Sinn U18

The Sinn U18 is a tangible piece of naval history, a diving watch crafted from the very steel that once formed the outer hull of the German submarine U18. This isn't just a watch with a nautical theme; it's a direct link to a vessel that patrolled the seas for nearly four decades, accumulating an impressive 192,842 nautical miles – the equivalent of circumnavigating the globe nine times. This impressive service record, meticulously kept by a former crew member, adds a layer of authenticity and provenance that's rare in the world of horology.

Sinn's relationship with submarine steel isn't new. For two decades, the company has utilized a specialized steel developed by ThyssenKrupp for its U series of diving watches. This steel, originally intended for the outer hulls of Type 206 and Type 212 submarines, is prized for its exceptional strength and seawater resistance. However, the U18 stands apart. Its steel isn't fresh from the factory; it's steel that has endured the relentless pressures of the deep sea, the corrosive power of saltwater, and the constant wear and tear of active naval service. This history is palpable, giving the U18 a character and depth that goes beyond its technical specifications.



The transformation of this historic steel into a watch case was entrusted to Sächsische Uhrentechnologie GmbH Glashütte (SUG), a renowned watch case manufacturer based in Saxony, Germany. SUG, a long-time partner of Sinn, is known for its meticulous craftsmanship and ability to bring even the most complex designs to life. The challenge with the U18 lay in the unique geometry of the submarine's outer hull. Unlike the typical steel bars used for watch cases, the U18's steel came in curved sheets. This required a different approach, with each blank individually fed into the machining process by hand. The water jet cutting process also increased tool wear, and the finishing process was more complex due to the steel's prior military use. Despite these hurdles, SUG's expertise ensured that the final product met Sinn's exacting standards while retaining the inherent character of the original submarine steel.

The dial of the U18 is a captivating representation of the ocean depths. The high-gloss finish, visible through a clear, anti-reflective sapphire crystal, features a dark bluish-green base tone reminiscent of the sea at around 30 meters – a nod to the U18's operational depth of up to 100 meters. Stylized air bubbles, rendered in metallic blues and greens, create a three-dimensional effect, adding visual depth and a sense of movement. The dial also pays homage to the U18's legacy, displaying the number of nautical miles traveled and the submarine's type designation.

Turning the watch over reveals a case back engraved with a silhouette of the Type 206 submarine, further reinforcing the connection to its maritime origins. The U18 isn't just about aesthetics; it's a serious diving instrument. It has been rigorously tested according to European diving equipment standards and certified by an independent institute. It boasts water resistance and pressure resistance to an impressive 2,000 meters (200 bar), ensuring its reliability in even the most demanding underwater environments.



The technical details of the U18 reflect Sinn's commitment to functionality and durability. The watch is powered by a Sellita SW300-1 self-winding movement, a reliable workhorse known for its accuracy and robustness. The movement features 25 jewels, a frequency of 28,800 semi-oscillations per hour, and a seconds stop function for precise time setting. It's also anti-magnetic according to DIN 8309 standards, protecting it from the potentially disruptive effects of magnetic fields.

The 44mm case is crafted from the high-strength, seawater-resistant German Submarine Steel, satinized for a sleek, understated look. The diver's bezel, also made from the same submarine steel, features Sinn's TEGIMENT technology, making it exceptionally scratch-resistant. The captive bezel design, with minute ratcheting, ensures that it won't be accidentally dislodged during a dive. The crown is positioned at 4 o'clock, a design choice that prevents it from digging into the back of the hand during active use.

The dial's indices and hands are coated with luminescent material, ensuring excellent legibility in low-light conditions. The watch is also equipped with Sinn's Ar-Dehumidifying Technology, which enhances functional reliability and prevents fogging of the crystal. This is achieved through a combination of a drying capsule, special seals, and a protective gas filling.

The Sinn U18's use of German Submarine Steel is a significant part of its story. This particular steel, sourced from the decommissioned U18, is not just any steel; it's a material with a proven track record of performance under extreme conditions. The steel for the outer hulls of the Type 206 submarines, and later the Type 212, was specially developed by ThyssenKrupp to withstand the immense pressures and corrosive environment of the deep sea. This makes it an ideal choice for a diving watch, offering exceptional strength, durability, and resistance to saltwater corrosion. The steel underwent rigorous testing, not only according to standard DIN 8310 for water resistance, but also to the diving norm DIN 8306. It has been tested to meet European standards, making the watch reliable for even a professional diver.



