Spock: Forgive me doctor. I'm recieving a number of distress calls.
McCoy: I don't doubt it!
At approximately 01:32:50 on the Blu-Ray, you can see a diver releasing the mechanical whales. He is on the far right side of the screen, you can make out his head, body and left hand. He is visible for a good 8-9 seconds. If you have a different media source, it's during the Bird of Prey decent. You see a closeup of Kirk, followed by a closeup of Uhura and Gillian, then a close up looking down on the harpoon. It's in the following scene. See more...
The scene in which Chekov and Uhura beam onto the Enterprise aircraft carrier was originally slightly different. It was scripted that they would sneak onto the ship undetected, but the American Navy believed that it would be impossible for two intruders to get past a military security force. So it was re-written that the transporter had enough energy to beam the pair onto the carrier, but not to get them back off. See more...
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Star Trek IV: The Voyage Home (1986) - 5 with pictures
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