Diver
A diver's umbilical is a group of components which supply breathing gas and other services from the surface control point to a diver.
For shallow water surface supply air diving, the diver's umbilical is typically a 3-part umbilical comprising a gas hose, pneumofathometer ("pneumo") hose, and diver communications cable, which usually also serves as a lifeline strength member. The "pneumo" hose is open at the diver's end and connected to a pressure gauge on the surface gas panel, where the supervisor can use it to measure the diver's depth in the water at any time.
A 4-part diver umbilical will also have a hot water supply hose for the diver's exposure suit.
A 5-part diver umbilical will also include a video cable to allow the surface controller to see the video picture transmitted to the surface from the diver's hat camera (video camera mounted on the helmet, facing forward).
For saturation diving from a bell, a typical diver excursion umbilical may be an 8-part umbilical with a gas supply hose, gas reclaim hose, hot water hose, pneumo hose, tracking hose, comms/lifeline cable, video cable and hat light cable.
When there is risk of the umbilical cable being damaged by scratching on rock or coral, the umbilical bundle may be over-braided with a polypropylene braid cover.
Early diver umbilicals were simply the individual components bundled together and taped every metre or so with duct tape. These bundles tend to distort and produce kinks in the components caused by bending (particularly dangerous if the kink is in the divers gas supply hose), and require frequent maintenance.
More recent umbilicals comprise all the components laid together like a twisted rope, so that there is no chance of a kink, no separate lifeline component is required, and no tape is required to hold the umbilical together. An additional component such as a video cable for a diver's camera, or a hat light cable, can be added by manually wrapping this additional component into the lay of the existing cabled umbilical.
Read more about this topic: Umbilical Cable