Seiko Tuna dive watch

Innovation – no helium escape valve

Of all the Seiko dive watches the Seiko Tuna has the most distinctive / original design, in fact, possibly of all the dive watches on the market (exception Omega PloProf). This unique design comes more from necessity than aesthetics. The key to this styling lies in the depth this watch can withstand.  When diving at extreme depths a combination of mixed gases are used to protect the diver’s from “the bends” (external reference *).

A proportion of these mixed gases is HELIUM. And there lies the problem. Helium particles are TINY … really TINY. They are small enough to enter the casing of a watch water resistant to even 600m. The problem arises during decompression. The helium gas cannot get out quickly enough. There is a build up pressure inside the watch which may cause the glass to blow off.

Patented Gasket Solution

Seiko looked outside the box for solutions. Instead of looking to ways of allowing the helium to get out … they stopped it entering in the first place. With a specially designed gasket and the titanium monochoque casing the problem was solved in a unique fashion. That was back in 1975 that the world was first introduced to the Seiko Tuna. The initial watches were driven by Seiko’s 6159 Calibre – 26 jewel – automatic movement.

In 1978 that the Seiko Professional Diver’s 600M became the world’s first saturation diving watch featuring a quartz movement. Driven by the 7549 calibre the Seiko Tuna was establishing itself as THE professional divers watch. In fact, to reinforce it’s superiority and prove it’s reliability Seiko undertook an amazing test.

In 1983 a Seiko Tuna with the 7549 quartz movement was strapped to the research submarine “SHINKAI 2000” (external reference *). Accordingly, down it went to an official depth of 1,062 meters below sea level. To emphasize, that’s nearly twice the maximum depth this watch is rated to. Needless to say, the Tuna performed with perfect accuracy. Due to this outstanding performance the Tuna booked it’s place in the Dive Watch Hall of Fame – and for very good reason.

HOW DEEP – how about 1000m!

Of all the Seiko Diving watches the Tuna is the first choice for many professional divers. It’s ongoing popularity lies in the depth this watch can withstand. The Seiko Tuna range (that’s a nickname – not an official Seiko nomenclature) is a PROFESSIONAL diver’s watch capable of withstanding the pressure from depths of 600m (now 1000m).

Nicknames of the most popular Tuna models

The Tuna range is littered with witty nicknames. Here’s a few: the Darth Tuna (all black version), Mini Tuna (correct, it’s a bit smaller) , Emperor Tuna, Yellow Tuna (yellow bezel and accent on hands) all the way back to aptly named original Grandfather Tuna

What to pay for a pre-owned Tuna

A question we get asked everyday for practically all the watches listed on the website. It’s all down to popularity, rarity, provenance and condition. Let’s start at the TOP end of the market. Don’t forget these watches are some of the finest timepieces in the world – in my view equalling the quality of some Swiss brands. The Seiko Sbdb013 Spring Drive Tuna Marinemaster is not going to give you any change from £2,500. If it says MARINEMASTER on the dial and it’s genuine, the starting price has to be around £1,000 for a “basic” automatic model. However, there are plenty of other versions available in particular, the solar and street Tuna models starting at £250.

Consider a Steeldive “Tuna” homage

Customers who admire the aesthetics of the Tuna dive watch may also like the Steeldive Tuna homage version. Not a fake, moreover a respectful and affordable tribute to this innovative dive watch.

These Tuna watches are just a few from the huge selection of Seiko Divers watches for sale including other popular models like the Seiko SKX009, the Seiko Turtle and the Seiko Samurai.