This time, we will discuss common issues such as waterproof, diving bezel, depth gauges, etc. from a special diving watch's point of view. Diving watch waterproof depth should be how much? Some manufacturers say that they produce diving watches with a water depth of 300m or more for recreational diving; others say that diving watches only need to be waterproofed by 200m; while others say that a waterproofness of 200m will suffice if they are specifically designated as diving watches . International Organization for Standardization (ISO) provides that a diving watch must be waterproof 100m. These depths far exceed the depth that a non-professional diver can infiltrate. Recreational divers up to no more than 40m (130 feet). Beyond that depth, they're diving into technical diving, which requires extensive training, special gas mixtures that require breathing, long decompression stops and some special gear. The reason why this difference is because: in the factory to do waterproof test, the watch is tested under artificial conditions, which is very different from the actual situation when the watch is immersed diving. To do the test, the use of a static watch, a new gasket, a newly assembled case, then nothing will affect its waterproof performance. The test equipment does not take into account the extra pressure that the wearer plunges into the water or the difference in temperature and pressure that the diver creates when he or she ascends or descends and this factor can cause the watch case to contract or expand. In addition, the watch's waterproof depth will decline with the aging of the gasket. Percussion and other major moves will make the case components are no longer as tight as the new time. All of these unmeasured factors provide watch companies with a few reasons why their watch will not be held responsible for leaks. What features will make diving watch leak? When wearing a watch diving to ensure watertight, you must have several major features. Almost all diving watch case has a screw-in bottom cover and crown. O-ring seals the crown, bottom cover and crystal glass. Case and crystal glass thicker than non-diving watches. Watches specially designed for deep diving usually have compressive features such as curved crystal glass or steel rims that reinforce the case's resistance (such as the Rolex Deepsea). What are the other features of a diving watch? Most diving watches have a rotating bezel for measuring the passage of time. They also usually have luminous marks and hands that can be read underwater. The ISO standard requires a dive watch to have a preselected time device (rotating bezel to meet this requirement) and a dial that reads at night even 625px away. The ISO also stipulates that watches must have a pointing device that promptly learns that the watch is still on the move. A second hand meets this requirement. Most dive watches use steel, titanium or rubber bands, though some are made of nylon or various composite materials. Some diving belts or bands will also be equipped with an extension band to fit the size of the wrist after wearing the diving suit. Some dive watches also have a row of helium valves or a depth sensor. What is a row of helium valve? It is a watch in the diving tank balance device inside and outside the pressure device. Within the submersible tank, the diver inhales a helium-containing gas mixture. Helium molecules are so small that they penetrate the case and accumulate in the case. During the decompression process, the pressure inside the diving chamber drops faster than the pressure inside the case. This can cause watch crystal glass to burst. To prevent this, some watches have a gas valve on the side of the case that allows the helium to bleed out of the case during decompression, allowing the air pressure inside and outside the case to be balanced. A lot of dive tables have row helium valve it? Most dive watches do not have a helium valve, as only divers are only able to use them when diving in a submersible. Why most of the dive watch bezel can only rotate in one direction? Most diving bezel can only be rotated in one direction, ie counterclockwise, so that once the bezel is clockwise, it will not accidentally be crooked, resulting in less reported diving duration (usually refers to the total diving time ). Some watches solve this problem by setting the inner bezel because it does not accidentally be turned. Many bells only record the beginning of the 15-minute scale. why? This is a convention for diving watches that dates back to the mid-1950s (probably beginning with the Rolex Submariner). The original intention of designing these marks is unclear. An early Submariner's ad showed a diver setting a bezel to record the total dive time and then using a minute scale to accurately calculate his descent time. Why this information is useful has not yet been explained (and standard diving procedures do not require this). The common explanation for these scales is that they are used to record decompression retention time, but this interpretation is problematic. Because the diver re-sets the bezel at the beginning of each stop. Therefore, the bezel can not be used to measure the total diving time, which is the main purpose of the bezel. It is also possible to interpret these scales: 15 minutes is about how long a diver can stay at 130 feet (the maximum depth of recreational diving) without decompression stops. The scale should be used to remind the diver that he has reached the limit and helped him read the exact remaining time. This theory is confirmed by the Omega Seamaster, which has a first 20 minutes of calibration (the diver can stay at 110 feet for about 20 minutes, approaching the limit depth). The 20-minute scale on the bezel of the Seamaster 200 was brushed into the red of the fire engine, possibly as a reminder to the diver that it would take too long to stay in the depths. Depth measurement how the watch works? In most cases, an inductor (usually a diaphragm) is attached to the side of the case and deformed by the water pressure. The degree of deformation is converted to a depth in feet or meters and is indicated by a pointer on the dial. The Hollysys Aquis model uses another depth gauge: it has a thin capillary tube around its crystal glass with the opening of the thin tube facing outwards. Depending on the depth, as the water enters the tubule, the diver can read the scale next to the tubule to learn the depth (in meters). How many mechanical diving watch depth gauge? Few. In addition to the aforementioned Hollysys Aquis depth gauges, other robotic watches with depth gauges include the Platinum X Fathoms, the Aquatimer Deep Three, the Master Compressor Diving Pro Geographic and the Panerai Luminor 1950 Pangaea Depth Gauge In addition to the mechanical movement, these also have an electronic depth gauge). Some watch depth gauges record the deepest point of diving. why? There are three reasons. First, for safety reasons, the diving limit is dictated by the diving watch, which assumes that the diver will spend the entire dive time the deepest. To use a dive watch, divers must know the depths he can penetrate. Second, the diver must first dive into the deepest, diving rules. This can give him the most time to drain more oxygen as he dives to the bottom (the deeper you sneak in, the more dissolved oxygen in your blood). Third, many diving experts suggest that even in non-decompression diving that does not require reduced pressure, the diver will have to exhaust oxygen for a minute between the lowest diving point and somewhere in the middle of the surface of the water. Which one mechanical watch the deepest waterproof? CX Swiss Army watch 20,000 feet. This watch is made of titanium alloy, 75px thick, single crystal glass has 25px thick. In the era of diving computer, there is still the need to use diving watch it? Not really. In the event of a dive, the computer is out of power, and divers sometimes use the dive watch as a spare tire for a dive computer, but watch-type dive computers are now widely used and reasonably priced, and some divers use them as their console style Computer spare tire (or wear two watch computers). If a diver did use a watch as a spare tire, he also needed other spare tire equipment to provide the information a dive computer could provide: depth gauges, pressure gauges and diving watches. Why do so many people still have to buy diving watch? There are several reasons. Many people like to feel safe with a high level of waterproofing. If a watch can be worn in deep diving, they reason, then the watch is safe when swimming or snorkeling. Others like other features on the dive watch, such as rotating bezel or glow markers and hands. For many dive watch wearers, the look is the main attraction: sporty and technically strong watches are a symbol of fashion.