cold water survival while yacht racing
cold water survival while yacht racing

At MySail, we’re passionate about helping yacht owners and sailors get out on the water more often and enjoy the pleasure, excitement and camaraderie of sailing. However, we also want to promote safety in our our sport to make sure everyone can continue to enjoy it for years to come. To do this, we have partnered with Marine Safety Expert John Dalziel to share information on safety risks, prevention and response. Our first post in this series focuses on the effects of cold water and strategies to survive cold water immersion:

“It is impossible to get hypothermic in cold water unless you are wearing flotation, because without flotation – you won’t live long enough to become hypothermic.”

Mario Vittone (Maritime Safety Consultant and USCG Rescue Swimmer) wrote the above regarding the dangers of falling into cold water without wearing a suitable flotation device.

Records of death from immersion in cold water date back to ancient times. Circa 450 BC, Herodotus 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.

Even if you believe you are healthy, athletic, and a very strong swimmer, authorities ranging from Canada, the USA and Britain to Australia emphasise this may likely not be enough to save you if you fall into the water without wearing a flotation device – particularly if the water is 15 degrees C, or below.

Hypothermia is believed by many to be the greatest danger if you fall into cold water. In reality, a large proportion of those who die do so before the effects of hypothermia set in. The greatest hazard is the body’s initial reaction to immersion. “Short of being hit by a bus or struck by lightning, cold shock is one of the biggest jolts that your body can experience. If you gasp underwater, you will immediately drown.”

Fight your instincts, not the water’ to help stay alive. Cold water survival expert Professor Mike Tipton explains: “We often rely on our instincts but our instinctive response to sudden immersion in cold water – gasping, thrashing and swimming hard – is potentially a killer. It increases chances of water entering your lungs, increases the strain on your heart, cools the skin further and helps air escape from any clothing, which then reduces buoyancy. Although it’s counter-intuitive, the best immediate course of action in that situation is to fight your instinct and try to float or rest, just for a short time. The effects of cold water shock will pass quite quickly, within 60–90 seconds. Floating for this short time will let you regain control of your breathing and your survival chances will greatly increase. (References 6 – 10 below provide further information, as well as several interesting and informative videos).

The effects of cold water come in three phases. University of Manitoba professor and cold water expert Dr. Gordon Giesbrecht coined the phrase 1-10-1 to describe the three critical phases of cold water immersion.

1-10-1 is a simple way to remember the first three phases of cold water immersion and the approximate time each phase takes. The US Coast Guard Auxiliary describes the stages and their effects as follows:

Phase 1 – the Shock factor that creates the gasp factor and makes our breathing shallow and irregular. If the gasp factor causes us to inhale under water, it at minimum will cause shortness of breath, and the worse-case scenario is we inhale and fill our lungs. So in the first minute, we try to not, if possible, fully immerse our head and MOST importantly try to get our breathing under control.

Phase 2 – Incapacitation. No matter what swimming skill level, the cold water is going to impact our muscle movement and our ability to have the impulses that give the signal from the brain to have our legs and arms move. As always there are a lot of factors, such as actual water temperature, physical condition, etc., but figure you will have 10 minutes of meaningful movement. So, can you make it to shore or is your best bet to stay with your boat and try to get as much of your body as you can out of the water? Remember: 10 minutes before all the blood is drawn back to your core and you lose control of arm and leg movement.

Phase 3 – Hypothermia, which is the reduction of the body’s vital core temperature resulting in unconsciousness. Most of your body core heat loss will be through your head, neck, sides, shoulders and groin. In water temperatures less than 40 degrees F (4 degrees C) , you have roughly 1 hour.

and then:

Phase 4 – Post Rescue Collapse due to the stress on your heart – ALWAYS call Emergency Medical Services.

Vittone writes: “I lost count of the number of survivors I annoyed in the back of the helicopter because I wouldn’t let them move.  I had a rule – if they came from a cold water environment – they laid down and stayed down until the doctors in the E.R. said they could stand.  It didn’t matter to me how good they felt or how warm they thought they were. Because the final killer of cold water immersion is post-rescue collapse. Hypothermia does things besides making everything colder. Victims are physiologically different for awhile. One of the things that changes is called heart-rate variability. The heart’s ability to speed up and slow down has been affected. Getting up and moving around requires your heart to pump more blood, being upright and out of the water is also taxing, then any number of other factors collide and the heart starts to flutter instead of pump – and down you go. Victims of immersion hypothermia are two things; lucky to be alive, and fragile. Until everything is warmed back up – out of the water and dry is good enough – mobility comes later.”