Sinn's decision to use recycled steel from a decommissioned submarine adds a layer of historical significance and environmental responsibility to the U18. Instead of using newly produced steel, Sinn is giving a second life to a material that has already served a demanding purpose. This aligns with a growing trend towards sustainability and upcycling in various industries, including watchmaking. It's a way of honoring the past while embracing a more conscious approach to manufacturing.

The design of the U18 is a careful balance of functionality and aesthetics. The 44mm case diameter provides ample space for the dial and bezel, ensuring excellent legibility. The satinized finish of the steel gives the watch a tool-like appearance, emphasizing its purpose as a robust diving instrument. The captive diver's bezel, with its minute ratcheting, is designed for precise timing of dives, while the luminous markings on the dial and hands ensure visibility in low-light conditions.

The dial's design, with its deep blue-green color and stylized air bubbles, evokes the underwater world. It's a subtle yet effective way of connecting the watch to its maritime heritage. The inclusion of the U18's nautical miles traveled and type designation on the dial adds a touch of historical detail, reminding the wearer of the watch's unique provenance.

The U18's movement, the Sellita SW300-1, is a reliable and accurate automatic movement. It's a widely used movement in the watch industry, known for its robustness and ease of service. The choice of this movement reflects Sinn's focus on practicality and functionality, prioritizing performance over unnecessary complications.



The U18 comes with a satinized solid stainless steel bracelet. The bracelet complements the watch's overall aesthetic, providing a secure and comfortable fit. The 22mm band lug width allows for the use of a variety of aftermarket straps, giving owners the option to customize the look of their watch.

The overall construction of the watch demonstrates the commitment to excellence. The sapphire crystal is not only scratch-resistant but also anti-reflective on both sides, maximizing visibility of the dial in all lighting conditions. The screw-fastened case back and screwable crown contribute to the watch's impressive water resistance, ensuring that it can withstand the pressures of deep diving.

The Sinn U18 represents a convergence of history, engineering, and design. It's a watch that appeals not only to diving enthusiasts but also to those who appreciate the story behind the object. It's a tangible link to a significant piece of naval history, a testament to German engineering, and a symbol of sustainable practices.

The limited edition nature of the U18, with only 1,000 pieces available, adds to its exclusivity and desirability. Each watch comes with an engraved steel blank from the original U18 submarine, further enhancing the sensory experience and connection to the vessel's history. This makes the watch not just a timepiece, but a collector's item, a piece of history that can be worn and appreciated.



The U18 is a fitting tribute to the legacy of the Type 206 submarines and the crews who served on them. It's a watch that embodies the spirit of exploration, resilience, and innovation. It's a reminder of the power of human ingenuity and the enduring fascination with the underwater world.

The price for the set, which includes the satinized solid stainless steel bracelet is 3,230.00 €. This price point reflects the watch's unique materials, limited production, and the craftsmanship involved in its creation. It positions the U18 within the realm of luxury diving watches, appealing to collectors and enthusiasts who value both performance and provenance. The availability of the watch is limited, reflecting its exclusive nature as a limited edition timepiece.

Case: German Submarine Steel from the decommissioned submarine U18, satinized. 44.0 mm diameter, 15.5 mm thickness, 22 mm lug width. Diver's bezel made of German Submarine Steel, satinized/polished, with TEGIMENT Technology. Captive bezel. Screwable crown at 4 o'clock. Sapphire crystal, anti-reflective on both sides. Case back screw-fastened. Water and pressure-resistant to 2,000 m diving depth (200 bar). Low pressure resistant.

Movement: Sellita SW300-1. Self-winding mechanism. 28,800 semi-oscillations per hour. 25 bearing jewels. Seconds stop function. Anti-magnetic as per DIN 8309.

Dial: Blue-green with bubble motif. Indices coated with luminescent colour. Hour, minute, and second hands coated with luminescent colour. Date display.

Strap: Satinized solid stainless steel bracelet.

Price: 3,230.00 €

Reference Number: 1028.010

Notes: Limited to 1,000 pieces. Case made of steel from the decommissioned U18 submarine. Tested based on European diving equipment standards and certified by an independent institute. Includes an engraved steel blank from the original submarine U18.