Weighted down by more than 100 pounds of equipment, many divers believe that they must have very large buoyancy compensators. In fact, many divers use BCs with as little as 45 pounds of lift while others insist upon dual BCs with a combined lift of 160lbs. Obviously, one's dry land weight is inconsequential and a BC with 55lbs is usually enough to float nearly any diver. Many divers overweight themselves and then maintain a large reserve of air in their BC. Air in the BC. merely increases the drag resulting in a higher level of energy expenditure. Some divers insist on a reserve BC while others feel they are unnecessary. Generally the consensus is that while diving wet in an area with a deep or nonexistent floor (i.e. ocean or large cave) a redundant BC is a good idea. Many people feel that a diver diving a dry suit could use the suit for emergency buoyancy. This assertion is quite reasonable but should be practiced to determine one's proficiency.
In response to the technical divers concern over a loss of buoyancy several manufacturers have incorporated two bladders into one casing. These BCs have redundant exhaust valves and inflator systems. One should be wary of connecting both inflators at one time as a small leak from the inflator could continue adding air to the unaware divers BC. As the diver becomes more positive they will usually try to empty their primary BC remaining unaware of the secondary inflation. If the diver is unable to correct this problem quickly enough they may find themselves at the surface experiencing any number of maladies. The redundant BC inflator should be tucked away but within reach so that in the unlikely event of a failure an inflator can be connected. The spare inflator can be connected to the hose previously controlling the failed BC or to a hose attached to the corrugated hose but not connected to the power inflator.
Several of the new style BCs have become known as bondage wings because the contain numerous bands of flexible material that restrict the size of the wings and theoretically decrease their drag. When the BC is inflated the bands should stretch and allow the wings to fully inflate and when the air is released the bands shrink down the excess material of the BC. If one desires to use this system they must attach the flexible bands when the BC is inflated to insure that the bands do not prevent full inflation. The BC. should then be checked in the water to insure that the overpressure relief is not prematurely activated. Opinion, of course varies on the desirability of the system. As the wings get larger measures are taken to reduce their drag. Many divers still opt for the smaller size, eliminating the concern altogether.
The astute diver can make some fairly simple changes to their BC that will increase its ease of operation while also extending its longevity. First, one may cover the inner bladder with inner tube to protect its somewhat fragile design. The Seatech and ProSub BCs have a tougher casing then the early Diverite and are therefore less prone to puncture, yet the protective tube can be used for any style BC. The corrugated hose on nearly all BCs is far too long and is often impossible to streamline due to its length. By obtaining a much shorter corrugated hose and coupling it with a custom inflator hose the diver can significantly improve the cleanliness of their system. Finally, one should check all fittings on the BC and insure that they are secure. In some cases manufactures use one wire tie to secure the corrugated hose while a clamp would be far more secure.
