Some Interesting Sea Survival Facts

[Raphael Misson]

I'm reading this book called Essentials of Sea Survival by Frank Golden and Michael Tipton and have found all sorts of interesting facts in it that are useless to my book, but are interesting none-the-less. Not all of these are about the sea, some are about humans and factors important to their ability to survive in sea conditions. So I thought I'd post them in here. Note that this doesn't necessarily have to do with period.

"Between 1978 and 1998 more than 5,300 passengers were killed in ferry accidents around the world, making ferry travel 10 times more dangerous than air travel (Faith 1998). Most people are familiar with the story of the SS Titanic, popularized in and Oscar-winning Hollywood film, but the record to date for number of lives lost at sea in a single peace-time incident goes to the sinking of the passenger ferry Dona Paz, after a collision with a small oil tanker in the Philipine archipelago, on a calm moonless night on 28 December 1987. Of the estimated 3,156 people board the ferry, none of the crew and only 24 passengers survived. [1489 people died in the sinking of the Titanic]...

Because of the absence of compartmentalization on their cargo decks, car ferries have proved to be inherently unsafe." (Golden and Tipton, p. 3)

"Although the body uses most of its outer layer (the shell) as a variable insulator, the one exception is the scalp, where blood flow tends to remain constant regardless of temperature changes. In cold environments about 50 percent of total body heat production may be lost through the unprotected head of a lightly clothed individual in an equivalent air temperature of -4 degrees Celsius (24.8 degrees Fahrenheit)." (Golden and Tipton, p. 32,34)

"People acclimatized to heat produce a greater volume of sweat, but its salt content is less than those who are unacclimatized. this response helps those acclimatized to heat to conserve salt." (Golden and Tipton, p. 36)

I have always wondered about the process of getting "used to" warm temperatures.

"But because sweat evaporation, not sweat production, cools the body, sweat that drips off the body has no cooling effect. It merely results in dehydration." (Golden and Tipton, p. 37)

Somehow, I thought that was all interesting. I'll post more as I come across it.

[Coastie04]

Another thing that I read (unfortunately, a while ago and I don't have the source on hand), is that during WWII, when ships were sunk, it was often older sailors that survived, even though the younger ones were more physically fit. They found that the younger people were more active in organizing people to get together and doing the 'proper' things after a ship goes down, whereas the older crew would not bother with wasting energy organizing the whole crew and focus purely on their own survival.

I saw a little of this when I was in the Coast Guard. We ended up saving a large number of Cubans near Key West who's boat sank in 6' seas. We were to the point of searching for bodies when we found one older man (probably in his mid 50's) treading water with no floatation after 20 hours! It was quite amazing given the sea state, and he was obviously exhausted, but he did survive where other younger people didn't.

Coastie

[silas thatcher]

I have always wondered about the process of getting "used to" warm temperatures.

from my experience and others' stories, it takes about 3 months to get acclimated to a different climate...in the summer time and fall, i spend as much time as possible outside in case i end up on a job working outside ( construction )... yes, you can get used to the cold and the heat... i've been doing it for 21 years from 8* F to above 100* F... factor in wind chill in the winter and midwest humidity in the summer, the temps seem worse...

don't know if it is a situation of "getting used to" or merely becoming tolerant of the conditions...either way, what i have been doing seems to work for me...

btw... working at the local power houses in winter while the boiler is running, and i am working close to it sweating my arse off, and then having to go outside when it is below freezing... well, i haven't figgered that one out yet :)

[Raphael Misson]

From reading this, I'd say that changing into dry clothing and then layering it is the best bet. (Although you probably don't have that option.) The reason for layering may not what you'd think, though. It's because layers provide pockets of warm air. (Of course, this is far more important in submersion than in air.)

"In less severe environments underclothing absorbs the condensed moisture, becoming damp and replacing air. Because water has 24 times the thermal conductivity of air, this displacement of air from clothing by water will quickly and significantly reduce the effectiveness of clothing insulation. [in other words, damp (sweaty) skin does what it's supposed to and cools the body. So going from a very hot to very cool environment will make you cold faster.]

