cold water survival 1992-123

This publication is licensed toANGLO EASTERN GROUP

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A POCKET GUIDE TO

Cold WaterSurvival

1992 Edition

BINTERNATIONAL

MARITIMEORGANIZATION

London, 1992

Purchased by ANGLO EASTERN GROUP

Published in 1981

by the INTERNATIONAL MARITIME ORGANIZATION

4 Albert Embankment, London SE1 7SR

Second edition, 1992

Printed in the United Kingdom by Arkle Print Ltd, Northampton

12 14 16 18 20 19 17 15 13 11

ISBN-13: 978-92-801-1273-3

ISBN-10: 92-801-1273-2

IMO PUBLICATION

Sales number: I946E

The illustrations on pages 13 and 15 are

reproduced, by kind permission, from the

International Medical Guide for Ships, second edition

(Geneva: World Health Organization, 1988),

figures 2 and 3.

Copyright # International Maritime Organization 1992

All rights reserved.

No part of this publication may be reproduced,

stored in a retrieval system or transmitted in any form

or by any means without prior permission in writing

from the International Maritime Organization.

Published in 1981

by the INTERNATIONAL MARITIME ORGANIZATION

4 Albert Embankment, London SE1 7SR

Second edition, 1992 (ISBN-13: 978-92-801-1273-3

ISBN-10: 92-801-1273-2)

Electronic edition: 2006

IMO PUBLICATION

Sales number: E946E

The illustrations on pages 13 and 15 are

reproduced, by kind permission, from the

International Medical Guide for Ships, second edition

(Geneva: World Health Organization, 1988),

figures 2 and 3.

Copyright # International Maritime Organization 2006

All rights reserved.

No part of this publication may be reproduced,

stored in a retrieval system or transmitted in any form

or by any means without prior permission in writing

from the International Maritime Organization.


http://www.imo.org

Introduction

The purpose of this guide is to examinethe hazards of cold exposure that mayendanger your life, and to provide you

with advice on how to prevent or minimizethose dangers. A thorough understanding ofthe information contained in this booklet maysome day save your life.

The sinking of the Titanic in 1912 provideda dramatic example of the effects of cold waterimmersion. Partially due to a lack ofpreparedness with protective clothing, ofadequate flotation equipment, and ofknowledge of survival procedures, none of the1,489 persons immersed in the 08C water wasalive when rescue vessels arrived one hour and50 minutes after the sinking. Countless livescould have been saved had the survivorsknown more of how to cope with cold water;almost all of the people in the lifeboats werealive.

During the Second World War the RoyalNavy of the United Kingdom alone lost about45,000 men at sea, of whom it is estimated30,000 died from drowning and hypothermia.Many of those who drowned did so because ofincapacitation due to cold. Even today thepattern is similar.

It is important to realize that you are nothelpless to effect your own survival in coldwater. Body heat loss is a gradual process, andresearch shows that in calm water at 58C anormally dressed person has only a 50%chance of surviving one hour. Simple self-helptechniques can extend this time, particularly ifthe person is wearing a lifejacket. You canmake the difference; this pamphlet is intendedto show you how.

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Your body

An understanding of how your bodyreacts to cold air or water exposure,and knowing the steps you can take to

help your body delay the damaging effects ofcold stress, will help you in your struggle to stayalive in the event of cold water exposure.

Imagine your body to consist of an innercore and an outer layer. Within the core; yourbody produces a great deal of heat as a resultof normal body functions, such as physicalexercise and digesting your food.

Nature requires that your body core bekept to an ideal temperature of 378C. Anetwork of blood vessels running through thecore and the outer layer of your body picks upthe heat produced by the ‘furnace’ within thecore, and distributes the heat throughout thebody. Nature also gives your body a very

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accurate system to regulate automatically thecore temperature at 378C. For example, if thetemperature around you is high, as on a warmday or in a hot boiler room, the blood vesselsnear the skin of your body will enlarge,allowing more blood to flow to the outer layerand increase body heat loss. This will keep youcomfortable and keep the core temperaturefrom rising. If the surroundings are cool, yourbody will narrow the blood vessels in the outerlayer and keep that valuable body heat frombeing lost too rapidly.

Vessels enlarged Vessels narrowed

This regulatory system strives to keep thecore temperature of the body constant despitevariations in ambient temperature around you.The body can only do this within certain limits.There are levels of cold exposure when thebody must have help in maintaining the coretemperature at nature’s choice of 378C. Youmust give it that help by taking correct actionsand wearing protective clothing.

