Every year, it’s becoming safer to swim at sea. Ship designs have been developed that ensure their buoyancy under the most severe damages. Improving automatic navigation systems in the most difficult weather conditions. Reliable fire fighting equipment, etc..
Disaster relief actions at sea, lifeboat behavior.
And yet … Dry statistics show that in 1970 alone, 352 merchant ships sank (not counting vessels less than 500 tons of displacement) with a total tonnage of over 1 million tons. According to the Institute of the Economics of Maritime Navigation, in Bremen, from 1972 to 1974, 754 large ocean-going vessels disappeared into the deep sea.
, which often causes his death. An analysis of maritime disasters shows what a huge role lifeboats and rafts play in preserving the lives of passengers and crew. After the death of the ship, only 20% of those who were in the water can be saved, but the number of those saved who got to the boats and rafts is almost 80%.
Nowadays, in addition to spacious boats suspended from impressive davits that add a romantic touch to marine vessels, modest metal-like barrels and containers covering inflatable rubber rafts from the sun and rain are installed on the deck along the sides. Inflatable life rafts appeared in the navy and in aviation quite recently. In 1955, the First International Conference on Rescue Ships was held in Lisbon. It was first raised the question of the use of inflatable rafts as a means of assistance in an accident at sea.
But only five years later, at the II International Conference in London, 45 participating countries signed a convention according to which an automatically inflated rubber raft was officially recognized as a means of saving crews and passengers on ships with over 500 tons of displacement along with lifeboats and bots. In 1967, France, and subsequently other countries, obliged ship captains of any class, including fishing schooners and pleasure yachts, to have inflatable liferafts on board. Without them, today, the port authorities will not release a single vessel. Not a single airplane flying over the ocean will fly into the air.
Indeed, rafts have many advantages over other life-saving appliances (boats, boats, etc.). They have good stability, have high survivability and unsinkability. Easy to operate and reliably protect from wind and cold, sun and rain. With the help of an automatic device, they are quickly filled with carbon dioxide from a special cylinder, coming into working condition. This is especially important in the case of forced landing of a land plane. When the crew and passengers are at the disposal of a few minutes. For the time during which the aircraft remains afloat is extremely limited. For example, for the Douglas-DS-8 and Douglas-DS-7 aircraft, it is 24 25 minutes, and for the Lockheed-1049 airliner Superconstellation is only 10 minutes.
In the northern regions, an inflatable tent protects a person from the wind, water spray and rain at sea, allowing you to keep clothes dry. But most importantly, the air temperature in the tent area is always much higher than the outside. So, when testing a life raft of the Pioneer-Beaufort type, the air temperature in the tent area without using any means of heating was 4 20 degrees higher than the surrounding. The difference between the external and internal temperatures on a TUL multi-seat liferaft, which had well-sealed individual cocoons for each member of the flight crew, turned out to be even greater..
In 1972, Soviet researchers spent 5 days on PSN-6 rafts in the Black Sea. Throughout the experiment, the temperature inside the raft did not fall below 16 18 degrees, while the water temperature did not exceed 4 degrees. But even in hot tropical regions of the ocean, an awning plays an important role, protecting a person from the destructive effect of direct solar radiation. This was clearly shown by the data of an experiment conducted in the tropical zone of the Indian Ocean in 1967. True, the microclimate conditions on the raft were somewhat harsher than on an open boat. The air temperature, especially in the hot daylight hours, was higher than the outside by 3.5 5.4 degrees, and the relative humidity was 20-30% higher.
In addition, the tent somewhat impeded the circulation of air. This created a stagnation of the air masses, worsened the heat exchange conditions of the body. Nevertheless, the health of the subjects on the raft was much better than on the boat. They had a higher working capacity. To a much lesser extent, they suffered from thirst, and despite the high temperature and humidity, they experienced less thermal discomfort. In the event of a ship accident at sea, threatening him with death, passengers and crew occupy places in boats and rafts according to the schedule or direction of the captain.
In the absence of special devices, when the situation does not allow accommodation in rescue equipment directly on the deck, people descend overboard along the gangways, ropes with musings, using rescue nets. In this case, it is necessary to observe a strict sequence, maintaining the interval between descending ones, in order to avoid injuries. In the event of a forced landing on the sea of a land plane, leaving it and launching it on rafts is permitted only after the aircraft has completely stopped. The craft are held by the airplane with a halyard until all passengers and crew are accommodated in the craft. Only after this the crew commander, who was the last to leave the plane, cuts the halyard with a knife. Boats and rafts should move at a distance of 200,300 meters from a sinking ship or aircraft.
However, at the same time, continuous monitoring of the surrounding water area continues in order to timely detect and assist people who have not had time to use the watercraft. So that boats and rafts do not carry to the sea, they are connected among themselves by 15-30-meter halyards. When the boats are assembled and connected with each other, the commander organizes the provision of medical assistance to the victims. Checks if all people are there, and in the absence of someone conducts a search. To pull the victim out of the water, he is turned with his back to the boat, taken under the arms, clasping his chest, and then pulled aboard.
From the moment of embarkation in boats (rafts), all who are in them become a single crew, which reports to the commander exercising power corresponding to the status of captain of a sea vessel. The commander has many responsibilities and concerns. He should not only supervise all actions of the crew during autonomous swimming, determine the daily norm of water and food, but, most importantly, constantly maintain optimism in people. Confidence in a safe outcome of swimming, avoiding quarrels, despondency and especially panic. When urgent matters are completed, the commander distributes all further work on the raft among the crew members. Consistent with their abilities, professional knowledge and inclinations.
From the first minutes, a round-the-clock continuous shift is established on the boats. Change every 2 hours. The duties of the watchman include monitoring the air and the ocean. Timely notification of the commander of a change in meteorological conditions. On the appearance of ships and aircraft, the approximation of schools of fish and sharks. The watchman also monitors the safety of water and food supplies. It is obvious that the life of the crew largely depends on the serviceability of the craft. To avoid accidental damage to the shell of the air chambers, all those on the raft take off their shoes. Stitching and cutting objects (knives, hooks, etc.) are folded in one place, wrapped in a piece of cloth. Air leakage from the chambers is easily detected by ear by a characteristic hiss.
With a small puncture, rupture of the shell, the area around it is cleaned with sandpaper, lubricated with rubber glue, and then a patch of rubberized fabric is applied. Everything necessary for this purpose is stored in a special repair kit that is included with the raft. More significant damage is first plugged with rubber plugs or metal plugs to prevent a large air leak, and only after that a thorough, reliable repair is made.
But even in the absence of damage, air still seeps through the fabric, seams. Therefore, you have to periodically pump up the chambers with a pump or blow it with your mouth. This is not difficult to do, since the pressure that a person can create with a strong exhalation is close to the working pressure (about 0.14 atm) inside the raft chambers. The cameras should have a rounded shape, but not be tight, like a soccer ball. Since the air expands during the hot season, it is recommended to bleed it a bit. In cold weather, you must periodically swap the cameras.
With strong excitement, to give the raft greater stability, and deploy the boat with its nose against the wave and slow the drift, a floating anchor is lowered overboard. This simple device, resembling a small parachute, reliably does its job. So that the anchor cord does not wipe the fabric of the shell, it is wrapped at the place of attachment with a rag or bandage. If the raft is turned over to restore its normal position, a halyard attached to the opposite side is thrown over the bottom, and then it is pulled onto itself. In the absence of a suitable halyard, it is recommended to climb to the bottom of the raft, grab the board, and then, slipping into the water, try to knock it over.
Based on materials from the book Man in extreme environmental conditions.