Hypothermia in the Gulf?
Published: 4/5/2017

Because I have spent most of my U.S. Coast Guard career in cold water areas (two Antarctic, one Arctic icebreaker missions, Air Station Traverse City Michigan, and three tours in Kodiak Alaska), I have gained a tremendous respect for the sea and have learned that most offshore drownings are connected in some way or another to hypothermia. I have also learned that you do not have to be in "cold water" areas to succumb to hypothermia. For the purposes of this writing, I will refer to cold water as any water temperature that will lower the human body temperature below 98.6 degrees. (70 degrees F. or colder is fatal)

Cold water immersion is survivable if you take the proper steps. If you look at my “Seven Steps to Survival” page you will see that Recognition is the first step. If you fail to recognize that abandon ship, fall overboard, or ditching is possible, as some do, and if you fail to place floatation (life-vests and life-raft) in your boat or aircraft, you will likely be one of the many sad statistics stating, “The occupant was not wearing floatation".

While in the U.S. Coast Guard stationed in Kodiak Alaska, I had the privilege of serving with Dr. Martin Neimeroff (Captain). Dr.Neimeroff was the Coast Guard’s leading expert for cold-water immersion. I learned that hypothermia (lowering of body core temperature) has an adverse effect on the human body, even in small degrees. The human machine was designed to operate at a constant 98.6 degrees, and any variation up or down causes ill effect (hyperthermia/hypothermia).

When cold, the human body generates a small amount of heat through shivering (Stage One Hypothermia  98.6 F to 95.0 degrees). Feeling Cold, Shivering, Drowsiness, Slurred Speech, and Disorientation are all symptoms of stage one (mild hypothermia). Note: A person with “Stage One” hypothermia may appear to be intoxicated.

As you can see from looking at the hypothermia chart below, a variation of only 3.6 degrees from your normal body temperature can cause adverse effects that can severely affect your ability to do the things you need to do to survive.

Let's say your body temperature now drops below 95 degrees. You are now entering stage two Hypothermia (95-91 degrees). The symptoms include diminished shivering, decreased level of consciousness, and a slower rate of respiration. For the person in water (P.I.W.) without floatation, this is where you are starting to get into very serious trouble. The shivering you experienced in stage one hypothermia has caused you to use up a lot of energy. Once the shivering stops, your body will no longer have the ability to reheat itself. You will be very exhausted and your blood will be restricted from your arms and legs causing you to be unable to maneuver from on-coming waves and swells. You will start gasping in mouthfuls of water and will not be able to stay afloat, thus drowning will eventually occur.

Now move down to the next level. Stage Three (Severe Hypothermia) 91-86 degrees. Symptoms include muscle rigidity and loss of consciousness.

In the hypothermia chart below, you can see the estimated survival time in the water. This will vary from person to person and a lot has to do with body mass. For instance, a thin person would likely succumb quicker than a heavy-set person. The thicker the body mass, the longer the survival time.

The likelihood of dying from hypothermia is slim for a PIWwithout floatation. His cause of death would most likely read; Drowning due to the inability to keep his head out of the water. He drowned, but the drowning was most likely the result of being incapacitated due to the progressive effects of hypothermia.

Even though the chart shows the EXPECTED TIME OF SURVIVAL for a person in 75 degrees water to be from 3 hours to Indefinitely, the "Indefinitely" wording on the Hypothermia Chart is often misinterpreted to mean forever. It actually means that there are too many variables involved to establish a definite value. These variables include items such as; environmental conditions, sea state, the individual's age, overall physical and mental condition, body mass, acclimation to colder water, and ability to slow the loss of body temperature by performing the heat escape lessening position (See HELP & Huddle Below).