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Body heat loss and insulation

The body gives off its heat to the surroundingsin the following ways:

& Conduction is the transfer of heat by directcontact with cold water or other materials.Heat passes from your body, which is at arelatively high temperature, to a substancewhich is lower in temperature. Certainsubstances are better conductors of heatthan others. Water conducts heat manytimes faster than air.

& Convection is the transfer of heat by air orwater currents. Moving air is far cooler tothe body than still air. Cooling by wind isknown as the ‘wind-chill’ effect. Similarly,disturbed or moving water around yourbody is more chilling than still water at thesame temperature.

& Radiation is the transfer of heat by rays ofenergy without direct contact with othersubstances, such as a radiator heating aroom.

& Evaporation is the vaporization, or ‘dryingup’, of liquid, such as sweat or moisturefrom wet clothing. When the body gets toohot, sweating will occur and theevaporation of this sweat will help to coolthe skin. Although sweating can be veryuseful in providing you with a comfortablecooling effect on a hot day, evaporation ofmoisture from clothing can rob you ofvaluable body heat on a cold day.

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In almost all parts of the world, man cannotsurvive without the aid of clothes. Clothes bythemselves do not warm the body; the body isactually warmed by its own heat production.The body heat warms the layer of air trappedbetween the skin and clothing. It is this layer ofair that provides insulation. If the layer of air islost, then the insulation is diminished. This layerof trapped air between skin and clothing maybe disturbed by movement or displaced bywater. In either case, valuable warm air isdisplaced and skin temperature will fall. Heatfrom the body core will then be used in anendeavour to maintain skin temperature. Ifheat loss from the skin remains unchecked, thebody core temperature will fall.

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Hypothermia

The loss of body heat is one of thegreatest hazards to the survival of aperson at sea. The rate of body heat loss

depends on water and air temperature, windspeed, sea conditions, the length of time spentin the water, the protective clothing worn, thebody type of the survivor, and the manner inwhich the survivor conducts himself. Anabnormally low body core temperature can berecognized by a variety of symptoms. Veryearly during exposure, the body tries to combatthe excessive heat loss both by narrowing itssurface blood uesse1s (to reduce heat transferby blood to surface) and by shivering (toproduce more body heat). However, if theexposure is severe, the body is unable toconserve or produce enough heat. Body coretemperature begins to fall. When the bodycore temperature is below 358C, the person issuffering from ‘hypothermia’.

By then, discomfort, tiredness, poorco-ordination, numbness, impaired speech,disorientation, and mental confusion are wellestablished. As the internal temperature fallsbelow 318C, unconsciousness may occur,shivering is replaced by muscle stiffness, andthe pupils of the eyes may be enlarged. Theheartbeat becomes irregular and weak and thepulse is barely detectable. Although death mayoccur at any stage of hypothermia, when aperson’s temperature is below 308C it is verydifficult to be sure whether he is alive or dead.Death by hypothermia is then defined as afailure to revive on rewarming.

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Marked shivering

Progressive muscle rigidity

Shivering ceases

Dilated pupils that still react

No pupil reflexes

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36

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Symptoms of hypothermia

Confusion

Disorientation

Amnesia

SleepinessHeartbeat slows

Possibly abnormal heart rhythmsUnconsciousness

Muscles relax

Apparent death/ Death

Bod

y co

re te

mpe

ratu

re (

°C)

Time

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Ship abandonment

Ships may sink in less than 15 minutes.This affords little time to formulate a planof action, so careful planning is essential

to be ready in an emergency. Here are somesound pointers for you to remember whenabandoning ship:

1 Put on as many layers of warm clothing aspossible, including foot protection, makingsure to cover head, neck, hands and feet.Fasten, close and/or button up clothing toprevent cold water flushing through theclothing.

2 If an immersion suit is available, put it onover the warm clothing.

3 If the immersion suit does not haveinherent flotation, put on a lifejacket andbe sure to secure it correctly.

4 If time permits all persons should, beforeboarding the survival craft or in any caseimmediately after boarding, take somerecommended anti-seasickness medicine ina dose recommended by the manufacturer.Seasickness will interfere with your survivalchances as vomiting removes preciousbody fluid, and seasickness in generalmakes you more prone to hypothermiaand impairs your will to survive.

