Reprinted from Cave Diving in Australia, Lewis & Stace, 1980

On Monday the 23rd December 1974, two divers entered Piccaninnie Ponds intending to dive the 'Dog Leg' to about 60m. The previous day they had dived to about 42m in the same area using fishing line as a guideline.

They descended to 9m down the shot line where the victim attached his weight belt, as well as a full 72 cubic tank with regulator, to be used for decompression. Continuing, they descended to 60m without incident where the surviving diver had to switch on his reserve, and the ascent began.

During ascent, the victim became entangled in the fishing line and alerted his buddy. As the buddy was already on reserve, he could not assist for more than a minute or so before his own air ran out, so he was forced to abandon the other diver and head for the surface. Knowing that the victim himself was equally low on air, the buddy decompressed and left the water to raise the alarm, although it was certain that his companion would die if he was unable to free himself from the tangle.

The following day the victim's body was recovered by the Underwater Recovery Squad from 54m in the 'Dog Leg'. The body was found entangled in line from the waist down with face mask and regulator dislodged and arms outstretched as if asking for assistance. The knife was still in its scabbard, the CO2 orally inflatable vest had not been used and 700psi was still in the victim's tank.

There are many contributing factors which led to this fatality and they are as follows:

• Despite Army swimming qualifications there was no evidence that the two divers had any deep diving or cave diving training.
• The fact that they dived to 60m and then had to switch onto reserve air indicated a total lack of understanding of decompression requirements and air consumption.
• Relying on J-valve reserve air is simply forbidden as a safety measure in cave diving. Pressure gauges should have been used.
• At a depth of 60m under difficult conditions, both divers would have been under the influence of nitrogen narcosis, which dulled their ability to make necessary decisions such as inflating their vests, cutting the snaring guideline or shortening their dive time in the first place.
• Some of their equipment was chronically below standard. The victim used only a plastic Dolphin torch, and the guideline was an open-reel length of thin shark-fishing line, impossible to see in the gloom. This preparation is inadequate for a 60m dive.

As the victim was swimming close behind his buddy, his mask and regulator may have been accidentally kicked from his face by a fin. The shock of cold water on his throat probably caused respiratory inhibition and almost immediate death. The body would have then sunk back to 54m where it was found. Although the post mortem found that the cause of death was due to air embolism, it is more likely that the embolism occurred after death when the body was being recovered.

Accident Analysis
Cause of Death - drowning after running out of air
Major Contributing Factors - inadequate gas for the dive, inadequate training, inadequate equipment, diving too deep on air

More information on Piccaninnie Ponds

Piccaninnie Ponds 3D Map | Credit: John Dalla-Zuanna