Whether you are just starting your TDI Intro to Tech Course, or have over 200 Advanced Trimix dives, these six essential skills should be practiced on every dive.
by Mark Powell
Why do divers do stupid things? Well the short answer is because they are stupid. Now I know that the majority of the readers of this article are going to be divers and it’s not usually a good idea to start off by insulting your audience but bear with me. If you look at some of the recent diving incidents that have occurred such as the tragic double fatality of a father and son who died while cave diving on Christmas day, or the diver who refused to analyse his gas an ended up breathing 100% oxygen at 30m or the rebreather diver who jumped in with oxygen, diluent and handsets all turned off then you can see why I might say that. The British Sub Aqua Club publish a summary of diving incidents every year and a brief glance at this will show that dives do a whole range of stupid things. Not only that but they do the same stupid things over and over again. Most of the mistakes made each year are the same as the mistakes made the previous year. The short answer is that divers do not follow their training. It would be very easy to stop the vast majority of diving accidents if we could just force divers to follow their training. If you do what your instructor taught you during your course then you will avoid the vast majority of problems that occur. The thing is that you already know that, I know that, everyone knows that and yet hundreds of divers every day do things that break what they were taught in their training.
Is this because divers are genuinely stupid? or is it because they just act as if they are stupid? I believe that divers do stupid things because they are human and humans make mistakes. However that doesn’t mean that mistakes are inevitable. If we understand why we make mistakes we can potentially avoid them. If we recognise that each and every diver has the potential to make mistakes then maybe we will be a little more careful and a little less complacent.
We all have the potential to do stupid things because we sometimes get complacent, because we rush, because we are not very good at assessing risks, because we are often over optimistic. We do not always call a dive when we should, letting multiple little problems build up until they become a major incident. We trust our own powers of observation and can easily get fooled into trying to solve the wrong problem. Finally we often let other people influence us unduly.
I have tried to bring some of these ideas together and have given a number of talks on this topic at dive shows throughout Europe and the US. The video above was shot at TekDiveUSA (www.tekdiveusa.com) in Florida recently. This conference brought together technical divers from all over the world to discuss exploration, diving medicine and diving safety. As part of the conference I was asked to put together a short film which summarised why divers do stupid things. I hope this film helps explain why there is always a risk that we might do something stupid and hopefully will help you to avoid doing anything stupid in the future.
By Michael Thornton and Josh Thornton
Switching your diving gas in 8 easy steps
Safe technical diving begins with awareness. The first step is being aware of yourself. As you gain experience and comfort you become aware of yourself and your gear. The highest level of awareness is when you are aware of yourself, your gear, and your surroundings including your dive team. When you add complications, emergencies or any kind of stress your awareness will diminish.
Not being aware of you, your gear or your surroundings during something as critical as a gas switch can be fatal. It is important to follow a strict protocol while staying aware during any gas switch to minimize risk.
As with most diving skills there is more than one way to do things. By establishing a set protocol and adhering to it every time, the risk of making a mistake is reduced. The most common problems that arise during a gas switch are losing control of your buoyancy and changing depths unintentionally or breathing the incorrect gas mixture for the respective depth.
All deco bottles should be pressurized but with valves closed when not in use. This prevents losing gas unintentionally and minimizes the risk of breathing off of the incorrect regulator. Pressurizing is necessary to keep water out of the system and your gear working.
When performing a gas switch, the following steps will help:
- Confirm you are at the correct depth to make the planned switch and achieve neutral buoyancy. (Also have team verify)
- Identify the correct cylinder by verifying the MOD marking on the cylinder. (Also have team verify)
- Deploy the second stage and follow the hose back to the first stage to verify you have the correct second stage.
- After you have confirmed you have the correct second stage and cylinder, open the valve.
- Purge the second stage to remove any debris that may have entered during the dive, and confirm functionality.
- Swap regulators and breathe. (Signal team you are okay)
- Clip off primary regulator.
- Change gases on your computer(s). (Signal this and confirm it with your team)
As a team you should discuss where your cylinders will be mounted. Some common mounting protocols are: 1) rich mixes on the right and lean mixes on the left or 2) all cylinders on the left side and rotate them for easy access at the appropriate depths. Whichever protocol you choose make sure you can easily access all of the cylinders and verify with visual and tactile methods the various cylinders. Team gas switching protocols call for individuals to verify proper gas switches within the team. Some teams prefer to complete the switch one at a time to allow maximum control.
Labeling the cylinder near the neck allows the diver to see it (and in turn, verify the mix). An additional label on the side near the bottom of the cylinder allows the team to see the markings as well.
When switching from one deco/stage gas to another it is important to follow the same verification procedures listed above. To avoid confusion, switch to your back gas. This will allow you to stow the regulator from the first deco/stage cylinder and turn off the valve prior to deploying the second deco/stage regulator.