Sinn U1 Tegimented Diving Watch Review

Sinn U1 Tegimented Diving Watch Review

Sinn U1 Tegimented Diving Watch Review Wrist Time Reviews

Dive watches, especially Sinn, are arguably the ultimate tool watches.  They are typically rugged, water resistant, and usually offer some means to measure elapsed time.  However, few use their dive watches outside the office. "Desk-diving" is the most common destiny of a modern dive watch and to highlight the irony, for some reason the trend in modern dive watches is to be rated 500m or more, while, even a seasoned professional diver rarely ever dives past 200m...

Maybe the popularity of desk-diving watch lovers are to blame for a crowded market for dive watches. As a result, some of the most famous and popular watches in existence today are dive watches, e.g., Rolex Submariner and the Omega Seamaster, and that market also includes lots of bargain as well, e.g., Seiko Orange Monster, and some clearly overpriced watches like the Audemars Piguet Royal Oak Offshore Diver or the Hublot Oceanographic.

This review is about the Sinn U1 which is an affordable yet solidly made (even over-engineered) diving watch with all the necessary features and function needed in a dive watch.  This review is based on my experience using the Sinn U1 during four dives (Honolulu and Key Largo) as I got my PADI certification, it performed perfectly, not that I expected anything else.

Sinn U1 Tegimented Diving Watch Review Wrist Time Reviews

In this post I want to review the Sinn U1 in the context of these dives, while also attempting to debunk some myths about dive watches. After all, a dive watch might save your life when used in the context it was meant for, so understanding the features that are important vs those that are for show, is critical.

Scuba diving is a relatively new sport and activity. People used to visit the underwater world but mostly being attached to a boat with air pumped via a tube.  In the early part of the 20th century, various countries' navies included the so-called "frogmen".  These early professional divers would perform dives and underwater activities with specialized breathing apparatus...  In this context, watches like the Panerai Radiomir, with a Rolex movement, came into existence for their legibility and groundbreaking underwater performance.  However, they were large and mainly used only during the dive.

Sinn U1 Tegimented Diving Watch Review Wrist Time Reviews

With the invention of SCUBA (self-contained breathing apparatus) and a modern understanding of diving theory, the dive watch was born in the 1950s.  Rolex and other brands like Blancpain would eventually create the first true dive watches.  These are watches that could be used as daily wear but also be used as an instrument for diving.

The salient features needed for a dive watch are: water resistance; rotating bezel; and possibly a helium escape valve.  Water resistance is the key. Recreational divers reach depths up to 40m (rarely more) and technical divers limit is set to 100m.  A true diving watch therefore needs to be able to sustain the kind of pressure at these limits, anything more is really bonus.  Most diving watches are tested using an atmospheric pressure chamber hence the reason for 20 bars or 30 bars usually listed on modern diving watches.

Sinn U1 Tegimented Diving Watch Review Wrist Time Reviews

The rotating bezel was another key feature needed in the past. Today, it's still useful in that for me I use my mechanical watch as a redundant timing mechanism in case my digital dive computer would fail (e.g., battery dying). This is important since most single scuba tanks give you about one hour of dive at recreational limits, 60 to 100 feet and normal usage.  And you really don't want to be performing a dive not knowing how long you've been in the water.  If this is not obvious as to why, later on I give some more reasons.

Finally, a helium release valve.  This feature is strictly for professional divers who perform multiple dives in one day at saturation levels (also using oxygen/nitrogen mixtures to allow for longer dives) and thus need to enter decompression chambers at the end of their days.  In these cases, the watch crystal may pop out unless the trapped helium has a way to escape.  Working with COMEX, Rolex invented the automatic helium release valve we frequently now see in many dive watches.

Sinn U1 Tegimented Diving Watch Review Wrist Time Reviews

While the Rolex Submariner is the iconic and first true dive watch, it is not the only one worthy of your attention as a recreational diver. Sinn is a brand that I respect for many reasons.  Their watches are functional and have a unique style while also being no-nonsense tools that are affordable.  While as a fan of dive watches, I have a few, for my PADI certification dives I chose to use the Sinn U1. I will try to explain why I love this watch and why it's near the top of my list for functional, affordable dive watches.

First, the Sinn U1 has a unique simple dial. With squared minutes and hours hands rotating on a black dial with hour markers made of "lego-like" squares with a central etched marker that matches the hands perfectly. The seconds hand also has a square at the end and uses a red coloring at the tip to make it better contrast with the hours and minutes hands.

