Cold Water Survival

The first few seconds can be the most dangerous.


When we read about a sailor lost overboard in the storm, we think about PFDs and personal locator beacons, and accept the sea is unforgiving. When we read of novice boaters drowning in a local lake, we’re sad, but say that will not happen us because we wear PFDs. But when we read of a PFD-equipped sailor falling overboard and dying within minutes its a real eye-opener.

Spring sailing in temperate climates still carries the risk of cold water shock. With the water temperature in the low 50s, true hypothermia sets in at about 30 minutes. Swimming can be difficult after about 20 minutes. However, 50 degrees is well below the accepted threshold of shock. Most likely, when the icy water slammed into his face it caused an involuntary gasp. Its hard to recover from inhaling water, even for a strong swimmer.

Originally known as sudden disappearance syndrome, cold water shock has been known since the 1970s. Different from true hypothermia, which results from the body core temperature dropping over a period of 20 minutes to hours, cold water shock is immediate. Being cast headfirst into icy water is one of most severe shocks a human can face, with deadly effects. It is estimated that 20 percent of victims die within 2 minutes.

Physical effects

The instantaneous reflex is a violent gasp, totally unlike the one scary movies strive to cause. This results in a massive in rush of air, which can be fatal if you are underwater. Unlike the controlled plunges of the local polar bear club, where participants walk in via a beach and are attended by rescue swimmers in dry suits, MOB sailors plunge in head first, the result of tripping over the lifeline. Even with an automatic vest, your head will plunge 6 feet underwater before popping to the surface. If the first blast of inhaled water doesn’t drown you, you’ll arrive on the surface gasping and unable to swim and swallowing more. Drowning will typically occur in less than a minute. The initial gasp is followed by several minutes of hyperventilation, making any physical effort nearly impossible. Consequences include the inability to hold your breath or think clearly.

Instantaneous and massive increases in heart rate and blood pressure can cause heart failure in otherwise healthy individuals. Clear thought is impossible. Panic is likely, only serving to increase problems with breathing control and heart rate.

These reactions may appear to an observer as nothing more than panic. Flailing, spastic breathing, muddled thinking, and a racing heart fit the pattern. But victims include experienced sailors and strong swimmers who are not at all prone to panic. If you fall overboard in warm water and reasonable weather, your first concern might be embarrassment over screwing up the race, and later whether the boat would be back in the next half or hour so. It wouldn’t have felt life threatening.

If you survive the first critical seconds, then come the more traditional challenges of cold water exposure. Cold incapacitation and swimming failure begins in 5-20 minutes, the result of failed muscle control. In the absence of a PFD, drowning follows. Death from true hypothermia (cold core) takes considerably longer, at least 30 minutes in very cold water up to a few hours in cool water.

How do you keep this from happening to you? First, don’t fall in. The first line of defense is careful movement and the use of harness and tether systems as described in PS October 2018. If sailing a smaller boat, prone to capsize or swamping, dress for full water immersion. In cool water either a thin wetsuit or dry suit is effective. Once the water temperature drops below about 50F, only a dry suit is suitable. (See PS November 2018 and March 2009.)

If performing high risk activities on larger boats (hiking out, working on the bow, or leaning outboard) a dry suit is the smart option. It is our favorite foul weather gear for stormy conditions in cool weather; more agile than heavy foul weather gear and nary a drop of water will go down your neck. Small wonder is increased in popularity with offshore racers and sailors.

Unfortunately, once the air temperature gets above about 55F, dry suits get steamy, tempting the wearer to open the zipper and defeating the whole purpose. As the water temperature rises into the 50s, we like paddling jackets and dinghy smocks, with snug fitting wrist, neck, and waist seals. Water will sneak in pretty quickly, but shock is reduced and the seals reduce the exchange of cold water. The wearer is also more mobile than in conventional foul weather gear.

