersible pressure gauge.
Regulators and Submersible Pressure Gauges
The dawn of the new millennium is an exciting time to be a diver if for no other reason than the highly refined state of scuba regulators as a result you don’t need to spend a fortune when you are just starting out to get a high performing budget regulator. A good regulator will deliver sufficient air in a stable manner when at depths that far exceed those of the recreational diver. So why would you want a regulator with high performance when you will never de diving to those depths? Because of in the very unlikely event that there is an emergency situation, there is no such thing as “to much air”. Today’s high performing models will deliver more air more easily, with greater stability at greater depth, with less tank pressure and will stay “in tune” longer than ever before.
A regulator is designed to reduce the high pressure of a scuba tank to a breathable pressure. Modern scuba regulators are very simple and reliable devices with only a few moving parts. They have two stages: the first stage, which attaches onto the cylinder and the second stage has a mouthpiece. The high pressure from the tank is reduced to an intermediate pressure by the first stage. The second stage reduces the air pressure to a comfortable breathing level that is required for scuba diving. The first stage of the regulator will have an extra second stage, called an alternate air source. This is used to simplify sharing air with another diver in the really unlikely event that you have an out of air situation, which of course you all being good, safe divers will never happen. The alternate air source is usually bright yellow so it can be easily identified.
Submersible Pressure Gauges
The submersible pressure gauges allow you to monitor the amount of air in your tank during a dive, this allows you to calculate estimated dive times so you can return safely you exit points without running low on air. The submersible pressure gauge also connects to the regulator first stage. You can also tell your depth in increments of meters by using the depth gauge. A compass to aid navigation is usually included on the SPG’s. Our models also come with temp gauges as if that wasn’t all enough.
Thermal Protection
Most Divers require thermal protection; the basic forms are wetsuit (warm water diving), semi dry suits, and dry suits. There is a wide choice of suits, gloves, and boots to suit every divers need no matter where they are. Technology today means that all divers can enjoy warm comfortable diving.
Dive Computers
Dive computers are just getting better and there's no reason for the improvements to stop. Unlike regulators, which are probably as good as they're going to get until the next design revolution. Dive computer technology has just begun to show its full potential. Dive Computers have many benefits as opposed to the older dive tables, the computer works out how much nitrogen is in your body and then works out your total allowable bottom time which changes throughout your dive (with dive tables you work out your dive based on your greatest depth) after you start to ascend for instance (diving up a reef or wreck) and works out your new nitrogen levels accordingly. The computer also tells you how deep you and your assent rate (most modern computers warn you audibly or on the screen you if you ascend to quickly) The PADI system states that divers can ascend at no faster than 18m a min, the dive computers are usually set to 10m so when you are alerted about a speedy assent you have time to compensate and slow down.
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WOMEN AND DIVING
DOES ONE'S SEX AFFECT SCUBA DIVING?
There are two answers to this important question. The short answer is "no." Much has been written about the difference between men and women divers, and no self respecting dive columnist would stop with such a simple answer. But the fact is, the differences between men and women regarding scuba diving are, with one exception, minor and not significant. The one exception, of course, is pregnancy.
The long answer is that women, on average, have smaller lungs, a lower aerobic capacity, a greater percentage of body fat, and less upper body strength than men, and these differences have some effects on diving. Women tend to use less air/minute than men (because of their smaller lung volume), but in recreational diving that is rarely an important factor. Women may not have the same capacity for extreme physical exertion as men, but that too is of little consequence in recreational diving. Since women have a higher percentage of body fat in men, in theory they should have better tolerance to cold water. Although some think the higher percentage of body fat increases the risk of decompression sickness.
The long answer also recognizes that the menstrual period poses some concern for women, but this is not ordinarily a limitation. The long answer must also include the observation that men as a group seem to take more risks than women, and as a result show up more frequently in mortality statistics associated with cave, deep, and mixed gas diving.
However, except for pregnancy, the anatomic differences between men and women are simply not a big deal when it comes to scuba diving. Either sex can learn to become quite proficient both as a recreational diver or as a scuba diving professional.
SHOULD WOMEN EXPECT SPECIAL TREATMENT WHEN SCUBA DIVING?
Ideally, no. The stereotype of a weak, mechanically disinterested, and/or uncoordinated female is out of date and harmful to both sexes. Any woman who expects manual chores will be done for her (carrying her tank, attaching the regulator, etc.) because she is a woman, loses the opportunity to learn important skills and remain self-sufficient. Any man who abridges a woman's chance for self-sufficiency by insisting on doing things for her not only demeans her but also perpetuates an outdated stereotype. Also, if the woman is his dive buddy, he may weaken skills she may one day need to help him.
Scuba diving is a level playing field; it is no place for machismo behavior or sexism of any sort. Equality certainly reigns at the professional level. Hundreds of women instructors teach open water and advanced courses to men and women. Women run dive shops, operate dive boats and lead diving expeditions. Resorts that carry tanks, attach BC's or perform other dive-related chores for its customers do so for men and women alike. Obviously, scuba diving is no longer "a man's world" as it was perhaps a generation ago. Today, it should be as acceptable for a man to ask a woman for help with equipment or some other problem, as vice versa. When diving, women and men should wan t and expect to be treated as equals.
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WATER AND THE PHYSICAL LAWS THAT AFFECT DIVERS
WHAT ARE THE IMPORTANT DIFFERENCES BETWEEN AIR AND WATER?
The laws are particularly important in understanding what happens to air-containing spaces under water, particularly the lungs, sinuses, and middle ears. Before discussing air pressure under water, it will be useful to review important differences between air and water (Table 1).
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Water is much heavier than air. A cubic foot of air weighs 1/12 pound (lb). A cubic foot of fresh water weighs 62.4 lbs and a cubic foot of sea water weighs 64 lbs.
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Water molecules are made up of hydrogen and oxygen, chemical symbol H2O. Each water molecule contains two atoms of hydrogen and one atom of oxygen. Salt water contains salt (sodium chloride, chemical symbol NaCl) and other minerals in solution (i.e., dissolved into it, not chemically combined with the water). Salt adds to the weight of water, and for this reason sea water has slightly greater weight - and hence pressure - than fresh water (sea water contains approximately 35 pounds of salt for every 1000 pounds of water). It takes a depth of 34 feet of fresh water to equal one atmosphere of pressure, as opposed to 33 feet of sea water.
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Air is a mixture of gases, principally oxygen (O2, 21% of the air by volume) and nitrogen (N2, 78% by volume). Each gas exerts its own independent pressure, the sum of which equals the total air pressure (Dalton's law). Unlike water, air (and any other gas or mixture of gases) is compressible; the greater the pressure exerted, the more tightly packed together are the individual gas molecules. Regardless of the air pressure, however, water molecules are much more tightly packed together than air molecules. Compared to air at sea level pressure (1 atm.), water is about 800 times denser.
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Just as air has weight and exerts pressure on all sides of an object in the atmosphere, water exerts pressure around any object immersed in it. We can push water out of the way because its weight is distributed on all sides and the molecules can be easily moved. The resistance we feel under water reflects the extreme density of water (compared to air), and the fact that it takes time for water molecules to move out of the way.
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Water pressure, like air pressure, is a function of weight; the deeper one goes the greater the surrounding water pressure. The marked increase in water pressure with depth affects every scuba and non-scuba diver, indeed anyone who goes under water (unless inside a heavy vessel with walls that resist pressure, such as a submarine).
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