Seiko makes some of the best analog-dial dive watches. Their prices range from around $200 for an entry-level SKX007, to over $10K for examples from their “Skunk Works” division: Grand Seiko, whose quality surpasses many Swiss brands. “Tuna Can” is a sub-family of Seiko dive watches that has a protective shroud around the watch case, designed per request from professional divers back in the mid-1960s.
One of the newer “Tuna Can” models, the Marinemaster 600 Spring Drive, around since mid-2014, has largely flown under the radar in North America. It was initially released in Japan as a limited edition of 300 pieces (SBDB-008), graduating to a full production SBDB-009 (still Japan-only model), and just recently released in North America as SBDB-013.
Here are the differences between the models:
• SBDB-008 – black with gold accents, old style of strap
• SBDB-009 – all black, crown with S on it, new strap
• SBDB-013 – all black, crown with X on it (for Prospex, which is a marketing name in Americas)
This model retails for just under $2700 new, or around $1800 used. In my humble opinion, this dive watch represents some of the very best value for your money today. You can argue that a Sinn or used Omega Seamster costs the same, but let me tell you why this Seiko is far superior.
Lets look at the details:
Size, Comfort, Fit – 5/5
This Seiko is the smallest-wearing large watch I own. It’s 50mm across, but wears much smaller then a Rolex Deep Sea at 43mm. It has to do with a lug length (distance between band attachment points, measured up-down across the watch). The Seiko is 47mm while the Deep Sea is 52mm. While still a large watch, it feels small and is very comfortable.
• 50 mm case diameter
• 42 mm bezel diameter
• 30 mm dial
• 17 mm thickness
• 22 mm spring bars
• 22/20 mm strap
Case Design – 4/5
• Seiko uses a two-piece case design – inner case surrounded by a shroud, attached with four screws
• Titanium shroud titanium with black DLC coating covers most of the bezel with openings at 12-3 and 6-9
• Watch case and back are also titanium with internal stainless steel components
• Bezel insert appears to be ceramic, but I do not have a confirmation – somehow there is no information on bezel material available anywhere
• Bezel is a unidirectional 120-click design. It includes some sort of “special lubrication plate” to assist with turning. It’s nice and smooth when dry, but hard to turn when wet (WTF Seiko? This is a dive watch, right?) I’m not sure why, but even the manual states that it’s much harder to turn when wet. Dinging one point.
• Seiko uses their special and patented L-Shape gaskets/seals, ensuring additional resistance to gas penetration and certifying this watch for saturation diving, all without a Helium escape valve like most other saturation-dive watches.
• Crown is at 4 o’clock and is mostly recessed into the case shroud, providing protection against impact. Naturally it’s screw-in.
• Crystal is sapphire with anti-reflective coating. It’s recessed 2mm below the bezel, providing additional protection.
Strap – 4/5
This is one motherfucking stretchy strap!! It has about an inch of give on the wrist. If you are familiar with an Isofrane strap this is similar, but slightly softer and very comfortable. It’s one of those things that are really hard to describe …you just have to try one.
• 22mm at spring bars
• 20mm at the buckle
• DLC coated titanium buckle and strap keeper
• Seiko’s Extra-Strength silicone material has four times greater tear resistance compared to a standard Seiko strap
• Inside of the strap has micro-texture to assist with comfort by allowing airflow and water drainage between the strap and your skin
Functionality – 5/5
• It tells time (holy shit, it’s a watch! What a surprise !!)
• Diver bezel is unidirectional, with one-minute marks
• Gliding second hand with luminous reverse “lollipop” (more on this later; it’s truly gliding, not sweeping like 99.999% of mechanical watches)
• Power reserve indicator on dial, which is an “empty-full” gauge just like a car showing 12-hr increments for total of 72 hrs, with the last 24 hours in red (telling you to gas up the power reserve)
• Date is hidden between 4 and 5 o’clock markers
• Crown – time/date setting and winding
Water Resistance – 5/5
• Seiko is notorious for sand-bagging their depth ratings. Watch the video in the link below. I would guess my Tuna is good to at least 1200m (see video below).
Movement – 4/5
Spring Drive movement is just bloody amazing – humbly, I believe it’s a pinnacle of modern watch movement engineering and design. There is a video explaining Spring Drive in detail down below.
One can literally write a book on this movement, thus just a few highlights:
• 5R65 Caliber / 72hr power reserve / hacking (second hand is stopped during time-setting)
• Traditional rotor and mainspring is same as any automatic watch: the movement of the wrist charges the spring, thus providing power reserve.
• Electronic regulation system replaces traditional escapement. The frequency is 8200 times faster (NO BULLSHIT!!) than common escapement, making Spring Drive very, very accurate.
• Second hand glides, rather then sweeps. On a typical automatic movement, although hard to perceive, the hand ticks at a very fast pace (a few beats per second). Although smooth, it’s still “ticking”. The Seiko’s Spring Drive, on the other hand, is truly “tickless”.
• Highly efficient self-winding; my Tuna goes from 25% to 100% by making breakfast and washing dishes after.
• Accuracy is fucking Star Trek. Spring Drive is rated to fifteen second per months (officially). My example runs 0 seconds per day, constantly. I have traveled with this watch, it has been on a firing range (shotguns and handguns), I have swam with it, I have done Crossfit workouts with it, I’ve run with it, my two-year old played with it – still 0 seconds daily deviation.
• Long-term: to be seen. The Spring Drive hasn’t been around long enough to gather good historical data. A Rolex from 1965 will run great today (with service of course), but will this Tuna run this perfect 50 years from now? Time will tell.
Legibility – 5/5
• Seiko uses a new proprietary version of their LumiBrite luminous compound on SBDB009 – it’s actually really hard to believe, but it’s much more effective than Rolex’s Chromalight (their name for Super-LumiNova). The Tuna is also much brighter and longer lasting then Seiko’s Monster and 007.
• Dial, hands, bezel are all very legible in all lighting conditions.
Would I recommend this as a tactical watch?
Potentially. It’s a wonderful watch but lacks digital readout, and although the sapphire crystal is well-protected, it can still be shattered.