Snorkeling is swimming with a snorkel — a mask and a tube — that allows you to breath through your mouth when floating underwater near the surface of the water. Scuba diving allows you to go deep inside the water to examine the bed of the sea or lake, wearing a tight fitting diving suit, and breathing through an oxygen tank.
|Purposes||Recreational purposes, including cave diving, wreck diving, and ice diving. Professional purposes, including for civil engineering, underwater welding, offshore construction or for military purposes.||Recreational purposes include observing fish and algae and coral reefs especially in water bodies with minimal waves and warm waters; also interesting things to see near the water surface.|
|Technique||The swimmers entire body is under the water. The diver's nose and eyes are covered by a diving mask; the diver cannot breathe in through the nose, except when wearing a full face diving mask, but adapts to inhaling from a regulator's mouthpiece.||Head & nose underwater. The snorkel tube can flood underwater. The snorkeler expels water either with a sharp exhalation on return to the surface or by tilting the head back shortly before reaching surface.|
|Underwater duration||Can stay under water longer as one does not need to hold ones breath.||Need to hold breath to swim under the surface of the water.|
|Equipment||Pressurized gas tank strapped to the back of the diver, single hose, open-circuit 2-stage diving regulator with the first stage connected to the gas tank and the second to a mouthpiece, swim fins attached to feet, diving suit.||Diving mask, L or J shaped tube with a mouthpiece at the lower end and sometimes swim fins attached to feet.|
|About||A form of underwater diving with breathing equipment. Stands for Self-Contained Underwater Breathing Apparatus.||Swimming on or through a body of water with a snorkeling mask.|
|Training||Requires training in how to use the breathing equipment, safety procedures and troubleshooting. Although no centralized certifying or regulatory agency many dive rental and sale shops require proof of diver certification.||Requires no training. Snorkelers favor shallow reefs ranging from sea level to 3-12 feet. Deeper reefs are also good, but repeated breath holding to dive to those depths limit the number of practitioners and raises the bar on fitness and skill level.|
|Effect on Health||Effects of breathing compressed air such as decompression sickness, nitrogen narcosis, oxygen toxicity, refraction and underwater vision.||Greatest danger is not being spotted by jet skis & crafts, as a diver is often submerged under water with only a tube sticking out of the water. Contact with poisonous coral, dehydration and hyperventilation. Sun burn is also common with long hours.|
The scuba diving equipment is more complex and heavier compared to that of snorkeling. It comprises a pressurized gas tank filled with Enriched Air Nitrox with extra oxygen: 36% oxygen and therefore less nitrogen to reduce decompression sickness. In the "single-hose" two-stage design, the first stage regulator reduces the cylinder pressure of about 200 bar (3000 psi) to an intermediate level of about 10 bar (145 psi). The second stage demand valve regulator, connected via a low pressure hose to the first stage, delivers the breathing gas at the correct ambient pressure to the diver's mouth and lungs. The diver's exhaled gases are exhausted directly to the environment as waste. The first stage typically has at least one outlet delivering breathing gas at unreduced tank pressure. This is connected to the diver's pressure gauge or computer, in order to show how much breathing gas remains.
A swimmers’ snorkel is a tube typically about 30 centimeters long and with an inside diameter of between 1.5 and 2.5 centimeters, usually L- or J-shaped and fitted with a mouthpiece at the lower end; constructed of rubber and plastic. It is used for breathing air from above the water surface when the wearer's mouth and nose are submerged. The snorkel usually has a piece of rubber that attaches the snorkel to the outside of the strap of the diving mask.
In Scuba diving, as one descends, in addition to the normal atmospheric pressure, water exerts increasing pressure on the chest and lungs—approximately so the pressure of the inhaled breath must almost exactly counter the surrounding or ambient pressure to inflate the lungs. By always providing the breathing gas at ambient pressure, modern equipment ensures the diver can inhale and exhale naturally and virtually effortlessly, regardless of depth.
In snorkeling, the swimmers nose and mouth are submerged and covered by a mask. Breathing takes places through a mouthpiece connected to the L or J shaped tube that gets air from being above the water surface. If diving, the swimmer has to hold his breath, the tube is allowed to flood when underwater. The snorkeler expels water from the snorkel either with a sharp exhalation on return to the surface (blast clearing) or by tilting the head back shortly before reaching the surface and exhaling until reaching or "breaking" the surface (displacement method) and facing forward again before inhaling the next breath. The displacement method expels water by displacing its presence in the snorkel with air; it is a more advanced technique that takes practice but clears the snorkel with much greater efficiency.
Scuba diving requires training in how to use the breathing equipment, safety procedures and troubleshooting. However, no centralized certifying or regulatory agency many dive rental and sale shops require proof of diver certification.
Snorkeling requires no training. Generally shallow reefs ranging from sea level to 1 to 4 meters (3 to 12 feet) are favored by snorkelers. Deeper reefs are also good, but repeated breath holding to dive to those depths limit the number of practitioners and raises the bar on fitness and skill level.
edit Effect on Health
Hazards of scuba diving include adverse effects of breathing compressed air such as decompression sickness, nitrogen narcosis, oxygen toxicity, refraction and underwater vision.
The greatest danger of snorkeling is that snorkelers are hard to spot in the water by jet skis and leisure crafts, since a diver is often submerged under water with only a tube sticking out of the water. Contact with poisonous coral, dehydration and hyperventilation are other health hazards. Sun burn is also common as the back is exposed to the sun when spending long hours snorkeling.