Hace tiempo que lo vi en un programa de la tele pero no he encontrado mucha info al respecto:
https://en.wikipedia.org/wiki/Submarine_escape_training_facility
A Submarine Escape Training Tower is part of a facility used for training submariners in methods of emergency escape from a disabled submarine.
The facility, located at Fort Blockhouse, Gosport opposite HMNB Portsmouth, includes a fresh, chlorinated water column with a single escape chamber (as fitted to some classes of RN submarines) mounted at the base, through which students can conduct a fully representative escape cycle from 100 feet (30 m), closely replicating actions which would be required if forced to abandon a distressed submarine from depth.
Training includes ascents from increasing depths as a major element, but in addition is underpinned by lectures and practical training in how to survive within a disabled submarine, operation of emergency equipment and survival techniques on reaching the surface – a package of potentially life saving skills.
Owing to a combination of increased safety associated with modern submarine design, submarines operating in areas where escape would be impossible with current equipment and the risk associated with the conduct of training, the RN discontinued pressurised submarine escape training in March 2009.https://en.wikipedia.org/wiki/Submarine_Escape_Training_Facility_(Australia)
Training
Escape training is generally a five-day course. The course culminates in a free ascent in the facility's 22-metre (72 ft) vertical freshwater tank, with only one attempt permitted. New submarine trainees have to pass the course before they can be posted to a submarine, and submariners must requalify every three years.
Pressurisation of the escape tower takes less than 20 seconds to reach a maximum escape depth of 180 metres (590 ft) in order to reduce the risk of decompression illness. In 1995, training was changed to require two buoyant ascents from 9 metres (30 ft), wearing the submarine escape jerkin and two hooded ascents in the tower from 22 metres (72 ft) to reduce the risk of pulmonary barotrauma. Prior to 1995, candidates were required to perform two buoyant ascents from 9 metres, one buoyant ascent from 22 metres wearing the submarine escape jerkin, one hooded ascent in the compartment from 22 metres, and two hooded ascents in the tower from 22 metres.
https://www.researchgate.net/publication/5338840_Submarine_Escape_from_Depths_of_30_and_60_Feet_41183_Training_Ascents_Without_Serious_Injury
Submarine Escape from Depths of 30 and 60 Feet: 41,183 Training Ascents Without Serious Injury
Introduction: In the case of a submerged, disabled submarine, survivors may be forced to escape by entering the water and ascending rapidly to the surface. The large pressure changes involved may produce pulmonary barotrauma, arterial gas embolism, or barotrauma. To assess the likelihood of such injuries, we retrospectively evaluated medical problems due to submarine escape training among military personnel.
Methods: We evaluated 41,183 controlled ascents performed over the past 21 yr in the escape training tank at Go¨ lcu¨ k-Kocaeli, Turkey. Each trainee performed two free ascents from 30 ft and two hooded ascents from 60 ft. Before participating, candidates were screened by physical examination, spirometry, and chest X-rays; ear examinations for barotrauma were made after ascents. If a trainee failed to exhale properly during ascent, an instructor aborted the ascent and took him to a bell or side recess of the tank. Results: No record of pulmonary barotrauma or other major complications were found. Middle-ear barotrauma was observed following 1,643 of the ascents (4.1%), with rupture of the tympanic membrane in 35 cases. Discussion: Submarine escape ascents can be safely performed provided that subjects are medically screened and well trained.
Survivors who escape from a submarine are likely to be suffering from various combinations of traumatic injuries and burns from the original accident, to which the ascent may add barotrauma, arterial gas embolism, decompression sickness, hypothermia, and near-drowning (9).
In a free ascent, the submariner has no equipment over his head and must continuously exhale the expanding air from his lungs all the way to the surface to prevent potentially fatal consequences. In a hooded ascent, a head enclosure allows him to inhale and exhale and, therefore, requires less self-discipline.
Some navies train submariners in escape techniques using a deep tank called a submarine escape training tank (SETT). Such training allows the personnel to understand the submarine environment and experience the stresses of ascent under the safest possible conditions, and can also serve as a screening test for candidate submariners.
Despite its advantages, some navies are reluctant to perform SETT training because of its high cost and the fact that such training doesn’t reflect realistic open-sea conditions (4). In addition, trainees may suffer some of the same decompression effects associated with real escape. For instance, it has been reported that submarine escape training is associated with an incidence of PBT of 0.1 to 0.6 per 1,000 escapes for hooded ascent and 1 to 19 per 1,000 for free ascent (8). We believed that a new, up-to-date evaluation was needed to allow a better evaluation of the risks and benefits of SETT training.
METHODS
Candidates have to complete escape training to qualify as submariners, and then repeat it every 2 yr until age 35. All candidates fill out a health status questionnaire and undergo a detailed physical examination by a diving medical officer. A chest X-ray is used to rule out active tuberculosis, lung cysts, or bullae, and a sinus X-ray is obtained if indicated. Spirometry was added in 1994. Subjects are excluded from training for abnormalities in their physical examination, X-rays, or spirometry (i.e., if forced vital capacity (FVC), forced expiratory volume in one second (FEV1) or FEV1/FVC are less than 80% of predicted values). Middle ear examinations are conducted after ascent and squeezes are recorded if there is evidence of barotrauma or tympanic membrane rupture; under this procedure, a squeeze cannot be specifically assigned to ascent or descent. Candidates who are unable to perform escape training for some reason or had transient health problems are permitted to complete the training later.
