There are a number of things that divers can do to safely extend their air supply, here's some of the best.
Air saving techniques
It's an uncomfortable feeling when the dive has to be terminated prematurely because you have ran short of air. All new divers will breathe excessively for the first few dives and over a period of time their air consumption will level our. However there are a number of additional techniques that divers uses to safely conserve their air.
- Slow your breathing - Breathe slowly, where possible slightly lengthen the pause after inspiration, relax. Breathing deeply will provide a more efficient gas exchange in the lungs. It will take some practice and concentration to make it a habit underwater.
- Relax - The most important factor in saving air is pure relaxation. A stressed or anxious diver can easily consume twice or three times their normal relaxed consumption. This is particularly noticable with new divers who don't yet feel completely at ease in the water.
Make sure you are well rested an both mentally and physically prepared to make the dive.
Diving regularly builds up confidence levels, maintains diving skills particlarly buoyancy.
- Master Buoyancy - Your buoyancy will make have considerable impact on your overal air consumption, Carry the least weight you can and refrain from any pumping and dumping those suits and BCs. If you are too light you will be wasting energy and air swimming down and the same will be be true if you are too heavy and are having to swim up.
- Get Fit - The fitter you are the more efficient are your lungs and your Cardio Vascular system.
- Mask - Most divers use far more air than they need to to clear a mask, learn to clear it with the minimum of air.
- Avoid Waste - Where you can safely do so, use your snorkel as opposed to your regulator. Avoid accidental free flows as you enter the water and make sure your equipment including your mask is free from leaks.
- Stay Streamlined - The more volume an object has in the water the more water it has to displace in order to move itself through the water. Having a correct streamlined horizontal position in the water is an important factor. It effectively reduces the drag in the water and thereby considerably improves gas consumption. Ensure instruments are not dangling around. Drysuit divers can improve their drag by inflating their suit only with the minimal amount of gas needed in order to avoid a suit squeeze.
- Minimise your workload - Water is about 800 times more dense than air, where possible avoid swimming through it. Take a closer look at the reef, move slowly and where possible let the current take you. Avoid the underwater "route march" or marathon dives.
If the current is against you stay close to the bottom and grab onto fixed things and pull yourself forward. If you can avoid the current then do so, for instance swimming behind or in a wreck in order to be shielded from the current.
- Improve your Finning technique - Using an ineffective kick style e.g., "cycling" using will waste energy and thus air. Most effective practice is to kick from the thigh with legs slightly bent.
Recently there has been some major innovations with fins that porpose to increase their efficiency i.e., split fins.
- Temperature - The more the body gets cold, the more air will be required to maintain the core temperature. Additionally the body constricts the arteries near the skin surface and extremities, channelling all the blood towards the body core.
Make sure you are adequately protected from the cold with a good fitting Drysuit and insulation. See Diving in Cold Water for more information.
- DVPs - Diver Propulsion Vehicles extend the range a diver can make with a minimum of effort and hence a minimum of gas consumed. Care should be taken to ensure sufficient battery power to complete the dive.