Directed by: John Guillermin
Starring: Jeff Bridges, Jessica Lange, Charles Grodin, John Randolph
Visible crew/equipment: As King Kong jumps from one of the Twin Towers to the other, you can see the wires attached to him as he lands. (01:59:30)
Visible crew/equipment: When Jack walks into the hotel suite, a crouching boom mic operator and the mic pole he holds are reflected in the mirror.
Factual error: The fact that the respiration of a single animal - however large - could lead to an increase in the level of carbon dioxide in the local area is so absurd it is laughable. Carbon dioxide exhalation is part of a closed loop cycle and the CO2 exhaled by Kong would be matched by the CO2 taken in by the plants growing on the island. It cannot be otherwise. Elevated levels of carbon dioxide are incredibly dangerous and any animal living on the island - including Kong - would suffer if things got out of kilter.
Answer: He probably knew it wasn't deep. It's his island; he knew every inch of it. Besides, it's a pool, not an ocean. It most likely had a small underground tunnel which spilled out somewhere on the island.