Chapter 12 is a documentary entitled "The Making of The Abyss"
Additional Information by disclord
13/06/2013
Aspect ratio is only 1.90:1 due to Cameron not yet being fully comfortable with letterboxing. Later widescreen releases of The Abyss are in the correct theatrical ratio of 2.40:1.
Even though this is the theatrical cut, and listed as 140 minutes, it uses the long 10-minute credits familiar to fans of the special edition. Remarkably, a pan-and-scan VHS tape, 1561, has the original 5-minute theatrical credits, adapted for 4:3.