VTernovski
Contributor
Hi all, I used to assist with SCUBA classes some time ago and wrote this article to new my students for day 1 in their class, I thought you may find it interesting too.. feel free to use the text for your needs,
-VADIM
Dear Friends,
You are about to embark on a journey to see the world within a world. Two-thirds of earth's surface is water, and now everywhere I travel, I have to go diving. For me, going near the water and not diving is like coming to see the Circus but ending up staring at the tent instead. If you are like me, you will enjoy this journey immensely; you will be able to see and experience things that you have only dreamed about, you will be flying through space - what many call the inner space.
That world that I just referred to is filled with an element that's called Water. And you will know that water is indeed a foreign environment to us. It's a lot denser than air, and sound travels faster. As a matter of fact, so fast that our ears can't detect the direction of the sound, so we can't tell where it's coming from. It takes more energy to move though it, objects appear magnified and closer, our body looses heat faster, our eyes can't focus clearly without a mask, we need weights and countering bouncy devices to even get underneath, and last but not least, we don't have gills, so we can't breathe water. Thus far, you begin to realize that you need some sorts of equipment to go divining.
That equipment consist of basic things such as a mask, fins, bouncy devices and the use of Self Contained Underwater Breathing Apparatus (SCUBA) to breathe. Every piece of equipment is a life support system designed to keep you alive and functioning in this foreign environment and you will learn each function and operation of every single piece of gear that you will need for this class.
I'll start with a mask. Without a mask you can't dive, nor can you even snorkel. If you simply open your eyes underwater without any kind of mask, you will quickly realize that you can't really make out any objects, as everything is blurry. That is because your eyes cannot focus properly without an air space. The mask lets you "see". The mask should be your very first purchase! Get the one that fits you well. Fit is the most important, so try several masks before making a purchase. Avoid large volume masks with more than two windows, they will be harder to clear, less comfortable and have a plastic frame that is prone to cracking. When you buy a new mask, they come with an invisible film of coating on the inside to protect the glass. Use some non-gel toothpaste and rub it thoroughly to take this coating off, and then rinse it well, which will prevent it from fogging in the water. All diving masks need to have a nose pocket so we can "equalize" our ears as we descend. What you should look for is one with a low profile that fits your face comfortably and does not fall off your face when you place it there and inhale from your nose without a strap. See how far down you can look and also see how much side vision you have. Frameless or Freediving masks are very popular with SCUBA divers.
Remember, black skirts prevent reflection, which is useful for photography and videography, while masks with clear skirts let more light in which gives an illusion that you can "see" more and are popular with people who might be a bit claustrophobic.
Second purchase is your fins. Like with a mask, it's an essential piece of equipment because you can neither dive nor efficiently snorkel without them. If a mask lets you "see", fins let you "move"! Water is over 20 times denser than air, and your legs, being longer and up to 3-times stronger than the arms, are a perfect propulsion device when combined with an increased surface area of the fins. Once you learn proper propulsion techniques, you will quickly realize that well performed fin kicks can sufficiently move you through the water. Get fins that properly fit you, go for something simple that will last you for years. Try them on before buying a pair. I recommend going with an open-heel type fins. ScubaPro makes Jet fins, which are great for all types of kicks.
You will also need to purchase booties. Get booties first, and then try different fins that fit with you wearing the booties. Get 5mm or 7mm (6.5mm) booties.
Though snorkels are still a part of required scuba equipment, most divers choose to leave them in their gear bags or stowed away in their pockets. The truth is that Snorkels are really good for snorkeling; for diving, however, you always have access to air on the surface by swimming on your back. If the water is rough, you will probably use the real underwater breathing system (regulator) anyway to breath the supplied gas. The argument is that snorkels also have Dead Air Spaces, an area where carbon dioxide builds up. CO2 is a horrible thing for divers and breathing through dead spaces is the last thing a diver needs before or after a dive. Swim on your back while on the surface or breath through the regulator which should always have enough reserve air and giving it to you at the rate you need it. There are divers out there who keep snorkels either on the left side of their mask or on their ankle on any dive. The latter is a definite entanglement hazard and should be avoided. A snorkel on the mask, meanwhile, interferes with the regulator, the calamity of a dive and overall performance. Also, where lines or reels are used, or in environments where fishing takes place (hence lost lines, nets etc), they may mean an entanglement that could even lead to mask loss.
Good buoyancy comes with good training, practice and experience. Water is a funny substance. It's much more denser than air and there is the additional pressure. Because of the things we need to wear and carry, and because of our body's natural buoyant properties, we need weights to be able to go down. But then we also need something to counter those weights so we can come up and stay on the surface without effort. Too much buoyancy is not good. Neither is too little buoyancy. What we want to establish is a "state of equilibrium" in the water, at any depth and with any weight our suits or tank contents may impose on us. The really ancient form of buoyancy devices are called Horse Collars as they were worn in the front, at the diver's chest like a U-collar and inflated on the surface. Over the years the industry worked hard to find better options to these and came up with a kind of an air-filled jacket. These are generally called Jacket type Buoyancy Compensating Devices or BCDs. There are also other popular BC Devices such as back inflation BCDs and Backplate and Wing (BP/Wing) systems are also worth looking into.
