Summer was on the way and with a protracted stay in Sardinia on the agenda I wanted a watch that was both good on the beach, the bar, and of course, in the water. Not that I was going deep sea diving, but I wanted and needed something robust. I had seen the Seiko Prospex Marine Master SBDX011 watch before on Seiko and dive watch forums, and I also knew another Purist who owned one, but was keen to buy one and try it out. I had been impressed with the design and the use of materials even before buying, and the thought that the movement was an ‘almost’ Grand Seiko standard automatic made it even more appealing. Simply put: an original.



You will have to excuse some of the grubby pictures. This is the result of the watch actually been used for sailing, swimming, on the beach, and as some other Purists witnessed, I actually bashed the wash against a wall, and nothing! No dents, no scratches, the ceramic shroud did its job and protected the watch. It has been in salt water (admittedly not to the maximum depth!) and has been in continual use for 3 months.

I am fairly sure that Seiko does not recommend or even warrant the contents of this article. This is simply my own research, opinions, and use of the watch.



The watch is virtually indestructible, finished superbly, and original in design and concept. This is a ‘tool watch’; a working watch for very tough conditions, temperature variations, and 100 atmosphere bar pressure. There is no valve for the depth rating; the case resists pressure sufficiently without. It can dive a kilometre straight down. The only problem is that the watch is for professional divers and is (theoretically) only available in Japan! Why? Such a question is beyond me, as the watch represents some of the best value on the market today. And if you are into diving watches, then throw away some ‘also ran’ (that everyone else, including their pet has) like Panerai and Rolex, and get yourself a Seiko Prospex Marine Master!



At 48mm in diameter, it is a large watch and the extra mass to the watch comes from the ceramic shroud around the watch itself. The shroud has given the watch its ‘nickname’ on the web forums, and has become affectionately known as ‘Darth Tuna’. A side view of the watch and shroud make the name obvious!





[Separated at birth? ‘Darth Tuna’ (above) and ‘Darth Vader’ (below)]

The other use for shroud comes from protection around the watch itself. The design mantra behind the watch was to make sure that it could never harm the wetsuit and would fit over comfortably, and without impeding the movement of the hand. And this is where the design becomes subtle; the watch back is tapered so that the contact area with the wrist is minimal. The lugs are designed so that the watch will ‘sit up’ on the wrist making it wearable for a wrist of almost any size.



[The lugs are fitted under the case so the watch can fit on a wrist of almost any size]





[The benefits of the watch ‘sitting’ on top of the wrist: allowing full flexibility in the movement of the wrist]

The shroud being made of ceramic makes the watch almost indestructible; smack it against a solid object (not that I am recommending you do that) and the ceramic does not even notice the obstruction. Even if it did, you can easily replace the shroud by unscrewing the small allen key screws on either end of the shroud, lift it off, and replace. As easy as that!

Take the ceramic shroud off and the DLC stainless steel/titanium finishing is without fault. Given that the DLC titanium finishing is hidden by the ceramic shroud, Seiko are to be applauded for keeping the quality of the finishing throughout the watch. Any area of the watch that comes into contact with other surfaces (except the wrist) is ceramic (shroud and bezel) and hence keeps the watch scratch free and the black finish intact.





[The quality of the machining on the case and the finish of the DLC treatment is second to none]

In the manual that comes with the watch, Seiko recommend that the mono-directional bezel is moved from time to time. I found out why when swimming with the watch. The bezel is a very model of simplicity of form and function. Only one moving part: the bezel, with no barrings, only friction and the small steel spring that provides a uni-directional movement. The idea is if the bezel sticks, you can remove the shroud, flip the bezel from the case, wash with tap (sweet) water, dry, and replace. It works perfectly after cleaning. It is the very model of simplicity and function. Machined to precision so that the one part moves without lubrication, just the ceramic against the titanium with sufficient friction to ensure the bezel only moves when turned. The thin steel ring with the spring part provides the brake for the unidirectional movement.







[A small allen-key (not included with the watch) will unscrew the DLC screws and the ceramic shroud will simply lift from the watch case. Even the screws are exact and have a flawless DLC finish.]





[With and without ceramic shroud on the watch]









[Removing the shroud, the bezel can then be lifted, the mono-directional ring for the bezel, all parts can be cleaned, and re-assembled].

To borrow an ad slogan from a car brand: the lion goes from strength to strength. Seiko is now producing watches that are unique and original. You are not buying a Japanese interpretation of a Swiss or German watch, you are buying a Seiko, a Japanese craftsman made, originally designed and manufactured mechanical watch. The movement for the Marine Master is the 8L35; a first grade automatic movement (usually seen in the Grand Seiko line) that varies between 10 – 15 seconds a day (according to the manual). The 8L35 automatic with 26 Jewels and a 50 hour power reserve easily matches certified chronometer levels. The movements are made in Seiko’s in Shinshu atelier near the Japanese Alps and this is virtually a Grand Seiko movement in a dive watch.

The accuracy of the movement is reflected in the dial; its one of the things that I love about Seiko. The hands move from the bulky part (clearly visible in darkened conditions) to the exact point that indicates the exact minutes and hours. The subtleties do not stop there. The date window is in a different shade of silver to the hands. And the second hand is a different shade again from the hour and minute hands. The movement rotor itself is calibrated to be worn and for the watch to be in use. While the power reserve for the movement is 50 hours, it takes some time for the rotor to completely wind the main spring. It is a watch that is to be worn all the time, to be use, and in some of the more extreme conditions possible for a watch.

Unscrew the over-sized crown with the ‘S’ on it, and with two clicks out you set the hours and minutes. One click out and you set the date. Time setting is positive, disengages the second hand, and is therefore exact. Set the time to where you want it, push the crown in, and the time is set at that exact point. Given the time keeping abilities of the in-house 8L35 movement, and perpetual wear, the watch will not need the time set within the next month (at least).

Below the waves, the watch comes into its own. The luminosity of the hands and dial markers are clearly visible in dark or semi-dark conditions, the bezel is movable, and the all-black of the watch serves to only enhance the visibility of the time.









[Below the waves, the watch becomes an a highly visible dial of time]

The back case to the watch has a wave symbol and all details of the watch (including serial number). The watch is a mix of the different finishes, different black materials, and because of that, a unique look to the watch.



For the purpose, for the sailing (and taking the knocks), for swimming, for the abrasive nature of the beach, and for a watch to see the time at night, it does the job and more. As value for money, it is a world away, and other contenders in the dive watch space should be aware and wary of the Seiko Prospex Marine Master.

Andrew H This message has been edited by MTF on 2010-09-06 23:16:57 This message has been edited by AndrewD on 2010-09-08 18:23:15