Recreational Diving - Equipment
Early on in the 1950s up to the late 1970s homemade/converted equipment was common sight amoung recreational divers. This was partly due to the high cost of diving equipment and also due to the lack of availability on the market. Since the early 1990s dive gear has become big business with an almost inexhaustible supply of goods to satisfy the diving community. It cannot be over-stated how important equipment is to any type of diver. It often is literally the difference between life and death in the sea.
Regulator/DV, Console and Depth Gauge
Despite looking complicated this marvel of engineering is simplicity itself in operation, the silver metallic lump of metal (known as the first stage is screwed onto an air cylinder/tank containing air, the air cylinder valve is turned on pressurizing the Regulator set. What the 1st stage does is reduce the air pressure from the cylinder to an intermediate pressure.
The part you breathe off (normally) is the round blue colouredobject (Second Stage), you grip the mouthpiece of it in your teeth and seal your lips around the opening and breathe in. This causes the rubber diaphram inside to move inwards causing a lever to move which in-turn allows a valve spring (connected to the lever) to open and allow in air. There is another 2nd Stage coloured yellow and this is an alternate air source in case of an emergency (primary reg. malfunction). The 2nd Stage also reduces the pressure from intermediate to ambient (the surrounding pressure).
There are two types of regulator; Diaphragm and Piston type. If a majority of your diving is going to be deep and also in cold water (18oC or lower @ Surface) then I would recommend a diaphragm 1st stage. This is normally environmentally sealed, capable of resisting 'freeze-up' and more sophisticated. It is also heavier, more expensive and harder to service than its piston operated counter-part.
If a majority of your diving is going to be in warm water (Tropics/Sub-Tropics) a piston operated 1st Stage would be preferable. Normally light, cheap and very simple to strip down and service. In cold water though they can become a liability to freeze-up and subsequent 'free-flow'.
A pressure gauge which measures the amount of air remaining in the air cylinders is often referred to as the console or a contents gauge, it is shown in the picture above the blue second stage. This device (pictured) also includes a built-in depth gauge which measures how deep a diver is.
Another optional low pressure hose is added should a diver choose to dive with a drysuit.
Supplies air to you via the 1st and 2nd stages of your regulator. Heavy, tough and essential for scuba diving. Two types of cylinder: Steel and Aluminium. Steel is tougher than aluminium, can take higher pressures and is lighter due to the thinner cylinder wall required!
On the other hand aluminium cylinders are much better at resisting corrosion than steel and are sought after in the tropics due to these qualities.
To complicate matters further cylinders can come in capacities ranging from 1.5 litres up to a mighty 18 litres! Typically in rec. diving 12 litre cylinders are the norm with the smaller cylinders used as a bail-out and the larger ones for deep/technical diving. As well as sizes cylinders come in two size catagories: Short or 'Stumpy' (pictured) or Long. Smaller people (5"7 and below) often prefer the shorter varient and vice versa.
The cylinder itself is filled (via a compressor) with compressed air to between 200 and 300 bar. With such a great pressure only cylinders made for diving should be used. It is also necessary to have a visual inspection each year and a hydrostatic test every five (Regulations are subject to change).
With good care and maintanence a cylinder should last for a life time.
Essential for vision underwater. Without it we'd be almost blind on a dive. A good mask should seal effectively and not fall off the face when you lean forward (whilst inhaling through the nose). That test over the mask shouldn't leak underwater (unless your pull a face).
If you wear glasses then it is wise to have pescription lenses fitted. Contrary to what some experts say contact lenses CAN be worn under water but only if they are non-gas permeable (the soft lens type). With you mask off underwater your contacts are unlikely to fall out but as the gas permeable (hard type) are expensive I wouldn't risk it.
The lens must be scratch and shatter-resistant, tempered glass is the material of choice. Avoid plastic, which tends to scratch and fog more easily. The actual body material to seal against the face should be silicone rubber, this material is non-allergic to body tissue and lasts for a lifetime.
There are three types of mask : Standard, Silicone and low volume. Low volume is worth a look in if only for the lesser amount of 'squeeze' that occurs at depth.
The snorkal has evolved considerably over the years with the latest capable of expelling water yet allowing air in. The physics of it remain the same by providing air from the surface via a 'J' shaped hollow tube. They are quite cheap, light and handy for going skin diving and of course snorkaling. With aqualung donned it's usefulness diminishes but it can be useful for conserving air during a long surface swim (although swimming on your back accomplishes the same).
