thank you for a superb article. I just came home - read it¨twice and will read it again. Collection of pictures/data will be for reference,Im shure Ill come back to this many times. The Dive watches are the mythical, mystical, they represent dreams of exploration and unchartered frontiers - there is a lot of romantisicm in these old pieces to feed our imagination and dreams. You so elegantly bring it out by this article. I really enjoyed this read.
You clearly show that JLC have a tradition for dive watches, however I dont consider them "professional / heavy duty" like some of the stuff Rolex/Omega has done - these are watches to be taken seriously.
You raise the question regarding the Vulcain Cricket Nautical - this was released in 1961, while their first alarm watch was released in 1947.
thank you Nicolas
all the best