Watch & Jewelry
September 26, 2017
CITIZEN: A Diver's Watch Featuring Cutting-Edge Technology for Professional Use
CITIZEN
Pioneering a Legacy of "World Firsts"
Exploring the Design Philosophy of Promaster (Part 1)
CITIZEN has once again achieved a "world first." The Promaster, a professional sports watch cherished by fans worldwide, now features a 1000m saturation diving capability while incorporating a light-powered Eco-Drive movement. Eco-Drive eliminates the need for regular battery changes, a significant advantage, especially for dive watches. By avoiding the disassembly required for battery replacement, the watch's hermetic seal is better preserved.
PHOTOGRAPHS by Kaku OhtakiTEXT by Takashi Tsuchida (OPENERS)
A World-Class Sports Watch Unveiled at Baselworld 2017
Since its debut in 1989, CITIZEN Promaster has demonstrated exceptional functionality and supreme durability in harsh environments. Designed for specific actions in the realms of land, sea, and air, it has met the high-end needs of professionals. Simultaneously, the Promaster series has never compromised on design, offering a diverse lineup of models for professionals who value sporty aesthetics.
The "Eco-Drive Professional Diver 1000m," released on July 7, 2017, is the latest addition to the Promaster line. Its specification, enabling 1000m saturation diving with the light-powered Eco-Drive that requires no regular battery changes, is indeed a world first.
The robust and unique design, inspired by seashells, is reflected in the motif on the case side. The spiral shape, reminiscent of a conch shell, forms the model's substantial bezel, serving as a product icon and a tactile detail that intuitively indicates the bezel's rotational direction.
The case is crafted from Super Titanium™, chosen for its durability. It is lightweight, resistant to rust, less prone to scratches even in harsh diving conditions, and hypoallergenic.
The movement incorporates CITIZEN's proprietary "Shock Detection Function," which prevents hand displacement caused by shocks or vibrations. When a shock is detected, an electrical signal is sent to the motor, instantly locking the rotor. This function ensures the watch's accuracy even in environments where shocks are likely.
To withstand the water pressure at a depth of 1000m, the outer case features a special shape inspired by the structure of a seashell.
A bezel lock mechanism is integrated between the case and the bezel, providing an advanced safety feature.
The crown is a screw-lock type. In addition to enhancing water resistance, it prevents accidental operation when locked.
The luminous material on the hands and dial absorbs light quickly and maintains its glow for an extended period. A larger luminous area enhances visibility.
The vivid orange used for the minute and second hands, as well as the bezel lock, is highly visible underwater. This color choice was determined through actual underwater color difference tests. Every detail has been meticulously considered for the user's safety and security.
A Diver's Watch Designed for the Most Extreme Conditions
Illustration by Ken Nishimura (THE AMERICAN CHOP COMPANY)
Here, we would like to add an explanation of saturation diving.
Air diving involves descending into the water with a tank on your back, often referred to as a "back-first splash." Most recreational dives, including fun dives, fall into this category.
Saturation diving, on the other hand, is a method where divers are pre-exposed to a high-pressure environment in tanks aboard a vessel, allowing their bodies to absorb a saturated amount of oxygen and helium. The advantage is that, unlike fun diving, using helium allows the body to adapt, enabling longer, deeper, and safer dives.
In essence, saturation diving transcends recreational diving and is an extremely specialized technique used for tasks such as underwater exploration and rescue operations.
Consequently, equipment capable of saturation diving requires measures against helium ingress, in addition to standard waterproofing. Safety is paramount, and development proceeded with reliability as the top priority, adhering to ISO and JIS standards.
Page02. Toughness Leads to Trust, and Trust Leads to Confidence
CITIZEN
Pioneering a Legacy of "World Firsts"
Exploring the Design Philosophy of Promaster (Part 2)
Toughness Leads to Trust, and Trust Leads to Confidence
We now welcome Akihiro Saito from the First Product Development Section, Product Development Department 1, Product Management Division, who was responsible for the exterior development of the "CITIZEN Promaster Eco-Drive Professional Diver 1000m." He will provide insights into the technical aspects of the new model.
To begin, what were the main challenges in achieving 1000m saturation diving capability while incorporating the light-powered Eco-Drive?
"The electronic components within the movement are more delicate than mechanical parts. If helium gas penetrates the case and the internal pressure rises, it can cause malfunctions. Therefore, our challenge was to enhance the watch case's sealing to maintain an internal pressure that prevents malfunctions in the electronic components," Mr. Saito explained.
Addressing helium ingress presents a greater hurdle than standard waterproofing. According to Mr. Saito, the following guidelines were established to improve sealing:
1. Adoption of butyl rubber gaskets with low helium permeability and expansion of gasket size.
Gaskets function to prevent the ingress of water and helium by being compressed between metal parts. By reducing the helium permeability of these components and increasing their size, the amount of helium entering the case is minimized.