Water conducts heat away from the body at a phenominal rate and even in the tropics where water temperatures can reach the mid 30s without thermal protection our bodies would soon suffer from the cold. The wetsuit is the most widely worn form of thermal protection. The wetsuit is made from synthetic rubber (neoprene) that has been foamed or expanded. Gas bubbles are trapped inside the neoprene are separated from each other which prevents the suit acting as a sponge and absorbing all the water. The material streches also allowing a good fit combined with effective insulation. Although Water is allowed to enter the wetsuit (via the neck,ankles, sleeves and stitching) the close-fit keeps heat loss to a minimum and the water trapped inside soon heats up to body temperature. A loose fitting wetsuit however permits water circulation to flow freely and greater chilling results.
Wetsuits can come in a variety of thicknesses, some can be as thin as a tropical 1mm (called a skin suit) to as much as 9mm for the icy wastes. The pictured example is a one-piece wetsuit but others come in two or even three pieces. Often worn with the wetsuit (and drysuit) are gloves, bootees and hood. The latter is often underrated by some divers yet it is through the head that we loose 80% of body heat under water. Things to look out for on a wetsuit are reinforcement padding at the knees and elbows and spine pads for thickness and warmth.
Advantages with a wetsuit: They are relatively inexpensive and are light-weight. A westsuit is easy to use and is comfortable. Scant maintenance is required.
Disadvantages with a wetsuit: Due to the compression factor at depth it looses both buoyancy and insulation the deeper you go. Though the BCD can compensate for the loss of buoyancy, it cannot replace the insulation. On a second dive of the day getting into a soaking wetsuit on a cold day can be a real test of character!
Originally the realm of Commercial, Salvage and Navy divers. The first drysuits were difficult to don and remove and had no air inside them resulting in a 'squeeze' at depth, the latter was overcame by adding air. With the advent of the water proof zip and numerous other improvements the drysuit 'came of age' and moved into the mainstream of sports diving. The crucial difference between the drysuit and the wetsuit is that no water enters (or should enter!) a drysuit. Insulation is provided by letting air in via the push-button chest valve where the LP pressure hose connects. Insulation is augmented also by the use of thermals.
The foam-neoprene drysuit actually has two types: One that is loose, baggy and is intended to be worn with extra thermals underneath (commercial divers choice). The other is more tighter fitting and looks more like a wetsuit (prefered by sports divers). Extra quality is put into the stitching and seals allowing no water ingress when it is worn. With no water passing into the suit air has to added otherwise an uncomfortable (and sometimes painful) squeeze sets in (due to water pressure). Optional extras (for all types) can include hoods and dry gloves. Exhaust valves on all types tend to be on the upper arm and allow excess air to be vented (usually by a push-button operation).
The membrane drysuit is similar in operation to the foam-neoprene but the difference is that the suit thickness tends to be thinner and it is usually a lot baggier. Insulation is by both air and thermals but the design allows an additional layer of air between the thermals and the skin, arguably giving it greater warmth than the foam neoprene drysuit. This style of drysuit is cheaper than the foam neoprene but the weak link comes in the seals which are often vulnerable to puncture. Due to the squeeze on a membrane being more noticeable (because of the thin membrane) buoyancy is easier to maintain and the squashed under garments return to their former shape.
Advantages: The warmth factor; it cannot be overstated the morale and comfort the drysuit gives by sealing out the water over its wetsuit 'brother'. After the first dive on a chilly boat ride to the next you can guess who the divers keen to get back in the water are.
The Protection; with the additional layers worn it takes a lot more to cut through a drysuit diver. Additional buoyancy; with the added air in the drysuit should your BCD fail you have a built-in back-up!
Disadvantages: The price; drysuits are almost always more expensive than the wetsuit.
The BCD or Buoyancy Compensator. This vital piece of equipment is what divers use to maintain neutral buoyancy, it is connected to the 1st stage of the regulator via a low pressure (LP) direct feed hose. With this in place the diver can either add air or deplete air into the BCD via two buttons or orally for inflation. On starting a dive a diver normally deflates the BCD fully to sink beneath the surface and adds air as required to hover at a desired depth.
Shaped similar to a waistcoat it is quick to don and remove with quick-release buckles and snap releases the BCD has changed considerably from its simple 'life jacket' design. Variants exist but the pictured BCD is an example of a good quality 'all seasons' BCD.
In the late 1990s an independant system of inflation became 'vogue' especially in Europe. The design of the BCD was altered slightly to attach a small cylinder of air for use in emergencies requiring the BCD to be inflated without the main inflator hose. It also provided another source of air in the event of the main cylinders air supply running out. The trend has faded somewhat but from time to time they are seen.
BCDs are normally constructed from 400-1000 grade denier or cordua and the seams heat sealed airtight. The pictured example is considered amongst the best BCD design and evolution so far. It is very tough, has considerable lift (over 20 kilos) and is packed with useful accessories. Its drawbacks? The cost and it is heavier compared to other BCDs.
