A replica Fifty Fathoms Full Moon copies the Blancpain Fifty Fathoms Bathyscaphe Quantième Complet Phase de Lune, a 43 mm diver with a full calendar and a moon phase at 6 o'clock. Copies sell for roughly $80 to $350 and differ from the genuine mainly in movement type, moon disc printing, and calendar alignment. Buy one for the look, not for the 300 m water resistance of the original.
What is the Blancpain Fifty Fathoms Full Moon?
The full model name is the Fifty Fathoms Bathyscaphe Quantième Complet Phase de Lune. Blancpain pairs a dive watch case with a complete calendar showing day, date, month, and moon phase. The moon disc sits at 6 o'clock, while the day and month windows flank the center of the dial.
How close is a replica to the original?
Better replicas match the 43 mm case diameter, the ceramic bezel insert, and the gradient dial finish. The widest gap shows up in the moon phase disc, where printing looks flat and the stars sit closer together than on the real thing. Calendar fonts and the date pointer also reveal small spacing differences at close range.
What movement powers a replica moon phase watch?
Budget versions use a quartz module that drives the calendar and moon disc with a small stepper motor. Mid-range replicas use a Chinese automatic with a bolt-on calendar module, often built around the Miyota 9100 family. High-end replicas copy the layout of the Blancpain 6654 and claim a 72-hour power reserve that rarely holds up on a timegrapher.
Does the moon phase actually work?
On quartz replicas the moon disc advances once every 29.5 days through the crown or a recessed pusher. On automatic replicas the disc moves with the date change near midnight. Test it by setting the calendar forward one full month and watching the disc shift position.
Materials and finishing
- Case: 316L or 904L stainless steel, plus black ceramic or PVD coated versions
- Crystal: sapphire with inner anti-reflective coating on better grades, mineral glass on budget builds
- Bezel: ceramic insert with printed or engraved markings
- Strap: stainless steel bracelet with push-button deployant, sailcloth, or rubber
Water resistance and daily use
Genuine Bathyscaphe models carry a 300 m rating. Replicas rarely survive past 30 m to 50 m, and only when the caseback gasket seats correctly. Take a replica off before swimming, showering, or any dive activity.
Price tiers
- Budget, $80 to $130: quartz, mineral glass, printed moon disc, lighter case
- Mid, $140 to $220: automatic movement, sapphire crystal, better dial texture and lume
- Top, $230 to $350: closest case finishing, ceramic bezel, cloned calendar layout
What should you inspect before buying?
- Moon disc printing, star size, and disc flatness
- Calendar window alignment along the center line
- Lume evenness on hands and hour markers
- Crown action and smoothness when setting the date
- Weight and the depth of caseback engraving
Care tips for a moon phase copy
Wind an automatic replica daily or keep it on a winder so the calendar does not stall. Avoid setting the calendar between 9 p.m. and 3 a.m., when the mechanism is engaged and can jam. Wipe the case with a soft cloth and keep the crown pushed in to limit moisture entry.