This results in a legible dial in every aspect. Surrounding the dial is a rotating bezel with a lume marker shaped as a triangle used to indicate your entry in the water.  The unidirectional bezel has the right feel, a little play, but not much.  Markings on the bezel are well done, never overpowering the look of the dial, and have a red accent on the markers from 15 to 60 minutes, this is unlike most other dive watch bezels which tend to do the opposite (highlighting the first ten or fifteen markers).

Sinn U1 Tegimented Diving Watch Review Wrist Time Reviews

Another important feature needed for dive watches is legibility in the dark.  The Sinn U1 accomplishes this in spades as the lume is excellent, though it is not present on the bezel markers except for the triangle start marker at 12 o'clock.  In the dark, with a little charge, it's easy to clearly see the exact time as the hands and hour markers and minute markers are all painted with a layer of Super-Luminova that shines brightly for hours.

Sinn is known for over-engineering their watches. In this instance that happens in particular with the case. It's made from German Submarine steel and treated to increase scratch resistance. It's a hardening process Sinn calls "tegimentation". As far as I could see, this hardening works well as I had no issues with the case though my tegimented bracelet did see some minor scratches at the buckle while putting and taking off my BCD (buoyancy control device) jacket.

Sinn U1 Tegimented Diving Watch Review Wrist Time Reviews

Another interesting result of the special steel used by Sinn is that the resulting color is closer to titanium than it is to brushed or satin-finished steel. This is a good thing for a serious dive watch since the last thing you need underwater is a "blingy" watch. During my dive in Key Largo, we were encircled by a group of barracudas. Some coming as close to a foot from me and the iPhone I was using to film (see short video in this post).

The thing about barracudas is that while they rarely attack humans, they are a curious species and are known to try to eat any polished metal things you have hanging on you...  There are many reported cases of people losing their gold chain or charms from curious and hungry barracudas. Since the Sinn U1 case is hardly reflecting any light, that was a non-issue for me.

The movement in the Sinn U1 is the ubiquitous ETA 2824-2.  Nothing fancy here and from my experience provides accurate performance as you would expect.  However, one issue is that while the crown at 4 o'clock makes the case fit easily on my wrist, unscrewing the crown to change the date (position one) or the time (position two) with hacking seconds leaves some things to be desired.

Sinn U1 Tegimented Diving Watch Review Wrist Time Reviews

First, the crown seems to be fragile after unscrewing.  Also, the crown positions don't "click" so sometimes if I want to wind the watch (first position after unscrewing) I end up changing the date since it enters position one. Not sure if this is due to the fact that most ETA 2824-2 based watches tend to have the crown at 3 o'clock and while Sinn must have re-engineered the movement somehow to put the crown at 4 o'clock, the result is not the best it could be.

The Sinn U1 is a relatively heavy watch. On the tegimented bracelet, with a couple of links removed, it comes in close to 1/2 pound. The 44mm case is just right for my almost 7 1/2 wrist and is somewhat comfortable, while (again) heavy. This is especially true since as mentioned, Sinn places the crown at 4 o'clock instead of the common 3 o'clock.  This makes the crown easy to grasp while also avoiding putting any pressure on your wrist as you move your arm and your hand.

Certainly during the dive, on the heavy bracelet, it's perfect.  The extra 10mm for the dive extension is good for most diving excursions but clearly not as sophisticated as modern micro-adjustable bracelets that come with the new Rolex Submariner 114060 for example.

Sinn U1 Tegimented Diving Watch Review Wrist Time Reviews

The Sinn Rubber strap is more comfortable since it reduces the weight considerably (173g for the large folding clasp buckle and 155g for the small buckle).  However, the Sinn folding clasp (large) is sub-par.  While great looking, it is large and scratches easily and also not micro-adjustable. It has a diver extension but it's relatively long at about 10mm.  Sinn sells a smaller clasp version as well as tegimented steel versions.

Sinn U1 Tegimented Diving Watch Review Wrist Time Reviews

While I am not fully sold on the hardness of the tegimented steel, it does appear to be harder to scratch than non-tegimented versions. The part of any dive watch that takes the most abuse is the clasp---mostly from putting on and removing the BCD. On my tegimented bracelet, I did scratch it a little after a second dive, that time, in Hawaii.  Nothing major but enough to make me a bit doubtful about the technology.

