Only Online Auction

Hong Kong, Mar 03, 2021

LOT 153

Ref. 166.077, self-winding large diver’s, centre-seconds, date, black dial and revolving bezel; “Seamaster 600 Professional”, so-called “PloProf”; stainless steel

HKD 43,100 - 61,000

CHF 5,000 - 7,000 / EUR 4,700 - 6,500 / USD 5,600 - 7,800

Stainless steel, self-winding, horizontal rectangular-shaped, large diver’s wristwatch, water-resistant with screwed case-back (under the bezel), screwed winding crown protected by the crown guard, 60-minute graduated bidirectional revolving bezel with black insertfor the decompression times, black dial with centre-seconds and one horological complication:
· Half-instantaneous date the month (aperture at 3 o’clock)

Grading System
Grade: AA

Very good

Case: 3


Movement: 3 **
Dial: 3-04



Brand Omega, Bienne / Biel

Model “Seamaster 600 Professional”, so-called “PloProf”

Reference 166.077

Year circa 1971

Movement No. 33 131 598

Case No. unnumbered (scratched “19654”)

Material stainless steel

Bracelet stainless steel Omega bracelet à mailles milanaise (mesh links) with clasp (Ref. 37 / 1247 / 237)

Diameter 43.7 mm. (bezel)

Caliber 1002

Dimensions Length 180 mm. (approx.)

Height 45.1 mm.

Width 55 mm.

Signature dial, case and movement


Omega “PloProf”

Developed in conjunction with Comex and the legendary Jacques-Yves Cousteau (1910-1997), Omega conceived and developed what was probably the first waterproof watch designed and built solely for the diving professional. The watch took four years to come to the market after extensive testing and arrived in 1970. It was nicknamed “PloProf” by the French speaking development team and derives from the French term “PLOngeur PROFessionnel” (Professional Diver).

Comex used early models of the “PloProf” and continued their research into living underwater for prolonged periods. One Issue that still concerned Comex was helium infiltration, which carried the danger of causing a watch crystal to pop out during decompression. There is no proof that this problem occurred with any “PloProf”, and later tests by the American diving research centre Ocean Systems Inc. in Tarrytown, NY, certified that the “PloProf” was ‘more watertight’ than a submarine. However, Comex wanted to be sure to combat the helium infiltration issue, rather than trust improved watch-case sealing. They chose to continue their research work with Rolex and Doxa to test their new Helium Expulsion Valve (HEV) designs. HEVs were incorporated in the Rolex “SeaDweller” which Comex used reliably for many, many years.

During the 4 years gestation period the “PloProf” was tested to 600 m. at the Omega factory and to 1 000 m. in the Gulf of Lion, off the coast of Marseilles. It was used by Commander Jacques Cousteau during his series of experiments designed to test man’s physical and psychological capacities when working at depths of 500 m. During ‘operation Janus’ in 1970, three Comex divers wore the watch at a depth of 250 m. for four hours a day, for eight days whilst exploring the sea floor in the Gulf of Ajaccio.

The watch was very expensive and the top of Omega’s range at the time of its launch. It is unclear, and unlikely, that Omega recouped its development costs in the model’s life-span between 1970 and 1979. The “PloProf” was a hit with professional divers but its price, approximately twice that of a Rolex “Submariner”, kept many hobby divers away. The Swiss retail price in 1973 was CHF 690.- on Isofrane strap, and CHF 720.- on Milanese bracelet (known these days as ‘mesh’). These factors mean that today these watches are reasonably rare.