“Wearing those suits was like putting a bowl over your head – you could only see so far; everything else is black or dark green,” recalls Gooding. “You really get a sense of being confined.”

Billy Sunday (Robert De Niro) takes on a dangerous challenge to prove his superiority to Carl.

But the training paid off. “By the time we filmed the underwater scenes at the end of the schedule,” remembers the star, “I had been in the suit so many times that I became used to the weight, the awkwardness and the feeling of enclosure. I could pretty much just let go and have a good time with it.”

“We all wanted to have the experience – being in the suit, breathing air piped in from a hose, trusting someone with your life,” adds Tillman. “One of the scariest parts is the darkness: water at a certain depth is dark. How they get their work done is amazing.”

Charlize Theron as Billy’s long-suffering wife, Gwen.

Adds producer Robert Teitel: “These divers, especially the Master Divers, are like an exclusive club within the naval community. Other guys are in awe of what they do. There’s a ‘Top Gun’ thing about them.”

But the last word on the subject should probably go to the real Carl Brashear. He enjoyed the movie, even - or perhaps especially - the ‘elevated’ parts. And he remains immensely proud of what he achieved. But, he says, “I never referred to myself as a hero. I had a job to do and a goal to reach.”