Another scuba diver died last weekend. She was a German national who had been in Australia about six months. There seems to have been a spate of them. In February, a female British tourist died off Bondi and last December a female Japanese tourist died off Manly while diving with the same company as the British tourist and also last December a Sydney woman died after going missing on a dive trip in far north Queensland. In June last year a Japanese woman died during a night dive off Exmouth in Western Australia.
These incidents follow the famous case of the American couple left at sea after a scuba trip on the Barrier Reef in 1998.
Is there cause for grave alarm or are these cases the acceptable risk of an inherently risky undertaking? Two things stand out here: females and tourists are dying far out of proportion to their numbers among divers. I think also that Australia has a special problem, but more of that anon.
It is dispiriting because most scuba diving deaths are avoidable.
That said, scuba diving is a joyous sport. My feeling is one of privilege. Just a couple of generations ago, under the sea was a no-go area. Now, we can see the wonders and diversity of marine life. And in a world full of roads, power lines, McDonald’s wrappers, farms and almost blanket human meddling, the underwater is a wilderness, an Eden of natural purity. In any small patch of ocean reef there is an array of intricate subtlety – a crustacean with delicate feelers and legs, a nudibranch with colours from a Jackson Pollock palate, a graceful shark elegantly sliding along a gutter in a forest of yellow-orange kelp and a sea-horse that has taken on the shape and colour of the kelp itself. It is where God and Darwin co-exist.
But it is not worth going to your Maker early for.
What are the dangers?
First, to explain the physics of diving. Picture, if you will, a stone in a small balloon floating on the surface of the sea. If I grab the balloon and force it under the surface the pressure of water will push on the balloon, making it smaller. The deeper I pull it under the greater the pressure and the smaller the balloon will be compressed. Eventually, the balloon will be compressed so small that the stone inside will be enough to cause it to sink of its own accord. This is a matter of buoyancy. The less air in the balloon the more the stone makes it sink; the more air the more it floats.
A diver is like the balloon and the stone. Except the diver can inflate and contract the “”balloon” at will. The diver wears a buoyancy vest which has a bladder that can be inflated from the compressed-air tank by pressing a button. And air can be released from the buoyancy vest by pressing another button. So the diver can go to the surface by inflating the buoyancy vest and sink by letting air out of the vest.
To complicate matters, the diver has a wet suit which is full of air holes and keeps the diver afloat. To counteract this, the diver wears a weight belt with lead weights attached. Further, a divers lungs affect buoyancy. Breathe in and you go up. Breathe out and you go down.
The aim of a diver is to be neutrally buoyant. Start on the surface just floating. Start the dive with a little air in the buoyancy vest. Let it out and you sink. As you sink the pressure pushes on the wet suit and like the stone in the collapsing balloon you sink. You will sink to your doom unless you press the button to put a bit of air into the buoyancy vest to keep your buoyancy neutral. Neutral buoyancy is the aim of every diver.
Pressure has another effect. For every 10m you go down you add another atmosphere of pressure. The pressure at the surface is one atmosphere – that is, the pressure caused by the air in the atmosphere. Go down 10 metres, and the pressure reaches two atmospheres. That is, the pressure of 100km of air in the atmosphere is equivalent to 10m of water. Go down another 10m and the pressure is three atmospheres and so on.
Volume and pressure are related. If you take a one-litre sealed, flexible container of air down 10 metres it will be crushed to just half a litre, but with exactly the same number of air molecules in it. The diver is breathing this concentrated air. The oxygen just goes in and out. But some of the nitrogen gets absorbed into the blood. The deeper you go and the longer you stay down the more nitrogen gets saturated into the blood. It gets absorbed at a steady rate.
Now picture a sealed bottle of lemonade. Lemonade is made by forcing gas into the liquid at pressure and sealing it. If you rip the top of very quickly there is a sudden release of pressure and bubbles form – bubbles which were not there when the lemonade was sealed under pressure on the super-market shelf. If, however, you release the top very slowly, fewer, if any, bubbles are formed.
It is the same for the diver. If the pressure is reduced suddenly by coming very quickly to the surface where the pressure is lower, the nitrogen saturated in the blood forms bubbles, just like the lemonade. These bubbles can stick in the joints making them stiff – hence the “”bends” – but worse they can hit the brain and cut off the blood supply, causing a stroke or death. Or they can hit the lungs causing the rupturing of blood vessels and drowning the blood.
So a diver must come up slowly. If a diver has been deep for a long time, the diver should hover at 10m or 5m for a period to allow the nitrogen I the blood to dissipate slowly before coming to the surface.
In short, a diver must control buoyancy and must limit the length and depth of dives and the rate of ascent.
Another difficulty is that from about 30m and deeper, the nitrogen in the blood can cause nitrogen narcosis. People get a mild high which can cause disorientation and a lack of concentration.
