Tip of the Week

Stop Fighting the Laws of Physics

Over the years I had discussions weighting with number of divers who were obviously over weighted but kept saying they could not get down. The answer was not more weight but for them to stop fighting the laws of physics. Here are some of the hints I have given them.

Over Weighting

The ballast weight you carry doesn’t change during a dive, but it’s often the biggest problem. Many if not most divers are overweighted, 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. To displace a litre of water and balance the 2.1 pounds lead requires an air bubble in the BC of about one litre in volume.

But because an air bubble expands and contracts with depth changes, you have to be constantly adding or subtracting air from the bubble to keep its volume at one litre. Six extra pounds, which is not uncommon, means a 3 litres  bubble that grows and shrinks five times as

much with depth changes and needs five times as much adjustment in order for you to maintain neutral buoyancy. 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.

Try this: The first step is to 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.

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, 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.

What’s the ideal amount of weight?

With a nearly empty tank, say 50 Bar, with lungs half full and with no air in your BC, you should be close to neutral at the surface–floating with the water at eye level, for example–and only slightly negative at your 5 Meter- safety stop.

Try this: Do a buoyancy check after every dive and write it in you log book along with the type of tank and wetsuit.

Can’t stop moving.

Anxious divers tend to move their hands and feet more, and that propels them upward. This is one of the main reason why new divers are more likely to be overweighted. They try to overcome nervous finning by loading up on lead.

The amount of lead you need should be seen like a handicap with golf, you should work on trying to reduce it and there will be a natural level which you shall reac and at that stage you can improve by training (just like using a Pro in Golf think about a Peak Performance Bouyancy Course) or by changing your gear (upgrading your golf clubs). Keep working on it and you will enjoy your diving even more.

 

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