IWC FIRST AQUATIMER - Vintage Collectors Guide

IWC FIRST AQUATIMER - Vintage Collectors Guide



With the development of aqualung (scuba) gear post world war II, Dr Hans Haas and other experts brought a new and fantastic underwater world into the focus of beginner and amateur divers. Many films and books aroused the interest in diving of the post war public. Divers needed watches to monitor the remaining time available underwater, and a broad market for reliable dive watches was created.

Early dive watches were a single crown, with the important introduction of an external rotating bezel to help monitor scuba tank time.  This external bezel could be accidentally moved by contact with other objects.

In 1964 Enicar produced a variety of 2 crown diver watches, using Ervin Piquerez S.A. (EPSA) manufactured, and patented, waterproof cases, utilising an internal bezel.  These cases were either 36mm or 42mm in diameter and featured 2 oversize crowns.  EPSA made waterproof cases in these sizes for a variety of watch manufacturers, and IWC brought the first 2 crown watch with the name “Aquatimer” to the market in 1967, and perhaps as early as November 1966.

Some of the rarer and more prestigious examples of EPSA cases include the Univeral Geneve Polerouter Sub, the Longines 7150-1, the Vulcain Nautical Cricket diving alarm, the Lip Nautic-Ski and the Jaeger-LeCoultre Deep Sea Alarm, and the later Jaeger-LeCoultre Polaris with 3 crowns.


The first Aquatimer model carried the reference number 812, then 812 AD, and finally 1812 when IWC standardised on 4 digit model numbers in about 1972  It was waterproof up to 200m. The AD stood for the Automatic and Date functions provided by the IWC caliber 8541 movement used in the Aquatimer.

Below is a mint version of the Aquatimer 1812 on a Tropic strap, and early 812 models most commonly did not display the IWC logo.

Mint aquatimer 1812
Photo courtesy: member XX-FF


The watch was medium in size, 37mm diameter, and featured 2 large crowns, embossed with the IWC fish.  The large crowns supposedly made it easy to operate the watch with gloved hands.  The jury is out on the benefits of an internal bezel, versus the benefits of an external bezel, but the internal bezel gives a more “dressy” feel.

The dial featured an internal bezel, with tick marks at the 5-minute position, dual ticks at 12, numerals at 15, 30 and 45, and smaller minute tick marks from 0 to 15.  The hands were tritium painted baton shaped, with a paddle second hand.

The dial itself had raised fluted tritium painted baton indexes, and the date position is at 3 o’clock.

The internal bezel could be adjusted by the crown at 2 o’clock in one direction.

The IWC logo was or was not present, but the script, International Watch Co, in cursive, and SCHAFFHAUSEN below were a feature of the dial at 12 o’clock.  IWC watches from the middle 1950s to the late 1960s (such as the Ingenieur) did not feature the IWC logo, and if they were waterproof they used the fish logo crown.

Sometime in the late 1960s, (maybe 1970), an applied “IWC” logo was introduced on the dial above the script International Watch Co.  It is not certain whether this logo was used with much regularity and this is the source of some confusion.

The IWC AQUATIMER above AUTOMATIC featured at 6 o’clock, with T SWISS T below that index.

The case back featured a submarine image in a central ring, and the outside read AQUATIMER IWC WATERPROOF 20ATU, together with the EPSA case reference number.


Case back IWC Aquatimer
Image courtesy:


Four combinations of dial and bezel were available as in the extract below; black dial, black bezel; black dial, silvered bezel; white dial, silvered bezel; and white dial, black bezel.

The model number shown is 85353T, a short-lived numbering experiment by IWC.

1812 catalogue


Perhaps the earliest known model is the all white version below with a fish on the dial, thought to be a prototype, although IWC is embossed on the dial.  This has a thin pointer second hand and a short square-tipped baton hour hand.  The fish image is embossed on the crowns.  Model number 812 is engraved on the inside of the back case.

aquatimer 812
Photo courtesy: Konrad Knirim


The IWC caliber 8541 (23 jewels) powered the Aquatimer 812.

The mechanical automatic self-winding IWC caliber 8541 movement is rhodium-plated, with fausses cotes embellishment, and a shock absorber mechanism. It is constructed with 23 jewels, a straight-line lever escapement, and a Pellaton winding movement. It includes a monometallic balance that’s adjusted for heat, cold, and 5 positions, and a self-compensating Breguet balance spring.

In 1968 another Aquatimer was produced and manufactured in parallel, reference 816AD (or 1816), which, in contrast to the first model 812, had a pillow-shaped housing and a water-tightness of 300m. The caliber was the modified 8541, the 8541B (25 jewels).  The other characteristics are the same.

Aquatimer 816

This 816AD watch and succeeding Aquatimer models are not the subject of this article.

