The History of Scuba Tanks

A modern scuba tank looks almost nothing like its ancient predecessors. Mankind has been trying to explore the water since the time of the ancient Greeks, and possibly even before that. However, it was the Greeks that receive credit for implementing the idea of taking air underwater with you. They did so in the first millennia BC.

Their first attempts came in two varieties, one was a diving bladder. It was simply a double sewn leather sack that was oiled inside and out. The oil helped form a barrier to prevent the air from seeping out of the sack. A diver would wrap a length of cord around the neck of the sack and loosen the cord when he wanted to take a breath. It was not much for elegance, but it was a beginning.

The other air delivery system was a bit more involved, it was called a diving bell. We still use variants of it today. The first diving bells were large domes of metal that were attached to ropes. They were inverted and lowered from a ship to hang above a diving area. The inverted dome trapped a bubble of air beneath the waves, and divers could swim up to it to catch their breath, greatly extending the time they were able to spend below.

The scuba tank is a more direct descendant of the diving bladder than the diving bell. As technology improved, the bladders moved away from leather and towards metal. It took a few thousand years, but eventually we got the bright idea of pressurizing an air tank to maximize the amount of air it could hold. This brought up an interesting problem though. You see, the pressurized air needed to be depressurized to allow us to breathe it safely.

But even more intriguing than that, the air needed to be lowered to the pressure of the water at the depth of the diver. If it was lowered more than that, the diver would be unable to breathe because the water pressure would prevent his lungs from expanding. Diving tanks needed to connect to a variable pressure system that could accommodate for the diver’s relative atmospheric pressure.

One of the newer developments in diving technology involves closed circuit diving. You see, humans only utilize about 40-60% of the oxygen in any given breath of air. When a diver exhales into the water, that unused oxygen is lost. With the aid of air scrubbers, a closed circuit system takes a diver’s exhaled breath and recycles the oxygen in it back into the scuba tank. This leads to greatly extended diving time on an identical amount of air.

Closed circuit diving was originally developed by the military because it prevents divers from giving off tell-tale bubbles every time they exhale. Since its inception it has found a use in other delicate environment diving situations, such as photographing timid underwater wildlife. Another use is for ecologically sensitive areas, where the wholesale release of breath into the environment.

As you can see, underwater air supply has come a long way from leather sacks. Today’s recycling, pressure sensitive systems are a far cry from sewn up animal skins, and our diving abilities have expanded in step with these technological advances.