The Turkish Navy performs escape training in a SETT located in Go¨lcu¨ k-Kocaeli. The tank is 60 ft tall and 18 ft in diameter. Compartments on the side walls at depths of 30 ft and 60 ft allow simulated exit from a disabled submarine into deep water, followed by ascent to the surface. Emergency recesses in the sidewalls at 50 ft and 10 ft can be used by instructors to divert a trainee who is having difficulty during ascent, and an open bell is positioned to provide an additional stopping place at a depth appropriate for the specific profile. There is a recompression chamber at the upper deck that is always ready for immediate use during training.
The free ascents are performed from 30 ft at a rate of 375 ft min 1 using the Steinke apparatus (Switlik Parachute Co. Inc, Trenton, NJ) without its hood. There are two types of hooded ascents included in the database:
1) Most were performed at an ascent rate of 425 ft min 1 using the Steinke hood starting from the compartment at 57 ft, which was designed in 1981 to simulate submarines in use at that time. This involved complex manual procedures and slow compression of the escape trunk with resultant exposure to high partial pressures of nitrogen and carbon dioxide; the escape trunk was partly flooded and once the trainee exited into the tank, the instructor physically controlled the ascent rate, especially during the last 30 ft. 2) In 1999, the Turkish Navy began using Mk 10 SEIE hoods (Beafourt Airsea Equipment Limited, Birkenhead, UK). At the same time, a new compartment was added to the chamber at 55 ft to simulate escape from the newer class of submarines and to simplify procedures. A small proportion of the hooded ascents were performed using an ascent rate of 590 ft min 1 with the SEIE hood, starting from the 55-ft compartment, which was fully flooded before escape.
Before their initial exposure to the tank, trainees are given a detailed theoretical education by experienced instructors. The training protocol includes two free ascents and two hooded ascents. For each ascent, the trainee enters the appropriate training compartment by walking through an entrance hatch. The compartment is closed and its pressure is then increased at a rate equivalent to descent at 75 ft min 1. In case of ear symptoms, it is common practice to stop, ascend a few feet to clear the ears, and then continue compression.
When pressure in the compartment matches water pressure at that depth in the tank, the compartment is flooded, the hatch is opened and the trainee moves into the tank to perform the ascent. An instructor closely observes the trainee during ascent, and those who do not exhale properly are stopped and taken to the bell or a side recess for removal from the tank and examination by the doctor.
RESULTS
We reviewed the records from a total of 12,160 applications for initial or periodic training during the period from 1981 through 2001. Of those, 1,055 (8.6%) were screened out due to respiratory tract infection (30%), abnormal spirometry (25%), wax in the external ear canal (25%), subjective complaints (feeling bad or not ready to escape) (10%), and other medical conditions or current use of medication (oral steroids, muscle relaxants, digoxin, psychotropic drugs, etc) (10%). The remaining 11,105 applicants performed a total of
41,183 training ascents. The initial 30-ft free ascent produced middle-ear barotraumas (MBT) in 741 cases (6.7%), and those trainees were excused from the second free ascent. The 10,364 second free ascents produced MBT in a further 152 cases (1.5%). A trainee who experienced MBT at any stage in the training sequence was stopped, but was allowed to complete training a month or more later.
A total of 10,212 trainees made a first escape from 60 ft, 98.5% with the Steinke hood and the remainder with the SEIE hood. Some 9,462 trainees completed the second 60-ft ascent, thus completing the entire training sequence. There was no significant difference in the outcomes for the two hoods. MBT occurred in 710 (7.0%) of the first ascents and 40 (0.4%) of the 9,502 second ascents. Thus, the rate of MBT was 4% for all ascents. Of the affected individuals, 35 (2.1%) manifested tympanic membrane ruptures. There were no
cases of PBT, arterial gas embolism, decompression sickness, drowning or near-drowning, or traumatic injury.
DISCUSSION
A number of studies have reported the occurrence of pulmonary problems (PBT) and arterial gas embolism during submarine escape training. The highest incidence (3.6%) was reported by Ingvar at al. in a prospective study based on symptoms, signs, and chest X-ray findings (5). On the other hand, Ikeda at al. reported no PBT or embolism in their study of Japanese Navy ascents from 10 m using the Steinke hood (4). They suggested that the this safe record might reflect the relatively shallow depth, the use of a tank-entry hatch on
the bottom rather than the side wall of the compartment, the presence of an open bell near that hatch, the availability of two emergency recesses, and very careful medical screening of the trainees.
Routine spirometry has been carried out during the medical examination of military and commercial divers for many years. An association between the low values of FVC and PBT in submarine escape tanks was interpreted as a statistical association but was not used as an index of risk (7). Brooks et al. observed that among several measurements that indicated pulmonary obstruction, a low value for FVC was the variable associated with the occurrence of PBT during ascent (2). They concluded that screening out persons with an abnormally low FVC might prevent up to 25% of PBT incidents in submarine escapes and perhaps in diving accidents (2). Since 1994 we have disqualified applicants with FEV1, FVC, and FEV1/FVC of less than 80% of predicted values, and we assume that this procedure has contributed to the absence of PBT in this study.
Tetzlaff et al. recommend the assessment of expiratory flow rates in addition to conventional spirometry for screening diving candidates (7), and we plan to add peak expiratory flows of 25–50 and 75 as a test for future trainees. The occurrence of false-negative findings in plain film radiography makes it desirable to adopt computerized tomography (CT) for the radiographic assessment of PBT to evaluate the lesions and to characterize the accident, since even minor forms of PBT are considered to contraindicate future diving (7). However, the high cost of CT and absence of PBT in our experience mean that we cannot use chest CT as a screening test for our trainees. Our MBT rate (4%) may be lowered by a slower compression during the training. We conclude that submarine escape ascents can be safely conducted provided that the subjects are medically screened and well trained.
https://jmvh.org/article/submarine-escape-and-rescue-a-brief-history-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.
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