Tudor’s history is steeped in partnerships for research and development. One of the most well-known is its work with the French National Navy, the Marine Nationale (MN), in the development of the Submariner. The story begins in the late 1950s when the MN was sent a small batch of 7922 Submariner watches for testing. Small by today’s standards, these watches were just a touch bigger than a Rolex Datejust at 37mm with a small 6mm winding crown. These pieces were not, however, totally fit for purpose and so Tudor developed a thicker case and fitted it with a large 8mm “brevet” crown. These 7922s were much more usable and were rated to 100m. Ever striving to “go deeper”, Tudor then developed a “Big Crown” watch depth-rated to 200m — the reference 7924. The next issue was that during diving operations, the large crowns had a tendency to get knocked, which compromised the waterproofness of the case. Tudor’s response was the reference 7928, which featured newly introduced crown guards positioned either side of the 7mm winding crown, to offer protection to the crown when divers were carrying out their work. The 7928 subsequently had a near-decade-long production run.