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A major determinant of survival time in cold water and one that is largely overlooked is the sea state. Not only does this increase the risk of drowning because of increased frequency of immersion of the airway, it also increases convective cooling. It is concluded:

1.  That water is a very good conductor of heat.
   

2.  That the body immersed to the chest in a lifejacket cools principally from conduction and convection.
   

3.  The colder the water, the greater the thermal stimulation and heat loss. Consequently, the chance of death from cold shock, swimming failure, hypothermia, and post rescue collapse increases.
   

4.  The colder the water, the sooner the incapacitation of the hands very shortly after entry immersion.
   

5.  Grip strength and tactility is also reduced in cold water just at the critical time when it is most needed to initiate survival actions.
   

6.  If rescue does not occur within the first 10-20 minutes, then the ability to cling to floating debris, becketed grab lines, and do any physical self-rescue actions decreases.
   

7.  Even if the head is supported with a lifejacket, this is no guarantee that drowning will be prevented in cold, choppy water unless a splashguard is worn.
   

8.  One must avoid abandoning ship into cold water (wet shod evacuation) if possible. Whenever possible, one must leave the vessel at the last possible time and abandon directly into a liferaft (dry shod evacuation).
   

9.  If the abandonment occurs at dusk or in the dark, there is a high chance that the victim may become lost or drowned.
   

10.  Most important of all, is that once the immersion occurs in water below 15°C, the problems become worse.

Let us now consider a person who may be part of the crew, be a young child or an elderly tourist who suddenly, with little warning has to abandon ship wearing an approved lifejacket into Canadian inshore lakes or rivers. Unfortunately, there has just been such an abandonment, which ended up in tragedy, this typifies the problem and precipitated the study conducted in this report.

[This newspaper quotation was not strictly true in the fact that there was only one US registered yacht in the area. The water conditions were too choppy for it to get close enough to assist, but it did raise the alarm.]

Unfortunately, the children had to abandon directly into the water in their street clothes, quite unprepared for such an event. This is quite typical of a marine accident – it is sudden and unexpected and, indeed, rescue was quite near at hand (20 minutes). The two children probably drowned as a result of cold shock or swimming failure. The water temperature was 10ºC and the investigators did not enquire at what stage any witnesses last saw the children, so it is speculation. The fundamental question was not reported by the Board’s Investigation as to whether they could swim. Later, at the inquest, it was established that both children could swim. They certainly did not die from hypothermia because they were not in the water long enough. As previously stated, this further supports the fact that swimming in cold water without the protection of a lifejacket is potentially very dangerous and that swimming ability in warm water bears no relationship to that in cold water. They should also all have been wearing lifejackets when there was signs that the boat was in trouble. The lifejackets were stowed in a difficult place to gain access to them, so they were never used. They should have never been allowed to abandon ship into the cold water. They should have abandoned dry shod into a liferaft, but it was impossible to launch the liferaft due to the fact that there was no hydrostatic release, nor was it able to float away free. (Reference 63)

So, could the deaths have all been prevented? Probably.

Clearly, it is potentially very dangerous for any person dressed in normal street attire and particularly with no lifejacket to abandon any form of vessel irrespective of size or purpose in water below 15ºC. Even a lifejacket, if not worn properly or without a spray hood, does not guarantee the victim protection from drowning.

Transport Canada should introduce new regulations that can be implemented stepwise over a timescale of their choice. The basic principle must be that no human should be expected to abandon ship in Canadian rivers and lakes wet shod into water below 15ºC. For all newly constructed vessels it is suggested that implementation of this principle should start for the year 2003 and that by 2005 all older vessels must comply with this philosophy or be refitted. There will be some exceptions to this philosophy that will be discussed later.

By adopting this philosophy, this means that every passenger carrying vessel must carry a liferaft for a large portion of the year while the water temperature remains 15ºC. Stowage, accessibility and ease of launching is always a problem, but a particular problem for smaller vessels. Vessels that carry six to eight passengers may simply not have the space. However, these types of vessels due to the nature of their size and type of operations may be at most risk from marine accidents. The advice would be to insist that the passenger wear the most recently approved inflatable lifejackets while underway in water below 15ºC. The modern inflatable lifejacket is an excellent piece of safety equipment, it is light weight, comfortable to wear, unobtrusive, cool even on hot days and does not limit physical movement.