Many diving injuries and deaths are caused by divers coming up too quickly. They do so because they are running out of air, or think they are running out of air, through panic (usually unnecessary), because they are injured, or because gear has failed. When they come up to quickly the air in their lungs expands and can burst the lungs. In panic they hold their breath, keeping the expanding air in their lungs and increasing the danger of a burst lung. It may go against instinct, but you must breathe out when ascending. About a quarter of diving deaths are caused by medical disorders manifesting themselves under the stress of diving: heart, asthma, epilepsy, lung problems, diabetes or influence of therapeutic drugs.
A lot of diving deaths are due to drowning on the surface either after being injured on the way up or through sheer exhaustion.
So what are the lessons?
Training, fitness, quality of gear, experience, recency of previous dive and knowledge of the dive site are critical.
The commercial imperative is a danger. Diving schools that want to push people through courses so they buy expensive diving gear are a problem. A lot of emphasis is on fun and experience.
Australian experience can prove deadly for tourists. So many Europeans and Japanese learn to dive in tropical places, like Thailand or Fiji. Or they learn to dive in the enclosed Mediterranean. Conditions are usually calm and clear.
Then they come to Australia. They might dive the Great Barrier Reef where conditions are also usually calm, warm and clear.
Unfortunately, they imagine that all diving is like this. In particular, they picture the whole of Australia as a calm, clear tropical paradise and head for Sydney and other parts of the NSW coast. This coast, open as it is to the whole of the Pacific, is often rough, cold, full or currents and with low visibility. Suddenly, diving is not so easy. Low visibility can cause fear and panic in inexperienced divers. Surface waves and cold water can sap energy.
The death at the weekend was of a German woman who has been in Australia six months. The other recent deaths in Australia were all female tourists bar one, who was an Australian woman. This is telling. It is here that most attention is required. Is there a communication problem between Australian instructors and dive masters and divers? Is there an Australian she’ll be right attitude or an Aussie self-reliance attitude causing a problem, in contrast to the high-service attitude in other countries or the case of the US a plaintiffs’ lawyer syndrome which makes diver operators extremely cautious? Is there a macho Australian attitude that does not take sufficient care and notice of women’s often lower physical strength than males.
The most recent Australian male scuba deaths (excluding the two shark deaths) were of Pat Bowring in 1996 (but probably of a
heart attack) and in 1992 of highly bexperienced divers who apparently could not find their way out of a small compartment in a wreck after kicking up silt. All the recent deaths in Australia have been of people younger than their mid-30s.
It seems to me that diving schools and diving instructors need either extra training or to pay extra attention to the needs and capabilities of foreigners and females. It is significant that those facing a strange environment and those who are usually physically weaker are getting into difficulty. It is because they are being asked, pressured, led or misled into doing things that they do not have the fitness, strength or experience to undertake.
But with proper care, there is no reason why tourists and women cannot enjoy the wonders of underwater diving.
Despite some of the horror described above, diving in Australia is on the whole very good and diving operators very safe. But divers have to also look out for themselves.
Make sure you are fit for diving. Have a medical check before diving and every second year (or annually if over 45).
Make sure you can still swim 200m in under five minutes.
Is your gear in good condition?
Are you neutrally buoyant?
Never dive beyond your experience or capability.
Always dive with a buddy.
When in doubt abort the dive.
Carry a safety sausage (an orange plastic bag that you can inflate so you can be seen on the surface).
The list goes on.
There are some strong parallels with driving a car, except with diving you do not have the added risk or the other idiot. It means if you are sensible you are safe and you can enjoy the great privilege of diving.
Let’s look at the recent deaths.
Last weekend, the four divers involved decided to look at the trawler which recently sank off Jervis Bay in 60 metres of water. Now that is a deep dive. It will inevitably cause some nitrogen narcosis. Anything going wrong at that depth is hugely dangerous. Gear failure or anything requiring a rush to the top is much more likely to be fatal. You would need a lot of dives in very good conditions gradually building to that depth to avoid psychological stress that can bring on panic or medical disorder. She might have had too much weight.
The bizarre thing is that there is little point in doing dives this deep. Most of the colour is absent at that depth and sea life is less abundant. The best diving is between 10m and 25m.
The Bondi and Manly deaths were on much shallower dives.
The death of British tourist Nicky Sheen, 24, can probably be put down to inexperience. She had not dived in the open sea before and had only done a few dives in Thailand. She was required to swim out quite a distance to the dive site and instead of using her snorkel had apparently used her regulator and used up air so that she had much less air than the others on her dive. She apparently ran out of air and with her buddy rushed to the surface but did not make it. She should have done half a dozen boat dives and/or some very easy shore dives with an experienced buddy before attempting a shore dive with a long swim out.
The Manly dive death involved similar inexperience.
The diving industry remains largely self-regulating. In the wake of these deaths dive operators have improved safety. But unless more attention is given to foreigners and females there may be more deaths and that will result in regulation and its associated costs.
The warning is there: scuba diving has dangers as well as joys.