THE HENLEY WHALERS - Cold water Precautions Home
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Section 1 - Based on the recent safety email
Section 2 - Edited quotes from various sources. Four stages ... Table of effects. . ."Shock response" . . First Aid Considerations.
Version 27/12/18,
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(1) - Particularly for Cold-water Sailors:-

"Be prepared for the worst while hoping for the best.
Molly has capsized (accidentally) only 4 times since new (2003), but …
Believing; “It won’t happen to me”; or “I’ve always been OK”, could be fatal.
The Solent water temperature today is here > BrambleMet .

Some factors affecting survival time in water – in approximate order, “worst” to “best”:-
- - - - Not wearing a PFD.
- - - Water temperature.
- - Alcohol consumption and diet pre-immersion.
- Age of victim.
+ Physical fitness.
+ + Training/Practice/Experience.
+ + + Being obese!
+ + + + Protective clothing.


  1. Is your PFD (Personal Floatation Device) “in date”? - Will it turn you face-up if you are unconscious?
  2. Have you ever swum in one?
  3. Do you have drysuit/Goretex (or similar) outer layer, and insulating under layers?
  4. Do you know Molly’s capsize avoidance and recovery drill?
  5. When did you last practice capsize?
  6. Do you know where Molly’s survival blankets are?
  7. Do you know where Molly’s flares are – and how to use them?
  8. When did you last practice reefing Molly? – How long does it take?
  9. Can you recognise hypothermia? - Do you know how to treat it?

(2) - Edited quotes from various source:-

Four stages of an 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);
Stage 4 - post rescue collapse (on or shortly after rescue).

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

A table of effects, etc, states:- Water Temperature 4.5 to 10C

  • Loss of Dexterity (with no protective clothing)* = Under 5 min.
  • Exhaustion or Unconsciousness = 30 to 60 min.
  • Expected Time of Survival = 1 to 3 hrs.

  • Recommended Clothing* Drysuit with fleece or polypro layers, neoprene booties, beanie, gloves.
    Trapped water is some help in retaining heat.
    Trapped air is better, eg Preferably drysuit, (otherwise Goretex outer layer) over insulating layers.

    Always wear a PFD (Personal Floatation Device)

Cold water shock response is perhaps the most common cause of death from immersion in very cold water.

  • The immediate shock of the cold causes involuntary inhalation, which if underwater can result in drowning.
    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.

In cold water you will cool approximately four times faster than in air at the same temperature.
All efforts should be given to getting out of the water by the fastest means possible.

Physical exercise such as swimming or treading water, rather than remaining still in the water, will greatly increase heat loss and can shorten survival time by more than 50%.
Blood is pumped to the extremities and quickly cooled.

Sudden entry unprotected into cold water is very dangerous and should be avoided wherever possible.
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.

First Aid Considerations For Cold Water Victims

  • Treatment for hypothermia depends on the condition of the person.
  • Mild hypothermia victims who show only symptoms of shivering and are capable of rational conversation may only require removal of wet clothes and replacement with dry clothes or blankets.
  • In more severe cases where the victim is semi-conscious, immediate steps must be taken to begin the rewarming process.
  • Get the person out of the water and into a warm environment.
  • Remove the clothing only if it can be done with a minimum of movement of the victim's body.
  • Do not massage the extremities.
  • Lay the semi-conscious person face up, with the head slightly lowered, unless vomiting occurs.
    The head down position allows more blood to flow to the brain.
  • If advanced rescue equipment is available it can be administered by those trained in its use. Warm humidified oxygen should be administered by face mask.
  • Immediately attempt to rewarm the victims body core.
  • If available, place the person in a bath of hot water at a temperature of 105 to 110 degrees.
  • It is important that the victim's arms and legs be kept out of the water to prevent "after-drop".
    After-drop occurs when the cold blood from the limbs is forced back into the body resulting in further lowering of the core temperature.
    After-drop can be fatal.
  • If a tub is not available, apply hot, wet towels or blankets to the victim's head, neck, chest, groin, and abdomen.
  • Do not warm the arms or legs.
  • If nothing else is available, a rescuer may use their own body heat to warm a hypothermia victim.
  • Never give alcohol to a hypothermia victim.

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