The production of the first Submariner 5512 falls into the tail end of the 1950s Small Crown era. Their serial range comes prior to those of Small Crowns that were also produced around the same time in 1959. The Ref. 5512 has many more characteristics in common with the Ref. 5510 Big Crown, which it was meant to replace, than Small Crowns. The Small Crowns have a thinner case and a lower depth rating (100/330) and were clearly being phased out. The main difference between the 5510 and the 5512 is the redesigned case design which now has the famous Rolex crown guards. The 5512 is powered by the 1530 movement, similarly to the 5508 and the 5510 Big Crown. It is interesting to note that the dial size on the 5512 is the same as other Big Crowns, which are slightly smaller dials than the on Small Crowns..

Case No. 478,xxx

The first batch of the early 5512 featured one of the rarest insert variants. The "Long Five" insert with a red triangle at 12:00 was produced for a very short time. The original design probably called for a red triangle at 12:00 similar to other Submariner models from the same period. But it was faster and easier to produce a black and white insert, so the red triangle was replaced by the more common Long Five we are accustomed to seeing in the early 1960s.

One of most identifiable feature on these early 5512 models were the crown guards, hence their monikers. The Square Guards were probably too good at protecting the crown and made it difficult to unscrew or wind. This problem was caught early and many cases from the same serial range were modified to become "Eagle Beaks," which gave better access to the crown. Later, a more refined version of the Eagle Beaks were known as "Pointy Crown Guards."

The hands are made from a metal alloy that was Rhodium plated. They are also flat on top, a design that came to be known by collectors as "Gilt Hands." When the hands move about the face of the dial, the sweep-seconds hand appears to lightly graze the "Chapter" ring of the minute track. When it briefly glides over the minute hand, they are perfectly aligned.

The luminous material on the dial and hands from 1959 was manually applied Strontium also called Tritium which has a lower radiation level than Radium material from 1958 and prior. This material has a much stronger reaction when exposed to UV light than Radium. Even after the UV light is removed, there is a lasting reaction, especially in a dark environment. Please see the "Luminous" section for further information about characteristics of glow-in-the-dark materials used by Rolex.

The outer case back is rounded and the reference number 5512 is stamped inside the case back with a date code. The first batch of 5512 case backs is marked with III. 59. The Submariner 5512 was produced in 1959 at the same time as the last batches of  6536-1 and 5508 were being assembled.

In 1959, two distinct clasp designs were being commissioned by Rolex from bracelet maker Gay Frères. The Small Logo, which became the standard clasp for the Swiss Rivet bracelets until 1969 and the Big Logo which is coveted by collectors but was only produced until 1960. Additional details about end links and bracelets can be found here.

Small Logo clasp introduced in 1958

Big Logo clasp introduced in 1958