Heat Loss Underwater

Even when diving in tropical waters (27 C/78 F) divers may experience a significant loss of body heat.

Water is able to conduct heat more efficiently because is more dense than air. Therefore, energy is conducted easier underwater.

Underwater we lose body heat twenty times faster than in air. So it is highly recommended to dive with some kind of exposure protection at all times.

Failing to do so may lead to hypothermia, a condition in which your body cools so much it that it can´t function normally.

There are two types of exposure protection: Wet suits and dry suits. The first ones are usually made of neoprene rubber and the reason why they are called wet suits is because the diver gets wet when using them.

Wet suit reduce heat loss by putting a layer of insulating foam neoprene over your skin. Water enters at the wrists, ankles and neck and gets trapped between the diver´s  skin and the suit.

The diver´s body heats the water quickly, and as long as it remains trapped the diver remains warm. That is why is important that wet suits fit well.

A dry suit will keep the diver dry and it is a recommended option when diving in waters about 18 C/ (65 F).  They provide the most thermal protection of all suits used by recreational divers.

Because air conducts heat relatively poorly, dry suits insulate divers with a layer of air, as well as with insulating materials such as undergarment within the suit.

Scuba Diving Equipment - an Overview

Scuba diving equipment is designed to overcome the limits of human physiology in the submarine world and although the number of items may seem daunting to the beginner, everything has a clear purpose. Below we look at the main items of scuba diving equipment used in recreational diving.

Mask
Divers wear a face mask for the simple fact that it allows them to see underwater. The human eye is not designed to see in water, which has a different optical density to air. By simply having an air space between eyes and water the mask allows the diver to see, although the optical density means that all objects appear larger or closer when underwater. Traditionally masks were constructed from neoprene, which tended to age relatively quickly. Today's scuba masks generally consist of a lightweight plastic frame, glass lenses and a silicone rubber skirt that seals against the face. Modern masks also allow a smaller volume of air between the water and the face, which is an advantage because it means it is easier to equalize the pressure in the mask and simpler to clear of water.

Wet suit
While a wet suit is the most common type of suit worn in recreational diving, it is not the only type. Primarily to prevent the diver from losing body heat to the water, which conducts heat from the body at a much faster rate than air, a wet suit consists of a layer of low density neoprene which acts as an insulator and traps a thin layer of water between the neoprene and the diver's skin, also helping to minimize heat loss. The secondary function of a wet suit is to protect the diver from abrasions and other injuries, including stings and venoms.
When the water is too cold for a wet suit to be used divers can wear a dry suit, which as the name implies keeps the diver dry by sealing at the neck and wrists, while in warmer water divers can wear a lycra body suit which provides no thermal protection, but prevents against scrapes and stings as well as sunburn.

Fins
In the same way that fish glide through the water by moving their fins, scuba divers are able to propel themselves through the water by kicking their fins. Usually made of neoprene for the foot and rigid plastic for the blade, there are two main types; full foot and adjustable. With the former the diver simply places the boot of the fin over the bare foot, while adjustable fins have an adjustable heel strap and are usually worn over wet suit boots.

Scuba tanks
The scuba tank - also commonly known as a cylinder or a bottle - contains the divers breathing gas at high pressure. Usually the breathing gas is air, although in some circumstances other mixtures are also used.
The standard configuration in recreational scuba diving today attaches the tank to the BCD (buoyancy control device), often known simply as a jacket. The tank is attached to the rigid backplate with an adjustable strap and the BCD is then worn like a waistcoat and fastened at the front with a cummerbund.
As well as providing harnessing the scuba tank, the BCD is designed to allow the diver to adjust buoyancy in the water by either adding or reducing the amount of air held inside. Many modern BCDs also have pockets to hold lead weights, traditionally worn on a belt around the waist.

Regulators
The first stage regulator is attached to the top of the tank and reduces the pressure from the tank to supply the second stage as well as providing the air for BCD inflation. The latter supplies the diver with air at ambient pressure and is located in the mouthpiece on most modern equipment.

Scuba diving computers
Until relatively recently divers used tables to plan their dives, designed to reduce the possibility of decompression sickness. A depth gauge a dive watch were essential items to ensure the dive was within the limits of the table.
While divers are still taught dive table theory, most recreational divers quickly move on to buying a dive computer, which effectively calculates a custom table for each dive. More sophisticated models also connect to the air supply, so that they act as timer, depth gauge and air pressure monitor all in one.