Insisting on inherent buoyant lifejackets causes the potential risk of someone being trapped between decks due to the buoyancy. For school trips, Scout camps, etc., it would be prudent to insist that everyone wears an inflatable lifejacket and irrespective of this, all schoolchildren under age 13. (The teachers and leaders would then be showing an example to their students and also many of them are non-swimmers.) For rapid capsizements, such as the True North II there is still merit in carrying seat cushions and buoyant apparatus for those who cannot swim.

Certain catastrophic conditions will be faced by the passengers at the point of abandonment into cold water:

•  Very rapid sinking with little warning – life jacket donned

•  Very rapid sinking with little warning – no lifejacket donned

•  A slower, more orderly evacuation where the majority of people will don lifejackets

For the first two conditions the passengers may find that they have simply been washed over the side or physically ejected from the deck. This is the worst possible scenario.

The primary level of protection from drowning especially in cold water from cold shock will be their lifejackets if donned. To improve the likelihood that they are wearing lifejackets, the Masters need more education in ordering the donning of lifejackets when conditions start to get rough, not when it’s too late. This is what happened in the case of the True North ll. The two new Canadian videos on cold shock, swimming failure, hypothermia and post-rescue collapse should be introduced into the curriculum of the Marine Emergency Duties Course as soon as possible.

The secondary level of protection will be the liferaft and buoyant apparatus. Hopefully, if there is a slower, orderly evacuation, they can abandon dry shod into a liferaft. The victims who find themselves suddenly in the water, and particularly non-swimmers will require some immediate flotsam, jetsam or buoyant apparatus to cling to in order to control respiration and make their way to a liferaft. In theory, if all the new, regulated liferafts have automatic hydrostatic releases, then even in the dark it should be possible for the survivors to stay afloat long enough to locate the raft and board it, likely with assistance. For those already wearing a lifejacket, they will be able to swim a short distance to the liferaft.

For all victims, if the water is cold and they are dressed in street clothes only, they should not swim unless within metres of shore or a safe refuge, the likelihood of death from swimming failure is always present, hence the requirement for carriage of liferafts when the water temperature is below 15ºC.

The argument that liferafts are not necessary because vessels operating near shore in day time can expect other vessels to come to the rescue quickly is not supported. The M/V Bronx Queen flooded and rapidly sank in Ambrose Channel, New York on 2 December 1989 with the loss of two lives. The sea water temperature was 38ºF (3.5ºC). The US Coast Guard Inquiry (Ref 16732 Bronx Queen MC89006462) concluded "that buoyant apparatus which do not provide out-of-the-water capabilities do not provide adequate protection for people in cold water operations. Even with rescue resources on scene when the people went into the water, the shock of the cold water and period of time these people were in the water proved significant in this casualty." All nineteen people entered the water just as rescue arrived, so in retrospect, the loss of life was due to drowning from cold shock or swimming failure. Nor is the addition of an EPIRB going to speed up rescue to this type of response time. The Canadian response to an EPIRB ranges from 90 minutes to 2 hours. Death will occur within 3-5 minutes for those who have not donned a life jacket, or from swimming failure within 30 minutes if not clothed properly and supported by a lifejacket.

CONCLUSIONS  ^

1.  Up until fifty years ago, no one really understood the reason why people immersed in cold water died. It was attributed to an inability to stay afloat and vague terms such as "exposure".

2.  The massive loss of life at sea during the Second World War noted in the Talbot Report and McCance et al’s paper for the Medical Research Council initiated a lengthy and extensive research program to investigate the cause, in which hypothermia became recognized.
   

3.  Subsequently, a whole series of survival prediction curves have been produced, in different temperatures of water, the objective being to predict when death occurs from hypothermia.
   

4.  Survival prediction curves are of limited value only. This is because they do not take into account that death may occur from cold shock, swimming failure and drowning during early hypothermia. The curves should be revised to include these factors.
   

5.  Regulators, teaching establishments and survival suit manufacturers all concentrated their efforts on protecting the person from hypothermia. Indeed, in this regard they have done a very good job.
   