32.5Under 15 MinutesUnder 15 - 45 Minutes
32.5 - 40.015 - 30 Minutes30 - 90 Minutes
40.0 - 50.030 - 60 Minutes1 - 3 Hours
50.0 - 60.01 -2 Hours1 - 6 Hours
60.0 - 70.02 - 7 Hours2 - 40 Hours
70.0 - 80.03 - 12 Hours3 Hours - Indefinitely
OVER 80.0IndefinitelyIndefinitely


  1. Not defining, identifying, or precise.
  2. Having no fixed limit or amount.
  3. Too many variables to determine a set value

The water temperature in the Eastern Gulf of Mexico today, April 2007 is averaging around 75 degrees. If you look at the hypothermia chart above, you will see that you can become unconscious within three hours at this temperature.

Now, look at the chart below and determine the annual average temperature of the area that you do most of your boating in. If you take the warmest water (EYW) and average it over 12 months, you come out with an average water temperature of 79 degrees. Warm water that will whisk your body heat away twenty-five times faster than air and is capable of putting you in a dangerous situation. Especially if you are not wearing floatation.

Key West FL(MLRF1)78.3697075788285878786827672
Naples FL78.3666671778286878786817368
St. Petersburg FLN/A626468748084868684787064
Cedar Key FL(CDRF1)N/A586066738084868683766660
Pensacola FL69.4565863717884858682746558
Dauphin Island AL(DPIA1)N/A515360707582848480726256
Grand Isle LA(GDIL1)N/A616164707783858583777065
Eugene Island LAN/A515360687683858582746355

The major heat loss areas are the head, neck, underarms, sides of chest and groin. When you submerge your body in the water you immediately start losing heat throughConvection (the movement of water), and Conduction (coming in contact with anything cooler than the body temperature). Now add the compression caused by the vertical depth of your legs and waist within the moving water (ocean current), and your body core heat is whisked away at a very fast rate.

Conduction from moving water submersion will literally suck your body heat away twenty-five times faster than moving ambient air!

By assuming the Heat Escape Lessening Position (H.E.L.P.) or Huddle position (below), you can protect the vulnerable heat loss areas of your body (head, neck, underarms, sides and groin).

Please take note that this position can only be maintained with the help of a floatation device. Without the floatation, you would have to straighten your legs and kick, exposing your groin area, and move your arms outward to steady yourself, exposing your neck, underarms, and sides. By maintaining the H.E.L.P. position you can extend your survival time by several hours.

I am often asked about life-rafts. Are they necessary in the Caribbean waters? I say absolutely! By removing your body from the water, you increase your chances of survival by over 60 percent! By getting into a canopied life raft, you not only get out of that heat-robbing water, you can also protect yourself from wind and rain while keeping your extended heat loss within the small space of the fully closed life raft.

If your sinking or ditching occurs late in the day, you stand a good chance of an overnight stay. That’s 8-10 hours! A life-raft can be your best friend in this situation. By climbing into a life raft, you will greatly increase your survival time by getting out of the water. You will also increase your target size considerably and you should now have some signaling equipment that may facilitate in your being found and rescued.

Even on land, the life raft will provide a nice bright shelter with insulation from the ground (inflatable floor), a closable tent (canopy), and emergency survival equipment including, first-aid, signals, water procurement, fishing kit, etc.

As the Captain of your vessel, you are trusted to make the right decisions to protect you and your passengers should the unfortunate event happen. Don't let your ego stand in the way of ensuring the ultimate safety for you and your family.

Knowing that hypothermia doesn't just happen up North, and knowing how quickly hypothermia can affect your survival outcome, even in the "warm" waters of the Gulf of Mexico, is reason enough to carry the appropriate gear necessary to keep you and your loved ones safe.

The purpose of this writing is to educate gulf coast over-water travelers about a misconception that if the water temperatures are seventy degrees or above, you cannot succumb to hypothermia. You may last longer, but your ability to fight the waves and keep your head above the surface will be greatly affected.  Don't fall into that "warm water" mentality, believing that you can just sit out there and wait for someone to happen along. I have been involved in many offshore SARs in the Gulf of Mexico, and without floatation, or a way to get up and out of the water, the results are usually not good.

Floatation is required to assume the HELP or Huddle positions.

Credit: BRandy Boone