What is clear is that this extraordinary man, who accomplishedso much was a “regular Joe” who simply wanted to get the job done and who avoided most of the fanfare of his early competitors. This book is a great read about a legend and a legend-in-the-making—the father of American freediving. Dr. Terry Maas
Before his first record-setting dive, experts thought deep freediving would lead to certain death. The U.S. Navy Diving Manual stated that dives below 120 feet could prove fatal, and the 200 foot depth mark was seen as an absolute physiological barrier. This was based on the belief that the human thorax could not survive such compression. Bob proved these theories wrong and subsequently participated in medical experiments which revealed that the space left by the compressed lungs, which shrunk to the size of oranges on a very deep diver, was filled by blood shifting from the extremities.
Navy Diver Submariner
Bob grew up loving the sea, where he excelled in breath-holding underwater games. During his duty as an instructor at the Navy's submarine escape training tower, he could often be found holding his breath at the bottom of the 118-foot training tank. He was so relaxed he could spend five to six minutes at a time underwater and would occasional doze off. Curiosity and the urging of friends motivated Bob to test his limits on a world record attempt that would ultimately lead to him besting the famous European deep diver Jacques Mayol in three consecutive contests.
In addition to setting records and dispelling theoretical limits to human freediving performance, Croft developed two powerful tools that are used by his successors even to this day. He taught himself to overfill his lungs with a “packing” technique whereby he used his tongue as a pump to force extra air into his lungs. He also used the first scleral contact lenses in conjunction with fluid-filled goggles, which enabled him to avoid the large volume presented by normal diving masks—volume that would have to come from his shrunken lungs to equalize the pressure on his face.