Sleep and SeamanshipKrakenSailing
The young racer had been sailing for days without sleep, but he was ahead of the fleet in the Solitaire du Figaro, a grueling, singlehanded race off the coast of France. Sailing into the harbor to the cheers of the crowd, he stepped from his boat onto the wharf to accept their congratulations—then his safety harness jerked him back. There were no crowds, no wharf. He was standing on the gunwale of his boat surrounded by empty ocean. “I’ve heard similar stories from a couple of other sailors,” Damien Davenne, a chronobiologist with STAPS University in Caen, France, told me. “When they are hallucinating, they can’t tell what’s real and what’s not. It is believed that sailors have been lost at sea after stepping off the boat.”
Chronobiology is a young science dedicated to the study of biological rhythms—literally, the biology of time. STAPS university focuses on the science and techniques of sports and physical activities, and many French solo sailors consult its staff to help them manage their sleep while racing. But sleep deprivation is an issue that affects not just racers, but cruisers as well.
In fact, hallucinations are just one symptom of sleep deprivation, and it’s not only singlehanded sailors who go too long without enough sleep. Most cruising boats make ocean passages shorthanded, often with only a husband and wife aboard. Sickness, injury or—the worst case imaginable—the loss of a crewmember can place a heavy load on those still able-bodied. Heavy weather can also overwhelm self-steering systems, requiring a boat be hand-steered. Day and night at the helm, the sleep debt grows.
Finally, there are those times when a heightened watch is necessary, for example, when making landfall or navigating through heavy commercial traffic. In the latter case, the time between an empty horizon and a collision may be only 20 minutes. How then should a sailor deal with the thorny issue of getting enough sleep?
Sleep and Seamanship
Boston-based sailor Jonathan Green has some experience sailing alone. He won the 2013 OSTAR, a singlehanded transatlantic race, and currently campaigns Privateer, a Class 40 ocean racer he sails solo or doublehanded. Green also says he believes that hallucinating or running aground from lack of sleep is poor seamanship.
“You have to point at episodes like that and say, I failed there, I failed at the level of seamanship that I expect of myself,” he says, adding that sailing singlehanded doesn’t absolve a sailor from the obligation to keep a proper watch under the collision regulations (COLREGS) that govern all mariners.
Not that he hasn’t had his share of close calls. Near the end of the OSTAR, for example, only a day’s sail from Newport, Rhode Island, he was crossing Georges Bank, a riddle of shifting sands that pile up on the continental shelf. The wind was light, the fog thick, the current strong, and the bank crowded with fishing vessels. It took 24 hours to cross the shoals. Green’s competitiveness took him to the edge of his ability.
“That was the scariest part for me,” Green says, “the furthest I pushed sleep deprivation.”
In his essay “Freedom of the Seas: The Stoic Sailor,” Kings College philosopher Gregory Bassham notes, “The art of seamanship resides in a clear-eyed grasp of our agency: understanding the fine lines between what we can control, what we can influence but not control, and the vast world that is beyond our control. The annals of exploration and modern recreational sailing are replete with tales of sailors who came to grief from overestimating their agency.”
Signs of Sleeplessness
Lack of sleep is almost inevitable during a long ocean passage, and it has physical consequences, none of them good. Memory failure, difficulty thinking or concentrating uncontrollable mood shifts, poor balance and accidents are all symptomatic.
The U.S. Army has a keen interest in the ability of sleep-deprived soldiers to keep fighting effectively. To this end, a study for the Walter Reed Army Institute of Research found the ability to do useful mental work declines 25 percent for every successive 24 hours an individual is awake. “Sleep deprivation degrades the most complex mental functions, including the ability to understand, adapt and plan under rapidly changing circumstances. In contrast, simple psychomotor performance and physical strength and endurance are unaffected,” the study says. In other words, you can still do the work—you just can’t figure out what work to do.
