Pierre Cressoy wears a Panerai Radiomir

Near the end of Hell Raiders of the Deep, a captured Italian frogman sits in confinement deep inside a British battleship, and he keeps checking his watch. He has reason. Commander Silvani set the timer on a warhead beneath this same hull before the sentries pulled him from the water, and he alone aboard knows what 06:20 means. The film gives the moment a super close-up, the dial readable, the hands closing on twenty past six. The watch is a Radiomir reference 3646, the cushion-cased instrument the Decima Flottiglia MAS actually carried, a Rolex-built Oyster case wearing a Panerai dial.

The story is the real one, and this was the first movie ever made about the Decima Flottiglia MAS. Pierre Cressoy's Silvani is an adaptation of Luigi Durand de la Penne, the diver who rode a manned torpedo into the harbor at Alexandria, and the film also shows the unit's hidden base, a scuttled tanker called the Olterra moored at Algeciras, from which frogmen struck at Gibraltar. The main event is the attack that disabled HMS Queen Elizabeth and HMS Valiant. Many of the divers on screen were serving Marina Militare personnel, wearing the unit's massive Panerai compasses along with the watches. Duilio Coletti directed; Carlo Ponti and Luigi De Laurentiis produced; the score is Nino Rota's.

There is a detail in that close-up only a specialist would catch. The hour hand is not the divided type a 3646 should carry, which means the watch on Cressoy's wrist had received a new dial and hands after the war. That was standard practice rather than a prop shortcut: the radium lume of the originals destroyed its own zinc sulfide within three to five years, so no 3646 that stayed in service kept its original face. The example that belonged to Decima veteran Ernesto Notari sits in the Naval Museum of La Spezia today wearing exactly this kind of 1950s dial.