........about 5 years ago, I had a Tuna craving......well, I finally had a chance to own a vintage one as of late and was too happy about it, I sold it.......yup.....sold it ......and took an upgrade...........
......the darth tuna....
For the specs:
Drive system: Quartz
No Caliber : 7C46
Housing Material: Pure titanium (hard coating) and ceramic shroud
Glass material: Sapphire glass
Accuracy: Accuracy: ± 15 seconds per month difference
Waterproof: Waterproof 1000m saturation diving
Battery life: 5 years
Weight: 114 g
Thickness: 15.3 mm
Case Diameter: 48mm
It came in double boxed. An outer sleeve and the main box. Some hangtags and some branding and pricing which was mostly in Japanese so I totally have no clue what it says.
The box though is not your usual watch package, more like an over-sized pen box adapted to hold a watch.
Came with a warranty card and instruction manual also in Japanese. A battery replacement certificate for the 1st battery change (free of charge)
The case is made of Ti with a protective shroud made of Ceramic. Well thought of IMHO since the shroud will logically take the beating throughout its lifetime and ceramic will definitely hold up to the abuse and least likely to scratch. The whole watch is at 114g due to the Ti case which is quite contributory to the comfort despite the 48mm diameter and 15.3 thickness ( thick but at 1000M WR, I think they managed to keep it pretty low ).
I love the touch of the hex screws also, just makes the case interesting IMHO.
It has what the enthusiasts call a monocoque case. Meaning there is no access through the caseback, you will have to open the piece through the crystal side to get into the movement. Dive watch enthusiasts love this feature since chemicals such as sunblock wont affect the gaskets when it is frequently used for diving activities.
The caseback has some stamping which I believe is better made or minted than my other pieces from the same brand.
The absence of the lugs are replaced by grooves at the caseback where the straps attach so it looks like the straps are flushed within the caseback.
As with most dive watches, there is a rotating bezel. It is partially hidden within the shroud. Unlike the vintage tuna I previously got, it is very easy to operate. Grip is a easy and it clicks a good 120 full rotation. It also has a great gummy feel when you rotate. A good feel of high quality as you turn CCW.
It has a good sized crown. Sharp edges, great grip. Gummy as hell when you screw in and out. There is this feeling of quality when you screw down and up. It is also stamped with the "S" logo which is absent in the old Darth Tuna SBBN 011....an improvement in my books. Location is also nice since it is situated at the 4 o clock rather than 3 o clock so it doesn't hit the dorsal part of the hand, another comfort feature I guess.
Dial / Hands / Markers
The dial is as it should be, as a serious divers tool, it should be readable......easily. So, huge hands, precise edges, big markers. Overall.......legible, straight to the point. The day/date complication is also very legible. Some markings and branding on the dial well laid and didn't look cheap at all. My impression.....serious diver....
....the lume......well you'll have to see for yourself......worthy of a professional dive watch....
Crystal is flat. Im a sucker for curved crystals but in this one, Ill let it go. The flat crystal made the dial easy to read and the AR coating behind made reflections almost non existent most of the time.
Seiko 7C46 Quartz Movenment
I didnt have much info the the movement so I would like to quote something written by one of the dive watch enthusiasts when asked what was so special with the movement...
........from WUS member Jimmy (Poseidon Jim from NYC)
The term "Prospex" translated into English terms means (Professional Specifications), and the 7C46 quartz machine is only found and used in the SEIKO Professional Series Quartz Dive watches, namely the Tuna series and the prior Professional Ashtray models.
They the 7C46 movement & the Tuna series cases, were built with a specific purpose and intent in there specifications and ultimate design; and that was to be the best professional tool divers watch made! (So nothing was spared or held back in there design or quality of manufacture)
As we know, "Seiko" actually is the original father of this realized quartz watch technology that actually came out of the real world commercial diving industry as a answer to having a divers watch that could handle the rigors of deep depth.
Thus, they were designed with no cuts in quality or cost saving materials at all; but rather have advanced scientifically developed components and material in there make up.
The 7C46 is a (Hi-Tech) multijeweled movement with extremely "Hi-Torque tolerances and High efficiency" built in over prior 7 series quartz movements, which enable the 7-jeweled geartrain and pinions to motion & turn the hands in perfect sync to the energy-pulse, with much less kinetic effort via the electronic step motors that power them.
Thus making for a highly accurate and efficient full size quartz machine to perform strongly with much less resistance.
They also incorporate (dual-rate trimmers) which allow the watch to be perfectly synchronized for extreme accuracy, which aid in the longevity and add to there lifespan, while running well with in the stated accuracy specs.
They also enjoy the added benefits of, Low-Drain electronics while providing High-Torque Power to the gear driven train and Oversized Hands for optimal efficiency & extended battery life. As an added plus, this caliber also incorporates the E.O.L. (End Of Life) Low battery warning feature, of the seconds hand ticking at 2 second intervals when the battery voltage is low, thus alerting the owner its time to replace the battery cell.
They also provide the Premium Benefits of being designed in a full expanded size, and are incorporated into the advanced Titanium alloy cases that house them, which are also very highly advanced designs on there own rite built with advanced shock protection built-in specifically for this movement.
The cases also provide "Enhanced antimagnetic Gauss's law & thermal compensation technology, as well as full Helium/Nitrogen gas Prevention & Dispersion technology.
They simply are just the perfect combination of the utmost in quality craftsmanship, to enable them to easily handle the various extreme conditions of Commercial diving found around the globe, in any oceanic environment.
They also can be completely disassembled for cleaning & service many years down the road; that together with the other quality design features therefore make this movement, the absolute highest quality advanced Professional quartz divers watch movement in the world AFAIC.
These highly evolved movements, as well as the Tuna series Professional Dive watch cases & components, probably hold more advanced (patent designs) than any other watch in the world!
........end of quote ( I edited some misspellings, I hope you won't mind)...scan of the movement extracted from the web......
Strap / Buckle
Strap material has the right balance of softness but still stiff enough to feel stable. It can hold the heft of the piece. Has a nice blackened keeper and the Seiko tsunami logo printed at the edge to the rubber. Ive had other Seiko rubber straps and metal hardware and this by far is the most well made, even better than the other swiss pieces I have.
Until I had one, I never really understood what the fuss is all about. Ive had a few Seikos and couldn't pull a trigger at this price point then. I was thinking, why pay this much when you can get a similar watch from the brand at a much lesser price point. Well, There isn't a similar watch and the price point is reasonable with the technology, craftsmanship and quality thrown in this piece.
On comfort, it is light, comfortable and despite being close to 16mm thick, isn't wobbly on the wrist.
On the size factor, I have a 7.25 wrist and the 48mm diam doesnt dwarf my wrist at all. Im guessing this can look good on a flat 7 wrist and up.
I think if ever I dive with an analog ( which I don't do nowadays, I dive with a computer and a bunch of backups ), this might be the most deserving watch to tag along.
.........have a great weekend ;)