Eco-Drive
PROFESSIONAL
DIVER 1000m

Saturation diving is a special type of diving that enables divers to conduct long-term operations at depths where air diving (scuba etc.) is no longer possible. Going into a large high-pressure tank on the surface, the divers absorb a mixture of oxygen and helium until their bodies are “saturated” with the two gases; they then transfer to a capsule. The capsule is lowered deep into the sea and the divers, dressed in atmospheric diving suits, conduct operations with the capsule serving as their base. Professional saturation divers can spend several weeks living in the pressured capsule.

Helium is the greatest obstacle when designing a light-powered watch for saturation diving environments. Helium gas molecules are so small that they can easily penetrate the inside of a water-resistant watch. The helium then drives up the interior pressure of the case, risking damage to the glass and to the movement. The watch must be sealed to keep helium penetration to a minimum. We exhaustively performance-tested every aspect of the Eco-Drive Professional Diver 1000m—its structure, materials, assembly technique and so on—to achieve both water resistance and helium resistance (mixed-gas resistance) at a depth of 1,000 metres.

This is a world first for a light-powered watch.

Ordinary levels of airtightness are just not good enough when your aim is to keep out helium gas at a depth of 1,000 metres. That is why we subjected the Eco-Drive Professional Diver 1000m to helium pressure testing under all sorts of scenarios—when it was new, after long use, and even after servicing. Based on these tests, we created a structure that would maintain the right pressure to prevent damage to the movement while, of course, enabling the watch to display the right time. Among the safety features is an escape valve, which automatically opens and shuts according to the internal pressure of the watch. Driven by a combination of know-how and passion, CITIZEN’s engineers experimented with many different structures and materials before achieving the watch’s final robust specifications.

CITIZEN conducted verification and validation testing with the cooperation of JAMSTEC (Japan Agency for Marine-Earth Science and Technology) during the product development process of the Eco-Drive Professional Diver 1000m. The product prototype was attached to a basket on a manned submersible, Shinkai6500, to leak-test it and to examine the effects of high water pressure. We confirmed that the watch keeps running at depths far greater than 1,000 metres. Through these tests, we thus demonstrated that the Eco-Drive Professional Diver 1000m is a diver’s watch with extraordinary levels of reliability.

JAMSTEC is a national research and development agency under the Ministry of Education, Culture, Sports, Science and Technology. It contributes to the advancement of academic research and improvement of marine science and technology through basic research and development based on ideals of peace and human welfare.

We made extensive use of CITIZEN’s proprietary surface-hardening technology Duratect MRK to ensure that the Eco-Drive Professional Diver 1000m can withstand the water pressure at depths of 1,000 metres. By applying Duratect MRK to the case when parts like the crown tube and the escape valve tube were already in place, we bonded the individual components to the case at the atomic level to achieve a higher level of adhesion. (The technical name for the process is “solid phase diffusion bonding.”) The result was not just a tougher case surface, but durability capable of withstanding 1,000 metres of water pressure.

The Eco-Drive Professional Diver 1000m is assembled by CITIZEN’s skilled craftsmen. We assigned a team of experts to the job of manually assembling the glass and case of the Eco-Drive Professional Diver 1000m. In fact, that’s why we only produce 35 units every day. The craftsmen go about their work in a dust-proof cleanroom with the different components in front of them. The hardest task—closer to art than anything else—is attaching the glass to the case without it snagging on the rubber seal. This model is a work of art that can only be produced by hand, the culmination of CITIZEN’s technologies and techniques as a true manufacture d'horlogerie.

The design of the Eco-Drive Professional Diver 1000m is based on the sturdy turban shell with its robust, brick-like structure. In addition to adapting that natural shape for the watch exterior, we also devised a ridged bezel whose irregular shape is easy to manipulate even with gloved hands.
To enhance safety levels, we made the rotating bezel lockable and crafted the end of the strap into a special hourglass shape that reduces the risk of it coming undone.

The Eco-Drive Professional Diver 1000m is a model that combines safety and practicality with highly imaginative design.