The Diving Suit

People have been using underwater breathing equipment for centuries. Early examples are diving bells that trapped air for the diver to breathe. Then special helmets were designed that had an air supply pumped from the surface down a hose attached to the helmet. This idea was developed further to incorporate a suit and in 1839, when Augustus Siebe successfully tested the first surface-supplied air helmeted diving suit.
 
The Siebe-Gorman Diving Suit

The Otago Museum has an example of a surface-supplied air helmeted diving suit, almost identical to the original invented in 1839. The suit was still in use until the 1960s by the Otago Harbour Board for underwater salvage, inspection and maintenance work. Examples of the work included repairing the bottom of ships and helping to remove cars that had fallen into the harbour.
 
The suit is made from rubber and canvas, much heavier and more uncomfortable than the suits divers wear today. Despite this, the design of the suit makes it quite buoyant, and so, extra weights were needed to make the diver sink underwater. However, this still wasn't enough to keep the diver down so he also wore boots that had lead soles weighing 8.5 kg. This large amount of weight meant the diver could stand up and possibly walk around on the sea floor.

How did the diver breathe underwater?

The suit has a large detachable helmet and breastplate made of copper and the whole thing fitted together to form an air-filled, water tight environment for the person inside.
 
The diver needed a great deal of help with putting the suit on and getting into the water! Once underwater he could still breathe, using the air that surrounded his head and body. To ensure the air supply didn't run out there was another person on the surface hand pumping air into the suit through a hose attached to the helmet.
 
The suit had some clever designs. The diver could regulate the air pressure inside it to ensure it didn't get too high or too low, which could make it uncomfortable. This was done with valves that controlled how much air supply came in and how much was released into the water. Plus, the fresh air that was pumped in was directed over the inside of the glass windows in the helmet to stop condensation forming so the diver could see what he was doing. There was also a device like a telephone inside the suit so that the diver could chat to people on the surface.
 
The Siebe-Gorman diving suit has fascinated visitors for decades and you can find it in the Maritime Gallery at the Otago Museum.