Ref. 6204 Production year: 1953 to 1955.
The Submariner ref. 6204 differed considerably to the ref. 6200. It had a slimmer case, small crown, parallel hands (aka pencil hands), and had submariner printed on the dials with a depth rating of 600ft which was about 180 metres but marked as 200 metres.
a semi-concealed bubble back movement cal.A260 measuring 9 3/4 lignes.
The dot on the seconds hand was at the edge of the dial. Waterproof
efficiency was announced at 600ft (approximately 180m) but that was
always in doubt.
Ref. 6205 Production year: 1953 to 1957
This model was announced almost same time as the ref. 6204. The movement is identical with the ref. 6204. The only difference being the dial and the winding stem. Waterproof efficiency was the same as the ref. 6204.
watches, although popular, did not meet the water efficiency required
by Rolex, and dials had visibility problems and by 1955 were replaced
by the ref. 6536 and the ref. 6538 non chronometer versions. Rolex were
still at an exprimental stage with these watches and did not hesitate
to upgrade them.
Ref. 6536 and 6538 (Production year 1955 to 1958)
Both these models had the same new revolutionary innovative Cal.1030 movement in which the Rotor wound in both directions. New less bulbous "non-concealed" movement. Mercedes hands, gilt lettering on the dial, minute markers to 3pm on the bezel.
cases. The efficiency of the automatic operation winding was improved.
There were ofcourse some differences in that the ref. 6536 with its
slightly thinner case and smaller winder was waterproof to 100m and
the ref. 6538 was waterproof to 200m.
These were the first officially chronometer rated Rolex Submariners. Around the end of 1958 the Submariners ref. 6538 and the ref. 6536 were replaced by the ref. 6536-1 and a new ref. 6538.
The ref. 6536/1 also had a chronometer rated movenent, Cal 1030, 25 jewels, adjusted to temperature and 5 positions(without "-1" has a non-chronometer movement). The dial was a black gloss, gilt print, with deph in silver, and also note the case was not as thick as the Ref 6536 which it had replaced.
Surprisingly, the ref. 6538 kept the same model reference. The new ref. 6538 Submariner had a heavier case, bezel markings for the first 15 minutes, and a red triangle at the 12 position. It had a larger Triplelock style crown, and because the name had not yet been registered, the words "Brevette" around the circunference ("Brevet" is not a name but a french word meaning patent).
The gloss dial still had gilt printing but now also was printed with the words " officailly certified chronometer" under the word Submariner, and powered by a new 1030 Chronometer rated movement.
All shoulderless Rolex Submariners should have black gloss dials and are known as the James Bond due to the sporting of one by Mr. Connery in Goldfinger. It looks like he is wearing the military issue A/6538: Nato strap, fixed bars , large 8mm crown but no minute markers first five minutes on the bezel insert. For me the only true James Bond Rolex Submariner is the new ref. 6538 model.
To the best of my knowledge the main difference betwwen a "Non-Chronometer" and a "Chronometer rated" movement is that the chronometer rated movements is of a higher quality and must undergo testing to determine if they are within certain tolerances such as whether it gains or loses a certain number of seconds per day over a period of days.
are position and temperature tests. For a Swiss made watch to be called
a chronometer, it must meet certain very high standards set by the Swiss
Official Chronometer Control (C.O.S.C. - Contrôle Officiel Suisse
des Chronomètres). The requirements are very severe: 15 days
and nights at five different positions under rapidly changing temperature
conditions from 8º C to 38º C.
1959, it all changed once again. Rolex was still not content, but were
now close to its vision of the perfect diving watch. Two final experimental
shoulderless submariners were introduced:- ref. 5508 replacing the ref.
6536 and ref. 5510 replacing the ref. 6538. The new models were equiped
with new 1500 series movements, Cal 1530 and Cal.1560 were used.
The ref. 5510 is a
strange interim model, has a large 8mm "Brevette" crown. Guaranteed
waterproof 200m/660ft, and was only produced for a short period of time
and in very few numbers.