IWC Ingenieur SL

by Stephen Foskett (Grail Watch)

Ingenieur SL (for “Steel Line”) was a brand used for as series of watches in the Ingenieur family produced by IWC between 1976 and 2000.

The Original Ingenieur

The Ingenieur brand first appeared in 1954 and has been applied to watches designed for scientific, technical, and exploration usage. Most Ingenieur watches feature water resistance, anti-magnetic capabilities, and precise timing. In this way, the Ingenieur is similar to the Rolex Milgauss and Rolex Explorer. From the beginning, IWC Ingenieur watches have features a logo with “INGENIEUR” in capital letters above a lightning bolt from top left to bottom right.

The Ingenieur line began with the Ref. 666A and 666AD and was refreshed in 1967 with more modern styling as the Ref. 866. But the line was aging by the 1970s and sales were falling precipitously. Consumers wanted a new style of watch, and quartz movement technology allowed an explosion of new styles.

Gérald Genta's Ingenieur SL

IWC Ingenieur from the 1970's
© IWC

The Ingenieur brand was refreshed and advanced in 1976 with the launch of an all-new design penned by famed watch designer, Gérald Genta. This was a cushion case watch like his well-received Audemars Piguet Royal Oak, then a just few years old. It also resembled the contemporary Vacheron Constantin 222 and Omega Constellation, with which it competed. Genta designed three “SL” or “Steel Line” watches, of which only the Ingenieur was presented for sale.

Genta's Ingenieur SL Ref. 1832 featured a tonneau-shaped case with an integrated bracelet. The dial was surrounded by a screwed-in bezel with five “bores” to allow a tool to be attached, a signature styling element similar to the 8 through-screws on the Royal Oak. The guilloche dial had a checkerboard pattern said to resemble graph paper. The 40 mm case was considered extremely large at the time, giving this model the “Jumbo” nickname. Inside was IWC's anti-magnetic Cal. 8541B. At that time, IWC also produced a quartz version of Genta's Ingenieur design, Ref. 3003 with Cal. 2405. These models failed to achieve the success of the Royal Oak, and just 978 examples were produced.

The quartz model was updated in 1980 with the slimmer Cal. 2250, allowing the bulky case to be slimmed down to just 8 mm. This new Ref. 3303 was not much more successful, with only 369 examples sold in steel, gold, and diamond through 1985.

Lady Ingenieur models were also produced starting in 1980, with both 26 mm and 30 mm cases with quartz and automatic (F. Piguet) movements. These remained available through 1989, with a 25 mm titanium and yellow gold version introduced in 1983. A 32 mm titanium/yellow gold version for men was produced from 1984 through 1989.

In 1981, IWC introduced the quartz "Skinny" Ingenieur SL, Ref. 3305, which had a smaller case but still remained true to Genta's design. The 34 mm case was just 8.8 mm thick, bringing the watch down to more contemporary sizing. This was joined in 1983 by a "Skinny" automatic Ref. 3505. Lacking a compact-enough movement, IWC turned to ETA to supply the ETA 2892, finished to IWC specifications and known as Cal. 375.

Demise of the SL Brand

The first complicated Ingenieur was introduced in 1985 A perpetual calendar module was added to become Cal. 3757 for the Ref. 9240 Ingenieur Perpetual. It used a 34.5 mm case similar to the “Skinny” model with a movement similar to the groundbreaking IWC Da Vinci. This model lasted, with some revisions to the movement and reference numbers, through 1992. But the Perpetual Calendar did not feature the trademark INGENIEUR logo on the dial, nor did it include the initials “SL”.

In fact, the “SL” brand was retired after Ref. 3505, even though Genta's novel sandwich case would survive for another decade.

Another complication appeared in 1988, the Ref. 3734 Ingenieur Chronograph. This model used a petite 30 mm case, making it unisex for the time, thanks to the “Mechaquartz” Cal. 633 from Jaeger-LeCoultre. Versions would be produced for only a short time, with sales stopped by 1993.

Another major advance for the line came in 1989 with the introduction of an Ingenieur capable of withstanding 500,000 A/m without a soft iron cage. Instead Ref. 3508 had an escapement, balance wheel, and hairspring constructed of anti-magnetic materials like niobium-zirconium 25. Although advanced, these materials proved difficult to produce reliably. Just 3,000 examples of this petite 34 mm Ingenieur were made through 1992.

