Scuba Diving Basics: All You Need To Know

When I did my first Scuba Dive sometime in November 2018, I really wished I knew the Scuba Diving basics. Because as a general practice, it is always better to read about any adventure activity you are planning to try out. Not only does it make you aware of risks associated with it and help you mitigate them, but it also lets you enjoy the activity to the fullest. So here’s a brief guide on this amazing water activity which would definitely help you on your “D-Day” (Read: Diving Day).


Scuba diving is a mode of underwater diving where the diver uses an apparatus, which is completely independent of surface supply, to breathe underwater. Scuba divers carry their own source of breathing gas, usually compressed air, allowing them greater independence and freedom of movement than surface-supplied divers, and longer underwater endurance than breath-hold divers. An American named Major Christian J. Lambertsen had invented an underwater free swimming oxygen rebreather in 1939. He modified it in 1952 and coined a term “SCUBA” for it (acronym for Self Contained Underwater Breathing Apparatus). Source: Wikipedia.


There are certain terms and slangs that are associated with every adventure activity. Likewise, your scuba diving instructors would use certain terms (out of habit) which you can know beforehand here to avoid any confusion. Although you are not required to remember them by heart, it is useful to be familiar with them.


Wetsuit, Wetty, Steamer, Springy

  • Scuba Diving Wetsuit. Source: PADI
    Scuba Diving Wetsuit. Source: PADI

A wetsuit protects your skin and keeps you warm underwater. Wetsuits are made of closed-cell foam neoprene, a synthetic rubber that contains small bubbles of nitrogen gas. “Wetty” is a slang for wetsuit; “Steamer” is a long wetsuit and a short wetsuit is called “Shorty”, “Springy” or a “Spring suit”.

Buoyancy Control Device, BCD, BC

  • Scuba Diving BCD. Source: PADI
    Scuba Diving BCD. Source: PADI

Buoyancy (also known as the buoyant force) is the force exerted on an object that is wholly or partly immersed in a fluid. So when you, as an object dive into water which is a fluid, need to control this force. BCD does that for you – it gives you control in the water. It lets you efficiently float on the surface, kneel/ stand on the bottom, drift along, etc. The BCD also holds your tank.

Regulators: First Stage, Primary Second Stage and Alternate Second Stage

  • Scuba Diving Regulator. Source: PADI
    Scuba Diving Regulator. Source: PADI

The First stage regulator is basically used to attach your Primary second stage regulator to the cylinder valve and reduce high pressure gas to breathable pressure. The primary second stage is the regulator that you put in your mouth which allows you to breathe underwater. The Alternate second stage is a backup regulator in the event of an out-of-air emergency.

Integrated Weights and Weight Belts

  • Scuba Diving Weight Belt. Source: PADI
    Scuba Diving Weight Belt. Source: PADI

Weight belts are required to help the diver sink to the bottom of the sea. The diver either wears a weight belt or the weights are integrated in the weight pockets or even in BCD.

Pressure Gauge and Dive Computer 

A diver must carry the Pressure Gauge and Dive Computer every time he/she dives underwater. The pressure gauge shows the amount of air remaining in the cylinder.

  • Scuba Diving Pressure Gauge. Source: PADI
    Scuba Diving Pressure Gauge. Source: PADI

On the other hand, the dive computer measures the diver’s depth, dive time and also helps calculate how long a diver can stay at particular depths underwater.

Mask, Snorkel and Fins

As we all know, human eyes are not programmed to be able to see underwater. Hence, a perfect solution is to use diving mask to be able to clearly see the underwater life.

  • Scuba Diving Mask. Source: PADI
    Scuba Diving Mask. Source: PADI

A snorkel is optional but can be useful to preserve the air as a backup in the event of you running out of cylinder air and to bring you back to the surface.

The fins allow the diver to control the underwater movement and to increase the speed and agility. It also helps the divers to identify their buddy divers underwater.


Since it is not possible to speak underwater, the only means of communication available with divers is using hand signals. Although there are many hand signals defined in scuba diving, following are the most common ones:


  • Scuba Diving Hand Signal OK. Source: Wikipedia
    Scuba Diving Hand Signal OK. Source: Wikipedia

Join the thumb and index fingers to form a loop and extend the third, fourth, and fifth fingers. It is a way to let your buddy know that everything is fine and also to check if he/she is fine.

“Not Okay” or “Problem”

  • Scuba Diving Hand Signal Not OK. Source: Wikipedia
    Scuba Diving Hand Signal Not OK. Source: Wikipedia

Extend a flattened hand and rotating it slowly side to side. It is used to indicate something is wrong. It is generally followed by pointing to the body part where you are feeling the discomfort.

“Up” or “End the Dive”

  • Scuba Diving Hand Signal Up. Source: Wikipedia
    Scuba Diving Hand Signal Up. Source: Wikipedia

A thumbs-up signal is used to communicate to the buddy diver that you wish to go a certain distance up. It can also be used to indicate that you wish to end the dive.


  • Scuba Diving Hand Signal Down. Source: Wikipedia
    Scuba Diving Hand Signal Down. Source: Wikipedia

The thumbs down signal is used to indicate that you wish to “go down” or “descend” further down.

“Look at me”

  • Scuba Diving Hand Signal Look At Me. Source: Wikipedia
    Scuba Diving Hand Signal Look At Me. Source: Wikipedia

Point your index and middle fingers to your eyes and then to yourself. This signal is used to get your partner’s attention to further communicate something to him/her.


When you scuba dive, you are bound to experience the underwater pressure. As you move further deep down, the ambient pressure exceeds the pressure in your middle ear, resulting in discomfort/ pain in your ears. Hence, ear clearing is essential in scuba diving. It is also called as Ear Equalization. There are many equalization techniques in scuba diving. Most common is the Valsalva Maneuver (pinch and blow) technique. However, some divers often other technique useful. Some of them are:

  • Valsalva Maneuver: Pinch your nostrils and gently blow through your nose.
  • Swallowing: use your throat muscles to open the Eustachian tubes.
  • Frenzel Maneuver: pinch your nose, press your tongue against the back of your throat and try making a “K” or “ng” sound.
  • Lowry Technique: pinch your nose, blow against it and swallow at the same time.
  • Edmonds Technique: pinch your nose, blow and push your jaw forward.
  • Beance Tubaire Volontaire: Tense the muscles of the soft palate and the throat while pushing the jaw forward and down as if starting to yawn.


  1. Stay physically fit: Lack of fitness leads to overexertion, which can in turn lead to faster air consumption, panic and further resulting accidents.
  2. Check your gear: A divers survival underwater depends majorly on the equipment. Make sure you are carrying all the necessary equipment and you are aware of its usage. 
  3. Never hold your breath: According to Boyle’s law, the air in a diver’s lungs expands during ascent and contracts during descent. As long as the diver breathes continuously, this is not a problem because excess air can escape. Therefore, keep breathing through your mouth.
  4. Dive within your limits: Do not succumb to the peer pressure and dive beyond your physical and mental limits. Communicate any discomfort to your buddy immediately.
  5. Practice safe ascents: It is essential to ascend slowly and safely at all times.
  6. Rule of thirds: According to this rule, a diver should designate a third of his/ her air supply for the outward journey, a third for the return journey, and the final third as a safety reserve.
  7. Use the buddy system: NEVER dive solo.
  8. Practice vital skills: buoyancy control, mask clearing, perform CPR, hand signals, etc.
  9. Establish positive buoyancy at the surface: Establishing positive buoyancy at the surface conserves energy, preventing exhaustion and drowning.

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