Thus, dampness facilitates heat transfer across the layers of wet clothing...by evaporation, convection and radiation.

The wisdom of the old adage 'If you want to stay warm in the mountains, stay slightly cold' should now be apparent. By staying slightly cold, a person will minimize sweating and preserve clothing insulation. To prevent the condensation of water vapor within clothing, many manufacturers have replaced impermeable materials with those that incorporate vapor-permeable ('breathable') membranes. When new and clean, these membranes allow water-vapor to pass through the clothing while preventing the entrance of water. At least some materials appear to retain this capability when soiled, although salt water, oils, and other substances may degrade other materials." (Golden and Tipton, p. 45)

Some other stuff...

"The hands and feet do not produce much heat. Thus, the temperature of these areas depends primarily on the heat delivered by blood flow. When cold conditions reduce this blood flow by vasoconstriction [the narrowing of the blood vessels], the hands

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and feet cool quickly because of their high surface area. The best way to protect the hands and feet, besides insulating them, is to keep the body warm and thereby maintain their blood (heat) supply. The saying 'If you want to keep your hands warm in the cold, wear a hat' is accurate. A hat will reduce heat loss from the head (see the proceeding) and help maintain deep body temperature and thus peripheral blood flow.

Gloves and footwear will insulate, but will not maintain local blood flow if deep body temperature is falling. hence, even with gloves and special footwear, if deep body temperature falls, hand and foot temperatures will fall, albeit more slowly with extra insulation. The hands are particularly difficult to protect. As the thickness of gloves increases so does the surface area for heat loss [if I understand this correctly, better padded gloves make your hands "larger." Heat radiates out of your hands into the padded glove and is lost more quickly because the glove makes your hand larger and more able to dissipate heat. IF if understand it correctly. They don't explain it well.]... Fingerless mitts are therefore preferable to gloves." (Golden and Tipton, p. 48-9)

Of course, if you're handling cold things, then I would thing the value of padded gloves in protecting them from direct contact with the cold thing would be beneficial. However, from their point, it would seem that minimal padding would be preferable if you want to keep your hands warmer. It's not at all what I thought.

"A popular misconception about drowning is that it is caused by the weight of saturated clothing 'dragging people under.' This belief has lead to the misguided advice to undress in the water, an action that reduces total insulation. But because water does not weigh anything in water, it is not this that drags people under. Rather a loss of buoyancy occurs when air escapes withing the fabric of the clothing [they're wearing]. On initial immersion, air contained within clothing provides helpful buoyancy. After a time, which varies from seconds to minutes depending on the clothing worn and movement, the air escapes, thereby lowering the body in water and reducing the distance from mouth to water. This requires

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the person to lift the head higher out of the water to breathe [making breathing in water more likely]... The restriction to movement caused by wet clothing is a further encumbrance: It also increases drag if one is swimming. Even small waves on the sea cause a reduction in the mouth-to-water distance to become critical. Subsequent aspiration [breathing in] of water into the the lungs will further reduce the buoyancy of the body.

Rescuers describe how the sound of the rescue boat sometimes prompts people in the water to wave. In so doing, they disturb the trapped air from under their waterproof oversuit and suddenly sink (fishers wearing 'oilskins' are particularly prone to this problem). Although it is difficult to do, people who find themselves in similar situations should remain motionless and allow the rescuers to do all the work." (Golden and Tipton, p. 74-5)

"...seawater is more damaging and lethal to aspirate. Indeed, experiments have shown seawater to be twice as lethal as fresh water (Modell 1971)." (Golden and Tipton, p. 83)

The detailed reason for this is pretty intricate, but basically it is because fresh water can be more easily absorbed by the blood passing around the lungs, meaning that the fresh water can be removed faster. As the authors explain it, water in the lungs produces a sort of lesion or blister where the lung comes in contact with the bloodstream. This makes it impossible for the blood passing by the lungs to exchange CO2 for Oxygen. This is the real reason we "drown" - no oxygen can get into the bloodstream from the damaged lungs to be circulated throughout the body. You can survive with a little water in your lungs. Conversely, you can drown when your lungs are only partially filled with water because of the damage caused by the water at the blood interface.