Most existing Ingenieur models were phased out starting in 1990, with a single model making up the bulk of the range for the next decade. IWC again turned to Jaeger-LeCoultre for a movement, equipping the new Ingenieur Officially Certified Chronometer Ref. 3521 with Cal. 889/2 between 1993 and 2000. The case was again 34 mm and 8.8 mm thick, the same dimensions as the “Skinny” Ingenieur of the previous decade.

The Ingenieur Chrono Alarm Ref. 3805 was the only other Ingenieur model available in the 1990s. Introduced in 1991, it used the Jaeger-LeCoultre Mechaquartz movement from the short-lived Ingenieur Chronograph but fitted in a more masculine 34 mm case. The wedge-shaped push buttons at 2 00 and 4 00 would become the form for future Ingenieur Chronograph watches in coming decades.

Post-SL Ingenieurs

IWC Ingenieur Automatic
© IWC

The Ingenieur line was refreshed in 2005 with an in-house movement, Cal. 80110. This Ingenieur Automatic, Ref. 3227 strongly recalled Genta's Ingenieur SL but was an all-new design in a 42.5 mm case. The stainless steel model, Ref. IW322701, was joined by a titanium-cased co-branded Mercedes AMG model, Ref. IW322702/IW322703. IWC also launched a smaller Ingenieur model that year, the "Midsize" Ref. 4515. It housed an ETA 2892A2-based Cal. 30110 inside a 34 mm by 10 mm case reminiscent of the “Skinny” Ingenieur of two decades earlier. Rounding out the new lineup was a next-generation Ingenieur Chronograph, Ref. 3725. The case was massively enlarged to 42.5 mm with large wedge-shaped pushbuttons to operate the Valjoux 7750-based Cal. 79350. The steel Ref. IW372501 was joined by titanium AMG models, Ref. IW372503/IW372503.

The titanium AMG models were a hit, as was the new angular Chronograph case. So IWC began launching larger and sportier pieces. The most important was the Ref. 5005 "Big" Ingenieur with its massive 45.5 mm case and 8-day Cal. 51113. This was joined by a "Big" Chronograph, Ref. 3784, with the in-house Cal. 89361. These fit the “big watch” trend of the time and began moving the line away from Genta's 1970's design. 2009's Ref. 3236 "Mission Earth" was even larger, with a bulky case but no extra complications.

Screwed-On Bezels

Ceramic was in, as seen in Ref. 3234 with its ceramic bezel. But the 2011 Ref. 3765 Ingenieur Double Chronograph was the real breakthrough design. Gone was Genta's screw-down bezel, replaced by a 5-screw attachment system. This would be used on seven other references over the following years.

The main offering was now a less-expensive and smaller Ingenieur Automatic, Ref. 3239. The case was reduced to 40 mm but wedge-shaped crown guards reminiscent of the Big Ingenieur added to the visual bulk. Inside was IWC's Cal. 30110, a re-worked ETA 2892, since IWC still lacked a compact in-house movement. This was also the only anti-magnetic Ingenieur model of the era.

Like the F1 team, AMG introduced many models with exotic materials and design, including the Ref. 3224 Carbon Performance Ceramic, Ref. 3225 AMG Black Series Ceramic, and Ref. 3246 AMG GT. The complex Ref. 3792 Perpetual Calendar Digital Date-Month also included ceramic parts and reflected the racing/technical character, as did the new Ref. 3264 Dual Time Titanium and refreshed Ref. 3865 Double Chronograph Titanium. All of these featured the 5-screw bezel design first introduced in the Double Chronograph.

The crowning piece of the era was the Ref. 5900 Ingenieur Constant-Force Tourbillon. Not only was it the most complex (and expensive) Ingenieur ever, it was also the first hand-winding model to wear the name. Although it still had a 5-bore bezel and tonneau case like the Ingenieur SL, the Tourbillon no longer had a three-piece case. It would prove to be one of the last models to resemble Genta's signature design.

The Modern Ingenieur

The Ingenieur lineup was wiped clean again in 2017 with four new models introduced, none of which featured the Genta-style cushion case and five-bore bezel or the wedge-shaped crown guards and pushers of the Big Ingenieur. Gone too were the ceramic and titanium models that had been an Ingenieur hallmark since the 1980s. Even the Ingenieur name and logo disappeared from the faces of all but two models.