O as a dive computer

Frédéric Swierczynski at -267m at the bottom of the terminal shaft in siphon 3 of the Mescla cave (Var).

Definition

Small device crammed with sensors and electronics sometimes producing shrew squeaks. Worn on the wrist, on the console, on the mouthpiece and soon directly in the mask. It produces an avalanche of more or less vital numbers which reassure serious divers. The next models will integrate 6G, the Netflix subscription, the sanitary pass, the corkscrew and a much awaited toaster function ...

Synonymes

Decompressimeter | Data acquisition unit | Bendomatic | Dive computer |

Starter

It's a fact: we have been witnessing the progressive digitalization of the practice of diving for several years. Digitization, simulations, memorization: there is no doubt that we will soon no longer need to get wet, a helmet VR full face and connected gloves will be enough to experience deep emotions in a sofa.
I am fortunate to belong to the generation that has experienced several major technological revolutions. And at least two which constituted a real paradigm shift: the abandonment of “analog” in favor of digital. Sequences of zeros and ones that we can duplicate endlessly, memorize, tamper with in all directions with all kinds of twists without necessarily losing the original. And I have the analogy of video editing which, in the past, was done with tape and scissors: the removed sequences joined the skeins of impressed film in the large trash can called “bin”. No “trial and error”, better to know what and where to cut and editor was a job.

“Analogue” is now a fossil even if a certain snobbery sometimes brings back ghosts from the past: “analog film” and “vinyl records”… Yes, today everything is digital. And soon even our own lives ... The logo chooses in its time by Sony for his computers Vaio is also a perfect and brilliant illustration of this revolution.

Main course

In the beginning, it was simple, there were simply no instruments: in sponge diving, pearl diving, hunting, the depth was estimated in shades of blue and the immersion time in the capacity. pulmonary of each. We told in the post dedicated toapnea the exploits of the Greek diver Haggi Statti. The discipline had not yet been contaminated by the cancer of competition with its rules, its tests, its innumerable categories, its homologations, its figures to the third decimal place and other flattery for the ego ...

In the course of the development of autonomous diving with in particular the invention of the diving suit “Cousteau Gagnan“, We have added other trinkets to the basic panoply: watches, depth gauges and decompression tables. Yet they were often reserved for monitors.

Much later I got to know old seasoned divers (we are talking about thousands of dives in all the seas of the world, no “little swimmers”…) who in some cases did not need any instruments: the depth, estimated by the meter close, “by eye”, the duration deduced from the pressure of the bottle, the ascent by following the small bubbles, and a safety stop of a “certain” duration, by the ear, within six meters of turquoise streaked with foam and sun… And then, as one of those die-hards told me: there was always one of these computers in the pool to come and squint at…

Decompression at OK coral ...

When I was diving in the coral, around the island of the bull in the south of the Sardaigne, it was even easier. The flowering rocks at the bottom had been spotted with a depth sounder, at -125m. Most of a penta-block of trimix mixture was emptied there by hammering the enormous branches, the selling prices of which still leave me dreaming today.

We then had to release a balloon to signal our position to the moss and to the second corailleur taking over and who was already descending, weighed down with stones.

 

It was time to climb back up without laziness, pulling on the hardening regulators, using twenty-liter plastic jerry cans held firmly by the handle. It was then sufficient to tilt it slightly for the expanded gas to escape in large bubbles from the hollow bottom and thus to adjust the ascent rate. No stab, of course: what for? Then came, thrown from the surface, the 2 × 9 liter twin-cylinder of air, dancing like a lighthouse in the blue water: We were at least thirty meters away. Exchange of spacesuits and the landings began, connected to the hanger by a simple self-locking knot.
We went up gradually, guided by the pains in the arms, the shoulders… When it hurt, we then went back down a little to stay longer in depth before another attempt. Then came the hot water pipe and the narghile pure oxygen that we breathed at - 12 meters to accelerate a little all that ... 

But analog decompressimeters already existed (first models released in 1958!), Made of porous porcelain that moved in a graduated tube, all supposed to simulate decompression in human tissues. Those of the Italian brand SOS were also called “bendomatic” in the USA which said a lot about their reliability. I believe I used all the successive models and moreover to profit: they did not work so badly and we did not ask ourselves too many questions. In underground diving they even allowed me explorations impossible otherwise knowing that I was diving with two instruments, reassured by this apparent redundancy. It was always better than the watch / depth gauge / tables trio especially if, as I have told elsewhere, we sometimes exchanged our watches and depth gauges mid-dive for budgetary reasons ...

And then appeared the first electronic decompressimeters, quickly renamed “computers”. the Decobrain, first and the Edge (1983), then theAladin (1987), which has become a benchmark and has accompanied us for many of the firsts. And a multitude of different brands (Suunto SME-ML - 1986, Microbrain - 1988…), the differences mainly coming from the type of algorithm used for the calculations: Bühlman, RGBM, VPM and other proprietary systems…

Today's models have adapted to new diving practices, taking into account individual consumption, temperature, types of gas successively breathed in, the pressure of different gases and a number of other parameters including the complexity continues to grow.
The computerization of diving is in operation and the most advanced modern speleonauts now have real computers with data acquisition unit on board their thrusters and capable of recording the course and profile of the dive using gauges. of constraint, inertial cells and electronic compasses… One of my old dreams, realized, is that of topography in “real time”.

Dessert

All of these computers are worn on the wrist or integrated into the instrument consoles.

Their variable sizes have given rise to all the delusions over time, from giant screens, color, LCD TV-style, to small instruments with tiny buttons and gold edges that look like they came out of a jewelry store.

There is not a manufacturer that does not offer its model today and, like stabs, there are hundreds on the market.

 

We are witnessing a real obsession to make them look as much as possible like watches, obsolete accessories if there were any since the advent of computers but which nevertheless made the fortune of many Swiss watchmakers. As if this gesture of consulting his wrist was now part of our genome. When it is not an outward sign of wealth ... Even Apple made a watch! Connected, of course, but all the same ...

Of course, with the widespread use of recyclers, computers are everywhere with cross references in every piece of equipment. Some data is now even literally accessible under the nose! And soon, like fighter plane pilots, will they be integrated directly into the mask's field of view.

See you soon for a new definition of Scuba Bécédaire. The irreverent lexicon of diving, but not only. Because sometimes ...

Francis Le Guen

 

 

Café

The friend Vincent Defossez from the center of Marseille Aquadomia advises us to choose a dive computer. 

And repeat this time with the computer test Shearwater Petrel et Partridge, among the most popular in Tek and rebreather diving.