Ample thermal protection is important for a smooth, safe and enjoyable dive. Warm divers are happy divers. Cold can have a number of effects on the body and water conducts heat away from us faster than air. North East divers should wear a minimum two piece suit (with each layer being 7mm (6.5mm) to enjoy diving throughout the year. For Caribbean-type waters in the summer, 3mm wetsuit is fine. Given the price difference between a dry suit and a semi dry suit is minimal these day, it might be worth looking into purchasing a dry suit. Dry suits allow us to stay underwater longer, reduce DCS risks through proper thermal protection and do not reflect any crush or buoyancy loss with depth inherent with thick wetsuits. But you will need additional training with its proper use; so don't be rushing to get one just yet.
Underwater, Regulators are our lifeline and our only access to a comfortable and easy breath so they are the most important part of your equipment. Tried and tested regulators often work better and it is wise to avoid regulators with special fitting or non-standard parts. Regulators are made out of two components. A first stage reduces high pressure from the tank to a consistent intermediate pressure that is controlled by a second stage (mouthpiece) that delivers it to the diver's lungs. Balanced first stage regulators give divers a steady flow of air no matter what the tank content is. Most good second stages these days are 'downstream' in that if they malfunction, they will "free flow" rather than cut off a diver's breathing supply which is why you will be taught how to breathe from a free flowing regulator. A proper diver would carry two second stages, one as a primary and another as a reserve. Rinse your regulator well after every dive. Apeks and Scubapro make the world's leading regulators.
We need to gauge our depth, the time and the pressure in our diving cylinders on every dive. On most dives we also need to gauge our direction. A minimum of two time pieces are generally recommended, one required is a bottom timer (or a computer), the other one could just be a watch. We use a Submersible Pressure Gauge (SPG) to gauge tank pressure. The SPG is on a high pressure hose down the left of the diver. The gauge should be simple and reliable, and should be able to accurately measure the tank pressure in PSI. I recommend getting a simple brass gauge that shows 100 psi increments on a dial.
A knife is carried mainly for emergencies and because of this could be easily accessible to the diver with minimal movement. The best place to mount a knife is on the waist where it can be reached quickly, just like pulling out a gun! When you need it, it is there. A cutting tool such as surgical scissors can also be carried in the pocket.
Lights: Not every diving environment requires a light but when one is necessary it is advisable also to carry a backup one.
Enjoy!
-Vadim
-VADIM
Dear Friends,
You are about to embark on a journey to see the world within a world. Two-thirds of earth's surface is water, and now everywhere I travel, I have to go diving. For me, going near the water and not diving is like coming to see the Circus but ending up staring at the tent instead. If you are like me, you will enjoy this journey immensely; you will be able to see and experience things that you have only dreamed about, you will be flying through space - what many call the inner space.
That world that I just referred to is filled with an element that's called Water. And you will know that water is indeed a foreign environment to us. It's a lot denser than air, and sound travels faster. As a matter of fact, so fast that our ears can't detect the direction of the sound, so we can't tell where it's coming from. It takes more energy to move though it, objects appear magnified and closer, our body looses heat faster, our eyes can't focus clearly without a mask, we need weights and countering bouncy devices to even get underneath, and last but not least, we don't have gills, so we can't breathe water. Thus far, you begin to realize that you need some sorts of equipment to go divining.
That equipment consist of basic things such as a mask, fins, bouncy devices and the use of Self Contained Underwater Breathing Apparatus (SCUBA) to breathe. Every piece of equipment is a life support system designed to keep you alive and functioning in this foreign environment and you will learn each function and operation of every single piece of gear that you will need for this class.
I'll start with a mask. Without a mask you can't dive, nor can you even snorkel. If you simply open your eyes underwater without any kind of mask, you will quickly realize that you can't really make out any objects, as everything is blurry. That is because your eyes cannot focus properly without an air space. The mask lets you "see". The mask should be your very first purchase! Get the one that fits you well. Fit is the most important, so try several masks before making a purchase. Avoid large volume masks with more than two windows, they will be harder to clear, less comfortable and have a plastic frame that is prone to cracking. When you buy a new mask, they come with an invisible film of coating on the inside to protect the glass. Use some non-gel toothpaste and rub it thoroughly to take this coating off, and then rinse it well, which will prevent it from fogging in the water. All diving masks need to have a nose pocket so we can "equalize" our ears as we descend. What you should look for is one with a low profile that fits your face comfortably and does not fall off your face when you place it there and inhale from your nose without a strap. See how far down you can look and also see how much side vision you have. Frameless or Freediving masks are very popular with SCUBA divers.
