Short answer
A replica Fifty Fathoms Bathyscaphe 5200 copies a 43.6 mm Blancpain dive watch. The genuine watch runs the Blancpain caliber 1315 with a 120 hour power reserve and a 300 m water rating. Most replicas use a Miyota 9015 or a copy of the ETA 2824. Case metal is 316L stainless steel or black ceramic. No replica ships with a factory 300 m pressure test.
The genuine 5200
Blancpain sells the Bathyscaphe 5200 in steel, titanium, and black ceramic. Case diameter is 43.6 mm. Thickness is about 13.8 mm. Lug width is 23 mm. The bezel insert is sapphire on steel models and ceramic on the ceramic models. The dial has a date window between 4 and 5 o'clock. Water resistance is 300 m. The caliber 1315 uses three mainspring barrels, a silicon balance spring, and 120 hours of reserve at 28,800 vibrations per hour.
What replica makers change
Case
Most replicas measure 43 mm to 43.5 mm. Weight lands near the genuine watch on steel versions. Ceramic replicas use zirconia oxide or a coated steel core. Case back engraving copies reference numbers such as 5200-0130-B52A.
Movement
Three movements show up in replica 5200s. The Miyota 9015 runs at 28,800 vph with about 42 hours of reserve. The Seagull ST2130 and the Hangzhou 6300 copy the ETA 2824 layout. A small number of high tier builds use a decorated 1315 style movement with three barrels, but barrel count is hard to confirm without a teardown. None of these movements come from Blancpain.
Dial, bezel, hands
Dial printing is the first visible gap. Genuine text stays sharp under a loupe. Replica printing can show soft edges on the Fifty Fathoms line. The genuine dial uses Super-LumiNova. Replica lume varies in color and glow time. Bezel action differs as well. Genuine bezels index with firm clicks and almost no backplay.
Water resistance
A 300 m rating needs sound gaskets, a screw down crown, and a pressure test. Replica sellers quote 30 m to 100 m. A watchmaker can test a replica on a dry pressure tester. Most replicas hold 3 bar to 5 bar after gasket grease. Do not swim with a replica unless it is tested.
Checks before you buy
- Case diameter: 43.6 mm on the genuine watch. Ask for a caliper photo.
- Lug width: 23 mm. A 22 mm strap leaves gaps at the lugs.
- Date position: between 4 and 5 o'clock.
- Crown: screw down, signed on top tier copies.
- Crystal: sapphire with a domed profile.
- Movement photo: rotor engraving and bridge finish.
- Bezel: 60 minute scale, aligned at 12.
Price bands
Replica 5200s sell in three bands. Entry builds run $120 to $200 with a 2813 movement and mineral glass. Mid builds run $200 to $380 with a 9015 or a 2824 copy, sapphire, and a ceramic bezel insert. High builds run $380 to $650 with better case finishing and a decorated movement.
What stays unknown
Factory names, movement origin, and pressure test results are not verifiable from a listing. Serial numbers on replicas do not match any Blancpain service record.