5 Avoid entering the water if possible, e.g.board davit-launched survival craft on theembarkation deck or by the marine escapesystem. If davit-launched survival craft, amarine escape system or other means ofdry-shod embarkation are not available,use over-side ladders or, if necessary, loweryourself by means of a rope or fire hose.

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6 Unless it is unavoidable, do not jump intothe water from a height greater than 5 m.Try to minimize the shock of sudden coldimmersion. A sudden plunge into coldwater can cause rapid death, or anuncontrollable rise in breathing rate mayresult in an intake of water into the lungs.On occasions, it may be necessary to jumpinto the water; if so, you should try to keepyour elbows to your side and cover yournose and mouth with one hand whileholding the wrist or elbow firmly with theother hand. Avoid jumping onto the liferaftcanopy or jumping into the water astern ofa liferaft, in case the ship has someremaining headway.

7 Once in the water, whether accidentally orby ship abandonment, orient yourself andtry to locate the ship, lifeboats, liferafts,other survivors, or other floating objects. Ifyou were unable to prepare yourself beforeentering the water, button up clothing now.In cold water, you may experience violentshivering and great pain. These are naturalbody reflexes that are not dangerous. Youdo, however, need to take action as quicklyas possible before you lose full use of yourhands: button up clothing, turn on signallights, locate whistle, etc.

8 While afloat in the water, do not attempt toswim unless it is to reach a nearby craft, afellow survivor, or a floating object onwhich you can lean or climb. Unnecessaryswimming will ‘pump’ out any warm waterbetween your body and the layers ofclothing, thereby increasing the rate ofbody heat loss. In addition, unnecessarymovements of your arms and legs sendwarm blood from the inner core to the

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extremities (arms and legs) and thus to theouter parts of the body. This can result invery rapid heat loss. Stay calm and take upa good position to prevent drowning.

9 The body position you assume in the wateris also very important in conserving heat.Try to float as still as possible – with yourlegs together, elbows close to your side,and arms folded across the front of yourlifejacket. This position minimizes theexposure of the body surface to the coldwater. Try to keep your head and neck outof the water.

10 Try to board a lifeboat, raft, or otherfloating platform or object as soon aspossible in order to shorten the immersiontime. Remember: you lose body heat manytimes faster in water than in air. Since theeffectiveness of your insulation has beenseriously reduced by water soaking, youmust now try to shield yourself from windto avoid a wind-chill effect (convectivecooling). If you manage to climb aboard alifeboat, shielding can be accomplished

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with the aid of a canvas cover, a tarpaulin,or an unused garment. Huddling close tothe other occupants of the lifeboat or raftwill also conserve body heat.

11 Keep a positive attitude of mind about yoursurvival and rescue. This will improve yourchances of extending your survival timeuntil rescue comes. Your will to live doesmake a difference!

Treatment of theimmersion survivor

The treatment for hypothermia will ofcourse depend on both the condition ofthe survivor and the facilities available.

Generally speaking, survivors who are rationaland capable of recounting their experiences,although shivering dramatically, merely requireremoval of all wet clothes and replacementwith dry clothes or blankets. If possible, theyshould be taken from the water horizontallyand carried this way, or else be returned to thehorizontal (or, better still, to the unconsciousposition illustrated on page 15) as quickly aspossible and kept this way. Hot sweet drinksshould be given but only if the victim is fullyconscious with gag and cough reflexes. Rest ina warm environment not exceeding 208C(normal room temperature) is alsorecommended. Alcohol or smoking, as well asmassaging or rubbing the cold skin, should beavoided. However, always bear in mind thateven conscious survivors can collapse andbecome unconscious shortly after rescue. Theyshould therefore be kept resting horizontally,with their legs slightly elevated (the ‘shockposition’), and be watched for at least twohours.

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In more serious cases, where the survivor isnot shivering and is semi-conscious,unconscious, or apparently dead, immediatefirst-aid measures will be necessary to preservelife while awaiting medical advice on moredetailed management procedures. This adviceshould be sought as soon as possible and firstaid measures should not be delayed whileadvice is being sought. The recommended first-aid measures for such an immersion survivorare as follows:

1 On rescue, always check the survivor’sbreathing, carotid pulse for one minute (asillustrated), and pupillary reaction.

Carotid pulse

2 If the survivor is not breathing, make surethe airway is clear (remove dentures, if any)and start artificial respiration immediately(mouth-to-mouth or mouth-to-nose).