2. Double-layering of gaskets to prevent potential failures.
In the event of a malfunction, if one gasket fails, the second gasket will compensate for its function.
3. Enhancing the precision of metal processing.
The cut surfaces of the metal parts that sandwich the gaskets were processed using the same procedure to minimize variations. Furthermore, by reducing the cutting speed, the surfaces were smoothed to improve adhesion with the gaskets.
4. Minimizing assembly variations.
Multiple gasket shapes and lubricants were tested, and settings were chosen to minimize variations during assembly.
Mr. Saito noted that dealing with helium countermeasures involved continuous "trial and error," as failures were infrequent and the causes of ingress were not visually identifiable. However, his eyes held a determined glint, reflecting the success achieved by the engineers.
A Highly Durable Exterior Combined with CITIZEN's Proprietary Surface Hardening Technology
CITIZEN possesses the technology to harden the surface of pure titanium, a material that is gentle on the skin but soft and difficult to process, using its Super Titanium™ technology. Specifically, this model utilizes three types of its "Duratect" surface hardening technologies, each with different hardness levels.
The main case employs Duratect MRK for high hardness. This involves introducing special gases at high temperatures, allowing the film, 20-30μ thick, to permeate the surface. Simultaneously, solid-phase diffusion bonding is performed, atomically joining the pure titanium case with the precisely machined titanium alloy crown pipe. By exchanging titanium atoms, the bond is strengthened, enabling it to withstand the 1000m water pressure.—This hardening technology also involves such technical aspects.
The watch case features Duratect MRK surface hardening technology. This not only hardens the surface and makes it scratch-resistant but also enables a strong bond by solid-phase diffusion joining the pure titanium case with the titanium alloy pipe components (crown and helium escape valve).
The lock ring on the rotating bezel, treated with DLC coating. Parts of the DLC have been intentionally removed to enhance durability.
This model also features a vibrant orange color. This color is used for the minute hand, which indicates dive time, the second hand, which confirms the watch is operating correctly, and the alert for the bezel lock. It's designed to catch the eye if the screw-lock crown is not fully secured.
Engineers obtained diving licenses and personally tested the color's visibility underwater. This rigorous testing confirmed that orange offers the highest visibility.
Prioritizing practical testing over mere imagination reflects the engineers' commitment to ensuring user safety and security.
Page03. The Significance of Promaster: Meeting the Demands of Professionals
CITIZEN
Pioneering a Legacy of "World Firsts"
Exploring the Design Philosophy of Promaster (Part 3)
The Significance of Promaster: Meeting the Demands of Professionals
A saturation diving waterproof watch with helium countermeasures is truly a professional-grade timepiece. Furthermore, using an Eco-Drive movement, which is more susceptible to helium gas than mechanical movements, represented uncharted territory even for CITIZEN, a company with extensive experience in manufacturing waterproof watches.
The first Promaster model, born in 1989.
The Promaster series was born in 1989 with its first model, designed to meet the demands of hard-use scenarios.
It has served as a benchmark, demonstrating supreme durability in harsh environments and offering functionality across the domains of sea, land, and air.
The series has evolved over time, with expanded functions such as sensors and the integration of Eco-Drive movements.
Exterior developer Mr. Saito shares his thoughts:
"The unknown realms, far removed from daily life, are something we can only imagine. However, we believe that this very imagination aligns with Promaster's concept: 'GO BEYOND. Beyond Imagination.'
Human activity has expanded to unprecedented levels, and with it, professional-use timepieces have undergone remarkable evolution. The "CITIZEN Promaster Eco-Drive Professional Diver 1000m" stands as a monumental testament to this progress.
It will undoubtedly serve as an inspiration for future creators and be passed down through generations.
"CREATORS ~ The Shape of Challenge"
#1 GO BEYOND: Beyond Creation - CITIZEN Promaster
On History Channel (CS national broadcast),
Scheduled for broadcast around 8:45 PM on July 1st (Sat) and multiple times between July 2nd (Sun) and July 31st (Mon).
CITIZEN Promaster Eco-Drive Professional Diver 1000m
Product Number: BN7020-09E
Movement: Light-powered Eco-Drive (Cal. J210) ±15 seconds per month, 1.5-year power reserve on full charge
Key Features: Date display, charge level indicator, unidirectional rotating bezel, bezel lock, luminous hands and markers (and 12 o'clock bezel marker)
Case Material: Super Titanium™
(Duratect DLC + MRK + TIC)
Case Size: Case diameter 52.5mm, Case thickness 22.2mm (design values)
Band Material: Urethane (with extension band)
Glass: Sapphire crystal (anti-reflective coating)
Dial Color: Black
Water Resistance: 1000m saturation diving
Release Date: July 7, 2017
Price: ¥260,000 (excluding tax)
*Includes special presentation box