What are the benefits of summer diving?

　　History

　　The ancient Greeks and Turks are sometimes called the "fathers of diving" of modern times. They had dived into the Aegean Sea to pick sponges as early as two thousand years ago. Later, humans invented another diving equipment-the diving bell. In 1819, German engineer August Tesibi invented a diving device that was very similar to today's diving suit, and independent breathing equipment for diving appeared in the late 19th and early 20th centuries. In the 1930s, divers began using glass-piece rubber goggles and masks. The two Frenchmen who made the greatest contribution to modern diving were the two Frenchmen who invented the "scuba" in 1943, the first breathing device with an automatic breathing regulator. The breathing regulator controls the flow of air so that the air pressure in the diver's lungs is always equal to the water pressure.

　　type

　　Generally, diving is divided into two categories: one is bare-handed diving, which means holding one's breath or diving into the water with only three equipment: goggles, snorkels and fins; the other is scuba diving, which means using scuba and other equipment to dive. Generally, amateur scuba divers can dive to about 130 feet (40 meters). Experienced and physically fit divers can dive to a depth of 200 feet and do light work. The deepest limit for scuba diving should be about 300 feet. Most freehand divers can only dive to 30-40 feet (9-12 feet) below the surface of the water, but they should return to the surface for ventilation in about 1 minute.

　　Basic rules

　　Principle of two people traveling together: two people must be together from entering the water to landing; the coach shall not allow the companion to land on his own; the two must keep in touch frequently.

　　What to do when you're alone: ​​Stay calm, float a few meters up, look for your companions, surface when you can't find them, and watch for bubbles. If there is still no sign of your companion after more than 10 minutes, you should return to the place where you entered the water. Please do not hunt aquatic animals unless necessary. Check the remaining pressure gauge every 10 meters.

　　water entry position

　　Frontal upright diving: The water depth must be more than 1.5 meters, stand your feet forward and backward, hold the mask with one hand, and press the air tank strap with the other hand.

　　Entering the water with your back facing forward: Sit on the side of the boat facing inward, and enter the water with your back facing forward.

　　Sitting frontally into the water: suitable for beginners.

　　Enter the water sideways: Lie down on the rubber boat and roll into the water.

　　Essential equipment

　　Mask, fins

　　Snorkel: Used by scuba divers to conserve air in their tanks while resting or swimming on the surface.

　　Buoyancy adjustment device: maintains neutral buoyancy at any depth. Scuba cylinder: used for breathing in the water supply.

　　Regulator: Reduces the air in a scuba tank to a usable level.

　　Comprehensive instrument: integrates time, depth, direction, temperature and air supply to provide a clear view at a glance.

　　Wetsuit: Maintains body temperature and protects against bumps and scrapes.

　　Things to note

　　The most common danger in diving is "diver's disease", which is when divers suddenly rise to the surface from a high-pressure underwater environment, causing a large amount of gas (mainly nitrogen) dissolved in the blood due to high pressure to be quickly released, forming bubbles. When these bubbles circulate into small blood vessels, they form air embolism, blocking blood flow. Some bubbles stop in the alveoli, causing them to rupture as the air expands. When "diver's disease" occurs, there will be skin Itching, musculoskeletal pain, blurred vision, limb weakness, paralysis, dizziness, dizziness, shortness of breath, and even coma or death. The treatment method is to send the patient to an artificial high-pressure environment, and then slowly reduce the pressure to normal atmospheric pressure.

　　Air embolism: Air embolism is the enemy of divers. Due to the high-pressure gas in the air tank we breathe underwater, when we float up too fast, it will cause the alveoli to rupture. Therefore, do not stop breathing when rising, pay attention to the speed of rising, and take big and slow breaths.

　　Nitrogen narcosis: It usually occurs when divers reach 30 meters. But most of all, it will reduce people's thinking and judgment ability, just like being drunk, and in severe cases, it can lead to death.

　　Ascent: Control the ascent speed within 18 meters per minute, that is, do not exceed the rising speed of the bubbles you exhale; do not stop breathing; when rising, look up at the water surface, you can extend your right hand to specify the direction, pay attention to your back, and slowly rotate your body.

　　Adjust ear pressure: For those who are diving for the first time or who have not been diving for a long time, the pressure of the water can cause discomfort or even pain in the ear canal. At this time, you should hold your nose with your hands and blow air into the nasal cavity with force, so as to increase the air pressure in the ear canal and offset the pressure of the water. If you experience unbearable pain in your ears while diving downwards, you should surface immediately.

　　People with the following conditions are not suitable for diving: cold、nerve Allergies, ear and nose problems disease , heart disease, high (low) blood pressure, drunkenness, and diabetes.

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