If you consider that divers rely on a good watch in order not to die, one could expect designated divers watches to be quite robust timepieces. In Germany, where we are based, a divers watch has to fulfill certain criteria before being allowed to be called a divers watch. These watches are usually watertight to a pressure of 20 bar and over. They are also fitted with large indexes and fingers so that they are easy to read through your goggles in the dim light of the deep blue sea at a distance of at least 25 cm. They will also have to have a timer or a bezel which can be turned to indicate the time a diver needs to consider when calculating the remaining oxygen in his or her tank and to keep the intervals needed when ascending back to the surface. This bezel can only be turned one way so as to eliminate the possibility of it being moved by accident, increasing the diving time over the oxygen supply and thus causing a horrible death through drowning.
|housing diameter:||48 mm|
|housing height:||14 mm|
Since the going theory stipulates that the earth is not flat and the sun is not the sun-god Ra in his golden chariot, but that we actually live on a ball of dirt flying around a star, it is obvious that the daytime will never be the same on any two points of different longitude at any given time. Now if you were going to be precise, then you are actually in a different time of day than your neighbours to the east and west of you. But that would be splitting hairs, or would it? Anyways, important people decided a long time ago that for practicalities sake, they would divide the globe into 24 time zones that are one hour apart. Of course one had to find a compromise between geographical position and national borders in order for ordinary life to function. Since the industrial revolution, people adhering to the same principles of time measurement have become essential to the workings of our society. But you will find that every so often a time zone will shift in order to make life easier or more profitable in one country or region. For example the UK is considering not of moving to a different time zone, that would be rubbish of course, since they invented it, but of adopting “double summer time” in one year and then only going back one hour at the end of it. This would effectively put them in the same time zone as the rest of Europe./ World time
Water tightness or impermeability, surprisingly enough, is the degree to which you can expose your watch to the element water. A watch can be water repellent to a variety of degrees, from surviving the odd splash, to keeping the watch fully functioning long after your crushed body has hit the ocean floor. Please note that these are always theoretical values. Water behaves very differently at different temperatures and with varying salinity. So we took our crayons and made you this rough guide (which, by the way, is in no way legally binding and we will not be held accountable for your watch if you ruin it)::
FYI: 10m is 1 bar is (roughly) 33 ft is (exactly) 0.986923267 atm