Seiko “Tuna” SBBN017: Hands-On Review

Seiko “Tuna” SBBN017: Hands-On Review

Postby koimaster » March 2nd 2018, 9:48am

A Brief History

The Seiko Tuna lineage has a long and interesting history with Japanese saturation diving. Seiko released its first dive watch – the iconic “62MAS” – way back in 1965. It was a very capable dive watch, but didn’t reflect the evolving challenges presented by saturation diving.

Traditional dive watches were typically worn over a wetsuit, needing only to resist water penetration at depths of up to 200 meters. Saturation diving was developed to allow divers to work at greater depths for longer periods, surrounding the divers in a high-pressure chamber filled with helium and oxygen. This greatly reduced the problems caused by decompression sickness, but created a new problem for dive watch manufacturers.

In 1968, the Seiko design team received a letter from a diver in Kure City complaining that his Seiko dive watch was experiencing failures in saturated environments. The chambers were pressurized with a mixture of helium and oxygen, and since the helium molecule is much smaller than most other gas molecules, it easily penetrated the small tolerances of the watch case. This resulted in the dive watch filling with helium gas, often causing the crystal to pop off in the process.

Most watch companies at the time, namely Doxa and Omega, had solved this problem using a “Helium Escape Valve”. This was basically an additional screw-down valve that was opened manually to release pressure within the watch. Ikuo Tokunaga and his team decided to eschew this approach and take a clean slate as they began the development of the perfect professional dive watch.

7 years later, Seiko had realized its vision with the release of the Seiko 6159-7010 (“Grandfather Tuna”), a watch that precipitated many technical breakthroughs and resulted in over 20 new industrial design patents. The titanium monocoque case, ceramic shroud, L-shaped gasket, and vented rubber straps were all firsts for the industry. The result was a watch that achieved Helium tightness without the use of a Helium Escape Valve, and served as a reliable companion for both saturation and traditional divers alike.

Today the Seiko Tuna lives on in close to two dozen different configurations, including vintage models and modern limited editions. For those averse to Quartz, you can even obtain this model with Seiko’s legendary hybrid spring drive movement, although it is significantly more expensive.

For more information on the history and evolution of the Tuna, a complete guide can be found in another blog post – Behind the Shroud: The Ultimate Seiko Tuna Collector’s Guide. ... -183428485


“Your heart was warm and happy

With the lilt of Irish laughter

Every day and in every way

Now forever and ever after."
User avatar
Posts: 34934
Joined: December 16th 2009, 11:00pm
Location: Oregon

Re: Seiko “Tuna” SBBN017: Hands-On Review

Postby foghorn » March 2nd 2018, 9:52am

I had one and sold it. Cool looking watch but , like the Ecozilla , just too damn big.

Why, he's no fun, he fell right over.
User avatar
Founding Member - WIS
Posts: 17150
Joined: December 18th 2009, 11:00pm

Return to Seiko and Citizen

Who is online

Users browsing this forum: No registered users and 1 guest