[Silver]

wool has great warming properties, i have a couple of wool commando sweaterd (woolie pullies) that i wear over a long sleeve turtle neck shirt, it is great at holding body heat in even when it got damp from the rain.

[Raphael Misson]

According to these authors, most of the warming benefit of fabric comes from the air trapped within them because it can be warmed by the body without being lost as quickly through fabric leakage. When bodily warmed air escapes through fabric, it will be replaced by cool air from outside the fabric. At least that's how I understand this.

"Alcohol impairs the ability of the liver to maintain blood-sugar levels (Haight and Katinge 1973). Consequently, in cold environments, such people [as are drinking alcohol] are at increased risk of developing hypothermia. Furthermore, besides not having a normal shivering response [because it is impaired by alcohol - shivering raises the body's core temperature and is beneficial in cold temperatures], they perceive less discomfort from the cold and are less aware of the danger they are in. It is probably this reaction that has led to the myth that alcohol 'keeps the cold out!'" (Golden and Tipton, p. 105)

"In contrast to whole body exercise, leg-only exercise can keep deep body temperature higher during cold-water immersion than remaining at rest. This suggests that the arms are a major area of heat loss in cold water. this seems logical given that the arms have a larger surface-area-to-mass[weight] ratio than the legs..." (Golden and Tipton, p. 135)

I think it's interesting that they suggest kicking your legs, but keeping your arms still - in fact, keeping them wrapped around your torso may improve core body temperature.

"Both carbohydrate and fat metabolism contribute to the body water stores, whereas protein matabolism will tend to deplete these stores. A product of protein metabolism is urea, a compound that is excreted by the kidney [via urine] and, in large amoungs, is toxic to the body. The volume of water lost in excretion of urea depends on the amount of protein being matabolized (2 to 3 milliliters for every gram

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of protein). In starvation conditions, even when a person is not eating any protein, the body begins to consume its own muscle protein (catabolism) as a source of vital energy." (Golden and Tipton, p. 144-5)

So eating meats and other proteins can reduce your chance for survival when you are not getting enough water. Just fascinating.

"Survivors should consume no water in the first 24 hours because the body's reserves should be able to cope in the early stages. Much of the water drunk in this period will be excreted, wastefully, as urine. Thereafter, survivors should restrict intake to about 500 milliliters (just over a pint) a day unless supplies are plentiful, in which case they may drink up to a liter (just over a quart) a day...

When water is plentiful, protein, which is likely to be abundantly available [fish], provides a valuable source of energy. But when water supplies are severely limited, survivors should avoid protein as much as possible to conserve water. The loss of body water, required to excrete the urea from protein metabolism, may hasten death from dehydration long before death from starvation would occur. Thus the benefit to body energy is outweighed by the penalty to water balance." (Golden and Tipton, p. 147)

Edited August 6, 2009 by Raphael Misson

[Raphael Misson]

Let's discuss dehydration and what to do and not to do!

"There is an immediate slaking of thirst [after drinking seawater], followed quite soon by an exacerbation of thirst that requires more copious draughts of seawater, and then still more. The victim then becomes silent and apathetic 'with a peculiar fixed and glassy staring expression in the eyes.' The condition of the lips, mouth, and tongue worsens, and a peculiarly offensive odor of the breath has been described. Within an hour or two delirium sets in, quiet at first but later violent, and if unrestrained the victim may jump overboard. If restrained, consciousness is gradually lost; the color of the face changes, and froth appears at the corner of the mouth. Death follows shortly after.

