a bcd (buoyancy control device) is designed to help divers maintain neutral buoyancy; it's simply an inflatable vest. the bcd can be inflated during descent as air is compressed causing the diver to lose buoyancy. the reverse is true during ascent. the bcd should be deflated as the air expands during ascent.
bcds can be inflated automatically by pressing a button that allows low-pressure air from the tank to flow through the low-pressure hose connected to the first stage of the regulator. the bcd can also be inflated orally, which can come in handy when trying to conserve air or in out-of-air situations. fully inflating bcds at the surface makes for easier surface swims.
deflating the bcd is as easy as opening the oral inflation valve at the highest point possible above the divers head.
options in the bcd are jacket-style where the air bladder is around the torso, or a bcd that has the air bladder only in the rear around the tank. extra features include pockets for gear and weights. especially useful are those with pouches around the tank for weights to keep them out of the way.
air sources are among the most crucial scuba items, obviously! the primary air source is called the regulator while the alternate air source is for use when your buddy is in an out-of-air situation.
the main consideration when buying a regulator is comfort. there are specially designed regulators for smaller mouths (i have one!). also you should try breathing out of the regulator - they can usually be adjusted to give air at different levels of inhalation. a regulator is not something to budget on - a regulator that won't deliver at depth can be lethal!
alternate air sources can be attached to the first stage and look just like another regulator but with a longer hose. other alternate air sources can be integrated into the low-pressure inflator for the bcd, and are designed for the primary diver to use and the regulator to be surrendered to a buddy who is in an out-of-air situation.
the
tank is an item that is optional to buy even for the advanced diver. they
require yearly inspections and may be easier to simply rent. a diver with
a tank has to go to a dive shop anyway for an air-fill, so might as well
pay the minimal fee to rent the tank as well rather than invest in one.
the purpose of weights is to allow the diver to descend. a good rule of thumb to decide on the proper weight to use is to weight yourself to neutral bouyancy at the surface with your bcd fully deflated. make sure to weight yourself in the water type (salt or fresh) you plan to dive in because there is a difference in density.
the majority of weight must be ditchable for emergency situations. if you have a weight-integrated bcd, the ditchable weight will be in removable pouches on the bcd. otherwise the ditchable weight will be attached to a removable weight belt. the remaining weight can be in ankle weights and distributed among pouches on the bcd. i find the ankle weights helpful to prevent my feet from floating up.
gauges for scuba diving include a spg (submergable pressure gauge), compass, and a dive computer.
the spg is a must for gauging how much air is remaining in your tank. usually a dive will begin with 3000-3500 psi. it is usually a good idea to start the ascent with 500 psi, to allow for air during the safety stop and to swim back beneath the surface.
a compass is necessary for good navigation. compasses include a lubber line and headings for easier reading. compasses can be popped into a watch band to wear on the wrist, or can snap into a console with the other gauges.
a dive computer is the best invention for scuba divers since sliced bread! computers will tell you your depth, the time of your dive, and most importantly when you need to start your ascent to avoid a decompression dive. since the body will load nitrogen into its tissues at depth, decompression illness is a risk when excess nitogen is allowed to accumulate. computers will keep track of all dives and will account for nitrogen building as well as nitrogen depletion during surface intervals.
