At Work Under Water The weight of the diving helmet, weights, boots and rig is about 180 lbs in total. This is obviously very heavy on the surface, although in the water the buoyancy of the suit and helmet neutralises this weight. The diver can make himself lighter or heavier, depending on what work he has to do, by operating the air exhaust valve on the back of the helmet. He has control over his own buoyancy and can even inflate the suit to bring him to the surface. The Copper helmet and rig is still used today and is preferred by divers for certain types of heavy work.

Life-Saving Apparatus Over the years many submarines were sunk for a variety of reasons. The difficulty in rescuing crew from these wrecks was extreme, bearing in mind the early diving equipment available. Methods of submarine escape began to develop, including miniature diving bells which could be either attached to the outside of the submarine or lowered down to it. These devices could also be used for other submarine rescues. The device shown on this card could hold several people who sat in the water with their heads in the air space inside the upper part of the bell.

Artificial Respiration Drowning, for professional divers is a hazard they live with daily. Death can occur in seconds, so it became essential to develop an apparatus for resuscitating those who became victims of the sea. The respirator shown overleaf is an early oxygen supply system to be used in conjunction with resuscitation procedures. As you can see from the picture, procedures have changed somewhat over the years. this method has given way to Expired Air Resuscitation (Mouth to Mouth). Oxygen sets are now a compulsory part of every dive boat’s equipment, as oxygen is also used to treat cases of the bends or Caissons disease.

Diving Bells In Use – Dover During the construction of Dover harbour, large square shaped Diving Bells were used to enable construction workers to work on the sea bed, clearing obstructions, laying pipework or concrete. This type of bell had no air lock to pass materials or men through. The bell was raised and lowered with the workmen sitting on benches around the edge. The bottom of the bell was open to the water and the water was kept out by air pressure pumped from the surface. The workmen were subject to the same decompression rules as divers and could suffer ‘the Bends’ if brought up too quickly. They operate with the same Decompression Tables as Divers use.

Airlock Diving Bell Plant The picture overleaf shows a purpose-built barge equipped with an air lock diving bell system. The bell was lowered over the site down through the centre of the barge and was connected to it by a steel shaft down which the men entered. The barge was also equipped with rescue equipment including a decompression chamber. The barge would have been hove to with six or eight anchors to keep it in place; good weather was obviously required. With this mobile system work could continue for 24 hrs with changes of workmen.

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