Perhaps the simplest in build and design but the most crucial to movement underwater. The source of many an hours debate amongst divers as to whose are the fastest, whose is the lightest and perhaps, whose is the coolest? Often wrongly referred to as 'flippers'. (DO NOT say this in front of other divers as it is the mark of the total new guy and uninformed).
Two main types of fins: Full foot and open heel.
Full foot fins are favoured by snorklers, swimmers, occasional warm water divers and free-divers. They are worn bare foot, slipped into akin to a close fitting shoe and are slightly lighter than the open heel variant.
Open heel are almost always prefered and worn by scuba divers. Divers wearing these normally wear boots or bootees which are secured into the fin by a stout strap at the heel. These fins can accomodate a range of sizes, are often very comfortable and when out of the water the divers feet are protected somewhat by the boots.
Both fin types can be obtained with 'Extras' built in. These include:
Vented slots for reducing/channeling water resistance, split fins are useful for turning faster with little or no resistance (though they are reputed to be a liability in a current), Very rigid material 'blade' fins are o.k. under water, very good at the surface.
Flexible strength material (excellent performance underwater, not so good at the surface).
The first true dive computers emerged in the 1990s and are a popular item. The micro-processor and depth gauge combine to provide a diver with information on-the-fly for his decompression requirements, time spent under water, depth and other features. The model pictured left can actually be worn like a normal watch for every day use! Some models also tell how much air is left in the air cylinder and what the air consumption rate is. One highly advanced Dive computer even goes as far as analysing the oxygen content of a cylinder! A drawback of using a dive computer it is that they take out some of the thinking to planning dives and can be expensive.
Necessary for conducting a night dive, some wreck dives and cave diving. Essentially a dive torch is a torch that has been environmentally sealed from water ingress (normally using 'O' Rings). On a dive in daylight you will find that even a small pocket dive torch can restore the colour lost at depth. There are many different choices when it comes down to dive torches but a basic 'grip' style torch fits the bill nicely for recreational dives. Consider carrying a pocket style torch in case your primary torch fails.
Every diver on every dive should carry a knife. Traditionally carried on the ankle and usually quite large. In recent years there has been a trend where the knife has become smaller and carried on the BCD or on the forearm. Its primary use was and is (despite what PADI thinks!) defense against certain hostile marine life. As this is unlikely the more common use for the knife is perhaps less dramatic but no less important if entanglement befalls the diver. Arguably the best knife to select would be a titanium make as they are rust proof and light. Stainless steel is a good option. Despite the name suggesting otherwise stainless steel can suffer from corrosion, is not as hard as ordinary steel and requires regular sharpening.
A vital aid to underwater navigation, the compass allows an experienced diver to negotiate poor visibility and perform complex search patterns. The compass can be attached to a console or worn on the wrist. Sealed to withstand great pressure and housing a rotating bezal to swim on a predetermined heading. They often feature a 'window' that can be used when fixing and moving off on a navigation bearing. Be sure to hold a compass away from any metal objects otherwise you may de-magnetize your compass!
The dive camera is an excellent medium in which to capture your experiences underwater and have them remembered long after.
The customised u/w camera is one that is originally for dry land use but is inserted into a custom built waterproof housing. The housing is normally see-through and has corresponding switches, levers and wheels to activate the controls of the camera. Customised cameras are useful for having your cake and eating it; if you want the camera underwater, you use the u/w housing, finished diving, take it out again. The downside is that housings are expensive (they are custom built in most cases), bulky and a 'fogging' effect on the housing can arise with digital cameras (due to the heat output). Care and consideration should be paramount with this type of camera as some housings can be unforgiving should you neglect the 'o' ring checks. It is also possible that some camera housings are not commercially available for certain camera types. The cost of camera and housing often exceeds the price of a dedicated underwater camera!
The dedicated waterproof camera is specifically designed for underwater use first and foremost. They tend to allow many scopes of underwater photography using accessories. The camera and housing are one integral item and to that end its usually smaller and lighter than its customised counterpart. Maintenance is straightforward and they tend to be simple to use. Only specific makes of camera are available for this variant and therefore selection can be limited.
The Dynamic Propulsion Vehicle or DPV as it is better known is a lightweight and useful accessory for zipping around a dive site. Essentially the DPV is an underwater propeller you grip onto which is powered by a battery with all the electrics environmentally sealed. Most are depth rated to the 40m range making it suitable to recreational depths and can cope with mild currents.
For additional security when visibility is poor a buddy line can be deployed to keep two or more divers together. If diving with an SMB this can be used as a makeshift buddy line by the buddy of the reel holder taking hold of the line. With two divers or more tethered with a buddy line and with familiar in signalling techniques diving in zero visibility is possible.