A bit of history...
Water-resistant watches made their first appearance in 1942. Not least because of the underwater equipment available, the pressure-tightness initially only extended to ten bar. Shortly afterwards instruments for professional use came on the scene, which easily withstood depths of up to 200 metres.
Because air supply is always limited, time spent under water is extremely precious. To ensure the hours, minutes and seconds can be easily read, and as a reminder to divers to return to the surface in good time, product designers not only provided their diving wristwatches with striking illuminated dials and hands, but also incorporated a useful rotating bezel. For safety reasons, the rotating bezel can now exclusively be turned in an anticlockwise direction. In this way the time for remaining under water as displayed by the watch can only be reduced in the event of an accidental change, never increased. Because the inventor company had placed their unilaterally positioned rotating bezel under patent protection in the 1950s, their competitors either had to be content with copies that could be displaced on both sides, or proceed in a completely new direction.
This is precisely the option chosen by Ervin Piquerez SA (EPSA), based in Bassecourt in Switzerland. In 1956 the experienced watchmaking company presented a design of a new kind. The “Super Compressor”, water-resistant to twenty bar, boasted a truly innovative special feature: an integrated spring mechanism prevented compression and the damage that this could cause to the rubber sealing ring when the case was being screwed down. The outstanding features of this newcomer also included two crowns, one for winding and adjusting the hands, the other for deliberately adjusting the internal diving time rotating ring in both directions. The sophisticated design really made sense. Accidental actions and incorrect operation of the “device for individual preselection of a diving time” (as specified by the relevant standard) were almost impossible. One of these customers was Alpina. In 1967 the cooperative brought its “Alpina 10” on to the market. The “Super Compressor“ case, water-resistant to up to twenty bar, housed the 572C automatic calibre.
2016 Seastrong Diver Heritage
Just 50 years later, the highly regarded diving watch is back in the Alpina Collection, this time as the “Seastrong Diver Heritage”. Its illustrious predecessor from the 1960s is recalled in two operating elements in the right case flank and the rotating ring which was (at that time, for good reason) shifted into the inside of the case. With the help of the crown, the rotating ring can be quickly and easily adjusted at “2”. The 60 minute division is also useful for non divers. For example, the arrow can be positioned so that the approaching hour hand indicates when parking time is running out.
Thanks to the modern case design, the classic stainless steel case (now increased to a diameter of 42 millimetres) with its engraved screwed case back resists water pressure up to 30 bar, corresponding to a diving depth of 300 m/1000ft. The modern AL-525 automatic calibre ensures timekeeping. This is the equally reliable, robust and accurate SW 200 from Sellita. Alpina has refined it with its customary attention to detail, giving the ball bearing mounted rotor the asymmetric form signature to the brand. The balance wheel completes 28,800 vibrations per hour. Fully wound, it has 38 hours of power reserve.
