The ballast weight you carry doesn't change during a dive, but it's often the biggest problem for divers who struggle with perfecting neutral buoyancy. Many divers are overweighted for the type of diving they do, carrying more lead than they need. That makes buoyancy control more difficult because every extra pound of lead has to be balanced with an extra pound of buoyancy.
But because the air in your BC expands and contracts with depth changes, you have to be constantly adding or subtracting air from your BC. So extra lead means extra thrust up or down when you change depth, and requires extra fiddling with your BC valve controls. Sometimes it means nearly constant fiddling.
Here are our tips for taking off that extra weight.
Just do it. Take off two pounds before your next dive. Can't get below the surface? Before you reach for the lead again, make sure you really need it. Getting below the surface, especially on the first dive of the day, can be surprisingly difficult and can trick you into carrying more lead than you really need.
Be patient. The plush lining of a dry wetsuit can trap a surprising amount of air, and therefore buoyancy, in its fibers, and it takes a minute or so to get fully wet.
Reach up. Hold the inflator hose over your head and stretch it upward a little so its attachment point to your BC is highest. At the same time, says Linda Van Velson, a PADI course director, "dip your right shoulder and squeeze the BC against your chest with your right arm." This maneuver encourages the last few bubbles to find the exit.
Rock backward a little. Many BCs trap a bubble of air just behind your head. Rocking backward as if you are in a La-Z-Boy recliner moves the exhaust hose over the bubble and lets it escape.
Relax. Many of us move our hands and feet more than we realize, especially at the beginning of the dive. To counteract that, hold your right arm still at your side (your left is holding up your exhaust hose), extend your legs and point your fins straight down so they have the least resistance to sinking.
Exhale. Another tendency is to hold your breath, and a lungful of air adds as much as 10 pounds of buoyancy. Exhale and hold it until you start sinking, then take shallow inhales until you get below five feet.
Force it. Another option is to use your body weight to generate some downward momentum by lifting part of it out of the water, then letting it fall back. Lying on your face, jackknife your upper body downward, then lift one leg, then another, out of the water. The weight of your legs will drive you downward, and once your fins are in the water you can kick down.
Use the line. If the dive boat is tied off at a mooring, use the line to help pull yourself down. This trick also works for divers who need to go down slowly to equalize.
Get a little help from your friends. Ask your buddy to gently tug your fin and pull you down for the first few feet of your descent. Usually, by the time you're in 10 to 15 feet of water, you should sink without help.
What's the ideal amount of weight? Use our Buoyancy Calculator to determine what's right for you.
Read our Tips on Neutral Buoyancy for more secrets on achieving a the feeling of weightlessness underwater.