In Partnership - Inside The Line: Citizen Promaster Sea

The first true dive watches appeared in the decade following the end of the Second World War. This was thanks to the invention, and widespread adoption, of scuba gear. Diving prior to the advent of the Self-Contained Underwater Breathing Apparatus was largely confined to research, military diving, and professional salvage operations, but with a little training just about anyone could learn to scuba dive, and enjoy an experience of the ocean, which for most of human history had been forbidden to mankind.

Mechanical dive watches represented a whole new genre of watchmaking. They had to be engineered to be water resistant, of course, but as the dive watch was an essential tool for anyone strapping on scuba tanks and venturing into the ocean’s depths, they had to be as reliable, robust, and readable as their designers could make them.

As diving technology advanced, however, the dive watch itself continued to evolve, and one of the most truly revolutionary dive watches came from Citizen, in 1985.

Proving A Watch Is Waterproof

Prior to then, Citizen had already created water resistant watches, and one early example was tested publicly in a most unusual way. The 1959 Parawater was the first watch Citizen intended for use by divers, and the company set out to prove that when they claimed it was water resistant, they weren’t just blowing bubbles. Citizen attached 130 of the watches to specially constructed buoys and set them adrift in the Pacific Ocean, off the coast of Japan. The watches were completely exposed to the elements as, propelled by the ocean currents, they drifted across the Ocean to the west coast of America, where they were recovered, after about a year – still fully functional and water-tight.

Citizen would go on to make many other models of dive watches – along more modern lines than the non-turning bezel equipped Parawater; these included its very popular Seven Star diver’s watches, which were manufactured with depth ratings ranging from 100 to 200 meters. But the 1985 debut showed not only that Citizen had mastered the art of the traditional dive watch, but that it was ready to, so to speak, plumb new depths as well.

[{ "x": 0.08, "y": 0.57, "text": "First ever electronic dive watch with built in electronic depth gauge" }, { "x": 0.66, "y": 0.38, "text": "Digital display of depth"}, { "x": 0.68, "y": 0.68, "text": "One way rotating dive watch bezel, for timing bottom time and decompression"}]

The Revolutionary Citizen Aqualand

This was Citizen’s now-legendary Aqualand, which was the very first wristwatch ever to be fitted with an electronic, digital depth gauge – an essential tool for both serious amateur and professional divers, and one which heretofore had required divers to wear an additional, bulky, mechanical depth gauge instrument, in addition to a dive watch.

Had there been depth gauges in wristwatches before? Yes, but these had not been especially accurate – they consisted in the pre-electronic era, of simple hollow and transparent tubes which would gradually fill with water as the diver went deeper, and pressure increased.

<p>["1992", "Aqualand Air Divers Cal. 5810", "The depth sensor in the original Aqualand was an unprecedented advance in 1985, but it did have one disadvantage – as depth information could only be displayed in the relatively small LCD panel, legibility was not ideal, especially in low visibility conditions. This 1992 model represented a solution to this problem – for the first time, in an Aqualand watch, the electronic depth sensor’s information was displayed by a high-visibility analog hand (with 1/10 meter increments shown in a smaller sub-dial for good measure)."]</p>

<p>["1993", "Aqualand Cal. C023", "The Aqualand continued to evolve through the 1990s, taking design cues from both the needs of professional divers and the trends of popular culture. This early '90s iteration of the Aqualand retains the LCD panel depth readout of the original Aqualand, and pairs it with a fully lumed dial to maximize legibility. Both the original caliber C020 and this updated caliber C023 had depth gauges calibrated to sea water, which has a specific gravity of 1.025. Divers could still use these watches in freshwater lakes, but readings would differ slightly."]</p>

<p>["1994", "Promaster Hyper Aqualand", "The Eco-Drive Hyper Aqualand was more than just a dive watch with a depth gauge – it was a dive watch combined with a fully featured dive computer. Both maximum and current depth could be displayed, along with dive start, finish, and elapsed times. In addition, there was an alarm for ascent rate, a low battery warning (critical for an instrument on which someone’s life might depend), and even an elapsed surface time after dive indicator. All these capabilities made it, at the time, the most capable dive watch Citizen had ever made."]</p>

<p>["1998", "Promaster Eco Drive Aqualand, Cal. U100", "Probably the type of watch for which Eco-Drive energy generating systems has proved most significant is the category of dive watches. There are few other genres of wristwatch for which it is more crucial to ensure that an unexpected complete functional failure does not occur. The addition, therefore, of Eco-Drive technology to an analog dive watch, for the first time in this model, was a giant leap forward for improving reliability and functionality. Also present, of course, was the signature depth meter, in its characteristic housing on the flank of the case."]</p>

<p>["2017", "Citizen Eco Drive Promaster 1000 Meters", "Just as the original Promaster Tough represented the reduction of the field watch to its absolute functional essentials, so the Promaster 1000 meters represents an interpretation of the ultimate evolution of the simple dive watch. Ceding the tracking of multiple elements of a dive to the modern wrist-borne dive computer, it amplifies the most critical elements of a dive watch to their maximum. The huge, brightly luminous dial and massive one-way locking bezel carry echoes of some of the most famous dive watches of the pre-quartz era, and the 1,000m rating makes it suitable for the most demanding professional saturation diving."]</p>

The Aqualand changed all that. Its combination of ultra-precise digital depth gauge with a watch capable of also telling the time, put all essential functionality into a single instrument. Moreover, the Aqualand could also log maximum depth and dive time for retrieval after the dive was completed, and it had another feature: a rubber strap, printed with a no-decompression limits chart.

The air that a diver breathes is delivered under pressure, and during a dive, nitrogen (which makes up about 75% of the Earth’s atmosphere) gradually dissolves into the diver’s body tissues. Come up too quickly, and the nitrogen doesn’t have time to dissolve out – instead, it forms bubbles (like a can of soda opened too quickly). This can cause severe pain and other problems – decompression sickness, or “the bends” as divers call it. Divers therefore make periodic “decompression stops” while ascending, to give the nitrogen to harmlessly pass out of the body. The Citizen Aqualand, with its accurate depth meter and timing functions, was a quantum leap forward in dive safety. With the time and depths to which a diver could safely dive without having to make decompression stops, printed right on the strap, divers for the first time had a single, all-purpose, rugged and reliable instrument that could be used under any conditions, below the waves.

Since then, Promaster diver’s watches have continued to evolve, to include improved technology, materials and designs to meet the needs of today’s divers, and future generations of aquanauts – tools that can easily handle the most unforgiving professional environments, but also more than satisfy the toughest requirements of wear on terra firma as well.