Sinn U15, U16, and U18: Submarine Steel on Your Wrist

Sinn marks two decades of submarine steel dive watches with three special editions: the U15, U16, and U18. Each model is built from the actual hulls of decommissioned German Navy submarines—U15, U16, and U18—turning proven naval engineering into reliable wristwear. Beyond tracking hours and minutes, these watches link you to thousands of nautical miles of undersea service.

With water resistance from 500 to 2,000 meters, plus Sinn's in-house technologies like TEGIMENT surface hardening and Ar-Dehumidifying systems, the series delivers more than a story—it delivers true dive-ready performance.

Bottom Line Up Front

Submarine Steel: A Legacy Refined

From Hulls to Cases

Sinn's journey with submarine steel began 20 years ago, when the brand recognized that the same tough, corrosion-resistant steel used on Type 206 and Type 212 subs was perfect for dive watches. But these aren't just made from leftover materials—each watch case is cut from actual hull sections of the retired U15, U16, or U18. It's a direct transfer of naval history to your wrist.

The Ships Behind the Watches

• U15 logged 200,045 nautical miles over 36 years.
• U16 covered 207,000 nautical miles in 38 years.
• U18 recorded 192,842 nautical miles, also over 38 years.

Breaking Down the Trio

U15: Smaller Size, Full Strength

With a 41 mm satinized case and 500-meter water resistance, the U15 is the most compact. Its SW300-1 movement offers a healthy 56-hour power reserve. The dial's blue-green finish (inspired by submersible depths) pairs with Sinn's TEGIMENT bezel for scratch resistance. At 74 grams without a strap, it's comfortable for all-day wear—probably 170 grams with the strap, though Sinn's manual and site don't say for sure. Kinda annoying, but yeah, they only list the no-strap weight for all three models. Still, the U15's slim 11.2mm case keeps it easy on the wrist.

U16: Bulkier, With 1,000m Under Its Belt

Stepping up to a 44 mm case and 1,000-meter water resistance, it matches the U15's paddle hands and is the same size as the U18, minus a few mm's in the case thickness. The SW200-1 movement runs for 38 hours on a full wind. It weighs 113 grams, giving it a reassuring heft on the wrist.

U18: Deep-Dive Champion

The U18 boasts 2,000-meter water resistance, sports sword hands and different markers, and adds Sinn's Ar-Dehumidifying Technology to keep its internals fog-free. A SW300-1 movement provides the same 56-hour power reserve as the U15. At 15.5 mm thick, it's the heftiest of the bunch, backed by a three-year warranty.

From Decommissioned Sub to Desk Diver

Crafting Each Case

Sächsische Uhrentechnologie GmbH Glashütte (SUG) handles the specialized manufacturing. They take hull segments that saw decades underwater and machine them to Sinn's exact tolerances. This isn't standard “submarine-grade” steel straight from a mill; it's metal that has real hours logged beneath the waves.

Sinn's Tech Edge

All three get TEGIMENT Technology on the bezel for added scratch resistance. TEGIMENT significantly enhances the hardness of materials like stainless steel by transforming the surface itself, rather than applying a coating, to provide superior scratch resistance. TEGIMENT was first used in 2003 with the 756 Duochronograph and has since outgrown its stainless steel origins, ensuring that Sinn watches don't just tell time—they endure it.⁴

The U18 features Sinn's Ar-Dehumidifying Technology to fight moisture—the stealthy enemy of mechanical watches. A drying capsule, ultra-sealed EDR gaskets, and protective gas filling create a near water-free environment, preventing oil breakdown, crystal fogging, and precision loss.⁵ This keeps the U18 as reliable as the day it was made.

Aesthetic Ties to the Deep

Dial Details

A high-gloss, dark bluish-green dial captures the color of the ocean at about thirty meters—where these subs often hovered. Stylized bubbles add dimension and echo a submarine environment.

Each dial features its submarine's actual mileage, and the case back is engraved with that Type 206's silhouette. You also get an extra steel blank cut from the original hull. It's a tangible piece of German naval history you can hold.

Why the U-Series Matters

At prices between €2,990 and €3,230, the U15, U16, and U18 hold a unique niche in the dive watch market. They aren't built around contrived backstories or marketing fluff. They come from real submarines that served real missions. With only 1,000 pieces per model, they're exclusive but not unattainable.

Final Take

Sinn doesn't just nod to military history—it forges a direct link by crafting timepieces from actual submarine hulls. The U15 lets you wear a slice of that legacy on your wrist, a daily reminder of steel that once cut through the deep. The U16 scales up in both size and depth, while the U18 pushes the limits of extreme performance. If you're lucky enough to acquire one, you're not just wearing a watch; you're strapping on a fragment of maritime prowess, a tribute to the engineering that sent these vessels beneath the waves. And beyond their storied origins, these timepieces are stunningly designed, seamlessly marrying form with function.

References

Footnotes

1. Sinn U15. Sinn Watches. https://www.sinn.de/en/watches/all-watches/u15.html ↩

2. Sinn U16. Sinn Watches. https://www.sinn.de/en/watches/all-watches/u16.html ↩

3. Sinn U18. Sinn Watches. https://www.sinn.de/en/watches/all-watches/u18.html ↩

4. Sinn TEGIMENT Technology. Sinn Watches. https://www.sinn.de/en/sinn-technologies/tegiment-technology/ ↩

5. Sinn Ar-Dehumidifying Technology. Sinn Watches. https://www.sinn.de/en/sinn-technologies/ar-dehumidifying-technology/ ↩