Correct Buoyancy

Buoyancy, basically if you float or sink, is one of the most important skills a scuba diver learns, and one of the first skills many divers forget - or don't use correctly.

There are three types of buoyancy - Neutral (that's the ideal!), Negative (you sink), and Positive (you float.) Scuba classes spend about one hour in the pool working on buoyancy - having you float at eye level, balance on fin tips, and hover in mid-water. Ideally, a diver should be neutrally buoyant throughout the entire dive. The reasons for this are many.

Reduces Silting - you stay off the bottom

Reduces Air Consumption - less kicking

Environmental impact - you don't grab and bounce off coral

Greater comfort - you are not constantly moving and kicking

More to see - less movement to frighten fish

It is relaxing - you can just hover in place

Better photos - you stay stable and can maneuver better

Apart from the diver's buoyancy compensation vest, there is one piece of equipment that impacts buoyancy more than any other - the weight belt. That simple row of lead weights that helps offset your tendency to float (positive buoyancy.) What is the correct amount of lead to use? If you use a full wet suit, the rule of thumb is 10% of your body weight plus 5 lbs. Each person is a little different, and salt water requires more lead than fresh water. Of course, if you are in warm water with no wet suit, you need only a few pounds of weight. You can usually figure out the correct amount of lead during your pool training.

Neutral Buoyancy test: Put on your equipment, put on your weight belt, and while on the surface take a deep breath and hold it. Remove all the air from your Buoyancy Compensator. Do you float or sink? You should float at eye level with the surface of the water. Exhale - you should sink. If you don't float at eye level while holding your breath, and sink when exhaling, you are weighted incorrectly!

Correct buoyancy starts by being neutral on the surface! It's easy for warm water divers. Cold water divers have to wear wet or dry suits, and these compress with depth. Cold water divers have to constantly add and remove air from their Buoyancy Compensator to stay neutral.

If you want to really weigh yourself accurately, get to a pool and bring along a bunch of 1/2 lb and 1 lb weights. Add and remove weights until you are perfectly neutral! The bottom line - practice the skill and use it. Spend a few minutes during every dive working on buoyancy, and after a short while it will become second nature!

Richard C. Drew started diving in 1973 and has been teaching scuba diving since 1978.
Photographs by Richard C. Drew.

Back to Article Page