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Thus, although drinking seawater may provide temporary respite from the signs and symptoms of dehydration, it will ultimately hasten death through excess sodium in the body (hypermatremia) before the final throes of death from absence of water (anhydration) occurs." (Golden and Tipton, p. 149-50)

"When the body is depleted of water (dehydrated) the concentration of naturally occurring salts in the remaining body fluids, blood, and tissue fluids increases above normal levels. It is believed that this rise in salt levels is responsible for many of the undesirable side effects of dehydration. Excess alt in the tissue fluid bathing the cells will reduce the fluid within the cells, significantly affecting their function. It is postulated that this reduction of the intracellular fluid of brain cells causes the reported madness in those who have drunk large quantities of seawater.

...

Normal body fluid has a concentration of about 0.9 percent sodium chloride (salt), which is approximately 9 grams of salt in solution per liter (1.06 quarts), a level that the body attempts to control rigidly through physiological means. Unadulterated seawater, on the other hand, has a concentration of around 3.0 to 3.9 percent salt (35 grams per liter in solution). Thus, if someone drinks one liter (slightly more than a

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quart) of seawater, the level of salt in the body will rise above the tightly controlled level. The body will initiate a physiological response to rid itself of this excess by increasing the excretion of urine. But because the maximum concentration of salt in urine is about 2 percent (20 grams of salt per liter), after excreting a liter of fully concentrated urine an additional 15 grams of salt remains to be disposed of. This can only be achieved by excreting about another three-quarters of a liter of urine, which will further deplete the body water stores. So, the result of drinking a liter of seawater is a net loss of three-quarters of a liter of body water. Alternatively, if the body cannot excrete the 15 grams of salt because it has insufficient water to waste as urine, then the salt will be retained in the body and distributed throughout the extracellular fluid (ECF). This higher concentration of salt in the ECF will drag fluids out of the cells to dilute the raised concentration in the ECF. The result is that

1. dehydration becomes worse.

2. the rate of decline in performance accelerates, and

3. the onset of death approaches more closely.

It should be understood that drinking urine (2 percent salt plus urea) is also contraindicated and dangerous." (Golden and Tipton, p. 151-2)

"Fish Eyes and Spinal Fluid

Both fish eyes and the fluid of the spinal column of fish offer another source of palatable fluid. Both the Baileys (1974) and Stever Callahan (1987) testify to the luxury of having fresh fish eyes to suck or chew when in a dehydrated state. The survivor can obtain the spinal fluid by making an incision through the spine just above the tail, with the fish held head down. By lifting the fish to the head-up position, you can collect the clear fluid in a container or suck it out. Although the volume of fluid obtained by either of these means is very little, it is satiating and has a positive psychological benefit.

Turtle Blood

Turtle blood has a salt concentration similar to that of human blood and is easy to collect -provided one is caught- and thus may help prolong survival. A turtle has about 500 milliliters of blood per kilogram (about 0.8 ounces per pound); therefore, a 20-kilogram (44-pound) animal will provide approximately one liter (one quart) of blood. In addition, stored beneath the shell of the turtle is a quantity of fat, which will provide both a valuable source of food and metabolic water. By reducing catabolism, the fat will also conserve body water." (Golden and Tipton, p. 157)

"Holding on to a full bladder of urine offers no advantage to body water balance; water cannot be reabsorbed from the bladder." (Golden and Tipton, p. 206)

Edited August 16, 2009 by Raphael Misson

[lady constance]

Mission--

interesting read-- feels like i am at work at a lecture of current topics in grand rounds....

hmmmm this is my day off-- i w2ill read this one at work and my coworkers will be amazed tosee such things on a pirate board --

that anyone outside our profession can hanlde concepts of ECF versus ICF

[Raphael Misson]

Well, this is a bit OT, I just thought it was interesting and other people might find it so. It does sort of tangentially relate to marooning and shipwreck victims, although they didn't know it then. There was certainly no one in the 17th century worrying about the salinity of extra-cellular fluid...