David Leigh usually dives year round in the Costa Brava in Catalonia. You can find more information about scuba diving equipment at http://www.CostaBravaScubaDiving.com

Replacing Worn Out Drysuit Seals

Drysuits are worn by rafters, scuba divers, kayakers and boaters to keep them warm and dry when they are in a cold environment. It is necessary to have some kind of exposure protection when the temperature is as low as 15 degrees Celsius. Water is kept from entering the body of a drysuit through built in seals located at the ankles, wrist and neck area. Over time, the seals may crack or tear as the rubber ages, making the drysuit useless for its intended purpose. The seals may be repaired, however, by following these steps.

Remove the old seals - Expose the interior of the suit where the seals are located by turning it inside out. Carefully cut the seal, leaving the bonded parts intact. Keep the cut straight and avoid uneven edges. Sand the edges of the suit to roughen them. This will allow the glue to hold more securely. Thoroughly clean the rough edges with alcohol and let it dry.

Prepare the suit to receive a new seal - Get a plastic container (flower pot, traffic cone, or a bucket) that fits into the opening of the seal (wrist, ankle and neck) and wrap it with a piece of waxed paper, secured with tape. Insert the wax-wrapped container in the seal opening to create a fixed gasket opening and put a rubber band around it to prevent it from sliding out. Get another plastic container and slice off both sides to mimic a large plastic ring. These pieces will help hold the new seal in the right position.

Mix the glue for the seal and apply to the mating surfaces - Put on latex gloves and mix an equal portion of Cotol and Aquaseal on a dry plastic tray. Evenly apply the Cotol and Aquaseal mixture on the original seal and leave it exposed. Allow it to dry for 10 minutes. As with the old drysuit seal, turn the new seal inside out. Fold back the edge of the new seal and apply a light coating of Cotol and Aquaseal mixture on its edges where the old seal will be fitted. Apply another layer of adhesive mixture to your old seal.

Attach the new seal - As both old and new seal are coated with the adhesive mixture, cautiously position the new seal and apply a pressure on its glued edges over the original seal. Smoothen out and clean up any bubbles or folds between the old seal and the new seal.

Secure the seal for drying - Using some more waxed paper, neatly cover the replacement drysuit's seal and use tape to secure it. Be careful not to allow the adhesive of the tape to come in contact with the seal or any part of the drysuit. Get the plastic ring that you have created earlier and wrap it with waxed paper. Use tape to secure the wax paper and put the ring over the seal.

Final Steps - After allowing the adhesive mixture to cure for a minimum of 10 hours, take off the waxed-paper and plastic ring. Apply adhesive mixture on the edge of the new seal (where it meets with the drysuit). After an hour, take out the plastic container and turn the suit outside out. Insert back the plastic container and put on a light coat of adhesive mixture on the edges where the old and new seal meet. Let it cure for one day.

A new drysuit is quite expensive so replacing just the seals will cost you much less and greatly extend the useful lifetime of your suit.

Find out more about kayaking drysuits at Basic Kayaking 101: Paddling for Beginners.
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How to Dive Inside Scuba Dry Suits

As its name states, a dry suit will keep you dry inside water. You may wonder why. The reason is that you need to keep your body temperature. Some waters or seasons are too cold for using a wet suit. Also some activities, that are more static (like sub aquatic photography), will required more insulation than more energetic ones.

Even divers with a lot of experience diving with wetsuits find it challenging to use scuba dry suits. Some say that is like learning to dive again.

But let's have a look at the main issue with this type of equipment: air. Dry suits are filled with air. It is precisely this air between the suit and your skin which helps maintaining your body temperature (as you already may know, water absorbs 25 times faster the body heat than air).This air in your suit means some trouble when trying to control your buoyancy. As any other airspaces, they are compressed when pressure under water gets higher, which causes folds, squeezes and pinches. No worries here. There is an easy way to prevent this: just let some air in the suit through the appropriate valve (in most suits is the one on your chest) as you descend.

It could also happen that you are distracted by something that gets your attention in the bottom or a bit deeper than you are currently in. Naturally and guided by curiosity instead of security, you got for it head down. What occurs then, is that all the air goes to your feet and expands (as the pressure there is smaller because they are the highest point). So you are suddenly and steadily pulled up and you struggle to regain control of the situation. (A quick ascend can cause decompression sickness, DCS which can be lethal if not addressed immediately) Don't panic! The solution is simple: bring the air to the upper part of your body so you can release the excess of it. The trick is to roll yourself in a ball and then turn till your head is up. In that position, use the valve in your arm.

Scuba dry suits are fantastic tools to help you have a great diving experience in situations in which a wetsuit would not be sufficient, like sub aquatic archaeology or exploring shipwrecks. Our only advice is that you make sure you follow the appropriate training and certification before you get yourself in one and that you acquire the necessary practice.

