IWC Ingenieur SL
Both Rolex and IWC saw the need for a watch for engineers and scientists in the 1950s, combining rugged automatic movements, water-resistant cases, and anti-magnetic concepts in the Rolex Milgauss and this IWC Ingenieur. The concept has remained for over 50 years, with the IWC Ingenieur family spawning many models, including an iconic redesign by famed designer Gerald Genta, a pivot to motor racing, and the use of exotic materials like titanium and ceramic.
The Ingenieur had become somewhat stale by the mid 1970s but famed designer Gerald Genta had shown a stylistic path forward with his groundbreaking Audemars Piguet Royal Oak in 1972. Genta designed three “SL” or “Steel Line” watches for IWC, of which only the Ingenieur was presented for sale. The production “Ingenieur SL”, introduced in 1976. Like the Royal Oak, Patek Philippe Nautilus, and Vacheron Constantin 222, the new Ingenieur SL had a “sandwich” case, with both the caseback and bezel being removable. But unlike those others, the Ingenieur used a novel approach The Bezel and crystal were screwed in place like a screwed caseback using five “bores” spaced around the circular bezel. This resembles the Royal Oak's screws but is significantly different technically.
Genta's Ingenieur SL case was much larger than previous watches, with an integrated bracelet and tonneau shape. Measuring 40 mm by 38 mm around a 30 mm dial, the “Jumbo” nickname seemed appropriate for the time. Poor sales spurred IWC to search for a smaller and thinner movement to allow the watch to be reduced in size starting with the thinner Ref. 3303 but culminating with this Ref. 3305.
Introduced in 1981, the “Skinny” Ingenieur SL was much more appropriate for the times. It used a quartz movement, the ETA-derived Cal. 2250, in a 34 mm diameter, 8.8 mm thick case. Although it strongly resembled the original Ingenieur SL, these tighter dimensions give the dial a more crowded look. The rest of the design remained the same, with lumed sword hands, simple bar markers on the hours. Most models lack the checkerboard guilloché dial of the original, and most feature a date window at 3 00 and the “INGENIEUR SL” logo above 6 00.
The original quartz Ref. 3305 came in stainless steel or gold filled versions, with a solid 18 karat yellow gold Ref. 9730 offered as well. Other versions include the Ref. 3315, steel with a leather or textile strap, gold Ref. 9703, and diamond Ref. 9721 and 9724.
IWC also procured a small automatic movement from ETA, Cal. 375 (ETA 2892), which they used to create a smaller Ingenieur SL Automatic, Ref. 3505. It shared the same “Skinny” case as the Ref. 3305 Quartz model, including the soft strap version, Ref. 3515, and the a solid gold Ref. 9225. A pair of special diamond pave models, Ref. 0914, were produced for the Sultanate of Muscat and Oman. These original “Skinny” Ingenieur SL Automatic references were introduced in 1983 and offered through 1985.
ETA introduced the smaller 2892-2 shortly after this watch was released, and this was adopted by IWC starting in 1985 as their Cal. 3752 or 37531. Watches with this movement are quite similar to their predecessor, with the same case and materials, but have new reference numbers. The steel/bracelet model became Ref. 3506, while the steel/strap offering was 3516. The gold models were Ref. 9230 and 9236, with the diamond bezel offering becoming Ref. 9231. Most of these continued to be offered through 1989.
The old "Jumbo" Ref. 1832 remained on offer through about 1985 alongside the slimmer "Jumbo" quartz Ref. 3303. But most buyers were more interested in this “Skinny” 34 mm Ref. 3305/3505/3506 offering through the end of the decade. Another option was the tiny “Lady” Ingenieur in 26 mm Ref. 4501 or 30 mm Ref. 4503 quartz or 30 mm Ref. 4413 automatic.
In 1985, IWC introduced one of the first titanium watches, the 32 mm quartz Ref. 3350 "Ingenieur in Titanium" for men and 25 mm quartz Ref. 4550 "Ingenieur in Titanium" for ladies. These models were offered in yellow gold and “mixte”, and were also available through 1989. The company also produced a perpetual calendar model, the Ref. 9240 and Ref. 3540 and introduced the first Ingenieur chronograph, Ref. 3733.
The “Skinny” 34 mm Ingenieur SL offerings were replaced by the automatic Ref. 3508 "500,000 A/m" Ingenieur in 1989. The chronograph was replaced by the larger Ref. 3805, and the other models were retired.