What is the minimum required length of a standby diver's umbilical?

The correct answer is based on the operational guidelines established to ensure the safety of divers in the event of an emergency. The minimum required length of a standby diver's umbilical must be sufficient to reach the primary diver while also accounting for additional distance. This is crucial because if the primary diver encounters a problem, the standby diver needs enough length to safely reach and assist.

The requirement to add an extra 1.5 times the length of the primary diver's umbilical provides a safety buffer. This additional length ensures that the standby diver can maneuver effectively without being restricted. It allows for variations in dive profiles, possible entanglements, or the need for additional reach that may arise during an emergency. This standard is designed to enhance the safety of divers by providing adequate resources for a response in case of an emergency, which is a fundamental aspect of diving safety procedures.

In terms of operational efficiency and safety, a fixed umbilical length, or one that merely matches the primary diver's umbilical, would not account for varying situations that might arise underwater. Hence, the emphasis on a length that exceeds just reaching the primary diver reinforces the priority placed on comprehensive safety measures in diving operations.