A fake Fifty Fathoms 45mm is a replica of the Blancpain Fifty Fathoms Automatique 5015, the 45 mm dive watch with a sapphire bezel and an automatic movement styled after the calibre 1315. Good replicas copy the case diameter, lug width, and dial layout closely. The differences surface in bezel click action, lume endurance, date printing, crown engraving, and movement finishing. Learn the genuine numbers first and you can grade any replica in about ten minutes.
What the 45 mm Reference Actually Is
Blancpain lists the Fifty Fathoms Automatique 5015 with a 45.00 mm case and roughly 15.40 mm of thickness. It carries a unidirectional sapphire bezel, a 300 m water resistance rating, and a clean dial with broad luminous markers. The 45 mm size is the largest standard case in the modern line, so it wears heavy on a 6.75 inch wrist and sits flatter at 7.25 inches and above.
Specs Worth Matching
- Case diameter: 45 mm, measured across the bezel without the crown.
- Thickness: about 15.4 mm from caseback to the top of the domed crystal.
- Lug width: 23 mm on the strap versions.
- Bezel: unidirectional, 120 clicks, sapphire insert with a lume pip at 12.
- Crystal: domed sapphire with inner anti-reflective coating.
How to Inspect a Replica Step by Step
- Measure the case with digital calipers across the 3 and 9 o'clock points and record the number.
- Measure thickness from the center of the caseback to the crystal peak.
- Rotate the bezel one full turn, count the clicks, then test for back play at each stop.
- Charge the lume with a phone light for 30 seconds and compare the glow after five minutes.
- Inspect the dial print under a loupe for letter weight, spacing, and marker alignment.
- Examine the crown engraving and feel for grinding while you set the time.
- View the movement through the display back and identify the base calibre and rotor finish.
- Weigh the watch on a kitchen scale and compare it against the listed weight for the genuine model.
Common Tells
The bezel is the first giveaway. Genuine sapphire inserts sit flush and click with firm, even resistance. Cheap replicas feel loose, rattle along the outer edge, or stop short of the 12 o'clock marker. Lume is the second tell. Budget replica lume glows bright for two minutes and fades inside an hour, while genuine Super-LumiNova stays readable for hours. Date fonts, logo thickness, and the polish on the case flanks fill out the rest of the list.
Movement Options
Most replicas run a 25 jewel Asian automatic, often based on a Miyota 9015 or an ETA 2824 pattern, with a decorated rotor shaped to suggest the Blancpain calibre 1315. Higher tiers use a clone with a free sprung balance and a longer power reserve. Ask for a movement photo before buying and check that the rotor engraving matches the caseback text. Water resistance is not guaranteed on a replica, so keep it out of the pool unless a watchmaker has pressure tested the seals.
Wearability and Straps
A 45 mm case with 23 mm lugs needs a sailcloth or rubber strap to balance the mass. NATO straps work but add height. On smaller wrists the lugs overhang the case edge and the watch reads larger than its measurements suggest. Measure your wrist in millimeters before ordering.
Care and Service Notes
Have the seals checked yearly if the watch goes near water. Keep the bezel track clean, since grit under the ratchet spring causes the loose feel that identifies a replica. Store it on a soft surface to protect the sapphire insert edge.