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Dangers associated with Submarine Escape Training - Medical Screening & Associated Dangers

Submarine Escape Training involves hyperbaric exposures of up to 4 bar with a rapid decompression phase. Particular attention must therefore be paid to the respiratory and ENT systems, as well as other conditions which may prejudice the safety of hyperbaric exposure.
A trainees medical history will be screened and a strict medical must be passed before pressurised training can take place.
All trainees will complete a 9 metre familiarisation dive in a recompression chamber.

In order to make any escape from a submarine you will first of all have to open one of the escape hatches. Unfortunately there will be many tons of seawater pressing down on the upper hatch and the only way to open it is to equalise the pressures inside with that on the outside. This can be done by either flooding the whole escape compartment and then doing a Rush Escape, or by flooding the escape tower, either way the problem arises that you are now breathing air at increased pressure which means that your lungs will contain more air than they can safely hold here at the surface. As you make your escape and rise through the water the surrounding pressure reduces allowing the air inside your lungs to expand.


Any attempt to hold your breath during the ascent would be fatal.
So on the way up if your head is in water (Buoyant Exhaling Ascent) you will need to blow out all the way to the surface to get rid of the excess air.

In the SUITED ascent we overcome this challenge by putting our head in a hood full of air allowing you to do the most natural thing in the world – to breathe normally.

Another significant challenge is time exposure to pressure, divers suffering from decompression illness or “the bends”,and we as submariners are vulnerable in the escape scenario. If we were to exceed either of these time limits and return straight to the surface he would be liable to suffer from decompression illness.

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©2006 Ian Callow