Four hammers and gongs, a minute repeater and a Westminster chime. While this inventory of horological functions might already make an impression on watch connoisseurs, the picture is far from complete. Activated by an innovative repeater slide, the striking mechanism of Bvlgari’s new Grande Complication model L’Ammiraglio del Tempo is presented with a detent escapement and a constant-force device; the latter is a regulating organ that embodies the ultimate level of horological complexity.
Meaning The Admiral of Time in Italian, L’Ammiraglio del Tempo refers to the maritime universe and evokes the era of sailboats and seafaring conquests of the history’s great naval powers: France, England, Spain and Portugal.
The detent escapement originated in the 18th century, a time when these maritime nations vied for dominion of the world’s oceans. It was also a time when watchmakers competed to produce the most accurate time-keeping instruments. There was a very good reason for this: in an era when satellites did not exist, sailors determined their geographical position at sea by astronomical observation, as well as by using the most accurate possible time calculations. The difficulties inherent in these methods were compounded by the necessity of ensuring the greatest possible stability of the time standard – meaning on-board timekeeping instruments – despite the inevitable pitching and rolling of the ship. Generations of watchmakers dedicated themselves to solving this conundrum.
One of the most important inventions emerging from this period was the detent escapement, which provided a degree of reliability unparalleled at the time. Not only did it guarantee the regularity and rating precision of marine chronometers and any other mechanical measuring instrument, the escapement served an intermediate function of regulating on the one hand the energy supplied by the barrel spring and on the other its retransmission and redistribution to the balance. This it did by delivering energy impulses that guided the movement of the hands, while enabling them to indicate the time with extreme precision.
While contemporary devices involved two impulses imparted to the balance via the lever, the detent escapement was, and still is, built in such a way that the entire device generated a single impulse by retransmitting energy directly from the escape-wheel to the balance. While today, this not might seem very meaningful, it was of crucial importance to sailors two and a half centuries ago since the ensuing reduction in friction between the moving parts led to appreciably improved precision.
Setting the finishing touch to L’Ammiraglio del Tempo, its movement is equipped with a constant-force device. A permanently wound intermediate spring positioned in the gear train connects the mainspring to the escapement and transmits regular torque to the escapement with very little loss of energy.
In the lexicon of horological complications, the detent escapement is far more complex than the tourbillon; it is also one of the rarest devices in this miniature format. The vast majority of mechanical watches are fitted with lever escapements and, indeed, very few other types of escapement are used. The reason for this restricted choice often stems from the difficulty in miniaturisation and ensuring reliability within the small space afforded by wristwatches.
The elaborate 516-part movement used in L’Ammiraglio del Tempo is housed within a case belonging to the Daniel Roth line.
One particular element plays a specific role in the activation of the striking system: one of the lugs is, in fact, mobile and serves as a repeater slide that glides from 7 to 8 o’clock to trigger the minute repeater. This highly innovative device ensures a smooth case middle that is unperturbed by the usual sideways protruding repeater slide.
The 50 mm-diameter case in 18K pink or white gold frames a partially open dial revealing the detent escapement as well as the striking hammers and gongs. The “solid” part of the dial is made from a plate in black or blue gold according to the metal of the case.
This ensemble is topped by a bell-shaped sapphire crystal that provides tantalising glimpses of the hand-crafted Côtes de Genève and circular-grained movement finishes.
L’Ammiraglio del Tempo is issued in two extremely limited series of 20 in 18K pink gold, and 10 in 18K white gold. Each watch bears its individual number on the sapphire crystal disc adorning the crown.
Model: L’ammiraglio Del Tempo
Manufacture-made mechanical hand-wound movement, Minute Repeater, Westminster chime, detent escapement, 4 hammers and gongs, constant force device, cylindrical balance spring, three shock-absorbing systems; 56 jewels
Diameter: 38 mm; thickness: 9.38 mm
Movement hand-decorated with Côtes de Genève and circular graining
14,000 vph (2Hz); 48-hour power reserve
Case and dial
Case in 18K pink or white gold, striking mechanism activated by the sliding lug at 7 o’clock, domed-shaped sapphire crystal, transparent sapphire back
Dimensions: 50 mm x 45.75 mm; 14.90 mm thick
Dial made from a gold plate with opening revealing the detent escapement system and the striking mechanism; 18K pink gold hands
Black or blue alligator leather strap fitted with an 18K gold triple-blade folding clasp