In the MK-20 system, what does the term 'umbilical' refer to?

The term 'umbilical' in the MK-20 system specifically refers to the cable that provides both communication and gas supply to the diver. This dual-functionality is crucial for surface-supplied diving operations. The umbilical connects the diver to the surface support team, enabling continuous communication during the dive, which is essential for safety and coordination. Simultaneously, it supplies breathing gas from the surface, ensuring that the diver has a reliable source of air while underwater. This system allows divers to operate at depths or for durations that would be unsafe with self-contained breathing apparatuses. Understanding the importance of the umbilical is fundamental for efficient and safe diving practices, as it plays a vital role in maintaining the diver's breathing air supply and communication link to the surface.