Soft shells may also have possibilities. Once our tester found himself in 35F water, with ice around the edges. He was dressed not in foul weather gear or dry suit, but in Wind Blocker fleece tops and bottoms. The saving factors were that the wrist, waist, ankle, and neck closures were all tightly secured; not all soft shells have effective closures. Although very cold, it was more survivable than ordinary foul weather gear.


The last 12 months have been hard on ocean racers. It is more than coincidence cool or cold water was a common factor. In the UK, coldwater shock is considered to be the root cause of most drowning, including non-boating accidents.

We like certain features of manual inflating PFDs; they don’t go off inadvertently and climbing back aboard is easier. But cold water is different. Because of the high probability the wearer will be incapable of action for a minute or more, auto-inflation is the way to go.

We would like to see the makers of foul weather gear take a long hard look at what can be done to improve cold water shock resistance. Conventional jackets and soft shells could be fitted with effective internal neck seals. Wrist and waist seals could be upgraded.

We would like to see race committees post cold water warnings. It is common to require PFDs be worn above a certain wind speed. The race committee should at least recommend that protective gear such as a wet suit or drysuit be worn if the water temperature is below about 55 F. Our level of caution around the rail varies with the risk we perceive, and that level of caution goes way up when the water temperatures go down.

Most importantly, sailors need understand what being thrown face first into cold water feels like and how their body will respond to it. A diehard for traditional foul weather gear? Don’t fall off the boat in cold water, and don’t expect to survive more than a few minutes if you do. Its tough out there.

Tips & Technique
Darrell Nicholson, editor of Practical Sailor, grew up boating on Miami’s Biscayne Bay on everything from prams to Morgan ketches. Two years out of Emory University, after a brief stint as a sportswriter, he set out from Miami aboard a 60-year-old wooden William Atkin ketch named Tosca. For 10 years, he and writer-photographer Theresa Gibbons explored the Caribbean, crossed the Pacific, and cruised Southeast Asia aboard Tosca, working along the way as journalists and documenting their adventures for various travel and sailing publications, including Cruising World, Sail, Sailing, Cruising Helmsman, and Sailing World. Upon his return to land life, Darrell became the associate editor, then senior editor at Cruising World magazine, where he worked for five years. Before taking on the editor’s position at Practical Sailor, Darrell was the editor of Offshore magazine, a boating-lifestyle magazine serving the New England area. Darrell has won multiple awards from Boating Writer’s International, including the Monk Farnham award for editorial excellence. He holds a U.S. Coast Guard 100-ton Master license and has worked as a harbor pilot and skippered a variety of commercial charter boats.


  1. While I agree with the safety concerns in the article the author is misleading readers when he says Jon “disappeared almost immediately”.
    Here’s what is in the Chicago Yacht Club incident report –
    “On July 21, 2018, at approximately 14:26 CDT, Jon Santarelli, slipped overboard from the cockpit of the TP 52, Imedi, as she sailed northeast from the 14:00 start of the Race to Mackinac. The Imedi crew immediately tacked and circled back to Jon’s position in the water, never losing visual track of him, but were unable to stop the boat close enough to retrieve Jon, due to the 20-25 knot winds and 6-8’ seas. They circled again and came closer to Jon on the second attempt, this time with the engine running, but just as they got close to Jon, a wave forced the boat up and over Jon and he went under the boat from starboard to port. Imedi circled a third time, and this time they were able to stop the boat very close to Jon, but as they tossed Jon a line and he raised his arms, he sank below the water and was not seen again. His life jacket, which was reported as set for automatic inflation, never inflated and he was never seen to try to manually inflate it.”

  2. Google “Cold Water Boot Camp” and watch at least the half hour version. In Maine in is routinely shown at Safety at Sea training for fishermen at the Fishing Partnership one and two day sessions. Watching it you will learn the 1 10 1 rule: One minute to get your breathing under control, Ten minutes of useful motion with your hands and arms, and 1 hour before death from hypothermia. Of course these times are dependent on the age and condition of the swimmer and the temp of the water. In Maine, in March, the times are likely shorter for most of us.