Second purchase is your fins. Like with a mask, it's an essential piece of equipment because you can neither dive nor efficiently snorkel without them. If a mask lets you "see", fins let you "move"! Water is over 20 times denser than air, and your legs, being longer and up to 3-times stronger than the arms, are a perfect propulsion device when combined with an increased surface area of the fins. Once you learn proper propulsion techniques, you will quickly realize that well performed fin kicks can sufficiently move you through the water. Get fins that properly fit you, go for something simple that will last you for years. Try them on before buying a pair. I recommend going with an open-heel type fins. ScubaPro makes Jet fins, which are great for all types of kicks.
Though snorkels are still a part of required scuba equipment, most divers choose to leave them in their gear bags or stowed away in their pockets. The truth is that Snorkels are really good for snorkeling; for diving, however, you always have access to air on the surface by swimming on your back. If the water is rough, you will probably use the real underwater breathing system (regulator) anyway to breath the supplied gas. The argument is that snorkels also have Dead Air Spaces, an area where carbon dioxide builds up. CO2 is a horrible thing for divers and breathing through dead spaces is the last thing a diver needs before or after a dive. Swim on your back while on the surface or breath through the regulator which should always have enough reserve air and giving it to you at the rate you need it. There are divers out there who keep snorkels either on the left side of their mask or on their ankle on any dive. The latter is a definite entanglement hazard and should be avoided. A snorkel on the mask, meanwhile, interferes with the regulator, the calamity of a dive and overall performance. Also, where lines or reels are used, or in environments where fishing takes place (hence lost lines, nets etc), they may mean an entanglement that could even lead to mask loss.
Good buoyancy comes with good training, practice and experience. Water is a funny substance. It's much more denser than air and there is the additional pressure. Because of the things we need to wear and carry, and because of our body's natural buoyant properties, we need weights to be able to go down. But then we also need something to counter those weights so we can come up and stay on the surface without effort. Too much buoyancy is not good. Neither is too little buoyancy. What we want to establish is a "state of equilibrium" in the water, at any depth and with any weight our suits or tank contents may impose on us. The really ancient form of buoyancy devices are called Horse Collars as they were worn in the front, at the diver's chest like a U-collar and inflated on the surface. Over the years the industry worked hard to find better options to these and came up with a kind of an air-filled jacket. These are generally called Jacket type Buoyancy Compensating Devices or BCDs. There are also other popular BC Devices such as back inflation BCDs and Backplate and Wing (BP/Wing) systems are also worth looking into.
Ample thermal protection is important for a smooth, safe and enjoyable dive. Warm divers are happy divers. Cold can have a number of effects on the body and water conducts heat away from us faster than air. North East divers should wear a minimum two piece suit (with each layer being 7mm (6.5mm) to enjoy diving throughout the year. For Caribbean-type waters in the summer, 3mm wetsuit is fine. Given the price difference between a dry suit and a semi dry suit is minimal these day, it might be worth looking into purchasing a dry suit. Dry suits allow us to stay underwater longer, reduce DCS risks through proper thermal protection and do not reflect any crush or buoyancy loss with depth inherent with thick wetsuits. But you will need additional training with its proper use; so don't be rushing to get one just yet.
Underwater, Regulators are our lifeline and our only access to a comfortable and easy breath so they are the most important part of your equipment. Tried and tested regulators often work better and it is wise to avoid regulators with special fitting or non-standard parts. Regulators are made out of two components. A first stage reduces high pressure from the tank to a consistent intermediate pressure that is controlled by a second stage (mouthpiece) that delivers it to the diver's lungs. Balanced first stage regulators give divers a steady flow of air no matter what the tank content is. Most good second stages these days are 'downstream' in that if they malfunction, they will "free flow" rather than cut off a diver's breathing supply which is why you will be taught how to breathe from a free flowing regulator. A proper diver would carry two second stages, one as a primary and another as a reserve. Rinse your regulator well after every dive. Apeks and Scubapro make the world's leading regulators.
We need to gauge our depth, the time and the pressure in our diving cylinders on every dive. On most dives we also need to gauge our direction. A minimum of two time pieces are generally recommended, one required is a bottom timer (or a computer), the other one could just be a watch. We use a Submersible Pressure Gauge (SPG) to gauge tank pressure. The SPG is on a high pressure hose down the left of the diver. The gauge should be simple and reliable, and should be able to accurately measure the tank pressure in PSI. I recommend getting a simple brass gauge that shows 100 psi increments on a dial.
A knife is carried mainly for emergencies and because of this could be easily accessible to the diver with minimal movement. The best place to mount a knife is on the waist where it can be reached quickly, just like pulling out a gun! When you need it, it is there. A cutting tool such as surgical scissors can also be carried in the pocket.
Enjoy!
-Vadim
something that would prevent you from bouncing up and down in the water column?.. lol ..err. I hate spell checkers.
