In this blog post, we’ll explore everything from the definition and history of skin scuba to essential equipment, diving techniques, and safety precautions, covering the basics you need to know to explore the ocean safely.
Definition and History of Scuba Diving
Scuba diving (SKIN SCUBA) is broadly divided into skin diving and scuba diving. Skin diving, also known as snorkeling, involves wearing a mask, fins, and a snorkel to dive primarily at the surface or in relatively shallow waters. The term “SCUBA” in scuba diving stands for “Self-Contained Underwater Breathing Apparatus,” referring to diving using equipment designed to allow the diver to breathe underwater without relying on an external air supply.
Attempts to breathe underwater have been made for a long time, and various types of underwater breathing devices have been devised. However, a key turning point leading to modern scuba diving was the Aqua-Lung, jointly developed in 1943 by Jacques-Yves Cousteau, a French naval officer and explorer, and engineer Émile Gagnan. This device supplied compressed air underwater as needed for breathing and played a crucial role in the development of modern self-contained scuba diving. Therefore, the development of the Aqua-Lung in 1943 is regarded as a significant starting point in the history of modern scuba diving.
Skin Scuba Equipment
Skin scuba equipment can be broadly divided into skin diving equipment and scuba equipment. Skin diving equipment includes masks, snorkels, and fins. A mask is a piece of equipment made of materials such as rubber that fits snugly against the face, covering the eyes and nose to ensure clear vision underwater. A snorkel is a tube that allows divers to breathe near the surface without having to lift their heads above the water. Fins are fin-shaped pieces of equipment made of rubber or plastic that are worn on the feet; commonly referred to as “duck feet,” they increase a diver’s propulsion underwater.
Scuba equipment is used in addition to free-diving gear and includes a weight system, buoyancy compensator, air tank, regulator, wetsuit, diving gloves, and boots. A weight system is used to adjust the buoyancy caused by the diver’s natural buoyancy and the wetsuit. In the past, weight belts were primarily used, but recently, weight systems built into buoyancy control devices have become widely adopted. The amount of weight required is not determined solely by the diver’s body weight; it varies depending on the type and thickness of the wetsuit, the material and size of the air tank, the equipment used, and the type of water, so a fixed standard such as “one-tenth of body weight” should not be applied uniformly.
A buoyancy control device is commonly abbreviated as BCD or BC. A BCD is a piece of equipment that regulates a diver’s buoyancy underwater by inflating or deflating the internal air bladder; it also secures the air tank. It plays a crucial role in allowing divers to float comfortably at the surface or move steadily while maintaining neutral buoyancy underwater.
An air tank is a container that stores compressed breathing gas, and a regulator is a device that reduces the high-pressure gas stored in the air tank to a pressure suitable for the diver to breathe. A regulator generally consists of a first stage and a second stage, and is connected to a backup breathing device (commonly called an “octopus”), an inflator that inflates the BCD, and a residual pressure gauge (SPG) that monitors the remaining pressure in the air tank. The residual pressure gauge may be used separately or integrated with a dive computer.
A diving suit is equipment used to maintain body temperature underwater and protect the body from the external environment. It is generally divided into wetsuits and drysuits; a wetsuit minimizes heat loss by utilizing a thin layer of water, while a drysuit prevents external water from entering the suit. Diving gloves are used to protect the hands from cold water or the underwater environment, while boots protect the feet and ankles and help keep the feet comfortable when wearing fins.
Scuba Diving Methods and Precautions
Now, let’s learn about how to scuba dive and some precautions you should be aware of.
First and foremost, you must learn how to enter the water safely. Before entering the water, make sure your mask and regulator are properly secured, and check the diving environment and the condition of your equipment. There are several entry methods depending on the situation, including the “giant stride” entry—where you step into the water from a standing position—and the “backroll” entry—where you enter the water by rolling backward while seated at the edge of a boat. Since the actual entry method can vary depending on the boat’s design, water conditions, and equipment configuration, you should follow the methods taught in your diving training.
In scuba diving, it is generally more efficient to use fins to move rather than making large arm movements underwater. To move forward, divers primarily use their legs to perform fin kicks. When fin kicking, it is important to move smoothly and efficiently by using the legs and ankles appropriately without bending the knees excessively. Kicking slowly with a stroke size and speed appropriate for the situation—rather than kicking rapidly with small strokes—helps conserve stamina and reduce air consumption while ensuring stable movement.
Even in relatively shallow water, first-time divers may experience ear pressure or a sensation of fullness in their ears. This occurs because as you descend, the surrounding water pressure increases, creating a pressure difference between the middle ear and the external environment. To alleviate this pressure difference, you must continuously equalize the pressure during your descent. Common methods include the Valsalva maneuver—where you pinch your nose with your hand and gently exhale through your nose—and the Toynbee maneuver, which involves swallowing while pinching your nose. It is important not to force equalization to the point of pain. If your ears do not clear properly or you feel pain, stop descending; if necessary, ascend slightly and try again. If equalization still does not occur, you must abort the dive.
Since you use a regulator to breathe underwater, you may feel awkward—different from what you’re used to—and become overly conscious of your breathing, which can lead to hyperventilation. However, maintaining steady breathing is paramount underwater. Because lung volume and buoyancy change slightly with each breath, overly deep or irregular breathing can make it difficult to maintain a stable position and control buoyancy.
It is best to develop the habit of inhaling and exhaling comfortably and naturally, just as you would when breathing on the surface. In particular, when scuba diving, you must not hold your breath while ascending. As the surrounding pressure decreases during ascent, the gas in your lungs expands, so you must breathe normally to expel the gas. Holding your breath during ascent can cause lung hyperinflation injury and must be avoided at all costs.
If your regulator slips out of your mouth and water enters, do not panic; remove the water according to the methods you were taught. Generally, you can press the regulator’s purge button to expel air, or reinsert the regulator into your mouth and exhale forcefully to push the water out. It is important to thoroughly practice basic skills—such as retrieving the regulator and clearing water—during your diving training to prepare for such situations.
A buoyancy control device (BCD) is used to achieve buoyancy at the surface or maintain neutral buoyancy underwater. However, inflating the BCD to ascend rapidly in an emergency is not a safe practice. For a safe ascent, you must manage your ascent rate appropriately, breathe normally, and properly adjust your BCD and weight system. In particular, since the gas in your lungs expands as ambient pressure decreases during ascent, you must never hold your breath. Rapid ascent poses not only the risk of decompression-related issues but also the danger of barotrauma to the lungs and middle ear; therefore, you must follow the proper ascent procedures and your dive plan.
So far, we’ve explored the definition and history of scuba diving, types of equipment, diving methods, and safety precautions. Recently, many people have been able to experience scuba diving relatively easily through introductory dives or recreational diving. However, some people experiencing the underwater environment for the first time may, out of curiosity, engage in behavior that directly harms marine life—such as picking at coral reefs or poking fish. Yet, we must not forget that we are not the owners of the ocean, but merely visitors. Only by refraining from unnecessary interference with the underwater ecosystem and preserving their natural habitats as much as possible can more people safely explore the underwater world for years to come.
