In the mid-1970s IWC decided to redesign the Ingenieur to give it a more "fashion forward" look.  With the new model, IWC tried to emulate the concept of one of its rivals.  A few years earlier, Audemars-Piguet had scored a major success with a luxury steel sport watch, the "Royal Oak," designed by Gerald Genta.  Soon thereafter IWC hired Genta (who also designed the steel Patek Philippe Nautilus) to design a newly conceived Ingenieur, along with two new watches, the Golf Club and Polo Club.  These were all included it what IWC called its Collection SL. IWC's "SL catalog" from 1976/77 indicates that the SL designation originally meant "Steel Line" - a further indication that the new collection was intended to evoke the success of the Royal Oak as a luxury watch in steel.  However, with the subsequent inclusion of non-steel watches in the SL line, along with the passage of time, the SL designation is now more often viewed as meaning "Sports Line."

The Ingenieur, ref. 1832.

The Jumbo SL was most likely presented to the public in 1976 and was definitely available in stores in 1977.  It was a large watch on a substantial integrated bracelet and was available as an automatic with the enhanced, super-antimagnetic c.8541ES movement (the ref. 1832 and ref. 9232 in 18kt) as well with a quartz ebauche (ref. 3003 etc.).  All are truly rare pieces.  Because of its large case (40mm diameter, 12mm thick) the ref. 1832 Ingenieur is also affectionately referred to as the "Tresor" (German for "safe" or "strong room"), or the "Jumbo" or "Fat" Ingenieur.

Two pages from IWC's 1979 catalog featuring the "Jumbo" Ingenieur. Above left caption reads: An exclusive IWC model, stainless steel, sturdy stainless wristband, super anti-magnetic up to 1000 Oersted (80,000 Ampere/Metre), with special shockproofing, water-resistant down to 120 metres, sapphire glass with reflection-inhibiting coating. Same model in quartz (to 500 Oersted).

IWC sales figures show that these watches sold very poorly with only 534 of the automatic jumbos turning up in the sales records (see chart below).  Besides being a bit clunky, the Jumbo did not sell very well because of its high price and the fact that it was introduced during the peak of the "quartz crisis."  In hindsight, the Genta Ingenieurs could be called "Right Watch, Wrong Time."  To be sure, in its most recent catalog, IWC refers to the 1832 Jumbo as a "cult watch," an apt description for a piece of which less than 1000 were ever produced.

Roman numerals on white dials were used for some "Jumbo" Ingenieurs (as shown in the above pages from IWC's 1980 catalog) but only the quartz models. Also only available in quartz were the first ladies Ingenieurs.

Finally, there were two quartz versions of the Jumbo Ingenieur.  The first issue was more or less identical in size and thickness to the automatic and equipped with the quartz calibre 2405 (ref. 3003 or 9232 in solid 18kt gold).  The later issue was first produced in 1980 with the new quartz calibre 2250, a more comfortable bracelet and thinner case (ref. 3303, 9701 in 18k solid gold and 9720 with 35 diamonds).  The ref. 3303 (9701, 9720) replaced the 3003 (9503) in 1980.  It had almost the same diameter (40 x 38) and look, but was much flatter (about half of the height).  It was also now equipped with the quartz calibre 2250 (the ref. 3003 had the c.2405).

The following links are to the 1980 dealer sheets for the ref. 1832, ref. 3003 and ref. 9232.

Excerpt from IWC's 1980 catalog.

* Klassik Uhren says that records show that IWC ordered 45 cases for the 9232 automatic Ingenieur and 55 cases for the 9503 Ingenieur. Following customers' wishes (as there was less demand for quartz than automatic movements) they changed 10 reference 9503s from quartz to automatic movement. These thus have a reference code of 9503 (cases came with reference code already stamped inside). However, due to the different thickness of the quartz and automatic movements, this statement is a bit puzzling. It is also known that of the other quartz Jumbo Ingenieurs, there were 369 made -- ref. 3303 SS or Mixte (149 +160), ref. 9701 yellow gold (56), ref.  9720 yellow gold with 35 diamonds (4).

Ref. 1832 with black-waffle dial.

Detail of the dial showing the "waffle" pattern.

The Jumbo with a silver/rhodium-plated dial.

The Jumbo in steel and gold with gold dial.

The ref. 9232 -- Jumbo in solid 18kt gold.

Ref. 3303 quartz Jumbo Ingenieur.

The "Jumbo" Ingenieur SL "evolved" into the "Skinny" Ingenieur SL (ref. 3506) with ETA ebauche. Produced from approximately 1983-1989.

The Ingenieur 500,000 A/m, even more antimagnetic than the "normal" Ingenieur. On bracelet, it was the ref. 3508 (or 9238 in 18k), and on strap it was the ref. 3518 (or 9258). Produced from approximately 1989-1992.

The most recent iteration of the Ingenieur was the ref. 3521 and 9239 (18kt) featuring a JLC ebauche. This model has been listed in the catalog as recently as 2000, although only the 18kt Ref 9239 appears in the 2002 2001 catalog.