There’s more. A sleep deprivation study conducted by the University of Bonn found that after 24 hours of sleep deprivation in healthy patients, researchers observed numerous symptoms otherwise attributed to psychosis or schizophrenia. “We were surprised at how pronounced and how wide the spectrum of schizophrenia-like symptoms was,” says psychologist Dr. Ulrich Ettinger. This helps explain why some people get so testy at sea.
Eight hours of sleep every night: every school child has learned the minimum. It’s like a law of nature, except it isn’t, certainly not at sea.
The Mechanics of sleep
“If you sleep too much, you don’t win,” says Dr. Claudio Stampi, director of the Chronobiology Research Institute in Newton, Massachusetts. “If you don’t sleep enough, you break.”
Stampi is the wizard of sleep for singlehanded ocean sailors. His clients include Brad Van Liew, Mike Golding, Joe Harris and Dame Ellen MacArthur, the woman who broke the record for the fastest solo circumnavigation of the globe in 2005. Stampi’s research indicates 4.5 to 5.5 hours of sleep out of every 24 is the absolute minimum to avoid accumulating a sleep debt. However, it doesn’t have to occur all at once.
Sleeping eight hours through the night like your grade school teacher recommended is called monophasic sleep. Breaking that monolithic block of sleep into multiple naps is called polyphasic sleep. Taking frequent naps at sea is nothing new, even if it has a new name. Sailors are famous for falling asleep whenever or wherever they close their eyes. The best length for a nap, however, is a more complicated question and varies individually. In general, Stampi has found the most competitive sailors nap for only 20 minutes at a time, which allows them to frequently check performance and sailing conditions while still getting the minimum sleep. Less than 10 minutes, on the other hand, doesn’t seem to have any recuperative effect.
There’s also a dark side to naps, called sleep inertia. This is the gravity well you have to climb out of when woken at the wrong time. It typically last only a few minutes, but sometimes much longer, and can be a period of profound confusion, disorientation and impaired performance. You feel groggy, clumsy, stupid. You might feel even more tired than when you went to sleep. If you’ve woken to respond to a disaster on deck, the symptoms of sleep inertia can even be life-threatening. Although sleep inertia occurs in fully rested people, its effects are aggravated by sleep deprivation.
The question, then, becomes, “When are you more likely to suffer sleep inertia and how can you avoid it?” The answer, in turn, requires an understanding of the different sleep stages.
There are, in fact, five: 1, 2, 3, 4 and REM (rapid eye movement). Usually, you cycle successively through each of the stages, then begin again. A complete cycle averages 90 to 100 minutes with each stage lasting 5 to 15 minutes.
Stage 1 represents the transition between wakefulness and a light sleep from which you can easily awaken.
Stage 2 is light sleep; the brain waves begin to slow with only an occasional burst of rapid activity.
Stage 3 is the transition between light and deep sleep, a time when slow brain waves are interspersed with smaller, faster waves. Some people experience sleepwalking, night terrors and talking in their sleep during Stage 3.
Stage 4 is deep sleep; slow waves dominate. People awakened from this stage usually suffer some amount of sleep inertia.
REM Sleep is a time when the brain mimics activity during the waking state.
To prevent sleep inertia, avoid waking from slow-wave sleep (Stages 3 and 4) since those are the deepest stages of sleep, the stages when the body recuperates. Waking from slow-wave sleep feels like your head is stuffed with cotton. Better to wake during light sleep (Stages 1 and 2) or even REM sleep.
“A 50-minute nap has more sleep inertia than a 20-minute nap or an 80-minute nap,” Stampi says since, at 50 minutes, you’re usually in Stage 4 sleep. “If you wake up after 40 to 50 minutes, you’re likely to find yourself groggy and unable to understand what’s going on. You’re better off to sleep 20 minutes or 80 minutes.” After 80 minutes, he says, you should be on the backside of slow wave sleep.
