Diving watch

A diving watch is a watch designed for underwater diving that features, as a minimum, a water resistance greater than 10 ATM, the equivalent of 300 feet (100 meters). The typical diver's watch will a water resistance of around 1000 feet (300 meters), though modern technology allows the creation of diving watches that can go much deeper.

File:Rolex6613.png

Rolex Submariner model 6613, with a water resistance of 1000 feet (300 meters).

History

Early dive watches were often developed in response to military and professional needs. Omega SA probably deserves the honor of having created the world's first diving watch, with the Omega "Marine," introduced in 1932.

As supplier to the Royal Italian Navy, Panerai offered underwater timepieces in the 1930s, which were not only waterproof at 650 feet, but luminescent as well.

In addition, a large number of "canteen" style dive watches were made to military specification during and after WWII. However, these watches were made in small numbers, and were not intended for large-scale commercial distribution. Today, interest in these watches is limited to collectors.

In 1954 Lip-Blancpain's Fifty Fathoms waterproof watch came on the market in France. Various models were issued by Blancpain in small quantities to the military in several countries, including US and French Navy combat diver teams. The fifty fathoms was worn by Jacques Cousteau and his divers during the underwater film "Le monde du silence", which won the Palme d'or at the Cannes film festival in 1956, and in the US when TV star Lloyd Bridges wore a Blancpain Fifty Fathoms dive watch in a photo that appeared on the cover of the February 1962 edition of Skin Diver Magazine.

The Rolex Submariner was introduced at the Basel Watch Fair in 1954 which coincided with the development of self-contained underwater breathing apparatus, known as scuba. In 1961 Rolex began to include a skindiver handbook with the Submariner, then available in two models, one water resistant to 660 feet, the other, less expensive version, to 330 feet. It was the choice of watch for the character of 007 in the first ten James Bond films, causing the "Sub" to achieve an iconic status.

Characteristics

Diving watches can be analog or digital. Analog diving watches will often feature a rotating bezel, that allows for an easier reading of elapsed time from a specific point. This is used to compute the length of a dive. (See Tachymeter.) The bezel can be turned so the wearer can align the zero on the bezel with the watch's seconds or minutes hand. After a period of time passes, the elapsed time can be read off the bezel. This saves the wearer having to perform the subtraction that would be necessary if the watch's regular dial was used. It's also much easier to read this larger dial while underwater. On better watches the bezel is "unidirectional", i.e. it contains a ratchet so it can only be turned to increase the apparent elapsed time. Accidentally turning the bezel the other way, on cheaper watches, could suggest to a diver that the elapsed time was shorter than the truth, which could be highly dangerous. Digital dive watches usually perform this function by use of a standard stop watch function. Digital dive watches may also feature a depth gauge and logging features.

Many companies offer highly functional diving watches for optimum level of performance during an underwater dive. Most feature a rubber strap or metal bracelet, not a leather band, and some serious models are fitted with a helium gas release valve to prevent the crystal being blown off by re-equalisation of pressure when a diver returns to the surface. Some chronograph diving watches - such as the IWC Aquatimer Minute Memory and the Omega Seamaster Professional even have specially-designed push pieces that can be operated at depth without allowing water to enter the case. The vast majority of divers now use electronic, wrist-worn dive computers by manufacturers such as Suunto, Uwatec and Mares.

Many contemporary sports watches owe their design to diving watches.

Water resistance

The International Organization for Standardization issued a standard for water resistant watches which also prohibits the term waterproof to be used with watches, which many countries have adopted. Water resistance is achieved by the gaskets which form a watertight seal, used in conjunction with a sealant applied on the case to help keep water out. The material of the case must also be tested in order to pass as water resistant.

The watches are tested in still water, thus a watch with a 50 meter rating will be water resistant if it is stationary and under 50 meters of still water. For normal use, the ratings must then be translated from the pressure the watch can withstand to take into account the extra pressure generated by motion. Watches are classified by its degree of water resistance, which roughly translates to the following:

• 50 meters (1 meter is about 3.3 feet), which means the watch is suitable for swimming

• 100 meters; indicating it can be worn snorkeling

• 200 meters, suitable for recreational scuba diving

• 1,000 meters (roughly three-fifths of a mile).

Watches in this last category can endure deep-sea diving. Their gaskets are made of materials that can withstand the helium used in decompression chambers. Some have valves that let the wearer release the helium that has seeped into the watch so the case won't explode as the watch and diver adjust to normal atmospheric conditions, says Peter Purtschert, technical director at Breitling USA. The depth specified on the watch dial represents the results of tests done in the lab, not in the ocean.

Some watches use bar instead of meters, which may then be multiplied by 10 to be approximately equal to the rating based on meters. Therefore, a 10 bar watch is equivalent to a 100 meter watch. Some watches are rated in atmospheres (atm), which are roughly equivalent to bar. In the United Kingdom, scuba divers and others often use the word atmosphere (ATM) loosely (the correct term is "ambient pressure") to mean 1 bar (1000 millibars, or 100 000 Pa).

See also

• Underwater diving
• Watch