One-man submarine utilized by Ernst Stavro Blofeld (Charles Gray) in Diamonds Are Forever. Realizing his situation aboard his Baja California oil rig base is hopeless, Blofeld enters the sub and orders his crane driver to lower him into the ocean. Bond (Sean Connery), however, knocks out the driver and gains control of the crane and the sub. Literally in the driver’s seat, he begins to play with his longtime nemesis, eventually smashing the sub into the wall of a building, where it explodes.
“Originally,” recalled screenwriter Tom Mankiewicz, “in my first version of the ending, Blofeld was escaping underwater in his bathosub when Bond sees the submarine idling in twelve feet of water. Bond dives off the oil rig, holding the long string of a huge weather balloon, which he ties to the sub’s conning tower . . . And they were going to wind up in a giant salt mine. But this was all very long and involved. . . .
“First of all, Blofeld was going to die in the salt mine. . . . At that particular point, nobody knew what was going to happen in the next film. . . . Blofeld might have been in the next film, especially if somebody had a good idea.”
But, he added, “the picture was quite long at the time and . . . something had to go. So we said, ‘Let’s deal with Blofeld on the rig.’ Because, as you remember, we still had to get to our tag with Mr. Wint and Mr. Kidd on the ocean liner.”
 Tom Mankiewicz, interview by Steven Jay Rubin, Los Angeles, November 7, 1977.