Humane efforts to stay underwater have been through many stages. From the use of inflated goatskin floats and the diving bells around 1500 AD, it was in 1715 that Lethbridge invented the first personal diving “suit”: a wooden barrel fit with a glass (to allow vision) and two holes for the arms. He reported dives having autonomy of 34 minutes duration and 20 meters depth. In 1828, the Deane brothers constructed the first diving dress that had a helmet (copper) and air was supplied from a hose. The helmet was loosely attached to the suit and so the diver could only work in a full vertical position, otherwise water entered the helmet. Augustus Siebe modified that dress, fitting the helmet with a full length watertight diving suit and thus, correcting that. Siebe’s standard diving dress was used by the salvage team on the wreck of «HMS Royal George» outside Portsmouth, around 1840. Interestingly, after concluding salvage, an official commented that, of those having made frequent dives, “not a man escaped the repeated attacks of rheumatism and cold”!!!! Divers at this project were working in most instances at 20-25 MSW depth, for 6-7 hours every day. At that time, evolution and increasing use of tunnel / compressed-air working took place. During that time, with the construction of large projects and corresponding increased duration of compressed-air working, presentation and identification of Decompression Sickness became clear. It was then named “caisson disease” or “bends”. The same condition that we now call Decompression Sickness (type Ι) and, during works at «HMS Royal George» wreck, was characterized as “rheumatism”.
In 1905, US Navy designed and started using an advanced helmet (MK-V) that offered both natural protection and increased mobility to the diver. This helmet (with modifications) is still in use in many parts of the world.
The SCUBA era
The majority of diving activities worldwide today, are of the type previously described as SCUBA diving. SCUBA is an acronym for Self Contained Underwater Breathing Apparatus. The diver carries his own source of breathing gas and so, he does not rely on breath-hold, or on air provided from the surface. This form is used exclusively in recreational diving and in the vast majority of professional and scientific diving.
SCUBA dives with closed-circuit rebreathers have been performed since 1880, especially during World Wars for military use. However, the big change resulted from work of Jacques-Yves Cousteau and Emile Gagnan during WW II, when they managed to combine an advanced demand regulator for breathing with cylinders filled with compressed air and carried on the back. This way, they built the first effective and safe open-circuit SCUBA, known as Aqua-Lung (In open-circuit SCUBA, the diver inhales gas from the cylinders he carries and exhales in the water. In closed-circuit SCUBA, exhaled gas is recycled and after CO2 scrubbing is reused by the diver).
Development of Aqua-Lung was outcome of the progress that took place for over 100 years. Cousteau used his equipment successfully at 60 meters, without adversities and so, after the end of WW II, Aqualung became quickly a commercial success. It still remains the most widely used SCUBA device and it contributed remarkably to the fact that undersea world is open to anyone to explore – of course following appropriate training and fulfillment of medical criteria of fitness to dive.