A pontoon on the Great Barrier Reef
Divers being counted in by a divemaster
Queensland has one of the safest diving records in the world. Yet this week two American scuba divers apparently died in Queensland waters in bizarre circumstances.
They were apparently left behind when the diving boat returned to shore.
Give me a shark or faulty gear to deal with any day.
Good diving and boating practice should preclude such an event. Boat operators should know that one of the dangers of tourist diving is that so many couples go on day diving trips. Frequently they know no-one else on board. So it is hopeless yelling out, “”Is everyone here? Okay, let’s go.” One couple still in the water could be missed. A lone dive going on such a trip knowing no-one else is better off because no-one every dives alone, so you are always paired up. Someone might say, “”Hang on, where’s that chap I was diving with.”
Given those possibilities it is standard boating and diving practice to count heads going in to a boat and to count heads again when the dive is over before leaving the dive sight.
I have done about 30 dives on the Great Barrier Reef and about 150 all up, including dives in Malaysia, Belize, Turkey and Mexico. On most boats you give your name to the divemaster. In most boats you give your name to the divemaster who writes it down. That is the almost invariable practice in Australia and in Belize (another great reef-diving country). I cannot remember an occasion when it was not done.b
On the Barrier Reef most boats first go to a pontoon, like the one pictured. The pontoon is anchored to the sea floor. Some dive operators then transfer divers to a smaller craft moored at the pontoon and go off perhaps up to a kilometre to do a dive. Divers should be counted going aboard and coming off the small craft as well as being counted off the pontoon.
Apparently in this case the same boat that took the divers out to the reef was used for the dive. Still, they should be counted on and off.
Queensland has one of the safest diving records in the world, as the Minister for Tourism, Bruce Davidson, has been at pains to point out. It averages one scuba death per 400,000 dives, compared to four times that in Japan and the US. But the figure can give a false impression. In Queensland most diving is reef diving which means warm, calm shallow water and good weather. Colourful tropical reef, of its nature is in relatively shallow water. Danger for scuba divers usually arises in deep, cold, rough waters. So Queensland’s record is as much a consequence of good conditions than good practice.
Nothing can save you if you are left behind and no-one comes to rescue you.
You can survive a long time in water above 25 degrees, even without a wetsuit. At 20 degrees you will last about eight hours; at 10 you have two hours at best; at 5 you might have half an hour.
A wetsuit improves your chances. The two Americans had wetsuits. The reef water temperature this time of year is about 28 to 29 degrees. With a wetsuit you would not die from exposure. You are more likely to die of thirst or exhaustion (if you have no buoyancy).
The American divers were experienced. It is likely they allowed less experienced divers into the water first, as a courtesy. It is likely they were more economical with their air, so could stay down longer. It is likely that in shallow water they might use a considerable portion of their 50 bars of reserve, whereas less experienced divers would surface. In all, they could have been down for quite some time after the other divers got on board.
On surfacing, they would have been mildly alarmed, but would assume the boat had to go back to the pontoon for some emergency and would return. They would probably stay at the dive site in their full diving kit, but with the buoyancy vest inflated, at least for a while. The buoyancy vest is part of the scuba outfit. It is connected to the tank and while underwater the diver lets air in and out of it to control ascent and descent.
It would take a while for the true situation to sink in. Then they would have to make a decision about whether to swim to the pontoon, which might be several hundred metres away, and maybe against a current. They would also have to decide whether to ditch their weight belts and other scuba gear. It is expensive stuff and you don’t do it lightly. In hindsight it is easy to say, of course they should ditch their gear and swim for it. But the reality of danger hits the consciousness slowly.
Despite these deaths, scuba diving remains a safer sport than many with a more benign reputation like football. It is a safe activity precisely because its inherent dangers are recognised and catered for. But it only takes one error for the consequences to be catastrophic.