On a cool February morning in 1967, Navy diver Bob Croft packed his lungs with air and plunged into the Atlantic, descending more than 200 feet without a mask, fins or scuba tank. By most measures, Mr ...

Vitomir Maričić burst out of the water, stripped off his goggles, and gulped for air. His head was pounding. Blood vessels in his brain had dilated, creating swelling that pressed against his skull.

​Robert Croft, who has died aged 91, was a US Navy diving instructor whose record-breaking feats of deep diving in the 1960s transformed scientific understanding of how the human body ...