41mm Black NAV-D Type II – Pilot’s Quartz
I’ve just added another gem to my collection of tritium-illuminated timepieces: the Black NAV-D variant of the Pilot Series. I purchased it directly from the Manufacturer in Canada, and it was shipped to me promptly. I previously owned a Marathon GPQ, so I was excited to receive this upgrade. While the overall case diameter of the Marathon NAV-D is significantly larger than the GPQ, the dial and crystal sizes are the same, which came as a surprise.
Why I Love this Watch
It’s not just an accessory; it’s a piece of genuine military equipment with a rich history.
- Authentic Military Heritage: My watch is a direct descendant of models used by the U.S. Air Force, making it a truly authentic piece of military gear.
- Rugged, Purposeful Design: The asymmetrical case isn’t a stylistic choice—it’s a functional feature designed to protect the crown from damage in the field. This “function over form” philosophy is a core part of its appeal to me.
- Comfort: It feels quite light, which I like. It’s not very thick either, so my shirt sleeves slide over it easily. The strap that comes with it is a single pass-through and is very smooth and flexible. It’s thin, but not too thin.
- Legibility: The clear, high-contrast dial, lit by T25 tritium tubes for constant visibility, shows that every design choice was made to ensure the watch is a reliable tool, not a fashion statement. I would have preferred T100 over T25, but it is what it is.
What I Don’t Like
- Bezel Stiffness: The bezel on this watch is definitely hard to turn. It is seriously stiff. Think about whether this is a deal breaker for you before you take the plunge.
- Water Resistance: 60m is all that this watch is rated at. I feel a military watch should be at least 100m with 200m being preferable.
The Marathon NAV-D, or Navigator with Date, is a line of military-spec watches produced by Marathon Watch Company. It’s a modern and updated version of a watch originally developed in partnership with the U.S. Kelly Air Force Base in 1986. The NAV-D is a popular choice for military personnel, pilots, and watch enthusiasts who appreciate its rugged durability and no-nonsense, purpose-built design.
Design and Specifications
The NAV-D is known for its distinct, asymmetrical case design. This “bird-in-flight” profile provides an oversized crown guard to protect the screw-down crown from accidental bumps and snags, a feature highly valued in tactical and field environments.
- Case: The NAV-D is available in two main case materials:
- High-Impact Composite Fibershell: This is the traditional material for the Navigator series, offering an incredibly lightweight (around 40g) and durable package. It’s a direct link to the original military-issued models. This is the version I purchased.
- Stainless Steel (SSNAV-D): A more recent addition to the lineup, the stainless steel version offers increased heft and durability, with a screw-down crown that boosts water resistance. It is quite a bit more expensive, considering the internals are the same.
- Dimensions: The watches typically have a 41mm case diameter, an 11mm thickness, and a 48mm lug-to-lug distance, with a 20mm lug width.
- Movement: The NAV-D models are generally powered by a high-torque, Swiss-made quartz movement, such as the ETA F06.412, which is known for its shock resistance (HeavyDrive system) and high accuracy (PreciDrive system), often rated to ±10 seconds per year. Automatic versions with a Sellita SW200-1 movement are also available (SSNAV-D Auto).
- Lume: A signature feature of Marathon watches is the use of T25 self-contained tritium gas tubes on the hour markers and hands. These provide a constant, soft glow in low-light conditions without needing to be “charged” by an external light source. This is a crucial feature for pilots and military personnel who may be in prolonged darkness.
- Crystal: The watch is protected by a scratch-resistant sapphire crystal, which is also designed to withstand rapid changes in air pressure, making it suitable for high-altitude flight.
- Bezel: It features a bi-directional rotating bezel with a 12-hour scale, which can be used to track a second time zone or as a simple elapsed timer.
- Water Resistance: The water resistance varies depending on the case material. The composite models typically have a 60m rating, while the stainless steel versions (SSNAV-D) have a more robust 100m rating due to their screw-down crown.
- Date Complication: As the name suggests, the NAV-D is distinguished from the standard Navigator by its date window, which is positioned at 4:30 on the dial.
- Strap: Mine came with a ballistic nylon or DEFSTAN nylon strap, in keeping with their military heritage.
History and Heritage
Marathon has been a key supplier of timepieces to the Allied Forces since 1941. The original Navigator watches were designed in 1986 for the U.S. Air Force, specifically to meet the needs of pilots and other military personnel.
The original steel-cased Navigator was initially sold almost exclusively through government contracts and was not widely available to the public. In the 1990s, a new military standard allowed for the use of a composite case, leading to the well-known lightweight Navigator model that saw use in conflicts like Operation Desert Storm.
Due to popular demand from military watch enthusiasts, Marathon re-engineered the steel Navigator in recent years, introducing the SSNAV-D. This modern version combines the classic design with updated materials and technology, such as the sapphire crystal and increased water resistance, while maintaining its authentic military purpose. Many of the watches are also given a NATO Stock Number (NSN), a testament to their continued use by government and military entities.
The asymmetrical case design on the Marathon NAV-D serves a single, crucial purpose: to protect the crown. The watch was developed for pilots and paratroopers, who operate in demanding environments where the watch could easily be damaged. The extended portion of the case on the right side of the watch acts as a massive guard, shielding the screw-down crown from accidental impacts against cockpit walls, gear, or other objects.
This design also helps to prevent the crown from digging into the wearer’s wrist during movement, making it more comfortable for extended use. The asymmetrical shape is a direct result of Marathon’s “function first” design philosophy, where every element is engineered to serve a specific, practical need in a high-stakes setting.
Technical Specs
| Specification | Detail |
|---|---|
| Model / Reference | NAV‑D (Navigator with Date), Black version: NAV‑D |
| Case Material | Composite high‑impact fibreshell (standard NAV‑D) Steel version uses 316L stainless steel (SSNAV‑D) |
| Case Diameter | 41 mm |
| Case Thickness | ~11 mm |
| Lug-to-Lug | ~48 mm |
| Lug Width | 20 mm |
| Bezel Type | Bi‑directional rotating bezel with 12‑hour scale |
| Crystal | Sapphire crystal <– a must have for me |
| Movement | ETA High‑Torque F06 quartz (3 jewels) |
| Functions | Hours, Minutes, Seconds, Date (date window between 4 and 5 o’clock) |
| Accuracy / Other Features | EOL (End‑Of‑Life) indicator for battery PreciDrive & HeavyDrive / shock protection (in steel version) |
| Luminous / Illumination | T25 Tritium gas tubes on hands, hour markers, and bezel pip (constant glow) |
| Water Resistance | 60 meters. Push / Pressure crown (composite) The steel version often uses a screw down crown |
| Crown Type | Push / Pressure crown (composite) The steel version often uses a screw-down crown |
| Special Features | NATO Stock Number (NSN) in some versions Battery hatch / coin‑open battery access in the steel version Offset / asymmetrical case designed for crown protection |
| Weight | Steel version: ~80 g on nylon strap Composite version: ~40–50 g |
| Case Back | Stainless steel metal case back (composite case version) |
| Variants / Editions | USMC version, Duvdevan special edition, desert tan & sage versions |
