BCDs

What to look for in a BCD

How the BCD started

The BCD (Buoyancy Control Device), as we know it today, is very different from the original models that were adopted from the Mae West, a vest that was designed to be an inflatable life preserver for airplane pilots during World War II. Its purpose then, for divers who began using it, was simply to provide surface flotation at the beginning or end of a dive, or a means of self-rescue for an injured or disabled diver. Very soon, however, divers began to experiment with this new device, and found that by adding air to it underwater, they could offset the loss of buoyancy that occurred at depth when their wetsuits became more compressed. A revolution was born, but it was one that took many years to evolve into the BCD as it is designed today.

With the advent of the power inflator, the BCD underwent a dramatic transformation in a short period of time. The jacket-style design was born, which integrated the BCD into a complete system that included the cylinder and regulator, and could be donned or removed all at once. In addition to providing a more comfortable harness system to hold the cylinder, modern design provides a balanced distribution of the air inside its bladder. This gives the diver the ability to swim underwater or rest on the surface in an equally comfortable and relaxed position, without struggling against buoyancy that pulls them in only one direction. SeaQuest have been pre-eminent in the design of the BCD. They invented the (Advanced Design Vest) ADV which is the basis of modern BCDs. SeaQuest hold several important patents to this day.

Which BCD suits you?

Many BCDs may look fine on the display stand but there are thousands of short cuts that can be taken in the construction of a BCD. The BCD is a critical component of your safety and comfort. It has to be reliable through thousands of inflations and deflations, be able to withstand being dragged across rocks and reef, as well as being exposed to sand, salt and sun. It must be tough, reliable and a good fit. After studying the following information, you should be able to make an informed decision.

The type of exposure suit you will be wearing, and your body shape are two factors you need to consider in selecting your BCD. Most importantly, however, you should consider the type of diving you will be doing and the activities you may wish to pursue. If you will primarily be travelling to warm water destinations or casual recreational diving, you may be happiest with a more basic and streamlined model that is lightweight and easy to pack for the trip.

When choosing a BCD, there are many optional features to consider, and it is important to understand the benefits before making a purchase.

Inflation Systems

A good measure of a BCD is its inflation system. Take a close look at the BCD’s power inflator. Many cheaply made BCDs do not make their own inflator. They will look and feel inferior. A well-controlled rapid inflation can be a critical safety factor. In an emergency you want your inflator to work quickly and well. SeaQuest is famous for producing the best inflator in the world.

The industry standard Trimline Inflator has recently been upgraded to the Powerline Inflator. This inflator surpasses CE standards for rapid inflation. It incorporates a secure dumping mechanism and allows the low-pressure hose to be neatly clipped to the corrugated hose. The environmentally sealed high flow Schraeder valve is extremely reliable. SeaQuest also manufactures the optional Air Source for divers wishing to streamline their dive equipment. The optional Air Source combines the power inflator and octopus regulator functions. It eliminates one hose while keeping the Octopus in an easy-to-find loc

High Lift

At greater depths additional wetsuit compression makes the need for high lift capacity very important.

It is also important to give divers added security at the surface. Extra lift capacity is critical for those who regularly train divers or may be required to assist another diver.

SeaQuest uses a number of innovations, such as a 3D air cell gusset to give extra lift without squeeze.

Choosing the Right Material

The word 'denier’ is often used as a measurement of fabric quality. However, denier refers to the weight of the thread, not the quality of the woven material. There are plenty of cheap 1000 denier fabrics available, but few that meet the rigid specifications that companies like SeaQuest require.

While thread weight may be a factor in durability, it is far less important than the thickness of the urethane coating on the inside. This is used to ultrasonically weld the material to provide an airtight seal. This internal coating also helps to protect against internal salt crystal abrasion, which may damage the air cell.

Beware of fabrics which claim to 'stretch like a balloon’ as this puts a lot of strain on the seams and the urethane coating. There are better ways to provide additional buoyancy. The quality of the exterior fabric, rather than just the weight of the thread, should also be taken into consideration. Armorshield Cordura, an exclusive SeaQuest fabric, is seven times more durable than standard nylon and 14 times more durable than cotton. Armorshield Cordura is lightweight, exceptionally resistant to punctures and tears, and quick drying.

