Guidelines for Proper Weighting
We all know that most new divers tend to need a bit more weight than seasoned ones since Buoyancy Control takes several dives to master. I have over 3,000 dives and still have a challenge every once in a while. Here is the best rule of thumb for weighting that I have found:
Swimsuit or Dive Skin - Begin with 1 to 4 pounds / 0.5/2kg
Thin 3mm wetsuits or Shorty - 5% of your Body Weight
Medium Thickness 5mm suits - 10% of your Body Weight
Cold Water 7mm with hood/gloves - 10% of your Body Weight plus 3-5 pounds / 1.5/3kg
Neoprene Drysuit - 10% of your Body Weight plus 7-10 pounds / 3-5kg
Shell Style Dry Suits w/o undergarment - 10% of your Body Weight plus 3-5 pounds / 1.5/3kg
Shell Style Dry Suits w/ heavy undergarment - 10% of your Body Weight plus 7-14 pounds / 3-7kg
The undergarments vary quite a bit as they can realy add allot surface area to you thus increasing the amount of weight needed to stay neutrally buoyant.
Salt Water: (add to above calculations for Fresh Water)
100 to 125 lb (45-56kg) add 4 pounds (2kg)
126 to 155 lb (57-70kg) add 5 pounds (2.3kg)
156 to 186 lb (71-85kg) add 6 pounds (3kg)
187 to 217 lb (86-99kg) add 7 pounds (3.2kg)
Always do a buoyancy check before beginning your dive and also factor in that if you are diving with an aluminum 80 tank you will need to add a little more to compensate for the tank toward the end of the dive. If you are diving with a steel tank the same holds true except you will need less weight. That is why it is so important to perform a neutral buoyancy check before beginning your dive.