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Protection from the hazards of the environment should have highest priority, and, as one can survive some days without water and weeks without food, protection and water supply have by far a higher priority than nutrition. In water temperatures below 15°C crew must abandon ship by wearing cold water immersion suits in addition to modern inflatable lifejackets, even if they are kept initially safe in boats or life-rafts. Every effort should be made to board the life-raft dry if at all possible.
15.8.1 General Actions Prior to Abandoning Ship
Particular attention should be paid to the requirement to don as much clothing as possible, including gloves and head protection, preferably with a waterproof outer layer.
If time permits, and abandonment is orderly, extra clothing and blankets are as important as extra water.
15.8.2 Medical Actions Prior to Abandoning Ships
It is advisable to keep at least one small emergency pack in a waterproof container with inherent buoyancy in the ship doctor’s cabin together with his lifejacket. It should be easy to carry and capable of securing to the lifejacket or person, because for personal safety both hands are required to assist a casualty or to scramble down a rope or ladder.
The contents of the supplementary pack should be decided after checking the contents of the first aid pack of the life-rafts. It will be influenced by personal therapeutic practices. In addition to drugs (antibiotics, analgesics, anaesthetic and antibiotic eye drops and ointments, silicone ointment) such a pack should contain: scissors, curved artery forceps, safety pins, waterproof torch and spare batteries, bandages and tins of Vaseline impregnated gauge dressings.
15.8.3 Hazards of Immersion
Immersion after shipwreck is associated with many other hazards besides cold and drowning. Acute dangers to the individuals in the water include entanglement or traumatic contact with structures from the sinking ship, suction, inhalation and contamination with fuel oil, trauma from surfacing buoyant objects from the sinking ship and underwater explosions.
Surface fuel oil contact should be avoided as far as possible. Direct contact is not primarily dangerous due to negligible systemic toxicity. Swallowed it may cause vomiting, if inhaled it may produce pneumonia and if brought into the eyes it will produce conjunctivitis.
Burning oil at the sea’s surface is quite a hazard. If one has to jump from the ship into burning oil one may be able to avoid being burned if the following procedure is adopted:
- Remove lifejacket and cumbersome clothing.
- Jump feet first through the flames.
- Swim underwater for as long as possible.
- Then spring above the flames.
- Breathe using the breast stroke to push away the flames.
- Submerge and repeat until clear of the flames.
Suction hazards from a sinking ship depend on the survivor's proximity to the ship, its size and rate of sinking. The risk is much reduced if one is wearing a lifejacket.
A more realistic hazard, whether in the water or in a boat or raft, is the possibility of being struck or ensnared by some part of the superstructure as the ship capsizes, or being hit from below by the release of some buoyant object coming up from the sunken vessel. Risk is reduced in distance from the sinking ship and by adopting a vertical attitude.
Explosion may occur as a consequence of the initial damage or from other cause when the ship is sinking. Injuries may be produced as direct or indirect result of the blast, or from the thermal effects of the flash. Underwater explosions constitute a serious threat to the life of the survivor in water. Tissues surrounding air-containing cavities are typically affected. Injuries are determined by the distance of the victim from the explosion. Depth of water, nature of the seabed, flotation attitude of the victim in the water and clothing worn are interacting factors
15.8.4 Distress – Survival in Life-Rafts
Long term survival in life-rafts is a specific problem characterized primarily by cold, wet environment and insufficient potable water, at lesser degree by food deficiency. Keeping discipline and moral of the survivors inside life-raft is from utmost importance.
Disturbances of fluid and energy balance are closely related. They may lead to performance, health, discipline, moral and survival impacts. However, modern communications and location devices make it rather unlikely that survivors will spend the time needed for suffering nutritional deficiencies in life raft. Thus, supply and conservation of water is the crucial point.
Cold – Thermal Insulation
Thermal insulation in life-raft is highest priority. Free water inside life-raft reduces the insulation significantly. All measures must be taken from the very beginning for achieving control of any ingression of water. Common leaking sources are only partially inflated buoyancy tubes leading to inboard breaking waves and the open windward entrance.
Sitting position at the life-raft floor contributes to conductive heat transfer. This is aggravated be any free fluids sloshing around the floor (i.e. leaking water, condensation, vomits, urine). Fluids will accumulate in the depressions of the inflated floor printed by the sitting occupants. Additional blankets will find their beneficial use. If the risk of capsize is small it is recommended to get off lifejackets inside life-raft and use it as an insulating cushion instead (13).
Occupants in wet clothing should remove the outer layers, squeeze them dry, and put them back on. The manoeuvre will cost only little of body heat and will not affect heat balance over the long period.
Heat given off the occupants will warm up the environment within the life-raft reasonable quickly provided a good sealing of the apertures can be maintained. Atmosphere warming will be reduced by wearing waterproof clothing or survival suits.
Any dry clothing, preferably wind stoppers, capes and head coverings will reduce heat loss through radiation effects. This will lead to a prolonged period without cold shivering. During shivering the energy demands will increase significantly. However, good sealing of life-raft is difficult to maintain over the time. Cooling through evaporation will continue and must be considered even under obviously good sealed conditions.
