How Does the IWC SafeDive Internal/External Bezel System Work?

IWC Aquatimer Chronographs

Perhaps the most conspicuous technical modification on the new IWC Aquatimers is the external/internal rotating bezel aka “SafeDive”.  Naturally, many watch enthusiasts are wondering how exactly the new IWC “SafeDive” bezel works.  Allow me to explain with the help of some material and video provided by IWC, and a few pictures of my own.

IWC SAFEDIVE SYSTEM

IWC Aquatimer SafeDive Bezel 2014

Through the combination of the schematic above and the video below, you can get a good sense of how the SafeDrive internal/external bezel system works.  Note that the views you are seeing are from the back (the underside) of the bezel (i.e. the crown is on the left).  What appears to be a second crown on the left side of the case (again–right side in the images and video shown here) is actually a housing for the drive wheel and pinion.

For safety reasons, the internal rotating bezel can only be turned anticlockwise. This guarantees that even if the external rotating bezel is inadvertently moved, the dive time – during which the diver can return to the surface with no need for decompression stops – is not exceeded.

IWC Aquatimer Automatic on Side

photos by Perpetuelle

IWC Aquatimer SafeDive gear system

IWC Aquatimer Chronograph

Why Such a System?

The SafeDive combines the advantages of an internal rotating bezel with the ease of use of an external rotating bezel. The external rotating bezel with its SafeDive system can be moved simply and precisely in steps of one minute, even when wearing diving gloves or with cold fingers.

I hope you found this short primer helpful.  Please ask any more questions in the comment section below.

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  • goju1

    Kool report – thanks!
    Interesting that no one has thought of this before…

  • goju1

    Well, still can’t see how the outer bezel is secured and also interested to see more detail of the ‘o’ rings that seal off the inner bezel to prevent water ingress.

  • Bob

    The protective cover for the gear housing has small holes in it. For what purpose are these holes? To let water in and out? And why would that be? Thanks for your help. Loved this blog and video.

    • http://www.perpetuelle.com/ Perpetuelle

      Hi Bob — sorry for the delayed reply! Here’s what IWC tells me:
      The holes assist with drying/evaporation of the water; they are there so there is space above the safe dive system for it to properly operate.
      **
      Still seems to me like somewhat of an aesthetic decision — it is still not clear to me why they couldn’t just seal the whole thing up (ie no holes). I plan to explore this further next time I meet with the brand
      Kyle