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February 10th 2014

10 Feb 2014 Written by 

That’s heavy man
weightbelt Learning to dive can be an exhilarating and, without sounding too cheesy, for some people a life-changing experience. Taking your first breaths underwater makes you suddenly realize that there is literally a whole new world waiting to be discovered. But before you can dive around with ease, you'll need to learn some fundamental skills, such as buoyancy control and how to move in the water efficiently.
You’ll hear it over and over again that buoyancy is the key to becoming a good diver, and it’s true. But the secret to good buoyancy is also ensuring that you are correctly weighted.
We all have to wear weights when we dive in order to counteract our body’s own buoyancy. Most people will be neutrally buoyant whilst floating naked at the surface; they just don’t get too much opportunity to practice it! How dense your muscles, bones and fat are, combined with the thickness, age, and type of wetsuit will determine how much weight you are going to need when you decide to not dive naked.
Many diving instructors overweight beginner divers so that they don’t float up to the surface easily. After all, they’re going to be easier to deal with if they’re actually underwater! But that student will need to add a fair bit of air to their BC to stop them dragging along the bottom. If they rise up a bit, Boyle's law will take over and they'll have to get rid of all that expanding air. So for a while they'll be like a yo yo- wasting air and making their ears work harder than they need to. So it can take a lot more time for them to understand how to control their buoyancy. I would rather start my students if anything a little light, so that they are not having to add anywhere near the amount of air into their BC. I also brief that they should use their lungs to come back down if they find they are a little “floaty”. If they are consistently finding it hard to stay down I can give easily them an extra weight. The closer they are to having the right amount of weight, the less they will be adding and removing air through their BC, and thus the less they will be moving up and down in the water column.
On the advanced course, a lot of emphasis is placed on using the lungs to fine tune buoyancy, so the quicker the head start a student gets in their open water, the better. However, more often than not, on the buoyancy dive no mention is placed on correct weighting. Some instructors will perform a buoyancy check on a student and help refine the amount of weights they need, especially if they haven’t dived with them before or the student hasn’t dived in a while and can’t remember how many weights they normally have. But that's it.
But weighting is one of those things that the student needs to understand, so they can start to take responsibility for themselves as an autonomous diver. The least weird analogy I can think of would be learning to ride a bike as a young kid. At some point you become adept enough that your parents will take those stabilisers off. But with diving it’s your decision as to when to take the stabilisers off, and you have to experiment. If you’re being led by a dive professional on a dive, it’s always a good idea to discuss it with them, but if you want to experiment with having, for example one less weight just give it a go, your dive leader can always carry an extra weight during the dive.
To know how much weight you need, you have to be able to stay comfortably at 5 metres at the end of your dive during your safety stop. Air, like anything else, has a weight, and as you breathe through your supply, your tank is getting lighter. This can be a 2kg difference from the beginning to the end of the dive. So at the beginning of any dive you will be a little bit negatively buoyant. You don’t want to increase that by having too many weights. Statistics show that most divers that get into trouble are usually found to have been badly over-weighted. Remember, the deeper you go, the more negatively buoyant you become. If you’re a fun diver, you should hopefully be following this article. If you’re planning on learning how to dive and have read this far, hopefully you’ll be a dream student. But don’t worry; your instructor at Big Blue will help you get the weight you need. But remember, if we ask you to carry more weight than your friend, we’re not saying you’re fat!

Turtle traps
chinese-lanternsSo, you come to a tropical Island like Koh Samui or Koh Tao and, as you’re walking along the beach at night a friendly Thai approaches and asks if you’d like to buy a lantern to launch into the air, with a personalized message attached for good luck. Very romantic. But let’s think of it another way. How about a Thai person comes up to you, hands you some metal wire and some paper fabric, then says that you have to get in a boat, travel a kilometer out to sea and then throw it all into the ocean.. Sounds bad? Well that’s exactly what you’re doing if you chose the first experience! I don’t care how romantic or sentimental it all sounds, you’re basically littering the ocean.. So don’t do it!
To top it all off, when the wire mesh falls back into the ocean, it settles on the bottom and turtles come along to investigate it and get stuck. They then find it very difficult to get back to the surface to breathe, and often drown. So now you’ve read this, please don’t even go near the lantern sellers. They don’t understand the effects of what they are selling, they are just trying to make a living, but if no-one buys them they’ll quickly move on to sell something else.

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Read 1185 times Last modified on Tuesday, 24 October 2017 08:24

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