Amalia Perez is an amateur diver that provides useful information for people like her that are just learning to dive http://scubadrysuits.blogspot.com/ Check out more at http://scubadrysuits.blogspot.com/2009/06/dive-skin.html

What You Need to Know About Scuba Dry Suits

As water takes away your body heat 25 times faster than air, it is crucial to choose the appropriate thermal protection when diving. Several dives in a wet suit in colder water than 65ºF/20ºC will diminish your abilities and efficiency seriously. Under 55ºF/16ºC a scuba dry suit is essential.

The main function of dry scuba suits is to keep the diver dry: the dry suit has several seals that prevent the water from coming in. Frequently divers wear undergarments under the scuba dry suit because they create layers of air inside the scuba dry suit that improve thermal insulation. This means that a dry scuba suit can be used in a wide variety of water temperatures needing only to adjust the underwear type to go underneath. We must also consider when making the choice of underwear, the type and intensity of the activity we are planning to do and our body size.

Scuba dry suits are easier to put in and off than wet suits, but they also required specific and professional training (do not try to figure it out on your own!) and some practice to learn how to use them. Scuba dry suits have a buoyancy control system incorporated to help you maintain neutral buoyancy. This is achieved through valves: an inflator valve (usually in the middle of your chest) and an exhaust valve (usually in the outside of your left bicep). On top of this, you must always wear a buoyancy compensator as a back up to guarantee you a surface flotation device (in the rare case that the one on the suit would not work). It is important to remember that it is very difficult to control both systems at the same time and to do so could distract you from the basic measures to have a safe dive, so do never use them together!

Types of Scuba dry Suits: There are basically two types of scuba dry suits:

  • Membrane suit: a material called trilaminate. This material is very thin (1mm) so it requires more protective thermal underwear than a neoprene one.
  • Neoprene. The material is very thick (7/8mm) which allows lighter on non underwear. In deep dives, neoprene can be compressed to 2mm, loosing part of its insulation properties. However, it is possible to buy pre-compressed neoprene to avoid this inconvenience.

A Couple of Tips about Scuba dry Suits

You may want to consider the following recommendations when planning to dive with a scuba dry suit:
  • Check your suit a few days before the immersion: make sure waterproof zippers, seals and valves are in good condition and if not send them to repair.
  • When wearing the suit, your seals and neck seals must be correctly trimmed and adjusted. Latex seals are trimmed often till they are 15% smaller than your neck and wrist circumference. Neoprene seals need to be stretched over night: the neck on the widest part of the scuba tank and the wrist over a tin can.
  • Use the minimum amount of weight possible to help you achieve neutral buoyancy.
  • Make sure you choose a body that understands how your scuba dry suit works.
  • Practice, practice and practice till it becomes a second nature for you.

How to Maintain your Scuba Dry Suits

Rinse it well with clean fresh water after every dive. Check that seals, valves and zippers work correctly and have them fixed it not. You don´t need to rinse the inside unless is wet or damp (pay special attention to the bottom of the boots). Dry it out of the sun and without hangers. Do not storage it till it is fully dried to avoid mold and mildew.

The zippers should be lubricated wit bees or paraffin wax. For the seals you can use talcum powder or if you don´t have any, soapy water. To storage it, roll it and put it in a sealed bag in a cool dry place, away from sources of ozone (like hot water heaters or electric motors). In any case, the best is to consult your scuba dry suits manual for care instructions.

Amalia Perez is an amateur diver that provides useful information for people like her that are just learning to dive http://scubadrysuits.blogspot.com Check out more about diving suits at http://scubadrysuits.blogspot.com/2009/06/dive-skin.html

How to Become a Professional Diver

If you love to dive and want to have it as your profession, there are things you need to know about first. You can start by working on resorts, law enforcement, research institutions or even the military. Becoming a professional diver will make you explore a lot. You can explore caves, wrecks, and the bottom of the ocean. But before this, you need to undertake lots of training and gaining extra skills. After that, you can start making a living with the thing you love to do most.

For the first step, you need to have an Open Water Diver certificate that will come from the Professional Association of Diving Instructors of PADI. This organization has diving centers from all over the world. Having their certification will gain you more chances of being accepted as a professional diver.

Next step is for you to contact professional divers that you know, or maybe people from you area. Talk to them about the profession they have. Discuss with them the facts about becoming a professional diver and what challenges there is to watch out for. You can try calling resorts or other recreation centers that have scuba diving sessions. Universities are also good to ask about diving most especially if they are doing an ocean research.

