Most of what I know about this watch has been gleaned from French dive watch forums (see list below).
There was a project in the mid-90s to develop oil-filled watches in order to resist incredible pressures (below 300ATM). Beuchat approached a company called Innovation Capital who devised a watch which incorporated an oil-bathed movement (ISA quartz) and toughened glass. Beuchat therefore embarked on their models, which incorporated a Hydraulic Pressure System or HPS.
However, they were, apparently, pipped to the post by the Bell & Ross Hydromax with its whopping 11,000m WR. This set Beuchat back a bit, but they were able to use Bell & Ross' experiences (and indeed Sinn's) to modify their models (the 6,000m-rated Abyssal and the 4,000m-rated Genesis). Apparently they were able to modify the flexible membrane at the back of the watch to successfully remove any gas bubbles. This apparently works by allowing water to compress the flexible membrane through the small holes in the case. I'm not (yet) convinced by this explanation and need to do some more research...
The watch is not subtle - yellow and black scream "warning" or "danger". An odd combo, and one that's not used in too many designs. However, it's smaller (38-39mm) and a lot slimmer than many modern divers. The bezel is solid enough, with a decent "click" to it. There is no lume on the bezel.
The use of oil means that refraction is significantly reduced, allowing the watch to be read at all angles above and below the water.
The battery needs changing, so I'm going to have to find a Beuchat AD somewhere - presumably on the continent - or send it back to the guys in Marseilles...
As I said, it's an interesting piece - relatively rare (probably around 200 made) with an interesting history. Beuchat's new owners plan to release a new version of this watch in due course.
- Forum - MDP