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Discussion Starter · #1 · (Edited)
Seiko has just recreated the depth testing they've conducted during the 80s on the tunas, employing the JAMSTEC submersible for the task.

In the 80s they've strapped two 7549-7000 600m tunas to the hull of the sub, and lowered the vessel to a depth of 1062m aprox.. Since the watches survived intactly to almost double their nominal W.R., in the following year Seiko has relaunched the quartz tuna with the new cal. 7c46 and now 1000m of nominal W.R..



Exceeding expectations of water resistance

In its quest for constant progress, Seiko has long co-operated with organizations in Japan, USA and elsewhere who could assist with testing its diver's watches in extreme conditions. In May 1983, two Professional Diver's 600m watches were affixed to the exterior hull of ‘SHINKAI 2000', the Japanese manned research submersible created by JAMSTEC (Japan Agency for Marine-Earth Science and Technology). The watches were originally intended for use up to 600m, yet they withstood water pressure at a depth of 1,062m. The watches' legibility, precision and strength had passed the test with flying colors.
Courtesy: JAMSTEC

(bottom pic with two 7549-7000 600m tunas strapped to the robotic arm of the vessel)



Well, they have done it again, last September! And they've done it with random units of the SBBN013 and SBDX011:

https://www.youtube.com/watch?v=jnmNBQsA3Lk


If this has been posted already then I'm sorry....but since this is soooo cool, I guess it is worth to be watched again!

And kudos to Seiko for finally marketing properly la créme de la créme of their Prospex line. It was about time...

https://www.youtube.com/watch?v=RaMJxOfouF4
 

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Very interesting, many thanks for posting. :cool: Made me realise that the Jaquet Droz divers chrono that I got in 1968, rated 'waterproof' at 450ft/150m was still fairly innovative at the time (a rating that we take for granted as very low these days), something that I didn't appreciate at the time. :eek:
 

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i imagine that the water pressure pushing in on the crystal caused the second hands to stop? does that make sense?
 

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Super !!! Inspiring ;)
 

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3000m whoa. Thats impressive to see - thanks Chris. I was curious as to why they stopped. Maybe it was the crystal gasket did compress so much and the glass touched the hands as you say. Wonder if they restarted when they were brought up.

Good to see.

Nice to know that they can take that sort of treatment even if most never will. What wonderful little pieces of engineering.

Respect to Seiko
 

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Very cool read & video. Thanks for posting that Chris. I now know why they're so pricey, a test like that doesn't come cheap!
 

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Discussion Starter · #11 ·
Thanks for the comments, guys!

I know I now have a renewed (if that is even possible, ha!) love for my fishes!

And yes, the cause for them to stop at given pressures is due to the deforming crystal pushing in on the hands, mos def.
 

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Discussion Starter · #12 ·
BTW, anybody hot for the new tunas, SBDX014 and SBDX016, and also the new quartz ones (7c46) SBBN027 and SBBN029?

These new quartz tunas have a new composite for their shrouds. Seiko made them in a composite called 'cermet', which is a zirconia ceramic + metal alloy combo, in order to make them as scratch resistant as ceramic properties, but with the elasticity and impact absorbing properties of metal, which make them less prone to shattering from high and direct impacts.
 
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