Save up for the certification as a professional diver. It might cost you a few thousand dollars. It can be costly, but if you really love to have the job, then it is worth paying for. The PADI and the National Association of Underwater Instructors of NAUI offer programs that will help you gain the certification.

If you are planning to work abroad as a professional diver, you may want to learn a foreign language for that. It would give you the chance to be hired as a newbie for a resort that is part of the research team.

It will also help you land the job if you get an experience in sales. That is when you are planning to do recreational diving. Having the experience will gain you revenue as you can work on scuba shops and then make commissions with your sales. If you have the budget, you can also open your own store of scuba equipments.

Also, try earning the Divemaster Certificate from the PADI or from NAUI. This will gain you big points in becoming a professional diver. You are going to need the Advanced Water Diver Certificate with twenty logged dives before you can get a course for PADI while NAUI on the other hand will ask you to complete their Assistant Instructor certificate.

Related Articles How to Dive and Catching a Fish

How To Choose Diving Regulators

Balanced/Unbalanced/Overbalanced Diving Regulators

These diving terms can be confusing until you know what they mean - unbalanced diving regulators perform worse as the scuba diving tank empties, and should be avoided in all but the most basic diving.

A balanced diving regulator will deliver the same amount of air at all pressures and depths - balanced diving regulators are usually mid-range and are most common.

An overbalanced diving regulator is one which makes breathing easier as you go deeper - these are usually towards the top of the range.

Yoke/A-Clamp vs DIN

These are the two different types of fitting for attaching your scuba diving regulator to your tank. Your decision will probably be based on where you are diving - in the UK the A-Clamp fitting is most popular, whereas abroad the DIN fitting is more prevalant.

Technically speaking, the DIN fitting is better as you will need this if you want to use a 300bar tank - A-Clamp is only good for 232bar, although this is by far the most common.

If you buy an A-Clamp you can buy a DIN kit (around £25-35) to convert it though, and there are also A-Clamp adapters for DIN regs for a similar price.

Coldwater safe diving regulators

When diving in the UK, especially at inland dive sites you need a regulator that can still perform. The problem is that when the air goes from high pressure in your dive tank to low pressure you need to breathe, it cools a lot - sometimes leading to freeflow when in very cold water.

There are two main ways the diving regulator companies have come up with - one is to seal the first stage completely, which some manufacturers do (Apeks for example) while others have more sophisticated systems - Scubapro's TIS (Thermal Insulating System) for example is particularly good. If you are diving in cold waters (around 5 degree celcius or lower) then you really need to choose a good cold water regulator.

Piston vs Diaphragm Diving Regulators

A piston based regulator is very simple, and provide better performance at depth. Piston diving regulators cannot be overbalanced. Diaphragm diving regulators are more complex, but are less likely to have mechanical problems as the internal parts aren't exposed to the water, which can be the case with piston based regulators.

When buying a new diving regulator, don't worry about it - both provide perfectly fine performance for almost all recreational scuba diving.

Nitrox Ready Regulators

Most scuba diving regulators are suitable for up to 40% nitrox without any modification. If you require a higher o2 content then you need to go for a nitrox diving regulator - these are usually green to distinguish them and have been properly cleaned. One other consideration is that you can't use Nitrox with titanium diving regulators.

Real World Examples - Scubapro First Stages

Scubapro MK25 - A great first stage, this is a piston based, overbalanced scuba diving regulator with Scubapro's patented TIS system making it suitable for cold water.

Scubapro MK11 - A good mid-range reg, this one is an overbalanced diaphragm model, also with the TIS for cold water diving.

Scubapro MK2 - A very simple first stage, it is piston based and very compact. It comes with the TIS for cold water diving, but is unbalanced so only really suitable for first time or very occasional divers as a primary regulator. This is a very popular first stage for pony bottles because it is cheap, and you don't need a balanced reg for a pony bottle.

Real World Examples - Scubapro Second Stages

Scubapro X650 - Top of the range, this Scubapro second stage gives you a dive/pre-dive switch, a VIVA control system to set air flow levels, some small tweaks to make it easier to breathe - and it looks really impressive! This is generally coupled with the MK25 first stage.

Scubapro R395 - This is the workhorse of the Scubapro range, it is great paired with any first stage, and is very (very) reliable and a popular choice for scuba diving school kits. It comes with a dive/pre-dive switch to stop free flow when you hit the water - however cold it may be!

How To Choose Diving Regulators was written by Dave Huscroft, contributer to One Stop Dive - a website dedicated to providing all the information you need when choosing scuba diving equipment

Article Source: http://EzineArticles.com/?expert=Dave_Huscroft
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