However, on the non-tegimented folding large clasp that came with rubber bracelet I was able to easily scratch the clasp and that was a lot more than the bracelet. So maybe the tegimentation does work?  Of course, this is all anecdotal evidence and a more scientific experiment should help resolve any doubts. Until one is done, I'd say always get the tegimented versions if the price is not exorbitantly more than non-tegimented.

Since I also enjoy this watch for occasional desk diving, I got the Sinn leather strap.  This fits the watch perfectly and gives it a more daily wear feel and also a dressier look.  Since the weight is reduced to about 140 grams, it is also quite comfortable to wear on that strap.

Sinn U1 Tegimented Diving Watch Review Wrist Time Reviews

As expected, the Sinn U1 performed brilliantly during my last four dives.  Besides the scratches on both the tegimented bracelet and non-tegimented large clasp for the rubber strap, my only other issue is the fact that the dial, while very legible and visible under water, does suffer from some reflection issues. That is, in most lighting conditions under water, at short angles (45 degrees), the dial becomes essentially a mirror. This is mainly due to the AR coating and the fact that the crystal is flat. Domed sapphire crystals, like on Panerai watches, tend to be more immune to this mirror issue under water.

The Sinn U1 Tegimented on bracelet reference SI-255 retails for $2,420 with the non-tegimented on bracelet going for around $2,000. It is rated at 1000m and also passes anti-shock (DIN 8308) and anti-magnetic (DIN 8309) specification tests. While not necessarily limited, the production of the tegimented version is more restricted than the regular version.

Sinn U1 Tegimented Diving Watch Review Wrist Time Reviews

Sinn also has various other Ux models including the U2 which contains a GMT hand and the U1000 with water resistance in the 4000m range. Other models also exist with chronograph complication and one with a dial filled with liquid to increase even more the water resistance.  Again, nothing a recreational diver or professional diver will ever need.  Finally, Sinn also has black versions of most of its Ux divers including tegimented black versions.  These give the watch a military look that some will certainly appreciate.

Overall, while not a "perfect" dive watch, I have been highly satisfied with the Sinn U1. The simplicity of the Bauhaus design coupled with the unique engineering and style made it an excellent companion during my dives as I got my certification. My intention is to get the next levels of PADI certifications, so watch this space for more real live "diving" reviews.  I cannot wait to put my other divers to their intended use as I can hear them complain of too much desk diving!

Necessary Data
>Brand: Sinn
>Model: U1 Tegimented reference SI-255
>Price: $2,420
>Size: 44mm x 15mm (50mm lug to lug)
>Weight: 190g on bracelet and 173g or 155g on rubber straps (large and small buckle)
>Would reviewer personally wear it: Yes
>Friend we'd recommend it to first: Anyone interested in recreational diving looking for a solid watch and a budget of under $2,500
>Worst characteristic of watch: The bracelet diver's extension is not easily micro-adjustable.
>Best characteristic of watch: Simple dial with Bauhaus design with nothing superfluous or unneeded.

What do you think?
  • I want it! (5)
  • Interesting (3)
  • Thumbs up (0)
  • Classy (0)
  • I love it! (0)
  • frankwhite

    I have a Steinhart triton 100atm and it has the crown at 4. I’m positive that Steinhart didn’t have to do any re-engineering to make it work and I doubt Sinn had to either. I could be wrong but don’t you just gotta rotate the movement?

    • AndrewBistak

      frankwhiteThere is not any re-enginerring needed to place the crown at a different
      position than 3 o’clock  (unless the crown is on the left side, in
      which case a different date ring application is made as the regular one
      would put the numbers upside down).   The only thing that is done with
      alternate crown placements is that the dials are made with the movement
      pegs in adjusted positions so that they fit the movements differently.

  • Ulysses31

    While i’m not really a fan of this particular Sinn I can’t fault the legibility of the face which is of paramount importance for its intended use.

  • Cooperj1

    Interesting review of the U1 in use… Thanks. I want to mention that the braclet I have on my U1-T does have the ability to “micro” adjust. There are three positions visible on the side of the clasp.
    I am also interested in the black marks on your clasp. They appear to be rub marks like you may see on a floor from heavy black soles. Did you attempt to clean the off? If so how did that turn out?

