Many have asked me where "Cushion case" for the famous Gerald genta C shape case originated over the years. Which came first , who made it etc.
Here is patient zero. The earliest waterproof watch made by Girard Perregaux , the Amphibian is what really started it all. The water resistant case innovations from the early 40's Sea-Scouts , Sea Hawks and Amphibians were what led to the Deep Diver.
Not for purely aesthetic purpose , it was designed as GP wrote in the 1939 catalogue " curved comfortably fit a sailors wrist" essentially to be thinner at the lugs , and shorter than traditional straight long lugs , for comfort when sailors were paddling and pulling ropes to have less stress on the wrists compared to these traditional cases.
1939 Catalogue Scan
You can even see the case side beveling is remarkably identical to the famous Genta "Conny" that released 40 years after.The Amphibian tribute 39 Jewel gyromatic I sold to Amos Goh on its original 1950's advert wrote "The look of tomorrow on today's distinguished watch brand " and the statement couldn't be more correct.
Before this both Omega and Rolex used square cases with almost pocket watch conversion like wire lugs attached for their cushion cases which were no where as robust as the unibody lug and case stainless steel GP cushion case.The last time an Amphibian was sold publicly was in 2016 and all relumed and replaced movement.I would actually love to see a tribute model of this at 37mm as it is an extremely important piece of design history that GP doesn't even realize.