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CHAPTER 1

Currently within Canada, there are hundreds of thousands of persons being transported for business or pleasure over inland waterways, lakes and rivers. Depending on the local climate, transportation may occur throughout the year or be limited to when the passage is ice free. Irrespective, for a large portion of the year, particularly the winter, spring, and early summer, the water is cold.

Recently, (June 2000), there has been an accident in Georgian Bay where two children drowned after the True North ll sank within two minutes (Reference 64). The question has been asked as to what steps should be taken to prevent this from re-occurring. Carriage of lifejackets is already mandatory. Should there be any change in the regulations? Carriage of liferafts within Canada’s internal waterways is not mandatory when operating close to shore. Should a change of policy be made on this requirement? Finally, if there are to be any changes in policy on the wearing of lifejackets or carriage of liferafts, should it be related to the physical water temperature at the time the vessel is operating? These questions will be addressed in the following chapters with conclusions and recommendations.

Records of death from immersion in cold water date back to ancient times. Circa 450 BC, Herodotus (Reference 28) wrote of the sea borne expedition against Athens by the Persian general Mardonius. He clearly distinguished drowning from hypothermia, when he wrote, "Those who could not swim perished from that cause, others from cold." (Reference 18) In spite of hundreds of thousands of maritime disasters, the precise medical cause of death has been rarely noted. Death has commonly been ascribed to "drowning" or being "overcome by the sea". In the 18^th and 19^th century, James Lind (1762) mentioned the dangers of collapse after rescue (Reference 39), and James Currie (1797) observed deterioration of his subjects before improvement (Reference 9).

Loss of life at sea was accepted as an occupational hazard. Wrecking was not made illegal until 1807 and the Royal Navy’s use of impressments was not abandoned until 1815. Thus, such items as lifejackets, which could be used to aid escape were not encouraged. Shipwrecked sailors had to cling to wooden spars, and water and rum barrels. With the advent of iron ships around 1850, not only did the ships sink faster, but also there was less flotsam for flotation. Consequently, there was an increase in the loss of life at sea. In 1871, it was reported that 2740 British seamen lost their lives through drowning (Reference 5).

No one paid attention to the observations by Lawrence Beesley (1912) (Reference 4). He was a survivor from the Titanic who noted that the victims wearing lifebelts and in cold, but calm water had died of cold. The official cause of death was given as drowning. Nor did the large loss of life during the First World War bring about change. Hill and Campbell’s appendix to the Merchant Shipping Advising Committee Report on Life Saving Appliances in 1922 (Reference 46) is the first formal acknowledgement of the dangers of "cold". It was the inadequacies of life saving equipment during the Battle of the Atlantic in the Second World War that was the catalyst for scientific examination of the problem.

As Golden (1996) (Reference 19) clearly pointed out, official inquiries in an endeavour to prevent a recurrence, have been more interested in the cause of disaster than the cause of death of the crew and passengers. The recent issue of the Marine Investigation Report by the Transportation Safety Board of Canada on the sinking of the "True North ll" in Georgian Bay June 2000 extends to 63 pages (Reference 64). There are only five sentences assigned to the fact that two grade seven students died. One of the sentences curtly states: "The bodies were subsequently examined by the coroner who determined that the cause of death was drowning." There has been no thought put into why they drowned or even if they could swim in the first place. Thus, both funding and direction for research has sadly lagged behind the technological advances in ship design.

The Medical Research Committee (Reference 44) published a pamphlet in 1943 on "The Guide to the Preservation of Life at Sea After Shipwreck". This was based on the observations of naval medical officers who had treated survivors, and on 279 survivor interviews. This was the basis from which all the modern physiological research has been conducted.

Two other reports were to follow after the War that revealed the shocking loss of life at sea which could have been prevented. The first was the Talbot Report (Reference 55) published in 1946.This showed the inadequacy of the RN lifebelt and the Carley type floats. Over 30 000 men died after escaping from their ships, in other words, during the survival phase. The second was the Medical Research Committee report by McCance et al (1956) which investigated "The Hazards to Men in Ships Lost at Sea 1940 – 1944" and examined the cause of death at sea in greater detail (Reference 43).

