Quick answer
A fake Fifty Fathoms 45mm is a large watch, and that fact should drive your decision more than any logo. The real Blancpain Fifty Fathoms Automatique runs a 45mm case that is close to 15.5mm thick with long lugs, and a replica copies those proportions whether it copies anything else well or not. On a wrist under roughly 7 inches, the 45mm version will overhang the wrist bone and read as borrowed. If you want the Fifty Fathoms look on a smaller wrist, shop the 38mm or 43mm references instead. If you do want the 45mm presence, then judge the replica on four points: movement, bezel insert, dial printing, and crystal.
Why the 45mm case is the hard part to fake
Steel is cheap. Machining a case that keeps sharp lug facets, a crisp crown guard curve, and an even brushed-to-polished transition is not. I look at the lug profile from the side first, because that is where budget cases go soft. The genuine watch has a defined step along the case flank and a caseback that sits flat against the wrist. Cheap replicas round those edges off, and the watch ends up looking melted rather than machined. Weight is a rough proxy too. A 45mm diver in steel should feel substantial, not hollow.
Movement: the single biggest price divider
- Entry tier: a Chinese 2824-style automatic. It runs, it hacks, and it keeps time, but rotor noise and a plain finish are normal.
- Mid tier: a Miyota 9015 or a better-finished 2824 clone. Thin, smooth sweep, easy to service.
- Top tier: a decorated clone built to mimic the layout and finishing of the in-house calibre 1315, sometimes with a display caseback to show it off.
If the caseback is solid, the movement only has to be reliable. If it has a display back, the movement becomes part of the product, and a badly decorated rotor is the first thing anyone notices.
Bezel insert and crystal
The Fifty Fathoms is defined by its sapphire bezel insert and domed crystal. A replica with a printed or painted insert loses the depth that makes the bezel interesting, and the lume pip will sit proud or off-center. Check that the bezel turns with firm detents and no back play. On the crystal, look for a domed profile with a clear anti-reflective tint. Flat, over-reflective glass is a giveaway in photos more than on the wrist.
Dial printing and hands
Compare the date window position and the text weight against reference photos. Common faults include text that sits too low, hour markers that are unevenly applied, and lume that is a different shade on the hands than on the dial. Sword hands should be clean and flat, not chunky or bent at the tip.
Water resistance
Treat any water resistance claim on a replica as marketing until someone pressure-tests it. Gaskets can be present and still fail. I would not swim in one, and I would not shower in one either. A quick rinse under a tap is the realistic limit unless a watchmaker has opened it, greased the seals, and tested it.
Pre-purchase checklist
- Ask for a wrist shot on a known wrist size, not just studio photos.
- Request macro shots of the dial, bezel insert, and caseback engraving.
- Confirm the movement model and whether the caseback is solid or display.
- Ask the lug-to-lug measurement, then measure your own wrist.
- Check strap options. A 45mm diver needs a thick rubber or sailcloth strap to balance it.
Bottom line
The 45mm Fifty Fathoms is a statement watch, and replicas of it range from passable to quite good. Buy for fit first, then movement, then cosmetics. A well-chosen mid-tier example beats a top-tier one that is too big for your wrist.