If the heart appears to have stoppedbeating then cardiac resuscitation may beapplied. However, you should be certainthat there is no pulse at all (remember thathypothermia slows and weakens the pulsegreatly) and, once started, it must becontinued properly until the patient iseither fully rewarmed or delivered to ahospital.

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3 If the survivor is breathing but unconscious,lay him in the unconscious position asillustrated on page 15. This is necessary toensure that the person’s breathing is notobstructed by his tongue or by vomit.

4 Avoid all manhandling which is notnecessary to determine whether there areany serious injuries; do not even removewet clothes; do not massage.

5 Prevent further heat loss throughevaporation and from exposure to thewind. Wrap the patient in blankets and/or acasualty bag or large plastic bag andtransfer immediately to a (wind-)shelteredarea or, below decks to a compartmentbetween 158C and 208C, keeping himhorizontal, slightly head down.

6 Advice on rewarming and decisionsregarding further treatment shouldnormally be given only by a doctor. lf nomedical advice is immediately available,continue to apply the essential life-savingprocedures given in paragraphs 1 to 5above. In addition, if the rescued person iscold and appears dead, or if he deterioratesand/or the pulse and breathing are lost,warming should be attempted immediately.

Medical authorities disagree on thebest method of rewarming, but either an‘active’ or ‘passive’ method is normallyused,* i.e.:

* With respect to rewarming of hypothermia victims theInternational Medical Guide for Ships recommends the ’passive’method on board the survival craft (p. 262) and the ’active’method on board the rescue vessel (p. 268). However, where theperson treating the victim has been trained in only one of thesemethods of rewarming, in the absence of medical advice to thecontrary, only the method of rewarming in which the person hasbeen trained should be used.

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.1 ‘Active’ method of warming: this is donepreferably in a bath of warm water (388Cto 408C – hand hot) or alternatively usingheated blankets or sheets (about 458C, butnot hotter);

.2 ‘Passive’ method of warming: cut theperson’s clothing so that it can beremoved with the minimum of disturbance.Then wrap the person in blankets to reducefurther heat loss. Do not attempt to warmthe person by vigorous actions. Applyheating pads or hot water bottles under theblanket, to the person’s head, neck, chestand groin – but never place these warmobjects against the bare skin, as cold skin iseasily burned.

If active or passive methods of warming arenot available then apply body warmth by directbody-to-body contact with the rescued person.In addition wrap a blanket around both therescued person and the person or personssupplying the warmth.

In all cases try to monitor the pulse andbreathing.

Safe position for an unconscious patient: turn him face

down, head to one side; no pillows should be used under

the head. Pull up the leg and the arm on the side to which

the head is facing, pull up the chin. Stretch other arm out,

as shown. Clothes should be loosened at the neck and

waist, and any artificial teeth removed.

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The above basic guidelines on first-aidtreatment for the unconscious person areillustrated diagrammatically below:

START (Recover in a horizontal position

whenever possible)

1 Insulate to prevent further heat loss through evaporation and exposure to wind. Avoid unnecessary manhandling – leave wet clothes on and enclose in blankets and/or plastic bag. Move to sheltered location.2 Lay down in the unconscious position whenever possible.3 Oxygen should be given if available.4 If water was inhaled, encourage deep breathing and coughing.5 Request medical assistance.6 Watch person closely until shivering starts. In the absence of medical advice rewarm the person by either the ‘active’ or ‘passive’ method described in paragraph 6.1 or 6.2 (page 15).

1 Clear airway, check carotid pulse and pupillary reaction.2 Start artificial respiration immediately (mouth-to-mouth, mouth-to-nose). If a pulse cannot be detected, commence cardiac resuscitation.3 Insulate to prevent further heat loss through exposure to wind. Avoid unnecessary manhandling – leave wet clothes on and enclose in blankets and/or plastic bag. Monitor pulse, breathing and consciousness of victim and actively rewarm if the person appears dead or if the person's condition deteriorates.4 Seek medical advice. If medical advice is not available, continue resuscitation until the patient is either fully rewarmed* or delivered to a hospital.

* Note: In the context of hypothermia a person cannot be presumed dead until he is rewarmed and shows no bodily functions.

IS PERSON BREATHING? NOYES

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Cold injury

Another condition which may affectindividuals exposed to coldenvironments is acute cold injury. Such

injuries usually result from exposure to lowtemperatures, especially in damp conditionsand when wind speeds are high. Cold injuriesmay be of a freezing or non-freezing variety.