The pioneering work post-war was conducted under the auspices of the Royal Navy Personnel Research Committee and subsequently the Royal Navy Institute of Naval Medicine. This was basically summarized in Professor Keatinge’s monograph (1969) (Reference 35). As a result of all the aforementioned information, it had become clear that the human body cannot maintain its internal temperature when immersed in water below 25ºC when conscious and shivering. The body temperature must progressively fall until death occurs. However, there was much more to the problem than this.

Golden and Hervey (1981) (Reference 18) identified four distinct stages in which a human immersed in cold water may become incapacitated and die. However, what is most important to note is that stages 1, 2 and 4 were largely regarded as of academic interest only; so they did not have a large effect on survival policy, international regulations and survival equipment. All of the effort was concentrated on predicting the onset of hypothermia. Thus, there is still no consideration given to the physiological impact resulting from the first two stages of immersion in the design of emergency equipment. For instance, flares are still vacuum packed in polythene bags and as in the Estonia accident were not usable simply because no one had the grip strength or the tactility to open the bags. The bailer in the Estonia liferaft was wrapped in polythene and after attempting to open it with his teeth, the survivor finally gave up after he had lost several teeth!!

On initial immersion, there is a large inspiratory gasp followed by a four-fold increase in pulmonary ventilation, i.e. severe hyperventilation. This on its own can cause small muscle spasms and drowning. Along with this, there is a massive increase in heart rate and blood pressure. These latter cardiac responses may cause death, particularly in older, less healthy people. These effects last for the first two to three minutes, just at the critical stage of ship abandonment.

Death at this stage, between three and thirty minutes after immersion, appears to affect those who try to swim. It is also known that even good swimmers may be unable to swim for more than a few minutes in very cold water. "A good swimmer aged 20 recently disappeared within 5 minutes while he was trying to swim 50 yards from an overturned dinghy in calm water of a reservoir at 10ºC-11ºC." (Reference 36). The cause was thought to be due to the respiratory and cardiovascular responses already started in the initial immersion. An alternative theory was that the cold water contact with the nose and mouth induced the "diving response". This causes breathing to stop (apnea), a slowing of the heart rate (bradycardia) and even cardiac arrest (asystole).

After thirty minutes or more of immersion, death may occur from hypothermia. The reason for this is that water has a specific heat 1000 times that of air and a thermal conductivity of about 25 times that of air. Thus, when a body is immersed in water below body temperature (37ºC), it will inevitably cool to hypothermic levels at a rate dependent on:

•  Temperature differential

•  Clothing insulation

•  Rate of agitation of the water

•  Body heat production produced by shivering and exercise

•  Ratio of body mass to surface area

•  Subcutaneous fat thickness

•  State of physical fitness

•  Diet prior to immersion

•  Physical behaviour and body posture in the water

 As the deep body temperature falls, humans lapse into unconsciousness. Death may occur in two ways – drowning through incapacitation, and cardiac arrest. Death from drowning will occur in a lightly dressed individual even wearing a lifejacket, approximately one hour after immersion in water at 5ºC, or two hours in water at 10ºC, or in six hours or less at 15ºC (Reference 19).

 If the deep body temperature continues to fall, death occurs on average from cardiac arrest somewhere below a body core temperature of 24ºC. The lowest recorded survival temperature in an accidental victim is 13.7ºC (Reference 13). However, after surgical induction of hypothermia, there has been one reported incident of resuscitation from a body core temperature of 9ºC (Reference 48). Survival predictions were made from experimental data and case histories from shipwrecks.

The first classic survival curve was published by Molnar in 1946 (Figure 1, Reference 47). Included in here was the data from the Dachau prisoners (Reference 1). Survival predictions were later produced by Hall (1972) (Reference 21), and by the Canadian Red Cross from work conducted by Professor Hayward (1975, 1977, 1984) at the University of Victoria (Fig 2 Reference 23, 24, 25, 26).

A later predicted survival curve was published by Hayes et al (1987) derived from Professor Eugene Wissler’s Cold Water Survival Model (Figure 3, Reference 22). From this and the combination of previous work, Tikuisis (1995, 1997) has published the latest prediction of survival time at sea level based on observed body cooling rates (Reference 57, 58).

Figure 3: Predicted survival time against sea temperature for different levels of immersed clothing insulation – as derived from Wissler Model, Modified by Hayes, 1987.