In practice, Stampi coaches solo sailors to sleep in clustered naps. Sleep 20 minutes, he advises, wake up, check the boat and the horizon, then go back to sleep. You won’t be fully awake. You don’t have to be. “If you don’t stay awake too long, you’re still on a downward slope,” he says, continuing the sleep cycle started with the previous nap.
As part of his research, Stampi monitored Dame Ellen during her 2000-2001 Vendée Globe, a nonstop 94-day singlehanded circumnavigation, using a pair of Actiwatch sensors to estimate her sleep behavior. In operation, each Actiwatch measures movement through the use of an internal piezoelectric accelerometer. (Certain types of crystals generate a small electric charge when compressed —the piezoelectric effect.) Basically, whenever there’s any kind of movement, the piezoelectric crystal creates a small voltage spike, which is recorded by the Actiwatch’s internal microprocessor.
MacArthur wore one of the sensors. The other was placed on the boat. Data from the two sensors was then transmitted by satellite to Stampi’s Chronobiology Research Institute, where the boat’s data, filtered from MacArthur’s data, creating an approximation of MacArthur’s time at rest and, presumably, asleep.
Further analysis showed that over the course of the race she averaged 5.7 hours of sleep per day. Her longest period of uninterrupted sleep was 2.7 hours. Her longest period of uninterrupted wakefulness was 18.5 hours. She averaged 9.4 naps per day, 72 percent of them in clusters of three or more. Her average nap was 36.6 minutes. MacArthur was 24 years old at the time, the youngest entrant ever in that grueling race. She placed second.
“One of the major limitations of occasional napping is that sleep is allowed only after a more or less pronounced amount of sleep debt has been accumulated,” Stampi says he discovered in a field study of 99 sailors in single- and doublehanded ocean races. He adds, though, that “such sleep-deprived individuals are likely to be more sensitive to further sleep loss.”
Beyond that, while not everyone can adapt to ultra-short naps there is evidence it can be learned. In fact, practicing a sleep schedule ashore greatly help to avoid the initial sleep debt many sailors experience early in a passage.
To this end, Jonathan Green recommends not just experimenting with your sleep but logging the results. “Start with a half hour or a 90-minute nap,” he suggests. “Keep notes when you come out of your sleep, as soon as you wake up. Write down on a scale of 1 to 5 what you think your drowsiness level is, then make some adjustments. Sleep for 35 minutes and then sleep for 45 minutes. Sleep for an hour and 35 minutes or an hour and 45 minutes and do the same. Build up a data set of your level of drowsiness after certain sleep intervals and figure out what works for you.”
Before his first long singlehanded race, Green says he practiced napping at his office. Every day at noon he would close his office door, roll out a mat he kept beneath his desk and go to sleep. “Or try to go to sleep,” he says. “That was another interesting feature, how long did it take to go to sleep. What was my sleep ritual?” (Some sailors wear eye shades. Some brush their teeth and read a book.) “Learning your sleep ritual…can help you go to sleep in the quickest possible time frame,” Green says.
Of course, if polyphasic sleep is so efficient and frees up so much time why don’t more people do it ashore? Think about all those things you could do instead of sleeping! Unfortunately, while many people have tried it, they usually end up abandoning the practice out of boredom or loneliness. Having to nap every few hours can get to be pretty disruptive. And all those extra hours you’re awake at night? No one else is, so where’s the fun in that?
Dangers of Exhaustion
Hallucinations are not all you have to deal with. Take the experience of famed solo sailor Jean-Luc van den Heede, winner of the recent Golden Globe race. In 1995, van den Heede was nearing the end of the BOC Challenge leg between Cape Town and Sydney after sailing 6,700 nautical miles alone across the Southern Ocean. He was tacking the 60ft Vendée Enterprises through the Bass Strait between Australia and Tasmania, a body of water twice as wide as the English Channel and twice as rough, complicated by commercial traffic and strong currents. He had been awake for three days and was exhausted. “I had just passed Black Point and tacked. I had five minutes with nothing to do, so I put my head on a winch. Half an hour later, when I woke up, I was on the beach,” he said afterward.