  3. I take issue with the statement, “Because of the high probability the wearer will be incapable of action for a minute or more, auto-inflation [PFD] is the way to go.” According to the nautical KISS rule [keep it simple, sailor], a conventional foam-filled PFD, which has no mechanism to malfunction or inspect other than the strap buckles or zipper, is better in cold water because its failure rate is essentially zero.

    • The problem with conventional PFD is the fact that it is clumsy and gets in the way of racing the boat. Actually wearing a PFD is a choice. The auto-inflating PFD is very reliable and at least they will be worn. A dingy vest is another option but again on a large yacht it is clumsy.
      Obviously the choice of wearing is up to the captain. However the MOB procedures this yacht undertook directly impacted the success of recovering the crewman.

  4. After your first paragraph, the article imparts great information. Those of us in Chicago remain sensitive about the accuracy of any report on Jon’s tragedy. Don’t use that paragraph in this article when the Mac report says “The water temperature was about 70 degrees …”. Yes, it was a tragedy, yes, we were all then wondering, and given the destruction of the PFD remain wondering, what happened. But it sure doesn’t seem like either cold water shock in 70 degrees, or hypothermia since the skilled sailors were back twice to try recovery, in demanding wind and seas, in less than 15 minutes. I have a personal opinion, after having read the report, but I will discuss it with shipmates, not broadcast publicly.

  5. Correction. The water temperature in the Chicago Mac race was about 70F. This was correct in the initial publication, but the error crept back in. Thus, it was a poor example, and our apologies for this reporting error.

    Nonetheless, the gasp reflex is a common cause of drowning in cold water areas. This January a Baltimore man jumped in to recover a wayward dinghy and just sank.

  6. This is an example of how incompetence kills your crew.
    The Official Report of this MOB had Mr. Santarelli ALIVE during the third attempt to recover him.
    “Review Committee Report on the
    Fatal Accident Involving Imedi
    During the 2018 Chicago Yacht Club Race to Mackinac
    on July 21, 2018
    Published: February 25, 2019”

    The first attempt to recover Mr. Santarelli FAILED because the Captain never started the engine. With the engine powering the yacht the probability of success increases.

    The Royal Yachting Association does not at all teach ANY recovery under sail as they want to stress the importance of recovery by the best means possible and under sail is not the best, unless you do not have an engine. Recovering an MOB is not the time to test your sailing ability; START THE ENGINE and STOP THE BOAT. Maneuver to the lee of the MOB and recover. You can do all these fancy under sail maneuvers but you are likely going to kill your crewman, START THE ENGINE, STOP THE BOAT, MANEUVER AND RECOVER.

    In my opinion the crew of this yacht was incompetent.

    How often do YOU practice MOB recovery with your crew under adverse conditions?

  7. Of course the really big question still remains. Why wasn’t Mr. Santarelli tethered to the yacht?

    This is also the responsibility of the Captain. If conditions were so poor to impede an MOB recovery then those conditions should caused the Captain to order his crew to tether themselves to the yacht.

  8. Interesting comments. However, I have had a different experience having done frost biting for years.A simple kayak shirt with water proof cuffs and neck worked fine. Typically able to right the boat after capsize.
    On one occasion having succumbed to my wife’s suggestions I bought a dry suit. Hot as hell when racing. After a capsize where the boat was turtled and the mast was stuck in the mud by the chase boat trying to help I ended up swimming to shore. I was near frozen and only upon getting to shore realized my legs were barely workable. That dry suit did nothing to keep me warm. Dry yes. Incidentally, did you ever try to swim with a PFD on? You can’t at least with the type that holds your head above water.
    Norman Kellershon. JY 15, Centerport, NY

  9. I can’t speak to all manner of life vests, but you can swim in the ones I have tried, not very well of course, but short flipper like pushes with your arms and hands. A little better on your back. Try it!


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