The mysterious Aquastar ring of the Deepstar 20 atm... but how do you read it?
Undoubtedly, 2023 offered great emotions and a watch that I really liked was it, AQUASTAR DEEPSTAR 20 ATM.
But before getting to the point, it is a must to let you know the history of this brand founded by FEDERICO ROBERT:
DIVER, INNOVATOR, DISRUPTOR
Aquastar was founded in 1962 in the city of Geneva in Switzerland by Mr. Frédéric Robert. Mr. Robert, a diver, a sailor, a pilot, a watchmaker, a mathematician. He also represented Switzerland at the 1948 World Yachting Championship.
With extensive experience on the high seas, Robert decided to start a watch company focused on developing watches, watch parts and specialized tools exclusively for underwater activities, ranging from sport diving to professional scientific excursions and underwater exploration, with the ultimate goal of making all diving activities safer. It was November 1962 when Robert renamed his father JeanRichard™ company to "Aquastar", and it was here that a whole new diving legacy was born.
Aquastar marked the first time in the Swiss watchmaking world that a company dedicated itself to producing professional-grade watches and timekeeping instruments in a single market segment. And with a catalog that quickly expanded to include dive watches and other aquatic instruments such as diving compasses, depth gauges and thermometers, all adaptable to watch straps, Aquastar's mission soon became quite unique at the time for a watchmaking house Swiss.
It was during this period that Mr F. Robert distributed his range of diving instruments under the new name "Aquastar" almost exclusively through specialist shops rather than through regular retailers. Given the socioeconomic environment of the time, this nontraditional sales tactic seemed risky at first, but it reflected Robert's innovative approach to problem solving, a characteristic that would be reflected in his numerous patented designs, as well as the backbone that would defined the brand image. disruptive legacy many years later.
In the photo on the right you see one of the first timepieces created by F. Robert in 1958, a water-resistant watch with chronometer function, the “AQUASTART” (info taken from the site: https://aquastar.ch/).
There are 4 patents filed by Aquastar but today we will talk about the most enigmatic one which concerns the reading of the ring, i.e. patent CH394658A published on 30 June 1965 and filed for the first time on 24 May 1963.
Using the French Navy Deco chart of that period, we take a hypothetical depth for a first dive and the corresponding duration off the chart, a dive to 39 meters which is (about 130 feet) for 25 minutes. On the table, where depth and time intersect, there are two sets of numbers. The main number is the mandatory decompression time for this dive in minutes. The second number is the partial pressure of nitrogen absorbed into the body, known as the “C Coefficient”. This factor will be used later during a surface interval before a repetitive dive.
Now let's take a look at the bezel itself of the Aquastar. It has two staircases, an internal staircase and an external staircase. The internal scale is simply a traditional 60 minute elapsed dive time scale found on almost all other dive watches. The external scale is key to calculating repetitive dives, but more on that later….
Before diving, the diver will align the zero pointer, or luminous dot on the bezel, with the minute hand to measure the duration of the dive, a regular procedure that is performed to measure the time spent underwater during the dive .
During the dive the minute hand advances on the internal scale showing how many minutes have passed at a depth of 39 metres. Once the hand points to 25 minutes, previously determined and planned, the dive is over and it is time to ascend to the decompression stop. A 15 minute decompression stop should be made, after which the ascent to the surface should be completed.
Once on the surface, the external scale can be used to account for the release of nitrogen gas in preparation for the second dive. Here the previously determined “Coefficient C” is used, say 1.6. The 1.6 value on the outer scale of the bezel should now align with the hour hand, which will advance, showing the decreasing nitrogen absorbed values (1.5, 1.4, 1.3 and 1.2). If the decreased value is greater than 1.4, the nitrogen concentration in the body is too high and a second dive is not possible.
Now for the second dive. The second dive will be done at 30 meters as the second dive should be shallower than the first.
1st possible scenario: If we look externally at P=55-12 meter scale and choose 30 which is the planned dive depth, we will observe that the 6 minute mark on the internal scale aligns with the 30 meter mark on the external bezel. This is important because this value is what will be used to determine the “handicap/penalty” time for the second dive. The penalty is the time to be subtracted from the dive time indicated in the table for the 2nd dive. This means that when enough time has passed and the hour hand moves from the “C Coefficient” of 1.6, as previously determined by the tables in the first dive, down to a new “C Coefficient” of 1.1, 6 will be subtracted minutes from the time of the second dive scheduled on the dive table. Now, going back to the table, let's find the depth of 30 meters and then plan that dive for 30 minutes. Since this is a second dive, and the diver has been out of the water long enough to achieve a new “C Coefficient” of 1.1, 6 will be subtracted from 30, for an effective total of 24 minutes of diving. Note: The decompression time remains the same according to the table, so you need to do a mandatory 3 minute decompression and according to the table the new "C Coefficient" is 1.5.
2nd possible scenario: If the surface interval was not long enough to enter the 1.1 interval, and let's say the hour hand only reached the 1.3 interval, the number on the right will be used, which in this case is "3" as a multiplication factor to triple the 6 minute handicap/penalty, 6 x 3 = 18, 18 minutes must be subtracted from the 30 minute dive time. The new time for the second dive would be only 12 minutes. If the 1.2 range is reached, the 6 minute handicap would be doubled, then 12 minutes will be subtracted from the table's suggested 30 minute dive time, resulting in an effective total dive time of 18 minutes for the second dive.
If enough time on the surface exceeds the 1.1 range and moves into the "Normal" section of the scale, that's when we know all the nitrogen has been gassed out of the body. At that point you can plan a second dive as completely new (1st non-repetitive dive).
The Deepstar bezel was developed and patented based on scientific facts and research conducted in the early 1960s on gas saturation in the human body during diving. However, the above information is provided for historical verification purposes only and is not intended for actual use by tpday. The above repetitive dive scenarios and related calculations using historical French Navy tables from the 1960s have also been replaced or updated since then and are referenced here for historical verification purposes only.
Everything is clear right? Okay... even if you understood very little, I'll leave you a nice final photo with the subject of this article, the most beautiful DEEPSTAR in the history of underwater watchmaking.
