4. How did some crewmen manage to escape almost immediately after the collision ? From escape from the sunken submarine
Answers
Answer:
The disaster which befell the Russian submarine Kursk in August 2000 caught the world’s attention and became a galvanising event in drawing renewed focus on submarine safety in the new century. Public empathy worldwide seemed to be driven by the belief that when a submarine goes down there is little that can be done for the crew. However, the history of successful submarine escape and rescue is as long as the history of the submarine itself.
As submarine capabilities were gradually introduced in various navies around the world, a common question also emerged: what can be done in the event of a submerged accident that disables the submarine and prevents it returning to the surface? Essentially the answers remain the same.
There are two options available for the crew of a submerged disabled submarine (DISSUB); escape or rescue. Escape is the process where the DISSUB’s crew leaves the boat and reaches the surface without external assistance; while rescue is undertaken by outside parties who remove the trapped crew from the submarine. At the dawn of the modern submarine age the initial focus was given to escape. Appearing around 1910 the first escape systems were derived from the breathing apparatus used by coal miners. These used a soda-lime cartridge which binds large quantities of carbon dioxide, cleaning the air breathed. The system utilised in the first submarine escape was the German Dräger breathing apparatus, used when the submarine U3 sank in 1911.1 A number of similar systems followed; with the Davis Submarine Escape Apparatus (DSEA) being adopted by the Royal Navy in 1929 and the Momsen Lung used by the United States Navy (USN) until 1957.
These escape systems remained prevalent until 1946 when the Royal Navy held an inquiry into escape from sunken submarines. The inquiry found no difference in survival rate between those who used a DSEA to escape and those that did so unaided.2 As a result the DSEA was replaced with the ‘free ascent’ or ‘blow and go’ technique. Free ascent involved the crew member beginning the ascent with compressed air in their lungs. During the ascent the submariner breathed out at a controlled rate, allowing air to escape. This was a continual process, as the air expanded in the lungs due the decreasing pressure experienced en route to the surface. To limit the chance of being affected by decompression sickness, the escapee would use the bubbles of expelled air to judge the ascent by staying behind the smaller bubbles. To aid in the escape, a crew member might also use a life jacket or buoyant ring. In this case the rate of ascent was more rapid, which required the submariner to blow more rapidly throughout the journey to the surface. Buoyancy assisted free ascent continues to be practiced by Royal Australian Navy (RAN) submariners at the Submarine Escape and Rescue Centre at HMAS Stirling in Western Australia.
After a brief flirtation with free ascent, the USN implemented the Steinke Hood in 1962. Literally a hood with a plastic face mask attached to a life jacket, the Steinke Hood allowed the crew member to breath air trapped in the hood on their ascent following escape. Breathing in the trapped air reduced the chances of contracting the bends if the user breathed normally.
Free ascent and the Steinke Hood were favoured for their ease of use, but both systems had one glaring flaw: they failed to provide protection from the elements once the submariner reached the surface. This was apparent in 1950, when HMS Truculent sank following a collision with a merchant vessel within sight of the British shore. All of the 72 crew made it to the surface but only 15 survived with the rest swept out to sea by the tide and lost. These shortcomings were again evident with the Kosmsomlets disaster in 1989.
Of the Soviet submarine’s 69 crew, 34 of those who made the ascent to the surface later died from hypothermia, heart failure or drowning. In the 1990s a large percentage of the world’s navies operating submarines, including the RAN, replaced their existing escape systems with either the British developed Submarine Escape Immersion Ensemble (SEIE) or local versions of that design. Using trapped air, similar to the Steinke Hood, the SEIE covers the user completely and importantly, provides thermal protection. Further, the suit has an inbuilt life raft that, once on the surface, can be linked to other life rafts. The suit allows for an escape from 185 meters.