You are getting a bit confused, I think - those that worry about pressure tend to wear the hard suits, not “leggings” where the whole body is encased.These are closer to Space suits in that they are completely sealed.For recreational divers there are two reasons to wear some sort of suit - temperature and contact protection. But it’s mostly the first - water conducts heat away 14 times more than air of the same temperature which means that it is easy to get cold quickly.SO for cold weather diving, divers will wear so-called “dry suits”The neck and wrists have a tight seal and water cannot get inside the suit - people will wear regular clothing inside - t-shirts, sweat shirts, etc. They will add a hood and gloves to this which help them further reduce heat loss.For warmer waters, divers may use a so-called “wet suit” - these are made of neoprene of different thicknesses - some cover the whole body (but not the feet, head or hands)some cover only parts of the body - these are “shorties” where the legs and arms are exposed.For still warmer waters, divers may wear a Lycra “dive skin” - these provide no real protection against the cold, but instead protect the body from contact with things like fire coral, baby jellyfish and (which above water) sunburn.With any of these suits, gloves are not mandatory, but can be worn to help protect against the cold or against contact with something that could hurt.Note that some dive destinations ban the wearing of dive gloves of any sort, to prevent the temptation for divers to touch or hold on to sea life or coral. This is often an attempt to reduce damage to the reef caused by SCUBA visitors.
Hi,Diving is an extremely dangerous and sometimes a very toxic environment. You need protection from an environment that is completely hostile to human life. Water has a specific heat approximately 1000 times greater than that of air and a thermal conductivity 24 times greater than that of air, the body loses heat much faster in water than in air of the same temperature. So, even in water that is in the mid 80°’s F. You can and will eventually go hypothermic.Additionally, if you have ever noticed that when you take a bath your skin softens. The fresh/salt water is no different. The environment you are diving is full of objects that are extremely abrasive and, even razor sharp. So you need chafing gear to protect yourself.All divers need to breath air. Approximately 79% nitrogen 21% Oxygen being the most important to life. Your body requires a specific range of partial pressures of this mix to survive. At the deeper depths these ratios are often changed to compensate for the surface equivalent your physiology needs. In chemistry and physics, Dalton's law (also called Dalton's law of partial pressures) states that in a mixture of non-reacting gases, the total pressure exerted is equal to the sum of the partial pressures of the individual gases. What this means is as you dive deeper the gasses inside you are less than the gasses you are breathing. As you begin your dive (left surface) Your body will start to absorbe the difference until the gas pressures become equal. When you begin to end your dive (left bottom). Your body now has a higher gas pressure in relation to your environment and, therefore begins to release the absorbed gasses. Dalton’s law applies to all gasses that absorb.Your diving apparatus must be able to supply the necessary the gasses that are needed to sustain life regardless of the depth you are diving to.Commercial divers often wear surface supplies air/gas hard “hats” helmets for the same reason construction workers do. To protect your head from the environment. The difference being your diving rig provides 1) diving gasses, 2) communications 3) strength member to solidly connect you to the surface and, sometimes 4) a hot water hose to keep you warm in colder waters.In short, your equipment is used to both protect you and to sustain your life while in a high risk to life threatening environment. It is highly desirable to come back from the dive in the same condition you started it.I hope this helps.
I'll consider "deep" beyond 30m. which is a depth you can reach in recreational diving, with the same equipment you use since the basic training.As said before, any dive have risks and you can only say you are out risk when you reach safely the surface.So the main difference from the shallow to the deep diving is the time you will take to be in safety. Respecting a safe ascend rate of 9m/min, you take at least 3 minutes to go from 30 to 0m. So any stress/panic/malfunction situation will last a few minutes before you are "safe". Also, the deep dive involves a higher N2 pressure which means Narcosis and risk of bends. So you can add this to your "risk calculator".Beyond 40m, is almost mandatory to plan a deco stop due to the very short NDL (No-Decompression Limit). Have you ever planned one? It's sick. Some people relies on their dive computer to do it for them. I like to plan it manually and use the computer as a secondary safety equipment. Plus, deep dive mean higher consumption. Even if have a very good SAC (Surface Air Consumption), It will be 4x higher at 30m. So, let's say your SAC is 11L/min. At 30m, you'll have 37,5 minutes from the surface, to 30m then back to surface with 50BAR spare. (1650L/44L per minute). to go even deeper, add bigger cylinders, spare cylinders, different gas mixture, bottom mixture, equipment changes underwater, longer and multiple deco stops, longer bottom time, cold, and so on.Deep dives have more risks? TrueYou can handle it? Also true. With the proper training and the right equipment you can overcome the risks and do it safely.
Do deep sea divers breath pure oxygen?
