The reality of the Lotus Esprit was pretty funny. I saw the above water version of that at a Brit car event in Norcross (N ATL suburb) about 10 years ago. Basically a Esprit body over a John boat with maybe a 25 hp motor to move it around. The underwater stuff I think was all plastic models.
“The underwater stuff I think was all plastic models.”
“During filming of The Spy Who Loved Me, the submarine was piloted by ex-U.S. Navy SEAL Don Griffin.[8] The fictional history of the car in the film was that it was developed by Q-Branch of MI6, and its blueprints were stolen by KGB agent Anya Amasova (after Bond asked Amasova “How did you know about that?” Amasova replied, “I stole the blueprints of this car two years ago”). In filming, six Esprits were used (registration “PPW 306R”), though only one submarine.[3] Three of the Esprits were just empty bodyshells which were used to show each phase of the car-to-submarine transformation. A miniature model was used for the car’s initial underwater shot as it landed in the sea. Two unpowered dummy cars fitted with wheels were used to show the Esprit entering and emerging from the sea; the first was designed to be fired from an air cannon off the end of the pier, the second was towed by a rope buried under the beach with a sweeping brush fitted to the underside to cover the rope up as the car was tugged out.[citation needed] When an additional road car was needed for the chase sequences the producers borrowed Lotus chairman Colin Chapman’s personal vehicle.”
https://en.wikipedia.org/wiki/Wet_Nellie
Also: https://www.autoevolution.com/news/wet-nellie-the-second-most-famous-bond-car-35087.html