Corrected entry: Susan was wearing a 3mm wetsuit. Neoprene is inherently buoyant, and thus she could not have slipped under the water at the end of the movie while wearing a wet suit without additional weight (which she removed earlier in the film and dropped to the bottom). She would have immediately floated back to the surface.
Corrected entry: There is a scene in the DVD entitled "Not in the mood". In the scene, the couple are in bed naked. When you see a shot of Susan (taken from the foot of the bed), she has a strip of white fabric between her legs to avoid you seeing her lower vagina. But when the scene switches to a view of her sideways, the fabric is no longer there. (00:07:35)
Correction: The slightest movement of her leg would have dislodged it.
Corrected entry: They are both wearing 3mm wet suits. In the Bahamas, the summer water temperature is about 82 F to 85 F, sometimes cooler. That is about 17 degrees cooler than body temperature. Even with a wet suit, they would have been suffering from hypothermia in just a couple of hours.
Correction: According to hypothermia.org, they would survive over 12hrs in water over 68F. And acording to a kayaking site: 1) survival in water above 80F is indefinite 2) Minimal clothing is neede to survive in water above 80F. http://www.hypothermia.org/inwater.htm.
Corrected entry: The proper way to ditch a weight belt is to remove it and drop the weights, belt and all, and this is the way taught by all diver training agencies to all new divers. They remove the weights, retaining the belt, for no reason, despite this training.
Correction: There was no emergency in removing the weights she just wanted to lessen the pull on her body. The husband suggested she keep the belt in the event they needed it for something. In the end it helped as she used it to stem his bleeding.They were probably aware of the training but made a concious decision to ignore it for practical reasons.
Corrected entry: At the end of the film Susan removes her aqualung and life jacket. She immediately disappears below the surface of the water and does not resurface. As she had removed her weight belt earlier when she felt ill, the natural buoyancy of her body + the air in her lungs would make it impossible for her to sink in this way.
Correction: She could have been pulled down by a shark.
Corrected entry: Susan's hair changes lengths a number of times during the movie.
Correction: No, it only appears to be a different length when it's wet.
Correction: While Susan did drop her own weight belt, her husband never dropped his. In the scene before this one, she is seen setting him adrift for the sharks to eat. Since he is floating in that scene, it is likely that she took his belt off and used it to sink.