Beneath the surface

The submarine used in filming the 2018 TV-series Das Boot. But wasn't a sub, it was a faked up non-diving replica built in Malta.

I was then cast as the 'modified' American sub S-33 for the film U-571(U-571), also shot in Malta. The S-33 had been a real sub of WW2.

The story of the US movie is a lie presenting that the yanks snatched the Enigma code machine from an operational U-boat. 

Worse, they tried to present it as real. IMDB says

• The theatrical version contained some captions before the end credits, explaining that the Enigma was, in real-life, recovered by the British Royal Navy, and not by the American Navy as portrayed in this movie. The captions have been removed on the R2 DVD.

Footage, sets and models from that movie have been reused for other productions, including Submerged, depicting the loss of USS Sailfish, and the fictional Ghostboat. The Maltese replica is still afloat, moored in Marsa in the inner Grand Harbour. 

A special rig was built for the Das Boot production by a Maltese armory team, that allowed the submarine's anti-aircraft gun to both fire and recoil, something not done before with a blank-firing gun.

Malta, Germany (Munich), France (La Rochelle), and Czech Republic (Prague) were chosen for the location shooting, which started on 31 August 2017 and finished after 105 days on 20 February 2018. The budget was $32.8 million.