[Raphael Misson]

And the last of it (I've finished the book):

“Once the skin is broken, however, it is notoriously difficult to heal in the damp, salty environment of a life craft. Bacteria found on the skin which are relatively harmless on intact skin, will grow and multiply in an open wound and delay healing. Concurrent starvation and body-protein deficiency will further delay healing or even inhibit it totally.

…

In hot weather, the constant warm dampness of the skin beneath damp underwear promotes bacterial growth. It is better to go without underwear in such conditions and, if possible, expose the affected area to a moderate amount of sunlight periodically during the day. Again, washing two or three times a day with fresh water containing mild antiseptic will be helpful. After drying, gently massage some emollient, such as Sudocrem, into the skin over the pressure points. If pus is present, it should be released before cleansing, and the area dotted with iodine or other suitable antiseptic.”

"Holding on to a full bladder of urine offers no advantage to body water balance; water cannot be reabsorbed from the bladder." (Golden and Tipton, p. 221)

“With body cooling, the temperature of the extremities will fall long before that of deep body tissues, and the unprotected skin of an appendage can rapidly approach ambient temperature. The feet are particularly susceptible if they are inactive and dependent. In such circumstances the muscle pump, which plays such an important role in squeezing the venous blood flow ‘uphill’ to the heart, is almost nonexistent. Backpressure thus occurs on the venous side of the nutritional capillaries, producing a relative stagnation in tissue blood flow. Local swelling of tissues caused by a combination of poor circulation and dependency worsens this condition. Thus a vicious circle is established. In starving survivors, a deficiency of circulating protein contributes further to tissue swelling in the feet, because of the reduced osmosis less fluid moves back into the circulation from the tissues. Fear and anxiety are also predisposing factors for cold injury, as is anything else that decreases peripheral blood flow (for example, footwear or boots that become tight because of swelling of the dependent feet.)” (Golden and Tipton, p. 222)

"Wind chill is a major contributory factory in the etiology of cold injury. Relative air movement disturbs the boundary layer of air (forced convection) around the body and increases heat loss. This is the basis of the commonly used term wind chill. Siple devised the wind chill index (WCI) to show the physical relationship between temperatures and wind speed. People embraced the concept because it corresponded well with their subjective experience in the cold. But the index lacks a scientific basis in physical and biological terms because the cooling rate of a clothed living body in a cold environment is not entirely comparable

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with the cans of water Siple used in his experiments, a point that he himself recognized. Thus, the application of WCI to the clothed body unnecessarily exaggerates the danger. It is worth remembering that wind chill slows the cooling power of the environment, not air temperature. It is impossible for skin temperature to fall below ambient temperature, regardless of wind speed." (Golden and Tipton, p. 223, 225)

"Thirst is a poor indicator of dehydration. Dehydration can be well established before a person feels thirsty. Likewise, after rehydrating, the sensation of thirst disappears before the body fully rehydrates. Alcohol increases dehydration by removing more fluid from the body through the kidneys than is consumed with the alcohol in the first place. Thus the normal inefficiency of people with hangovers intensifies if they are working in a hot environment. They also are more prone to heat illnesses than those who are normally hydrated." (Golden and Tipton, p. 232)

That's good information for events!

"Dark urine means that the body is dehydrated; the aim is to keep the color of urine pale. In normal circumstances, a rehydrating drink should ideally contain sodium and sugar in the proportions shown in table 10.3 [Table showing 1/2 teaspoon of salt & five level teaspoons of sugar per quart of water.] This drink is not suitable as a sruvival ration because it includes salt." (Golden and Tipton, p. 233)

"Many people associate the UV threat with the presences of direct sunlight and infrared heat. A significant UV threat may be present, however, in the absences of bright light or strong infrared waves. Severe sunburns can occur on cloudy days or in the presence of strong cooling air movement.” (Golden and Tipton, p. 234)