Protracted exposition in cold conditions combined with insufficient energy intake will diminish shivering, thus reducing intrinsic heat production by muscular activity. With starvation, shivering will be almost absent. Body core temperature will fall. If dehydration is present cold related injuries are aggravated and cooling down of the body core will be enhanced.
Water
Dehydration in excess of about 5 percent body weight may be associated with headache, irritability, and feelings of light-headedness.
With losses of 10 percent, performance declines significantly. Further losses lead to hallucinations and delirium. Death usually occurs with acute losses of 15 to 20 percent of body weight. In a marine environment this occurs in 6 to 7 days.
For the average resting adult, recommended minimum daily requirement for fluid is 1 litre. In a survival situation this may be reduced to a daily in take of 150 to 450 ml of water for a limited 5-6 days period. Survival packs in life-rafts contain water supply of half a litre for a 5 day period per person.
Water balance can be maintained best on a diet which is rich in fat and carbohydrate but low in protein.
Survivors can reduce water requirements by minimizing energy expenditure and water losses (13,14):
- No drinking at all in the first 24 hours, except the injured.
- Never drinking seawater.
- Never mixing seawater with fresh water.
- Minimizing activity.
- Resting during the heat of the day.
- Optimizing the use of shade and breeze.
The life-raft survivor should reduce fluid loss by vomiting, thus taking the anti-seasickness tablets as soon as possible, either before or immediately when entering the life-raft.
Alternative safe means of acquiring water should be considered early (13):
- Collecting of rain is often the only source of water replenishment available to the survivor at sea.
It is a safe source; however, the initial wetting must not be collected using it for washing salt crystals from the collecting awning or canopy.
- Condensation water is a safe alternative.
- Seawater is no safe alternative.
Deaths in life-raft following the drinking of seawater seem to be the result of fairly rapid onset of respiratory failure mostly preceded by mental derangement. Delirium leads to apparent insanity, aggressiveness, risk of suicidal actions and death. Usually there are no typical signs of dehydration. There is no beneficial effect in mixing fresh water with seawater. In contrary it will lead to the same catastrophic events.
- Other safer alternatives are: Reverse-osmosis pumps and solar stills, if available; squeezed extracellular fish fluid (lymph) and spinal fluid; turtle blood.
Food
Death from starvation takes 40 to 60 days. Food is usually not the leading problem in survival at sea.
If sufficient hydrated physical and mental capabilities will be stable until bodyweight loss exceeds 10 percent.
Furthermore, the absence of vitamins, minerals, or trace elements is unlikely to pose a problem to life-raft survivors in the short term within a two months period.
For the average resting adult, daily energy expenditure is 1400 kilocalories. In a survival situation this daily requirement may be reduced to in take of 600 kilocalories for a limited period.
For prevention of catabolism and dehydration the food taken should be in the form of carbohydrate. This means avoiding eating protein unless fresh water is freely available. Fat reserves are plentiful, but glucose is required to enable the metabolism of fat. Protein reserves are also reasonably plentiful and can be used to provide the glucose to light the "flame to burn" the fat, but muscle wasting and protein deficiency disorders will quickly follow. A minimal daily intake of carbohydrate will help offset this. Food packs in life-rafts are assembled accordingly (13,14).
Morale and Discipline
In a survival scenario prospects increase significantly if survivors manage to react calmly, appropriately and effectively. An assortment of physical and psychological ailments in combination with other stressors can erode moral and decrease survivability at sea.
A leading person acting as a senior survivor in life-raft should set a good example, guide others, and contribute to a positive mental attitude until final recovery. Ship’s doctor is one of the trusted persons to take over the job.
Important rules for raising morale and discipline are:
- Never abandon hope for rescue (15).
- Keep comradeship on high level.
- Provide every survivor with special tasks.
- Avoid brooding.
- Monitor each other for suicidal actions.
- Set good example for others.
Other Common Problems in Sea-Survival
Sea survivors will suffer from additional health- and life-threatening problems as (13):
- Wind chill:
A major contributory factor in the aetiology of cold injury.
- Non-freezing cold injury:
Tissue temperatures between about 17 °C and -0,55 °C (freezing point of tissue fluid) lasting for a protracted period can result in a non-freezing cold injury. If feet are in water, the colder the water, the higher the risk of injury.
- Freezing cold injury:
After exposure to cold temperatures below freezing aggravated by high wind chill factor the temperature of the exposed peripheral tissue may drop below the freezing point of -0,55 °C.
- Heat exhaustion:
Dehydrated, resting survivors in a hot, humid environment are at risk. Prevention is good hydration.
- Sunburn:
Survivors in open rafts or boats are at risk of severe burns by direct and indirect UV rays, especially in equatorial waters.
- Skin ulcers:
Broken skin by abrasions and broils will not heal in the environment of a life-raft, wound cleansing can be done with some fresh water if no antiseptic is available.
- Seasickness:
Despite medications many occupant will still feel seasick and vomit. This will most probably cause a chain-reaction. If available, vomiting should be done in plastic bags. New medication (tablets) may be administered by absorbing through the lining of the mouth instead of being swallowed. Morale and discipline will be affected.
- Osmotic diarrhea:
May develop following swallowing of large amounts of salt water before entering the life-raft.
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