Deep Diving - Jenny Lord

Technical diving is diving outside of the normal realms of recreational diving, i.e. going deeper than 40m or going into ‘decompression’ where a direct ascent to the surface is not an option. Decompression is the term used for the amount of time the diver has to spend in the water at certain specific depths to allow the body to decrease the amount of nitrogen or helium that it has absorbed at the extremely high pressures involved in deep diving. Often various different gases are used such as ‘Trimix’ a blend of oxygen, helium and nitrogen that helps reduce the toxic effect of the oxygen and the narcotic effect of the nitrogen at deeper depths (generally below 55m). Deep divers also use ‘Nitrox’ to help them speed up the decompression time by reducing the amount of nitrogen their body is taking in.

Technical Diving Equipment

Technical divers normally use a twinset; two tanks mounted on their back to carry the large volumes of gases needed for deep diving. They will also carry stage tanks which are extra cylinders of different gas mixes for their decompression. Each tank has its own regulator and is marked according to what is inside the tank and at what depth it is safe to breathe.

A harness is used to attach the twinset to the diver with a wing sandwiched between them to allow the diver to maintain their buoyancy by adding air, compensating for the increased pressure changes as they get deeper.

A drysuit is normally worn to help keep the diver warm, this is a special suit which is sealed at the wrists and neck to keep the water out. Thick undergarments and sometimes even heated vests are worn according to the water temperature.

Heavy neoprene fins are used to help the diver propel themselves through the water. More drag is created by all the extra tanks that deep divers carry, so extra propulsion is sometimes supplied by a Diver Propulsion Vehicle, or DPV. Otherwise known as an underwater scooter, these make life a lot easier for the diver to cover long distances.

As it gets darker the deeper you go, technical divers who are going deep carry a torch, often with a long life battery that is worn on the harness and attached to the torch via an umbilical cord.

A special computer is worn which shows the depth the diver is at, as well as the time they have been there. It can also calculate how much decompression time the diver has to complete before they can surface.

The Attraction to the Deep Blue

For thousands of years man has looked at the sea and wondered what was below the waves. With the invention of the aqua-lung, people started to explore the undersea world and like any new place many wanted to expand beyond what was known, pushing the limits of the human body to discover more.

The concept of deep diving was born. The improvement of the equipment and our knowledge has allowed people to dive deeper, but still many look down and wonder what there is even further below us.