| One of the coolest things about divers watches, is | | | | involves rapid temperature changes. For a period of |
| that they are amongst the toughest watches on the | | | | an hour, the watch is first placed in forty degree |
| planet. These highly specialized sports watches are | | | | water, then when the time expires, is rapidly |
| designed with functionality first on the watchmaker's | | | | transferred to five degree water. The watch is left |
| priority list. This is because as a watch is subjected | | | | for a further hour before being moved back to the |
| to greater depth, the tougher it has to be to | | | | fourty degree water again for a final hour. |
| guarantee safe operation in a pressurized | | | | By far the longest test in the ISO procedure is to |
| environment. | | | | test the watch's resistance to the corrosiveness of |
| How Divers Watches Are Tested | | | | seawater and involves the diving watch being |
| There is a strict international standard that a true | | | | submersed in thirty centimeter water for a period of |
| divers watch must satisfy in order to be a certified | | | | over two days. This is why most diving watches are |
| diving watch. Watches must pass a series of tests | | | | manufactured from stainless steel, titanium, plastics |
| laid out in ISO 6425, to earn the right to print the | | | | or ceramics as these materials do not rust. |
| words "DIVER'S WATCH" on the case. Any watch | | | | Using A Diver Watch Under Water |
| bearing this marking will have satisfied the ISO 6425 | | | | Diving watches are also tested for the practical |
| testing procedure that is a special type of guarantee | | | | application of using a sports watch underwater. It is |
| that the watch will hold up under submarine | | | | mandatory that all diving watches have some |
| conditions. | | | | mechanism for keeping track of the total amount of |
| The first test in the ISO 6425 procedure is a | | | | time since the start of the dive. |
| condensation test. The test involves heating a plate | | | | Most analog diving watches use a unidirectional |
| to around forty to forty five degrees centigrade, the | | | | rotating bezel to track dive length, the bezel can only |
| watch is then placed on the plate and left for a | | | | be rotated one way and as part of the standard is |
| period of ten to twenty minutes. Over this period | | | | required to have distinctive markings at five minute |
| the watch will heat up to this specific temperature. | | | | intervals and a scale of sixty minutes. The watch is |
| Onto the watch's crystal face, a drop of water at | | | | required to have its 60/0 minute mark be legible at |
| room temperature is placed and left for one minute | | | | twenty five meters below the surface and the |
| and then wiped off. | | | | reading of the time legible itself. Analog diving |
| If there is any condensation seen to be forming | | | | watches achieve this with luminescent watch hands, |
| beneath the crystal face, then the watch fails the | | | | whereas most digital diving watches implement this |
| testing. No further testing is conducted from that | | | | with a back lit watch screen. |
| point on. | | | | Divers watches must also indicate that they are |
| Another test in the procedure requires that watches | | | | working, both at 25 meters and in complete |
| be tested at depths that are 25% below their rated | | | | darkness. Analog watches have a running second |
| depth in still water conditions. Slight weather | | | | hand with luminescent tip. When the battery runs out |
| variations can cause the density of seawater to | | | | they must present an "EOL" (end of life) indicator. |
| differ from between two and five percent and it is | | | | Divers watches are among the most rigorously |
| also well established by science that seawater is | | | | tested sports watches on the planet, meaning a |
| denser than fresh water. | | | | good one will likely last you for many years and be |
| Thermal shock testing is also applied to the dive | | | | completely safe to use in and around seawater, |
| watch as part of the testing procedure. The testing | | | | whether you are scuba diver or not. |