A summary of current predictive curves is given in Oakley and Pethybridge (1997) (Figure 4, Reference 50). From this work, it became possible to give advice that survival times could be extended if the survivors stayed still in the water and did not attempt to swim to keep warm. Furthermore, adopting a fetal position with legs together and arms to the side, or folded across the chest prolonged survival time. (Reference 14, 24, 32) All of these predictive curves are premised on the fact that the person using the curves is prepared to accept the assumption that death is due to hypothermia. They are all based on time to incapacitation. 

N/A is used to indicate that the author(s) did not provide an estimate for that water temperature.

Figure 4: Predicted periods (in hours) of immersion at different temperatures which are expected to result in "likely death". After Oakley and Pethybridge (1997).

Up to twenty percent of immersion deaths occur during extraction from the water, or within hours after rescue (Reference 19). This was first noticed in 1875, by Reinke, a police surgeon in Hamburg. He recorded cases of sailors who had fallen into the canals and harbour and died within 24 hours of being rescued. (Reference 16) During the Second World War, the Germans and Allies noted that some of those who were rescued alive, died shortly afterwards. Matthes (Reference 41) noted how ditched German aircrew who had been conscious in the water and aided in their own rescue, became unconscious and died shortly afterwards. McCance et al, 1956 (Reference 42) found that seventeen percent of those shipwrecked survivors rescued from the water at 10ºC or less died within 24 hours of rescue. None of the people rescued from water above 20ºC died.

When the Wahine Ferry sank in 1969 in Wellington Harbour, Mercer (Reference 45) reported that, of the 51 lives lost, twelve were alive on rescue, but died shortly afterward. In the 1994 Estonia accident, at least one person who was noticed to be alive in the water, lost consciousness when in a helicopter hoist, fell back into the sea and died. An extensive list of post rescue collapse incidents is reported in Golden’s articles on shipwreck and survival (Reference 16) and Golden and Hervey’s article on the after-drop and death after rescue from immersion in cold water (Reference 18).

Although the existence of the lifejacket has been known since biblical times (Reference 5), the first standard for lifesaving equipment did not appear until 1852. At this time, the United States introduced the requirement for "every (river) vessel, carrying passengers to be provided with a good life preserver…". This was followed by similar legislation in France (1884), Britain (1888), Germany (1891) and Denmark (1893). Following the Titanic accident, the International Maritime Organization formed the Safety of Life at Sea (SOLAS) committee, which required lifejackets to be carried on all passenger vessels. Most of the resolutions made in 1912 were not implemented until post-1918. Following the Vestris accident in 1928, men, women and children were noted to be lying face down and drowned in spite of wearing a life jacket. However, the second SOLAS convention precipitated by this accident ignored these facts and nothing in the lifesaving appliances regulations was changed. In the first forty-eight years of the 20^th century, both naval and merchant navy philosophy was directed at keeping people floating in the water. Little attention was paid to whether they floated face up or face down. It was not realized that allowing people to float in cold water without protective clothing was very dangerous until (a) midway through the Second World War when the pioneering work of Macintosh and Pask established flotation angles and self-righting criteria for lifejackets (Reference 51, 52, 53); (b) the publishing of the Talbot Report (Reference 55); and (c) McCance et als’ paper (Reference 43).

As a result, the SOLAS conventions of 1974, 1978, 1981 and 1983, concentrated on the prevention of hypothermia, i.e. stage three of the immersion incident (Reference 30, 31). This was done by establishing standards for life saving appliances, that is lifejackets, liferafts, and buoyant apparatus. What the international standards did not take into consideration was the effect of water temperature on the application of the standards. This has been left up to individual nations to legislate.

In summary, from 1945 until 1995 a great deal of scientific, industrial, training and legislative effort has been put into the prevention of hypothermia. As a result, in both Europe and North America, particularly Canada, there are very good survival suit regulations. There is also a very good training program on the prevention of drowning and the prevention of hypothermia conducted by the Red Cross and the Life Saving Society; this is strongly supported by the US and Canadian Coast Guard. Yet, there are still over 140 000 open water deaths worldwide each year (Reference 17). There are better international standards and education than ever before, so what is happening?

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