There are many bright-coloured BCDs available that look great until they are put in the field. Most of these colours will fade quickly after repeated exposure to salt and sun. The dye actually provides protection from ultraviolet light. Once the fabric fades further degradation will occur more quickly. That’s one reason why many of the top manufacturers have learnt to restrict the use and location of bright colours for BCD intended for high use.

The best fabric in the world used by BCD manufacturers for colour fastness and durability is Armorshield Cordura. It uses a special system called ‘colour lock’. There are three different levels at which a fabric can be dyed. The cheapest way is to dye the completed fabric, a better way is to dye the thread. Armorshield uses thread whose raw component materials are dyed with the final colour. This is what allows SeaQuest to advertise that its BCDs ‘fade to black’ in other words the colour is literally ‘locked in’.

Tank Traction System

One simple yet extremely important feature is the tank traction system. This rubberised insert compresses when the tank band is initially tightened. Under load and when wet, the tank band will stretch, the traction system expands to take up the slack and ensures the tank is firmly attached to the BCD. Many manufacturers do not have a similar feature, and it is an all too common occurrence to see cylinders slip out on the surface or even worse, underwater.

Weight Integration System

The benefit of weight integration is that it gets the weights off your hips and onto the BCD, improving comfort and buoyancy in the water.

SeaQuest invented the Quick Draw system which makes it easy to release weights and reinstall them after deployment.

The best designed systems feature non-ditch pockets that hold only a small amount of weight. Combining the Quick Draw system and non-ditch pockets, SeaQuest has achieved excellent buoyancy control and trim underwater, through strategic weight distribution.

A word of warning - be cautious of systems that offer 'optional weight pockets’. The facilities to 'add later’ increase cost without benefit until you pay for the option. The best system on the market today would have to be the Sure Lock™ integrated weight system.

Sure Lock™ Integrated Weight System

In keeping with SeaQuest’s tradition of innovation, they set out to develop the most positive locking weight system available. The objectives were clear, make it simple to release, easy to load in or out of the water & secure. The result is the Sure Lock™ mechanical weight system (patent pending).

The buckle releases quickly and easily with one simple pull. For easy re-installation of your weight pouches we have pre-opened the weight pockets on the BC and then improved the system even more by ensuring you will feel and hear the positive ‘click’ when the buckle lock. This innovative feature is available on the following BC models: Fusion, Pro Unlimited, Pro QD+, Diva LX, Libra, Black Diamond and the Balance.

Load Management System

The SeaQuest load management system is a patented combination of features that work in concert to deliver comfort, safety and security. While each of the features below work independently to ensure comfort, together the effect is nothing short of revolutionary. The high-end BCDs have all the elements of the load management system.

Independent Air Cell System

In many BCDs the adjustments to hold the tank securely to your back are joined to the air cell. Tightening the shoulder adjustment and cummerbund pulls the air cell tight around your body so that when you inflate the BCD it will become uncomfortable. To compensate for this it is natural to loosen the straps on the BCD. On land the tank will then hang low, placing strain on your lower back. Underwater it will flop around and on the water’s surface it will ride up around your ears.

The Independent Air Cell System eliminates any discomfort. A separate harness is locked into the back pack and attaches to the air cell by a system of clips and a floating lobe strap system. This allows the air cell to expand away from the harness, giving full inflation while securing the cylinder firmly without squeeze.

Ask your dealer for a demonstration.

Contour Back Pack

A stable harness requires a stable platform. Small, flat back packs, particularly on larger BCDs, act as a fulcrum, creating a gap between the lower back and the lower portion of the tank, putting excessive strain on the lower back. The contour pack is curved to the shape of the cylinder.

SeaQuest uses two different sizes of a Contour Back Pack to get the best stability. From medium-large sizes and up they use an extra large back pack and an extended back pack on the other sizes.

Sculptured Shoulder and Pivot Buckles

The final link in the load management harness system is a combination of patented swivel buckles and sculptured shoulders. The shoulders are heavily padded for extra comfort and the sculptured insert holds the shape of the shoulders so that the BCD is easy to don. The shoulders, where the air cell and harness meet, are contoured for excellent positioning on the body while allowing the air cell to inflate without any discomfort.

The shoulders are the pivotal point where the air cell and harness meet. They are contoured for excellent positioning of the BCD and joined by a patented pivoting buckle system, which allows the air cell to move into the optimum location relative to the harness for maximum comfort without squeeze.