File:US Navy 050220-N-3541A-013 Navy Dive Officer Lt.j.g. Charles Spenser has his hard-hat dive helmet checked before a dive from USS Grapple (ARS 53).jpg - Wikimedia Commons
My First Hard Hat Dive – Part One
Hard Hat Dive
Hard hat diver. vertical traditional lifeline heavy weighty cumbersome awkward Divers Archives - MarineThemes Stock Photo Library
Hard Hat Diving Suit Photograph by Carl Purcell - Fine Art America
In the past deep sea divers had suits with heavy helmets and an air hose attached. There are stories of the air failing. Because of the extreme pressure, they have found nothing