The story follows Gerard Butler’s submarine commander as he attempts to rescue the president of Russia when the leader is kidnapped by a rogue Russian general.
Interior sets of a Virginia-class Hunter Killer submarine were built at Ealing Studios, using blueprints approved by the US Navy, with the spaces expanded slightly to allow freer camera movement. The sets were mounted on a gimbal to simulate the movement of the sea.
A Bulgarian naval base in the city of Varna on the Black Sea coast doubled for exterior shots of Russia’s Polyarny base that in real life is a closed-off facility.
Interiors of the Russian base were built as sets at Nu Boyana Film Studios in Bulgarian capital Sofia. Nu Boyana has also recently hosted a new version of Hellboy and is currently home to Sylvester Stallone’s action sequel Rambo 5.