Sometimes bad habits and half-truths find their way into all elements of our lives. Those small snippets of information that sound like they should work or you just assume that that’s the way things are done (have you ever put a spoon in an open bottle of champagne to stop it going flat in the fridge?)
Well scuba diving is just the same. It’s full a little quirks that have become either part of courses’ ‘folklore’ or have become a standard, de facto or otherwise. Well I have a list of a few that I know of – perhaps you have some of your own! I would love to hear them.
Drink water, not caffeinated drinks before and after a dive as dehydration is a leading cause of DCS
I can’t count the times that a well-meaning DM or instructor has offered me a drink of water right before or after a dive to ‘reduce my chances of DCS’. Whilst a cup of water is always welcome on a hot day, a single cup of anything is unlikely to affect my body chemistry enough to be the deciding factor in a bend. Maintaining a normal level of body fluid is something that needs to be an ongoing process that is difficult enough even when not diving. The best evidence is that severe dehydration is only one of a number of possible contributory factors to DCS and it may just cause symptoms to manifest themselves more acutely than they would otherwise. Monitoring the colour of your urine output (pale) is still the best guide to your pre-dive hydration and being mindful of all the factors you can influence to reduce your chance of a bend.
Don’t wear your mask on your forehead, it’s a sign of a panicking diver
No, a diver calling for help or splashing for attention or trying to stand on you is the sign of a panicking diver. A mask on the forehead is the sign of a diver making themselves comfortable at the surface if they so choose. I would be careful in a breaking swell as I don’t want to lose my prescription mask, but in still water after a cave dive for instance it can be a comfortable place to put my mask.
It’s essentially the worst place to hold a cutting device and can even become entangled in fishing line, causing the problem it’s there to solve. Somewhere around the middle of the body that can be accessed by either hand is best place to keep a small knife, line cutter or trauma sheers. It’s makes them easy to get at pretty much regardless of body position, be located by a buddy and cost a fraction of the cost of some ‘dive knives’ I see on peoples legs.
Always wear a snorkel
They have their place I admit it. That is in my kit bag. OK so some agency instructors have to have one as part of their training standards, and you were probably sold one on your first course (can you see a connection there?) I see divers on boats where the snorkel is actually getting in the way and may cause a problem. If you need to surface swim, do it on your back. If you are at the surface at the end of a dive in a breaking swell keep your regulator in. Trust me, it’s OK to take it off now (see, no dive police).
Always surface with 50 bar in your tank
Why? What am I supposed to do with it? Does that tell me at what gas pressure I start back to the surface with? No of course not and that really is the important pressure to know, when to START the ascent and head home (cave divers call it ‘turn pressure’). You need to know how much gas you AND a stressed buddy are going to need to make nice slow, safe ascent if you are sharing gas and it’s way more than you think (I will show you how to work that amount out in another blog).
Don’t go into deco
Everybody who is diver and is reading this has made a deco dive. Think about it – by definition, if you are ascending and reducing the ambient pressure around you then you are starting to move the Nitrogen out of your body tissues; this is decompression. Ascending, off gassing, supersaturation and decompressing are all the same thing, it’s just that when diving within recreational ‘No decompression limits’ the amount of deco you have to do is less or the same as your ascent time without stopping. So the problem isn’t deco as such but there are three issues that a recreational diver does not have the proper training to manage (and are what technical training courses will start to cover). They are not knowing how long their ascent time needs to be based on their bottom time, at what depth they must make their stops, how long they have to be and most crucially if they have enough gas to perform that ascent. So unplanned deco is really our culprit… so get some training!
So these are my diving myths busted; there are dozens more. It comes down to being a thinking diver, constantly evaluating and questioning what is presented to you (as a ‘fact’ in diving is rarely every so).
Blog courtesy of www.divelife.com.