Blancpain Fifty Fathoms Bathyscaphe Moon Phase 5054 Rose Gold 2024

Reference 5054-3640-76S is the Fifty Fathoms Bathyscaphe carrying a complete calendar and a moon phase, in red gold on a matching bracelet. Putting a calendar of this kind inside a dive watch is an odd thing to do, and it is the reason this one is interesting rather than merely expensive.

A complete calendar is not a perpetual and not an annual. It shows the day and the month in twin apertures under twelve, the date on a pointer hand running to a ring around the dial edge, and the moon in a window at six — but it counts every month as thirty-one days, so it needs correcting five times a year. The compensation is legibility: everything is on one plane, read at a glance, with none of the recessed sub-dials a perpetual forces on the layout.

The awkward part is the correctors. A calendar normally needs pushers set into the caseband, and pushers are holes. Keeping a watch sealed to thirty bar while giving it that many correction points is the engineering problem the Bathyscaphe case had to solve, and the flatter, quieter Bathyscaphe profile absorbs it better than the full Fifty Fathoms would have.

From the watch itself: an 18 ct gold case, marked thirty bar on the back, over a movement of twenty-eight jewels adjusted to six positions, visible through a sapphire back and driven by a red gold rotor. Forty-three millimetres across.

Mint, 2024, offered as a full set with the diver's logbook and travel case. A second hand gold diver that has been treated as jewellery rather than equipment.

Every watch is authenticated by an independent watchmaker before it changes hands, never by us. Viewing by appointment at our Collins Street boutique in Melbourne, insured delivery Australia-wide. We source specific references on request.