    • So, there are some micro adjust but need a tool to do so. For me, compare to the new Sub that’s not optimal. The marks are from putting and removing BCD. Did try to remove. It’s better but still showing. Please note that the large buckle strap is not Tegimented steel.

      • Cooperj1

        True you cannot adjust it on the fly… As for the marks well they are battle scars that give you the excuse to talk about your barracuda story. 🙂
        BTW there is a slightly audible click to the crown positions but unless it is very quiet you would not notice. I have to say it could be better or more robust.

  • MarkCarson

    Encountered a 4 foot barracuda once while snorkeling in Kealakekua Bay on the Big Island 30 years ago. He was swimming along parallel to me. I turned to him (which scares away most fish) and he did not budge. I was over 100 yards off shore and alone and without my “Hawaiian Sling” (3 prong spear) as it was a marine preserve. I did not appreciate that he was not scared of me. I know what an arsenal of teeth they have so I was not happy with my “companion”.

    Thanks for Sinn review Max. Looking forward to follow up reviews. Next time you are on Oahu, let me know and I will buy you a beer.

    • Cool story. They are scary, especially since there is usually more than one. In my case, there must have been 10 or more. Will ping you next trip to paradise 🙂

  • yawatch

    Just a minor correction: The Sinn U2 is not really a true GMT. The 24hr hand on the U2 will move when you adjust the normal time hands. Hence it acts more like a UTC where the 24hr hand can only be moved in 1hr increments.
    For water resistance, the Sinn brand is impossible to beat, but they don’t live up to their reputation of toughness. I owned a Sinn U2 S and the tegimented PVD case got many scratches. The movements are also normal standard ETA’s, only using Top grade and not Chronometer grade. The german DIN standards are the equivalent of normal swiss ones, so they don’t mean much, and the shock resistance is poor. This is not a watch you can do construction work with or swing a hammer while wearing. The ETA movement can’t handle the shocks. Real toughness I would argue is good shock resistance, so go with an Omega Speedmaster Pro (no rotor), vintage Lemania 5100 (if you can find one)  or something like a JLC tractor movement.

  • CG

    SCUBA is new? I’ve been diving since the 60’s! Not new… to me but that aside the Bezel should have absolutel NO slop at all, the face is quite handsome but ineffective for a quick glance for elapsed time since there are no markings indicating 15 minute intervals, the most common in diving. Lume looks very poor… based on your review coupled with the pix this is No Buy for diving only for street wear. Sad.

    • “Scuba diving is a relatively new sport and activity”. Emphasis on the word “relatively”. Compared to other sports, at a little more than 50 yo, it is new. This is not to say that professionals and one off did not dive, but recreationally (mainstream) the sport is even “newer”. Anyhow it’s semantics, think of it as old if you define “new spor”t as one created in the past 10 years… On your conclusion, I respect your opinion (everyone is so entitled) however I am sure it’s not widely shared since this watch is typically sold out at WatchBuys (US dealer) and the number of likes on videos, Facebook post, and the majority of comments disagree with your logic. Finally the lume is not the best I have seen, hence the pic, however it’s also not the worst. It will last for hours and that counts for something. I took the pic not right after a charge so that we get a sense of real usage of the watch…. I had no issues seeing the dial during dive, even at 50 feet. Finally, real world watch usage was one of my goals for this review, I believe the pics and videos kept it “real”.

      • CG

        Maximilien …I don’t write my opinion to reflect any “logic” per se, it’s just MY opinion based on my many years of dive experience and actually working in the diving industry at one time. I don’t believe validity can be ascribed to any item just because people differ in opinion. You must make your own judgement. I stand by my opinion; there should never be any slop or movement in the bezel, that’s a sign of poor manufacturing & design tolerances. The lume is very poor, in a night dive it is crucial that the lume be strong, though recharge is always done with a strong pelican type light held directly on your watch for a few seconds. Whether others like it or not is not my concern or reason for opining.

        • Well we at aBTW write for a wider audience so it’s more important to me to make things clear. Again, I disagree with statements on bezel and lume, based on my experience using the watch diving for 4+ hours. The lume pic was taken after at least a few hours on boat and diving and packing up to go home after sunset. Most lume shots you see are done right after a charge, not the case here. If I had done the same it would be lit up like a candle. In any case, thanks for reading and your opinion—good or bad I appreciate your time.

