312.87. Diving in an environment with an obstruction: When diving in an environment with an obstruction, the dive team must consist of at least 6 divers, including 2 divers underwater to allow 1 diver to lead the other diver’s umbilical to the location where an obstacle exerts a resistance when the umbilical is pulled on, 3 diver’s tenders and 1 standby diver on the surface, 1 of whom is the diving supervisor.