For decades, every Steel Navigator ran on quartz. The Marathon SSNAV-D Auto, reference WW194030SS-0101, changed that, becoming the first Steel Navigator with an automatic movement, here with a black NGM dial, date and a black ballistic nylon strap.

The step to a mechanical calibre is a meaningful one for this model. The Navigator was born in 1986 as a collaboration between Marathon and Kelly Air Force Base, and its steel form returned in 2023. Bringing in the Swiss Sellita SW200-1 automatic adds the sweeping seconds hand and self-winding convenience that mechanical watch fans look for, without changing the purposeful pilot's watch design that made the Navigator a classic. The movement uses 26 jewels and Incabloc shock protection and holds about 41 hours of power reserve.

The rest of the build is equally capable. The 41mm 316L stainless steel case stays slim at 11.5mm, uses a screw-down crown for 10 ATM water resistance, and wears a sapphire crystal. The bi-directional 12-hour bezel tracks a second time zone, and tritium gas tubes illuminate the dial and hands without any charging. The black dial has no government markings, and the date sits neatly at 4:30. The black one-piece ballistic nylon strap, made to MIL-S-46383B, threads beneath the case for security.

Marathon SSNAV-D Auto WW194030SS-0101 Specifications

• Reference: WW194030SS-0101
• Case: 316L stainless steel, 41mm, 11.5mm thick
• Movement: Swiss Sellita SW200-1 automatic, 26 jewels, Incabloc
• Water resistance: 10 ATM, screw-down crown
• Crystal: sapphire
• Bezel: bi-directional 12-hour
• Lume: tritium gas tubes
• Dial: black NGM, date at 4:30
• Strap: black ballistic nylon, 20mm lugs

A milestone Navigator, with a self-winding heart that the line had long been waiting for.