New to Scuba Diving ?

what does scuba mean?

SCUBA stands for "Self Contained Underwater Breathing Apparatus"

It was initially used to describe the system that first allowed divers to go underwater without being connected to an air supply on the surface.

Essential Skills

There are basically two ways to get yourself underwater with a breathing apparatus. One is to take a certification course from one of the sport’s major organizations, PADI (Professional Association of Dive Instructors) or NAUI (National Association of Underwater Instructors). The 20-hour course includes classroom, pool, and open-water components, and will set you back about $400, but the certification is valid for life. You’ll learn such vital skills as how to clear your mask when it fills with water, what to do if you’re low on air, and how to reinsert your regulator if it falls out of your mouth.

Option two is to take a "resort course," which permits you to dive with an instructor down to a maximum depth of 10 meters (33 feet). Our advice: Try the latter on your next tropical vacation to see if you like the sport before investing both time and money on training.

Beginners classes

Beginners classes are usually held for one or two days at a local pool and require only a mask, snorkel and fins as the basic equipment. Book work is handled in the classroom of a local dive shop. Additional gear, such as tanks, wetsuits and gauges are rented from a dive shop or the instructors themselves.
Basic skills are taught with a stress on safety. Breathing normally through a regulator (and not holding your breath), clearing water from a flooded mask or snorkel and learning underwater hand signals are some of the lessons to be learned during the first day of certification. Advanced skills like regulator recovery, refitting a mask underwater, regulator sharing and rescue techniques are introduced on the second day, though the teaching sequence varies somewhat with each instructor.

After basic training completed

Once basic training has been completed, the true test comes in the form of a series of open water dives conducted in a flooded quarry, lake, river or sometimes in the sea. Successfully repeating previously learned skills in an open environment earns the diver an open water certification. This means the diver will be allowed to participate in recreational dives in to depths up to about 40 feet. Deeper dives require additional specialized training. Diving in tropical areas is the most common setting for divers; wreck investigation, night diving and ice (arctic water) diving require more training as well.

Scuba Gear

Dive gear falls into two categories: required and gadget. Required gear includes a mask, snorkel, fins, buoyancy compensator (BC), regulator, dive computer or watch, weights, and often a wetsuit. Gadget gear is usually associated with a particular type of diving--night diving, underwater photography, or search and recovery--and includes knives, underwater slates, cameras, strobes, video recorders, lights, lift bags, lines, reels, and even underwater laser pointers.

A mask, wetsuit, and fins are worth owning because a proper fit makes all the difference. For convenience we recommend you rent a tank, BC, and regulator. The quality of rental equipment at most professional dive shops is generally pretty high. If you already own a BC, and don’t mind traveling with the extra 4 pounds, then bring your own.


Obviously an important tool, letting you see underwater. It also creates an air pocket in front of you face. This allows you to equalize your ears as you descend. You equalize by holding your nose and blowing. Try it next time you dive for something at the bottom of the pool.

To get a proper fit, put the mask up to your face and stop when it is barely touching your face. Do not press the mask hard onto your face. Ideally the mask should touch all around your face at the same time. There should be no gaps between the skirt and your skin.

Inhale gently. If the mask stays on it might be right for you. Check for any gaps between the rubber around your mask (called the skirt) and your face. My husband has chubby cheeks and can't find a mask with the perfect fit. It happens. You will become a champion at clearing your mask though.


Allows you to move easily underwater. There are two types of fins - full foot and open heel. Full fit fins go on your bare foot. You wear a bootie (like a sock) with open heel fins. Just put your foot in the fin and pull the strap over your heel.

We have the full fit fins since we only dive in tropical waters. They have worked fine for us. Full foot fins are usually less expensive than open heel fins. One advantage of open heel fins is that you have a scuba bootie on. This makes it easier to walk around a wet dive boat. It can get slippery and the booties help.

Fins should fit comfortably, not too tight and not too loose. Just like a shoe.


This allows you to breathe while swimming face down on the surface. I also use it if the water is rough and I'm waiting on the surface for other divers to get off the boat. Some people use their scuba regulators on the surface. Using a snorkel saves some air. It doesn't make that a big a difference though so do what is comfortable. The snorkel goes on the left side of the mask and attaches to the mask strap.

BCD (buoyancy compensator)

This fits like a vest and holds the tank on your back. This piece of necessary scuba diving equipment allows you to control your depth in the water. You put air in the BC if you want to rise in the water. There is a release mechanism (actually, usually two) that lets air out of the BC if you want to descend.

Air can be put into a BC in two ways. The first way is through the power inflater. You press a button and air goes into your BC. The second way is through the mouthpiece. It is at the end of a hose that is attached to your BC. Either way works. The hose goes on the left side of the BC.


When people first see this, this is when they really want you to explain scuba gear. The regulator/octopus is what allows you to breathe underwater. Obviously, a very important piece of scuba diving gear. The regulator attaches to the top of the tank (called the first stage). There is then a hose that has the regulator mouthpiece attached allowing you to inhale air underwater (second stage).

The regulator also consists of a second hose with another mouthpiece attached. This is called your octopus. The octopus has a longer hose and is usually bright yellow. In addition to being a backup to your primary regulator, the octopus is there to be used by another person in case of an emergency. The yellow color makes it easy to find. Both the regulator and octopus go on the right side.

Diving Wetsuits/Dive Skins

conducts heat away from you so these keep you warm underwater. A skin is a very thin piece of material (usually Lycra) with full arms and legs. It doesn't keep you warm but it protects you from scrapes and stings.