Freezing cold injury (frostbite)

Frostbite is the term given to the conditionwhen tissue fluids freeze in localized areas ofthe body; the hands, face, ears and feet areparticularly susceptible.

Cause

Exposure, particularly of bare skin, to lowtemperature, especially when combined withmovements of moist/humid air. Look-outs inliferafts or survivors in open boats areparticularly prone to this injury. Accordingly,consideration should be given to the length ofwatch period.

Diagnosis

Early signs of frostbite are:

1 extreme waxy pallor of the skin;

2 initial local tingling and stiffness – it isdifficult to wrinkle the face or wiggleaffected toes or fingers;

3 complete absence of sensation in the areaaffected; and

4 local hardness due to freezing of the flesh.

N.B. Be watchful for the early signs of frostbitein yourself and in others.

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Prevention

If bare skin has to be exposed to the elements,the periods of exposure should be kept to aminimum and freezing winds be particularlyavoided. Moderate exercise and massage at anearly stage will help to prevent the onset ofcold injury. DO NOT smoke; smoking reducesthe blood supply to the hands and feet.Alcoholic drinks should not be consumed.

Treatment

On detection of the above signs, immediatesteps should be taken to rewarm the frozenpart before permanent damage occurs. Getout of the wind. Rewarm the frozen areas byapplying them to a warmer part of the body,e.g. hands under armpits, cupped hands overcheek, nose, ear, etc. The frozen areas can alsobe rewarmed by placing them in water with atemperature of not more than 408C. Oncefreezing has occurred, DO NOT rub ormassage affected areas.

Non-freezing cold injury (immersion foot)

Immersion foot is the term given to thecondition when the temperature of local tissuesin the limbs (usually the feet) remains subnormalbut above freezing for a prolonged period. It iscommonly encountered by shipwreck survivorswho have been adrift and cold for several days.Usually the feet have been wet and immobile,but this injury can also occur in dry conditions.Other contributory factors are tight footwearand sitting still with the feet down as whensitting in a chair for prolonged periods.

Diagnosis

Feet become white, numb, cold, and frequentlyare slightly swollen. When returned to thewarmth, the feet become hot, red, swollen, andusually painful.

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Prevention

Every effort should be made by survivors tokeep their feet warm and dry. Shoe-lacesshould be loosened; the feet should be raisedand toe and ankle exercises encouragedseveral times a day. When possible, shoesshould be removed and feet kept warm byplacing them under the armpits, but outside theclothing, of an adjacent occupant.Alternatively, unwanted spare clothing may bewrapped round the feet to keep them warm.Smoking should be discouraged.

Treatment

After rescue, every effort should be made toavoid rapid rewarming of the affected limbs.Care should be taken to avoid damaging theskin or breaking blisters. Elevate the lower legsto reduce swelling and cover lightly.Remember: numb limbs do not feel heat or anyother pain and are very easily burned. Do notmassage affected limbs.

Summing up

We have briefly explained how yourbody responds to cold, what youcan do to help ward off the harmful

effects of cold and, finally, how to administeraid to an immersion survivor.

We will now sum up the story with anumber of important reminders. Follow them,for your life may depend on them.

1 Plan your emergency moves in advance!Ask yourself what you would do if anemergency arose. Where is your nearestexit to the deck for escape? Where is thenearest available immersion suit, lifejacket,

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lifeboat, or raft? How would you quicklyget to your foul weather gear, insulatedclothing, insulated gloves?

2 Know how your survival equipmentworks. The time of the emergency is notthe time to learn.

3 Even in the tropics, before abandoningship, wear many layers of clothing tooffset the effects of cold. Wear animmersion suit if available.

4 Put on a lifejacket as soon as possible in anemergency situation.

5 When abandoning ship, try to board thelifeboat or raft dry without entering thewater. Take anti-seasickness medicine assoon as possible.

6 If immersion in water is necessary, try toenter the water gradually.

7 Swimming increases body heat loss. Swimonly to a safe refuge nearby.

8 To reduce your body heat loss, try to floatin the water with your legs together,elbows to your side, and arms across yourchest.

9 In a survival situation, you must forceyourself to have the will to survive. Thiswill very often make the differencebetween life and death.

In conclusion, advance planning, preparationand thought on your part can be the mostsignificant factors in your struggle with coldwater immersion and in your survival.Familiarize yourself with the contents of thisbooklet.

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cold water survival 1992-123

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