6.  By the early 1980’s, it became clear that there were four stages of the immersion incident in which a person could die: Stage 1 - cold shock (3-5 minutes); Stage 2 - swimming failure (30 minutes); Stage 3 - hypothermia (greater than 30 minutes); and Stage 4 - post rescue collapse (on or shortly after rescue).
   

7.  Swimming ability in warm water bears no relationship to swimming ability in cold water.
   

8.  Manual dexterity is severely degraded in water below 15°C particularly at the time when it is required to do essential survival tasks.
   

9.  For those passengers with a potential heart conduction defect (middle-aged and elderly tourists), immersion in cold water increases the chance of fatal cardiac arrythmia (irregular heart beat).
   

10.  Even given the above, the layperson, is often still surprised that some people do not survive a lengthy immersion even though they are theoretically within the "safe" boundaries of the current, predicted survival curves. These people do not die of hypothermia per se, but from a variety of problems included in which is moderate hypothermia where a lowering of the body core temperature is enough for them to lose their physical ability and mental determination to keep their backs to the waves. They thus inhale the next wave and die from drowning in spite of wearing a life jacket.
    

11.  Even though there are well established teaching programs, regulations and much improved life saving equipment, there are still in the order of 140 000 open water deaths each year. What has been overlooked is the significance of the first two stages - cold shock and swimming failure as a cause of death. The precise details of these are described in this report.
    

12.  Research within the last ten years and documentation of witness testimony and boards of inquiry have confirmed that cold shock and swimming failure are indeed a very significant cause of death.
    

13.  From all the combined research on cold water accidents and scientific research, it has become clear that sudden immersion in cold water, i.e. below 15°C is very dangerous, it should be avoided if at all possible. Furthermore, a conscious decision to swim (and rescue oneself) or stay floating still in the water should not be taken lightly without assessing the pros and cons. It has now been shown that a person’s swimming ability in warm water bears no relationship to that in cold water.
    

14.  The severity of the effects of cold shock is directly proportional to the water temperature peaking between 10-15ºC.
    

15.  These scientific findings lead to the practical advice regarding the regulations requiring the carriage of liferafts and training of operators of passenger carrying vessels.

1.  Wherever possible, entry into water below 15°C should be avoided. Direct entry into a life raft should be the objective.
   

2.  Transport Canada should use this philosophy in the design, development and implementation of all new legislation in a step wise fashion. All vessels operating in Canadian lakes and rivers at 15°C or below should carry liferafts that can easily be launched and boarded by the entire crew and passengers.
   

3.  The only exception to this should be where it is physically or practically impossible to stow a liferaft. Under such conditions the passengers must wear inflatable lifejackets when on board.
   

4.  Operating a vessel close to the shore or in groups or the carriage of EPIRB are not a reason for waiving this requirement because death from cold shock will occur within 3-5 minutes, swimming failure in under 30 minutes, and darkness only hampers escape and rescue.
   

5.  The Marine Emergency Duties curriculum should be amended to include the two new Canadian videos on cold shock, swimming failure, hypothermia and post-rescue collapse.

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 ACKNOWLEDGEMENTS ^

I must give thanks to several people who aided in this report.

First, this work could not have started without the help of Jim Brock and John Murray from the Marine Safety Division of Transport Canada. They conceived the necessity for the work and reviewed the original draft.

The report could not have been completed without the help and assistance from Professor Mike Tipton of the University of Portsmouth, UK and the Royal Navy Institute of Naval Medicine. With the assistance of Professor Frank Golden, he has led the world in the research into cold shock and swimming failure over the last twelve years. The advice of both has been invaluable. Dr. Howard Oakley from the Institute of Naval Medicine was also most helpful in providing all the information on the Marchioness accident. Richard Hiscock informed me about the tragic loss of two victims in the sinking of the Bronx Queen in 3.5ºC water.

Victor Santos-Pedro was of immeasurable help with the final draft as was Carole Tipton who proof read the document and made excellent suggestions. Finally, Kimberley Howard and Laura Chaddock must be thanked for all the hard work in typing and formatting the final report. As a result of our cooperative endeavours, I hope that it will be a safer place for those who work or play over Canadian waters in the new millennium.

The opinion expressed in this report is solely that of the author. This research was conducted under Transport Canada contract number T8275-010075/001/SS.

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