A wetsuit can be full body (full arms and lets) or a shorty (short or no arms and short legs). It is usually made of neoprene. When you explain scuba gear, people always ask - "Can people breathe in those suits? It looks tight?" A wetsuit should be snug but you should still be able to breathe comfortably.

People typically wear 3mm wetsuits in the Caribbean. It's a personal preference. My husband and I only wear a skin if we are only doing a couple dives that day. If we are doing a dedicated dive trip, with 4 or more dives a day for a week, I'll usually wear a shorty wetsuit. It starts to get chilly after all that diving!


If you don't have a computer, you will need a watch or other timing device. You need to be able to track your dive time and your safety stop.

If this is your primary timing device (you do not have a computer), you need to go for higher quality. You do not want this to fail at 100 feet. You can get some good quality dive watches at reasonable prices.

If this is your secondary timing device, there is no need to get fancy here. It's easy to find cheap dive watches (some around $10) that are safe to 100-150 feet. These should be fine - with one caveat. Only use these if it is your secondary timing device.

My husband has been using the same dive watch ($20 or so) for about 100 or so dives with no problem. On the other hand, my watch which was similar failed after about 25 dives but I had my computer so it was no big deal. If you don't use a digital watch, you should buy a watch with a bevel.

Physics of Scuba Diving

Scuba diving is all about getting air into you while you're underwater. What complicates scuba is the way air behaves at depth, under pressure, in your body and in your equipment. To dive safely you need to understand all the things intuitively and how they affect the techniques and practice of scuba diving. As part of your scuba certification you will come to understand certain principles of physics, in particular the gas laws which apply to scuba. When you understand the gas laws all the intricacies of nitrogen management, offgassing and even rules of inflating and deflating your BCD will make more sense.

Scuba Diving Risks

Scuba diving is not a dangerous sport. Scuba diving is riskier than a sport like hockey or baseball, but less dangerous than street luge or mountain climbing. Modern scuba diving equipment is easy to use, very reliable and with the proper training and a responsible attitude scuba diving can be enjoyed safely. In fact, almost all scuba diving injuries and casualties are the result of recklessness or bad judgment.

There are certainly risks involved in scuba diving. Part of certification training is learning about those risks and how to avoid them. The majority of possible health problems are forms of barotraumas, which are all caused in one way or another by changes in pressure. Other possible risks are associated with higher absorption of gases, while other risks are more mechanical and environmental in nature.

Here are some of the risks associated with scuba:

  • Barotrauma (explained by Boyle's law)
    • alternobaric vertigo
      Dizziness or disorientation caused by unbalanced pressures in the inner ear. Most commonly experienced by stubborn scuba divers trying to dive with the common cold.
    • altitude sickness
      Headache caused by a quick ascent, usually associated with airplane travel.
    • barodontalgia
      Pain caused by tiny bubbles of gasses trapped in the teeth, usually in fillings or caps.
    • decompression sickness, a.k.a. "the bends"
      Nitrogen coming out of a solution in tissue which is caused by hastened decompression.
    • dysbaric osteonecrosis
      Rare bone lesions produced by long term exposure to high pressure environments.
    • embolism
      Nitrogen coming out of a solution in the body. It can be caused by accelerated decompression.
    • arterial gas embolism
      Gas coming out of a solution in the arteries. It can be potentially fatal.
    • cerebral embolism
      Gas coming out of a solution in the brain. It can be potentially fatal.
    • lung expansion injury
      It can be caused by holding breath while ascending.
    • pneumomediastinum
      Ruptured bronchus or alveoli in the lungs from excessive pressure. May be caused by holding breath while ascending.
    • pressure arrhythmias
      Abnormal heart rhythms caused by external pressure.
    • tinnitus, Eustachian & inner ear damage, Tympanic membrane rupture and/or hearing loss
      Inner ear damage can result from diving without equalizing air pressure in the Eustachian tubes. It is complicated or caused by water pressure and blocked sinuses and it can be extremely painful.
  • Non-Barotrauma (explained by Henry's Laws and Dalton's Laws)
    • co2 toxicity, a.k.a. hypercapnia.
      Too much CO2 in the body, usually caused by inadequate exhalation or air consumption during heavy exertion. Symptoms include shortness of breath, headache and/or confusion.
    • nitrogen narcosis, a.k.a. "rapture of the deep"
      The result of a toxic effect of high pressure nitrogen on nerve conduction. Symptoms are comparable to the effects of alcohol drunkenness.
    • o2 toxicity
      Toxic effects of absorbing too much oxygen. Symptoms include a burning sensation in the lungs, twitching, dizziness, vomiting and/or seizures.
  • Other physical and health hazards - Scuba Diving
    • dangerous marine life
      Most common injuries are the result of divers touching poisonous animals such as jellyfish, fire coral, urchins or stingrays. Attacks by large fish are extremely rare.
    • dehydration
      Dehydration is an inadequate bodily water level. Surprisingly common on boat tours; diving while dehydrated aggravates other health risks including nitrogen narcosis and hypercapnia.
    • hypothermia
      Hypothermia is a loss of body heat and early symptoms include fatigue and loss of judgment.
    • drowning
      An obvious risk if for any reason a diver breathes in water instead of air or just simply the loss of air.
    • running out of air
      Typically caused by irresponsible air management or scuba equipment failure.
    • underwater injury
      Common injuries include abrasions and cuts (from sharp coral), sprains, bumps and bruises. Studies show more serious injuries occur getting in and out of the boat than actually in the water.