"One of our submarines is missing..." This announcement is rarely heard but, when heard, it inspires deep feelings even for those who have no links to the sea.
Ever since human beings created the first submarines, there have been other, more claustrophobic people who have stared at the devices and thought: “Nope.” For many, the thought of the pipe and equipment-filled narrow metal confines is enough to trigger a fear of drowning even when they are standing on dry land.
The worst nightmare of every submarine is that the submarine gets stuck in the depths with its crew, because of a system failure, explosive, transfer error or collision. When vital-maintenance supplies are depleted and breathable air begins to deteriorate, the only thing keeping submarines alive is hope of rescue. At the same time, the logistical issues of evacuation of a sunken submarine require meticulous planning and coordination.
But everyone who has ever looked at a sub, has at some point wondered:
“If the boat goes down, is there any way out”?
Yes! Escape plans and tools are almost as old as submarine technology itself. Although the odds may always be stacked in favor of the merciless, cold depths of
the sea, a few dozen lucky people have taken that unintentional ride down to the ocean floor and lived to see daylight again.
Their stories teach us how to get out.
Once a submarine sinks and can no longer surface, it is termed a “distressed submarine”, or DISSUB. Conditions are likely to be fraught for those who have survived the initial accident. They face decisions that will drastically affect their chances of survival. The choice of whether to attempt escape or await rescue is heavily influenced by the conditions on board. If the situation is deteriorating rapidly, escape may be the only option.
In simple terms, the escape system involves equalising the pressure between the inside and outside of a specially equipped airlock (the escape tower) so that submariners do not get compression sickness when they ascend. Each crew member wears a suit that has a venting lifejacket and a hood to contain the vented (and exhaled) air. The hood keeps their head in air so that they can continue to breathe “normally”. The escape system has been tested down to 180 meters, which generally equates to the depth of the edge of the continental shelf.
The ascent itself is very rapid up to 2–3 metres per second but it is cold and dark until you approach the surface. Those who have escaped at depth describe a simple and relatively comfortable experience when ascending from about 90 metres. But beyond that, it gets physically harder and, from about 150 metres, it is increasingly risky and frightening, especially in the tower itself.
For the escape to be successful, everyone involved needs to be trained and most importantly, to make sure that the system works. Today, theoretical, and practical training is provided in many countries using submarine escape training facilities built at various depths for this purpose.
Apart from some training accreditation shortfalls partly due to instructors being exposed to an accumulation of high-pressure levels through a combination of professional and recreational diving the rate of accidents has been remarkably low. Turkish research, for example, reported 41,183 training ascents from 30 and 60 feet (9.1 meters and 18.3 meters) without serious injury. A low escape-training accident rate has also been reported in Australia, the United States, Canada, Japan, and Germany.
The training involves comprehensive practice with the mechanical systems and procedures in line with the established principles of competency-based training and assessment. It is, of course, unable to replicate the physical and psychological environment of a submarine accident, so one hopes that the messages conveyed during the training are strong enough to remain in place when stress levels are extreme.
While everyone hopes that the need for a real escape from a sunken submarine will never arise, it would be a great concern if the first time a submariner has the physical and psychological experience of escape is in the dark, in cold water, with no instructor support, and when their lifeand those of their colleagues depends on their capacity to remember the drill.
The escape process clearly contains risks some during training and many in the actual escape. It may be possible to avoid the training risks, but that merely transfers them to the poor person who is next in line to climb into the escape tower for real.
“The risks of doing escape training are far less than the risks of not doing escape training.”
The safety of the submarine and its personnel is inherent across all activities of the Submarine Enterprise. Safety is best achieved by ensuring design, upkeep, update, upgrade, and operations are always conducted at a high standard.
Training continues to be aligned with graduated near-realistic scenarios that best prepare its submariners for operations at sea.