The answer to the first part of your four part question is No! Divers do not breathe pure oxygen, not at any depth. Others have covered, more or less, the second part of your question - no need for me to be repetitive. The content of the exhaled gasses, forming the bubbles under water that you refer to, depends upon the mix used and that is determined by depth and desired duration underwater. It would be accurate at your level for you to say carbon dioxide and unused or residual elements depending upon dive breathe mix employed. What happens to exhaled gas? Unless you are on a rebreather system, these gas pockets or bubbles will float to surface level unless they meet something on the way up which will interfere with the surface tension around these gasses and cause them to break up. One small point to note; at sea level the air we all breathe is made up of 21% oxygen, 78% nitrogen, and 1% of other gasses. Although we breathe in this mixture, the average human body at rest actually only uses 5% of the oxygen that it breathes in!!! We exhale 16% of the oxygen that we breathe in - that is why we are able to resusitate other humans when we give mouth to mouth.
What is the pressure at work of under sea engineers and divers ?
Your going to have to be more specific
There are different diving suits used depending on the type of diving a person is doing. The main reason a diving suit is worn is to allow a person to retain their body heat. Water cools a body much faster than air so the colder the water is and the longer you are underwater, the more thermal protection is needed to prevent hypothermia.Someone who is diving recreationally in warm waters (such as Floida, Caribbean, Figi, Pulau, etc) may not wear a suit at all or will wear a wetsuit. The wetsuit is made of neoprene or a similar material that has thousands of tiny airholes inside it. These airholes act as insulation. A wetsuit allows some water to get inside it at the wrist ankle and neck openings, hence the name.Someone who is diving colder waters such as the Great Lakes typically wears a drysuit. A drysuit has seals that keep water from getting inside the suit and usually includes gloves, boots and a hood. The diver wears a thermal top and pants under the suit to keep warm. Some of these thermal garments even come with heating elements like those in an electric blanket that run through the fabric for diving in very cold waters.Commercial divers (who do things like underwater construction or demolition and dive much deeper than a re rational diver) have specialized suits that provide both thermal and physical protection. They spend far more time underwater and expend a lot of energy so need more help staying warm than someone who dIves for only 45 minutes before climbing back aboard the dive boat. Their dive suits can include a helmet with a full face mask and communications gear.
Because the sea’s often cold. At least it is here, even in summer, deeper than about 10 feet. Also,a suit stops the equipment chafing your skin. At depth, the water is about 4C, because that’s the temperature at which water has the greatest density and so will fall to the bottom.
Why sea divers breathe with nitrogen and helium but not oxygen?
Of course divers breathe oxygen, oxygen is the one component of any breathing gas that is required to support life. Oxygen is used by the metabolic processes of cells to produce energy with carbon dioxide as a waste product. The purpose of nitrogen and/or helium in the breathing gas is solely to "dilute" the percentage of oxygen. Unfortunately, while oxygen is necessary to sustain life our bodies have developed so that they can only tolerate oxygen pressures within fairly narrow limits. Too much oxygen can be just as fatal as not enough. Normal air is composed of approximately 21% oxygen and 79% nitrogen + other inert gases. Unfortunately for divers, the metabolically inert gases like nitrogen are absorbed into the body tissues under increased pressures like what is experienced underwater. When the pressure is reduced during the diver's ascent to the surface, these gases are released by the body tissues. If these gases come out of solution too quickly they can form bubbles which lead to the symptoms of decompression sickness. Nitrogen in particular also has a narcotic effect on the nervous system under sufficient pressure which can cause impaired judgement, mental confusion, loss of dexterity, and even visual and auditory hallucinations. Divers who go to deeper depths replace a portion of the nitrogen in a breathing mix with helium (creating a gas normally referred to as trimix). Helium does not have the narcotic effect that nitrogen does, and so divers using trimix can dive to deeper depths while maintaining better control of their mental faculties. However, helium is a smaller molecule than nitrogen and so moves more easily in and out of the body tissues so it requires more care to ensure it does not form bubbles and lead to decompression sickness. Hope that clears thing up. All divers breathe oxygen underwater, it is just the percentage of oxygen and the composition of the remaining gases that varies.
Deep undersea cables get cut?
Nobody's fishing down there, no ship carries anchoring gear to reach that far (for a fascinating could-be-called-an-exception to this, look up the ship Glomar Explorer, which was built by Hughes Industries to mine manganese nodules from the sea floor -- and find out what it was *really* built for and what it did. Also, oil drilling rigs are making holes in the ground in surprisingly deep water, check it out.) and no normal military submarine operates that deep. My thoughts, in no order of likelihood: Submarine cables are tough, but they're subject to chafe like anything else. Seems unlikely but conceivable that the cable could have snagged on something sharp and gradually worn through. I don't know how fiber cables react to seawater intrusion -- electric cables short out, but fiber might actually not care at all, depending on a lot of things. Someone with the right gear could send an ROV down to saw the cable. Hawaii is in a geologically very active area called "The Ring of Fire." If the wrong thing moved the wrong way on the seabed, could injure the cable. The cause will likely be determinable when they fish it up to repair it, assuming they don't simply abandon it and lay another. Whether they'll want to talk about it is another question.