A champion of the depths with the Luminor case
Officine Panerai had already excelled itself with a watch that was water-resistant to a depth of 1,000 metres. Now it has reached 2,500 metres with the new Panerai Luminor Submersible. Considerably exceeding the limits reached by the Luminor Submersible 1000M, this model has a new over-sized case of unbelievably complex construction.
Executed in titanium and steel, the case has a titanium back and the winding crown is fitted with seals designed to overcome every type of challenge. The water-resistance of the Panerai Luminor Submersible 2500M has demanded a long sequence of checking, with the case being tested to a pressure of 320 atmospheres. This has required the designers to optimise every element of the case, increasing the thickness in strategic places and applying the closest attention to the monitoring the critical points of this hyper-underwater watch: a genuinely professional model meeting the NIHGS 92-11 standards.
The bezel is of brushed steel with white gold numerals and markers. It stands out with the technically sophisticated process of its manufacture, in which the applied elements are soldered and riveted in place so as to withstand any situation in which the watch might be used. To improve the legibility of the diving times, the unidirectional rotating bezel with clicks at one-minute intervals has been constructed of two displaced sections; the inner part carrying the minutes has been subjected to chemical oxidation treatment by acids which makes the 60-minute scale absolutely indelible.
Great care has also been given to the construction of the helium valve, which is needed for dives to very great depths and for extended periods of time, in the course of which the underwater swimmer breathes a mixture of oxygen and helium gases. Helium has a simple molecular structure and it diffuses through the areas of contact between the parts of which the watch case is constructed. In the re-surfacing phase, the phenomenon of decompression takes place and, in order to prevent possible serious damage to the watch caused to the action of the helium, this gas is allowed to escape through the valve provided for this purpose, thus avoiding an excess of pressure inside the case.
The dial is designed for maximum clarity: black in colour, it has the date window at 3 o'clock, enlarged by the magnifying lens applied to the internal surface of the sapphire crystal which is 5.9 millimetres thick. The small seconds dial at 9 o'clock is made visible by the use of Tritium, a luminous substance applied also to a large part of the hands, and to the numerals and hour markers. The Panerai Luminor Submersible 2500M is fitted with the Panerai OP III calibre, with automatic winding, monometallic Glucydur balance, 21 jewels, an operating frequency of 28,800 vibrations/hour, personalised with the repeated inscription "Panerai" in the style of tapisserie decoration, the name being infinitely repeated on the bridges and oscillating weight.
The rubber strap is also completely new. It has moulded edges and the segments in contact with the case conceal a metal spring, the purpose of which is to maintain the correct tension of the watch and strap on the wrist of the swimmer in the course of a dive.