How should one use the bezel on diving watches like the Rolex Submariner?

　　Diving watchAside from their striking appearance and durability, the most interesting feature is undoubtedly their rotating bezel. The rotating bezel can also be said to be the most iconic characteristic of a diving watch.

　　The most suitable watches for the hot summer are undoubtedly diving watches, such asRolex Submarinerdiving watches of this kind not only feature striking aesthetics but are also exceptionally durable. Of course, the most interesting point is undoubtedly their rotating bezel. A rotating bezel with graduations can be regarded as one of the most iconic characteristics of a diving watch.

　　Specifically speaking, the rotating bezel of a diving watch is not merely used for timing, but rather serves to remind the wearer of their immersion time. For instance, common rotating bezel graduations typically feature 15, 30 and 45, which respectively indicate that the dive cylinder can support a submerged duration of 30 to 45 minutes. Furthermore, the first 15 minutes of a diving watch bezel feature a striking colour or marker, intended for taking a 15 minute safety stop for decompression during ascent. Therefore, once this period has elapsed, you can head back.

　　Naturally, the rotating bezel of a diving watch is also very simple and convenient to use. Typically, during a dive, one simply rotates the bezel to align the 0 graduation with the minute hand, and then by observing the minute hand's travel against the bezel graduations, the exact elapsed time of the dive is known.

　　Another point to understand is that the rotating bezel of a diving watch rotates unidirectionally, and must only ever rotate unidirectionally. Strictly speaking, some bidirectional rotating bezels on the market are not true diving watches. Why is that? To put it into perspective, if a unidirectional bezel is accidentally operated or knocked during a dive, it will merely advise you to surface prematurely. However, if wearing a watch with a bidirectional rotating bezel, and a clockwise operational error occurs underwater, resetting the already-begun dive countdown to zero, this could prove extremely fatal to a diver. Bidirectional rotating bezels are primarily used for calculating elapsed times, such as measuring the time a yacht takes to pass between two buoys, rather than for diving.

　　As early as 1953, Blancpain launchedthe Fifty Fathoms dive watch, which was also the first timepiece equipped with a unidirectional rotating bezel, and a patent was filed for it at the time. Around the same period, Rolex also introduced its first Submariner, but the Submariner only genuinely adopted a unidirectional rotating bezel in the 80s of the 20th century, following the expiration of Blancpain's patent protection.

　　Of course, the unidirectional rotating bezel is not without its flaws. Because it is not integrated into the case, but rather secured onto the exterior of the case, this creates minor clearances. Consequently, it is easy for tiny particles of silt to wedge into the gap between the case and the bezel during underwater use, thereby causing considerable damage to the watch.

　　The advent of the unidirectional rotating inner flange completely eradicated this hazard. For example,the Audemars Piguet Royal Oak Offshoreintegrates the unidirectional rotating bezel within the crystal, blending it seamlessly with the dial. Adjusted via a specially designed crown, this not only eliminates silt ingress, but the screw-down waterproof crown also prevents accidental bezel rotation underwater once locked, ensuring safety and reliability.