Most scuba diving incidents are caused by a series of little problems that add up to one big incident so we’re going to look at these with our learning cap on so we can avoid similar incidents. Now I have been witness to a few incidents and heard a few stories but remember to only report your experience and don’t guess and report things you think as truth. I have been lucky not to have been directly involved with any serious incidents but I’ve been close enough to a few.
Two big instigators are equipment malfunctions and poor judgement. Keep a level head, keep good care of your gear and stick to your training limits and you greatly reduce the chances of anything going wrong.
I have 1st hand experience of a few equipment malfunctions while diving and luckily none of them resulted in any injuries. The first one that springs to mind was me and another diver practising some search and recovery. Diver 2 ties a lift bag to an object to lift it, partially inflates the bag with their alternate when their primary 2nd stage begins to freeflow. Diver 2 turns to me, I donate my primary and switch to my alternate so they can breathe and we attempt to fix the freeflow underwater. We couldn’t fix the faulty 2nd stage so we both abort the dive and ascend to the surface and the regulators were serviced after we got back.
A similar case out in the Red Sea; I’m following a buddy pair around Shark and Yolander from Satellite reef when the swivel joint on Diver 2’s primary slips an O-ring and it freeflows. Diver 2’s buddy hadn’t noticed but because I was behind them I could see everything. Same procedure as before, donated air, couldn’t fix in the water, both ascended safely.
In both of these scenarios, the equipment was fine on the boat at the beginning of the dive so the important things to learn from equipment malfunction is to keep on top of your gear servicing and maintenance, practice your out of air drills and stay calm. Stay close to your buddy too, they are your best lifeline and if you stray too far then you'll have to find them and get to them without any air.
So far I don’t have any 1st hand experience of poor judgement incidents but there are plenty of reports to read up on. Overhead environments and Depth are the two most common situations that involve poor judgement. Overhead environments beckon you in but without proper procedures and equipment, they can be literally death traps. Get turned around in a cave with no line to lead you back out and you don’t have a lot of time to find your way out.
A diver I spoke to once said he had a pair of old gloves nailed to the wall in his shed with the fingertips worn down to nothing. They said they had been swimming through poor vis looking for a wreck and ended up inside the wreck unable to see a way out. They wore their gloves down to nothing trying to feel a way out but it took a long time and a lot of frantic feeling around hard rusty metal bulkhead. They made it back to tell the story, many others haven’t. If the vis is that bad then the dive isn’t worth it, it’s just not your day so it's time to turn around and head back up, the vis really isn’t going to improve the deeper you go.
Depth is the second one, blue holes and wall dives have plenty of divers going too deep and going missing. There’s a reason your first qualification is to just 18m and then 30 and then 40 and then 45. The deeper you go the more complicated it gets. At a certain point even with a fully inflated BCD you won’t float and need to ditch some lead. Too many people think if they can just swim fast enough they can swim down through that swim through and back up again but the deeper you go the harder it is to think because the increase of nitrogen in your system has a narcotic effect and you’re breathing at a much faster rate than you are used to because of both the pressure and the effort. Be humble, remember that little things turn into big problems, if you want to dive through that swim through then get the proper training and you can do it safely, I’m sorry to be the one to say this but you may not be that amazing that you can do it by yourself with no training.
Things to learn from this are not to go anywhere near your limits. If you’re not cave qualified or have all the gear you need, don’t even try. Monitor your gauges often and stay in your depth.
Sure they’re pretty but some marine animals just don’t like you. Most will swim away from you because if you put yourself in their position; they don’t know what you are, you could be a predator for all they know so it’s safer for them just to give you a wide berth and come back when you’ve gone. Sharks are the most obvious ones but as you should know by now that’s pretty much rubbish. Sharks aren’t out to get you like Hollywood movies. If you’re going to get hurt by an animal underwater it’s more likely to be fire coral, urchin.
I’ve been stung by fire coral before and it sucks and as with most other marine life incidents; it was my fault. I wasn’t paying attention on a drift dive and I brushed up against some and regretted it for the next month or two. Pay attention while you’re diving and sort out your buoyancy. Give marine life plenty of space and don’t touch anything. A lot of the time the most camouflaged things are the most dangerous. And stay clear of titan triggerfish, they’re nasty and might actually be out to get you.
I have been in or around the water near too many divers who have had heart problems while diving. If you have a heart attack at work it’s a pretty bad day but there are people around you to help and get you to a hospital fast. If you have a heart attack underwater they have to get you back to the surface and out of the water, which is easier said than done, before they can even call for help. You then have to get back to dry land before you can head to the hospital and chances are you won’t go to the nearest hospital. Because you’ve been diving you’ll be heading to a hospital with a chamber and they’ve been closing a bunch of them.
Keep on top of your health and take it seriously, don’t just laugh it off because you feel fine right now. It’s time to grow up and realise you’re not just putting yourself at risk. If something happens to you your buddy could hurt themselves getting you back and may need therapy if the worst should happen. Get checked out, it doesn’t take long, it’s not embarrassing but it could save a life.
While diving you have to bow down to the laws of physics, biology and chemistry. Quite a few bad things can happen to you underwater and I’m going to skim through a few of those quickly if you exceed limits or do things wrong. If you exceed the maximum depth of your gas mix then the air you breathe will become toxic. Below a certain depth, around 66 meters normal 20.9 percent air will become toxic because there is simply too much oxygen and the partial pressure has become too high and can lead to convulsions and worse. Ascending too quickly and the rapid drop of pressure will cause dissolved gasses in your tissues to come out of solution and form physical bubbles in your body where they really shouldn’t be. Subcutaneous emphysema, lung over-expansion, mediastinal emphysema, pneumothorax, arterial air embolism these are all very scary words for scuba divers so let's keep them off your medical charts so take your time when ascending.
This is what your dive computer is specifically designed to prevent. You tell it what you’re breathing and it will tell you how deep you can go and how long you can stay there. They also get quite upset when you ascend too fast. So the next time you see somebody ignore their dive computer or try to reset it so they can go diving again, they’re an idiot. All dive computers have a level of safety built in so you don’t even go close to your actual limits but remember that no dive computer knows exactly what’s going on inside your body they’re just guessing really because everybody is different. So the next time you dive right up to the limit, squeeze every second out of a NDL just remember that your computer is just a guide. And don’t even get me started on SPGs, they're not 100% accurate so don't take their readings as truth.