Hypothermia during saturation diving in the North Sea.

We recently suggested after laboratory experiments' that undetected hypothermia might account for unexplained casualties during working dives in the North Sea. At depths greater than 50 m in the North Sea water temperature is below 10°C. Heat is usually supplied by flooding the diving suit continuously with warm water pumped from the surface via the diving bell; its temperature is monitored at the bell, but not at the diver, and is regulated mainly on the basis of the diver's report of feeling hot or cold. We found that simulation of this with warm water at 290C around a thin man could produce progressive hypothermia with cardiac irregularities but without any serious sensation of cold. We are now reporting the body temperatures of divers during saturation diving operations using the conventional heating system at a depth of 130-145 m in the North Sea in August-November 1979.