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Hypothermia

Riding a personal watercraft is lots of fun. Sometimes you are having so much fun you don't notice the passage of time. The action of wind and water on your skin can, over time, drastically reduce your body temperature. This reduction in body temperature is called "hypothermia." One of the early symptoms of hypothermia is shivering. Once shivering begins, you must head in to shore and get rested and warmed up before re-entering the water. If this vital signal from your body is ignored, other progressively dangerous symptoms develop. Hypothermia can be fatal if it is not dealt with in its early stages. Exposure to water - even with a temperature as high as 75° - for one hour can result in early stages of hypothermia. The waters of the northern states can be extremely cold - frequently below 50°. The colder the water, the greater the risk to the unprepared person. A swimmer has a 50% chance of swimming 50 yards in 50° water before being overcome by hypothermia. In water, the body loses heat 23% faster than on land. Nearly 90% of boating fatalities are due to drowning and nearly half of those are attributed to the effects of immersion in cold water. Wearing wet or dry suits helps keep the body's core from losing heat. If your PWC is disabled, stay out of the water and on top of your boat.

Should an immersion occur, try to get out of the water as quickly as possible. Do not try to remove clothing or shoes. Air trapped between layers of clothing will aid, not hinder in keeping a person afloat and also protect from direct exposure to cold water.

Heat Escape Lessening Position

H.E.L.P. Position (Heat Escape Lessening Position)

If you have fallen off your PWC and are unable to re-board, hypothermia is a definite threat. In this situation you must resist flailing in the water. Try instead to maintain the H.E.L.P. position, as shown to the right, as you float in the water. This will help to retain the warmth in your body's central core. A rider and passengers should do what they can to get out of the water since a person in the water looses body temperature much faster, which reduces survival time.

Surviving a Cold-Water Accident

The following recommendations should be followed:

  1. When people fall into cold water is they often panic and have an "unstoppable gasping for air reflex" that is triggered by the immersion in cold water. This will result in panic and a need to "thrash in the water". A person in this situation must calm down both their breathing and movement.

  2. There's only a short time to perform the necessary life saving tasks.

  3. Put on or make sure the life jacket is on properly and buckled.

  4. Assist other persons in the party with putting on their lifejackets. At the same time make sure everyone is accounted for.

  5. Stay with the vessel and try to get everyone aboard, or if the boat is capsized get as much of each person's body out of the water as possible.

  6. Talk to everyone and attempt to calm them down.

  7. Always look for or signal for help with emergency equipment, or waving your arms or a flag.

If your vessel has sunk or floated away, the people in the water may not be able to perform a self-rescue. If you are alone you should conserve body heat by assuming the H.E.L.P. short for Heat Escape Lessening Position. If you are with others, stay in a group, huddle together and minimize your movements. Swim towards shore only as a last resort. If you must swim, conserve energy and minimize your movement. Swim on your back, use a flutter-kick with your lower legs, keeping your upper arms against the sides of your chest, your thighs together, and your knees bent. Keep a lookout for floating debris from your vessel that can be used to assist you. Many operators equip all lifejackets with whistles or carry small hand held signaling devices for these emergencies.

If you recover a person who has experienced a cold water immersion or hypothermia, have them lie down in a horizontal position, keep them calm, remove wet clothes and replace with blanket or dry clothes, and monitor them while you transport them for medical treatment. Treating the victim with a hot water bath or rapid warming may cause additional harm. Additional information on treatment of hypothermia or cold water immersion can be obtained thru your local Red Cross, Power Squadron or U.S. Coast Guard Auxiliary.

Victims may deny they are ill and want to decline medical care, or want to climb into ambulances or helicopters on their own. Remember their judgment may be clouded, and yours should prevail.

The following chart provides a general idea of survival times in water of varying temperatures. Factors that may alter these estimates include clothing or protective gear, the individual's health condition, and water conditions.

Water Temperature Exhaustion Death
32.5 Under 15 min. 15 min or less
32.5-40 15-30 min 30-90 min.
40-50 30-60 min 1-3 hrs.
50-60 1-2 hrs. 1-6 hrs.
60-70 2-7 hrs. 2-40 hrs.
70-80 3-12 hrs. 3hrs-indefinite

Falling into cold water triggers a gasping reflex, causing the victim to inhale water. Total immersion in cold water is very painful and the disoriented victim can quickly panic.

With these combined reactions, the victim may drown quickly. The best prevention for this danger is to wear a life jacket with a cold-water survival suit.

Swim Failure

After a person has been in cold water for 3-30 minutes there's a continued inability to hold one's breath, loss of coordination in the arms and legs results in a body-angle incompatible with swimming. This results in the use of excessive amounts of energy in an attempt to swim. There is reduced ability to match breathing with swimming efforts and as a result, it becomes more and more difficult to keep the head above water.

Cold Water Immersion

Quick response to cold water immersion is vital because the body is impacted immediately:

In the first 3-5 minutes, sudden immersion can cause immediate hyperventilation, panic, involuntary gasping for breath, or vertigo. There might also be sudden changes in blood pressure and heart rate of the individual. These are symptoms of "cold shock" that can all be fatal.

The next 3-30 minutes the muscles and nerves in the arms and legs cool, causing a loss of manual dexterity and strength. "Swim failure" occurs when someone, even a strong person, lacks the coordination and strength to swim, pull them selves out of the water or prevent their head from being submerged underwater.

After 30 minutes, depending on the water temperature, the victim's body type, their clothing, and their behavior in the water, long-term immersion hypothermia sets in. The body is losing heat, especially in vital organs, faster than it can produce it. Hypothermia eventually leads to loss of consciousness and death, whether or not the person is in the water or not.

If a person is lucky enough to be rescued, they are still in danger from collapse of arterial blood pressure leading to cardiac arrest in a post-immersion collapse. Also, any water inhaled by the person can damage the lungs, and problems related to the heart may develop as cold blood from arms and legs is circulated into the body's core.

Submersion accidents which lead to unconsciousness in waters colder than 70° occur with regularity. Oxygen needs are much reduced when the body is cold, therefore permanent brain damage from low oxygen states may not occur.

It is documented, that a 60 minute cold water submersion victim has been fully resuscitated. Similar to a hypothermic victim, these "victims of cold water submersion" appear cold to the touch, blue in color, with no noticeable respiration or evident circulation and their pupils are fixed and dilated.

Factors relating to surviving cold water near-drowning:

  1. Age of the patient - the younger the better the prognosis

  2. Length of submersion - the shorter the better

  3. Water temperature - the colder the better the chance of survival

  4. CPR - if appropriately applied the better the survival

  5. Water Quality - the cleaner the better the survival

  6. Struggle - the more struggle the worse the results

  7. Other injuries - burn, blast or fractures reduce the chance of survival

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