In Sea Kayaker Magazine Dr. Chris Brooks wrote: “Cold shock has been observed in people sensitive to cold at water temperatures as high as 77˚F (25˚C). In water below 60˚F (15˚C), the effects of immersion become significantly life-threatening to everyone. The lower the temperature, the more severe the symptoms. The effects of cold shock are completely out of your conscious control. If you don’t protect yourself from cold water, they will happen to you whether you like it or not. If you really don’t believe that it will affect you, the next time you take a shower, turn the cold water on full blast and aim it at your belly button. You will soon be a believer. Swimming failure is caused by rapid cooling of the muscles and nerves and can kill within about 5–30 minutes after immersion. It is much more common than you’d think. Newspaper reports about drownings often mention that the victim was “an outstanding swimmer, yet he only swam 50 yards and drowned.” Your swimming ability in warm water bears no relationship to your swimming ability in cold water.

People ‘enter’ the water for a wide variety of reasons:  intentionally (swimming, diving), and unintentionally (man-overboard, as a result of a vessel sinking or kayak capsizing, slipping off rocks or falling from a dock, the list goes on).  Offshore sailors are generally well-prepared for man-overboard situations, Sunday sailors often less so. Either way, understanding how your body is likely to react to a cold water immersion, and understanding how to manage your body’s natural response, will help you survive.

People who ‘fall into the water’ (about 25% of total ‘drowning’ fatalities in SW England) are almost totally unprepared to maximise their chance of survival. Here is a recommendation from the Royal National Lifeboat Institution:

Extend your arms, legs and life expectancy. Floating is not an easy skill in cold open water but most people can float, and the air trapped in their clothes as they fall in should make it easier. As little exercise as necessary can be undertaken to help stay afloat. The recommended floating position is to lean back in the water and keep your airway clear. Keeping calm will help maintain buoyancy. Some people find it helpful to gently scull with their hands and kick their feet to keep afloat. The main principle is to do as little as possible until you have control of your breathing. At this point you have a much better chance of avoiding drowning and surviving until you can swim to safety, call for help, or continuing to float until help arrives.

It is obvious why the concern about cold water immersion is important in countries such as Canada and Britain. However, even in Australia, it can be a concern. Australian water temperatures, even in December, in areas such as the Bass Strait and around Hobart are not much above the ‘cold water’ (15 C) threshold – in August many other ports are near or even below this temperature. Also, as Dr Brooks has pointed out, ‘cold water shock’ may be experienced in some people in temperatures as high as 25 C.

This edition of Mainsail looks at the effects of cold water on the body, and a real life example of someone who experienced a man-overboard in the Tasman Sea, and lived to tell the tail.

This article is intended as general information only, to make you aware of some of the hazards so that you can seek additional advice on how to prepare for emergencies. You could discuss these issues with more experienced sailors in your yacht club, and a great deal of information and training is available from sources, such as yachting/ boating associations, rescue and life-saving organisations and government agencies. Finally, you should enjoy your time on, and near the water – it can provide some of life’s greatest experiences. However, if things do go wrong, awareness and preparation could minimise the chances of an incident becoming a tragedy.

John Dalziel, P.Eng., is a naval architect, marine engineer and surveyor, and marine safety inspector based in Halifax, Nova Scotia, Canada.  With half a century of experience in the marine industry, he has sailed with the Canadian Coast Guard in the Arctic, and with the fishing industry, and has supervised the construction and refit / repair of many vessels. In the regulatory agency Transport Canada Marine Safety he was the Coordinator of the Atlantic Region Small (Commercial) Vessel Inspectors.  He has spoken internationally on maritime safety issues, and is currently an Adjunct Professor in the Dept of Industrial Engineering, Dalhousie University, Halifax, Canada.


(1) The Truth About Cold Water, Mario Vittone
(2) Cold Water Bootcamp, Dr Gordon Giesbrecht
(3) Perils of Cold Water, Gene Little, Commander, U.S. Coast Guard Auxiliary
(4) National Centre for Cold Water Safety
(5) Sea Kayaker – Cold Shock and Swimming Failure, Chris Brooks
(6) Cold Water Shock: A Bolt from the Blue, RNLI
(7) Respect the Water, RNLI
(8) How long can you survive in freezing water?, Mainsail
(9) RNLI says ‘fight your instincts, not the water’ to help stay alive, RNLI
(10) Cold Water Shock, RNLI
(11) Australian Sea Water Temperatures
(12) Marine Safety Victoria
(13) Transport Canada – Survival in Cold Waters – TP13822- Dr Chris Brooks