  • Cooperj1

    I would like to offer my own experience with the lume. I typically wear my watches to bed and recently I decided to do a bit of a test to see how long the lume would last. Just before bed I charge it for 60 seconds and then hit the rack. Consistently 7 hours later the lume is very legible.
    Granted this is a desk diver test but since most dive watches sold are desk divers I think my test is valid… 🙂

    • Cooperj1 yup, did not do such a precise experiement, however, I’d say my experience is similar.  Only my PAM 321 gives me better results (by far).  My Suby 114060 does well but less than the PAM and the Sinn.

  • PhilMaurer

    Welcome to Diving…
    But alas Nitrox aka Oxygen enhanced diving or what you refer to as Oxygen/Nitrogen mixtures are purely for shallow water diving due to Oxygen toxicity.  They allow for less Nitrogen loading while diving making shallow diving safer, and or extending bottom time in dives typically less then 80 feet.
    Deep Sat diving generally uses Tri-Mix, or Helium, oxygen, and nitrogen.  The deeper you go the less oxygen and nitrogen you want to prevent Nitrogen Narcosis or Oxygen toxicity. 
    The funny think about Helium escape valves is they are no longer needed.  Back in the day Deep Sat divers filled their dry suits with Helium, and that Helium under pressure would work into the watch, and if not released would spring out the glass on the watch.  This was due to Helium leaking in slowly as it is a smaller molecule then Water.  Today deep sat divers generally use Argon as the drysuit filler as it is much much cheaper, and does not have the nasty side effect of quickly removing heat from the body.  Helium conducts heat 6 times more efficiently then air, and argon 2 x less efficiently then air…  Which brings up the point that Helium escape valves are not needed. 

    Now why would you need an He escape valve…  For the few deep sat divers that would be entering a diving bell at depth with a Tri-Mix atmosphere, as otherwise the watch is on the outside of the suit anyway and would only be exposed to water.
    Again welcome to diving it is a great and fun sport, and remember to always be learning, it will keep you safe, and make diving that much more fun!
    I’ve been doing it for 12 years, and worked up into the DM program.

    • Great comment. Thanks for the clarification, tips, and information. Best.

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  • sips6678

    CG Maximilien I owned a U1 few years back, possibly 2008 which I sold 3 months after buying it for the exact reasons you describe. The bezel [not being firm enough] and luminosity were mainly the issues. One more thing, the bezel could/should have been 1,5 mm wider [the dial would still be large and legible] that would make it easier to read. I’m in my 50’s and the tiny markers of the bezel were also an issue.  In spite off my reasons for selling the watch, I somehow felt that I might have been in error for selling it. Few days ago a friend was travelling to Germany and asked if I needed anything from those parts. Was feeling itchy for a new watch and although was considering various options, I asked him to get me a Sinn U1. The first U1 was on steel teg. bezel – not black and thought to get this one with a black bezel. After looking the black bezel model, although it was teg. the fact that its PVD coated, made me change my mind. I don’t like PVD or DLC or any other coating on the basis that it is only a matter of time [short anyway] to wear out. I went for the exact model that I owned. For some reason the lume seemed better than the 2008 model [not as good as other watches that I own – not talking about tritium – Seiko MM 300 as an example and not high end watch] while the bezel is certainly different. 100 % firm and at the same time easy to handle.
    Back to the lume, the day I received the new U1 was wearing another Sinn, the 103 in titanium TESTAF. Much better luminosity and easier to charge.
    My overall impression is that my new Sinn is a value for money watch, under 2,5k and if it was manufactured in Switzerland/branded “made in swiss” would have been in a much high price range.

  • RogSmith

    sips6678 CG Maximilien but the Seiko is so goddamm ugly….

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  • rodrigo

    The movement has to be re-engineered? I think one could just rotate the movement a little.
    You would only need a new date disc to match the “new” 3 o’clock position.

  • R Khalifa

    I know this is a pretty old article, but I wanted to say thank you for providing this objective real-world review. It’s hard to find anyone who posts anything other than uniformly glowing reviews about Sinn watches these days, but the observations about the crown and clasp were helpful to me in making the decision to not pull the trigger on purchasing a U1. Those are precisely the nitpicks that would drive me nuts if I owned it. Still like the looks of the U1, but will have to enjoy seeing it on other peoples’ wrists – just not for me.

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