I never realized that about the decompression bezel, thank you so much for sharing this information.

~George
: In response to several Questions and Inquiries about the use and
: availability of these bezels, I would like to shed some light on
: this subject.

: Watches have always intrigued me and being of technical mind, I
: wanted to know how they worked and how to use them properly. I
: have owned Heuer Watches since 1966. They all have served me
: well and were used as TOOLS in my trade. There seems to be some
: confusion or lack of explaination on the use of and availability
: of DECOMPRESSION BEZELS. Here some Background and my experience
: on this subject.

: In 1972, I purchased my Heuer Autavia GMT 1630. I ordered a
: Stainless Steel Band, spare 24 hour and Tachometer bezel as well
: a Decompression bezel from the Heuer Time Corporation in
: Springfield, New Jersey. All accessories like replacement wrist
: bands and bezels were listed in their catalog and are original
: factory parts.

: In 1975, I purchased my Heuer Autavia GMT 11630 from a long time
: Heuer dealer in Zurich, Switzerland. While there, I also picked
: up a spare 24 hour bezel and a DECOMPRESSION bezel along with a
: Stainless Steel Band. Again all parts being original Heuer
: stock.

: So we can see that these bezels were available from Heuer in the
: 1970,s and not just in recent years as some comments seem to
: indicate.
: Here some Bezel Details : These bezels can be easily exchanged and
: mounted onto their respective cases but are NOT interchangeable
: between watches. This is due to the difference in the mounting
: diameter on the watch case and the plastic or mineral crystal on
: the watch. The 1630 bezel insert is slightly angled up towards
: the crystal whereas the 11630 is flat to match the mineral
: crystal. Both are shiny in appearance.
: The Heuer Diver 100 is also different since it uses the 11063
: Autavia case and employs a different design of the bezel and
: it's insert.

: Now to the USE of the bezel: Being a PADI certified SCUBA diver, I
: could see how a DECOMPRESSION bezel would be helpful to
: determine BOTTOM times in a dive. With the easy changeover of
: the bezels, it was a no brainer. At that time, 1972, the only
: other watch that offered a decompression bezel was the DOXA
: Diver but I saw no reason to purchase another watch when Heuer
: offered an interchangeable bezel to serve the same function.
: Here a couple of misconceptions: A scuba diver generally carries
: compressed AIR in his diving tank and NOT Oxygen. A
: decompression bezel is not a Depth Meter as implied in the Doxa
: write up. A diver wears a special depth meter on his wrist or on
: the instrument pod. The Bezel is simply a timing device to
: measure BOTTOM Time.
: In 1972, Heuer published a guide which explains their chronographs
: along with the various features such as Calculators-,
: Pulsometer-, Tachometer- and Decompression Scales and how to use
: them. This was very basic, but a start.

: Here an EXAMPLE of how the Decompression bezel should be used: The
: name is actually a misnomer. When a diver observes the bezel
: markings and surfaces at the proper time, he does not need to
: make decompression stops on the way back to the surface. The
: marking on the bezel originate from the FSSS, CMAS or the
: U.S.Navy Diving Manuals. They lay out the guidelines for safe
: SCUBA Diving WITHOUT decompression.
: 1. Generally, diving to a depth of 10 meters / 33 feet or LESS has
: no restriction on time spent under water.
: 2. Once we dive beyond the 10 meter /33 feet mark we must observe
: what is called BOTTOM TIME. This is where the BEZEL provides
: it's function.
: Example; Lets say we want to take some pictures of a sunken wreck
: which is located at 115 feet / 35 meters below the surface. When
: starting the dive we set the RED
: TRIANGLE marker on the bezel to match the MINUTE HAND on the watch.
: We dive down checking our depth as well as checking the minute
: hand. We take the pictures and
: observe when the minute hand points to our depth of 35 meters on
: the bezel, thus telling us that it is time to surface. Our
: BOTTOM Time was approximately 20 minutes.
: The RED 40 mark on the bezel reminds us that 40 meters is the
: maximum depth for SCUBA diving without Decompression stops on
: the way back to the surface. If this is not
: observed we could end up with the "Bends" (to much
: Nitrogen in the blood) and we could be in serious medical
: trouble.
: Note also that if you want to do another dive that same day or do
: multible dives, you must consult the Repetitive Dive Time
: Tables.
: Keep in mind that Heuer used 600 meters as a starting reference for
: their Bezel Numbers. (This allows safe margin for diving in
: fresh water inland lakes). This gives a additional safety margin
: for single dives just about anywhere.

: On a closing note I would like to mention that I have used the
: Decompression bezel many times and once I got back to do my day
: job (Flying Airliners) I changed my bezel back to the 24 hour
: bezel to tell me LOCAL TIME. Wonderful time pieces at work,
: Autavias are great, to all the Best, Heinz Rengel.