In August 1978, model 1822 was produced as a replacement watch for model 1816 due to technical difficulties in model 1816 with the 8541 caliber movement.  The only visible difference is the lack of the submarine engraving on the case back, but only in some watches. Both the 1812 and 1816/1822 models were offered jointly in the years of their production.

In 1982, after a total of 2000 copies of models 1812, and 1816/1822, production of these models ceased.

The all black Aquatimer is the most common model, the 812 did not feature the IWC logo.  The sweep second hand has a rectangular paddle tip, as opposed to the possible prototype above.


Aquatimer 812AD no IWC

Below, is a  later model 812AD with the IWC logo.  The 812AD model also came without the IWC logo as a transition model.

Aquatimer 812AD

A rare IWC stamped Gay Freres beads of rice bracelet shown below, as the tropic strap was more common.

Aquatimer bracelet


A black dial model with box and papers recently sold for $30,000.

1812 model IWC


1812 aquatimer


The black dial, silvered bezel model is shown below, without the IWC logo.


812 aquatimer
Image courtesy: Amsterdam Vintage Watches


And a model with IWC embossed.

aquatimer black dial white bezel
Image courtesy:


And, below, 2 images of the white dial, black bezel model.

This image shows the original Gay Freres strap, and the Cal 8541 engraving.
IWC 812
And, finally the white dial, silver bezel version.

white aquatimer
Image courtesy:  Meertz World of Time

White Aquatimer




Super Compressor is a trademarked name for specific case designs made by the case manufacturer Ervin Piquerez S.A. (EPSA). They designed a patented case sealing method that actually became more water tight the deeper the watch went. The deeper you went, the more pressure was applied to the case-back, pressing it against the O-ring gasket.

The patent extract is shown below.

epsa patent

The 2 crown Super Compressor case has crowns at 11 and 19 minutes, and the screw in version was covered by patents Brevet #317537 and Brevet #337462.   The EPSA logo is a dive helmet featured below on the inside of an Aquatimer case back.  The IWC Probus Scafusia motto also features on the case back.


IWC inside case back
Image courtesy:


Some later Aquatimer case backs did not feature the EPSA logo, but still referred to the EPSA patents, and had the IWC Probus Scafusia logo.

Aquatimer inside case back


Aquatimer crowns


IWC crowns


caseback Aquatimer


The IWC catalogue A01686/01.91  October 1989 describes the 8541 movement.

A patent, dated 7 June 1950, under the number 284841 effectively marked the birth of the Pellaton winding system that has remained such a central feature of IWC’s automatic movements to this day.

IWC’s Technical Director Albert Pellaton developed the revolutionary pawl-winding system that featured in the company’s first automatic movement, the 85 calibre. Pellaton’s design was destined to go down in the annals of watchmaking history.


IWC 8541 movement

The reciprocating motion transmitted to the ratchet support by the cam 1 had a dual function: it enabled the winding rotor mounted on the pivot 2 to rotate freely, and it also activated the shock absorber 3 which cushioned the rotor, the cam and the entire mounting from knocks in any direction. The heart-shaped cam (which had long been in use as a means of returning chronograph hands to the zero position) enabled maximum exploitation of energy, while both discs 4 on the prongs of the ratchet support, which rotated against the contact surface of the cam, considerably reduced the energy loss through friction. The rotary movement of the ratchet wheel 5 was transferred directly via its pinion 6 to the winding wheels 7 and 8 without the need for an intermediate geared coupling. Besides keeping the movement extremely slim, this also reduced production costs and, not least, eliminated a source of potential malfunction.

Two further IWC innovations were also protected by Swiss patent. Firstly, the combined automatic winding mechanism and movement and, secondly. the winding rotor mounting. One of the most outstanding external features of the IWC automatic wristwatch movement is the case with which it can be serviced: the winding rotor can be removed from its pivot 11 simply by loosening a single screw and pulling back the retaining fork 10.

IWC 8541 movement


The rotor mounting is likewise secured by one screw for easy removal, while the other two main elements in the automatic winding mechanism, the ratchet mounting with the fork and the ratchet itself, are both mounted under a single bridge, which is held in position by two screws. When the watch was being designed very special care was taken to ensure unimpeded access to the barrel. This can be detached easily, with no need for prior removal of other parts of the movement, once the two screws retaining the barrel bridge have been loosened. The efficiency of the winding rotor’s shock absorbing system has made it possible to fit the bearing with two sensitive rubies 12 and 13. These jewels, together with the slim, highly polished steel pinion 11, have helped to make the automatic winding mechanism highly efficient.

All this contributed to making the IWC watches with Calibre 8541 watchmaking masterpieces.

8541 cal aquatimer



Usually, in this series of articles, we make recommendations on watches in the series.  However, for the 812 Aquatimer, any version of the model is ultra-desirable.

However, the Gay Freres strap (type 12) is much rarer than the tropic strap.

812 aquatimer