diving | John Clarke Online

The Sojourner’s Dilemma; You Have to Go Home Sometime

There are sports, there are professions, then there are sojourns.

Astronauts are sojourners, as are pilots and mountain climbers and underwater divers. While the sojourner may have carefully planned his sojourn, warding off potential trouble by using good equipment and training, it is the return to normalcy that oftentimes presents the greatest and most unexpected danger.

Mountain climbers who reach the top of their mountain, don’t always make it safely back down. Astronauts reentering the atmosphere understand the risk of return all too well.

For scuba divers, return to the surface can be accompanied by decompression sickness and air embolism. When diving in cold water, the very act of rising towards the surface can induce a scuba regulator to free flow, spilling a precious gas supply.

For pilots the sojourn can end badly on landing. This fact has been in the news lately, where seemingly inexplicable crashes occurred in large transport aircraft. I shake my head and wonder why, knowing full well that once you take a sojourn for granted, it can devour you. I also know full well that I am not immune.

I was recently reminded of that during a short 34-mile flight returning a retractable gear aircraft from maintenance back to my home base, Panama City, FL. Most pilots know that, ironically, aircraft maintenance can be risky. While maintenance on diving equipment or airplanes is certainly a critical part of safe operation, at the same time it is an opportunity for a mechanic to inadvertently damage a critical component.

Snapshot gear light — Gear lights: one light is not glowing.

I have seen a maintenance-related failure of a scuba regulator, and I was about to see it with my aircraft as I followed a business jet towards a landing at our local airport. To keep traffic flowing smoothly I kept my speed up on approach until close to the runway. When I finally slowed enough to drop the landing gear I saw two green “gear safe” lights rather than the expected three. My main gear seemed to be down and locked, but the nose wheel lock indication was not glowing that reassuring green.

“Tower, I have a problem with my gear. I need to leave the area and sort out the problem.”

I left the airport airspace and spent a full hour burning fuel, running through all emergency checklist items, pulling G’s to help the gear lock down and waiting for a Southwest Airlines flight to arrive. The local airport, which receives quite a bit of commercial jet traffic (Delta and Southwest) only has one runway. If my gear collapsed on touch-down, that single runway would have been shut down for an hour or more, and arriving flights would have to land elsewhere. There are not a lot of good alternate airports near Panama City.

The sun was getting low, and I did not want to make that landing at night. Besides, my wife was below, waiting anxiously for whatever was going to happen. She was due to pick me up at the hangar, but she and I both knew the aircraft might not make it far past the touchdown point on the runway.

After flying past the tower twice and having them inspect the gear with binoculars, the tower controller said the gear looked down, but I knew there was no way to tell if it was down and locked. If the nose gear was not locked, it would collapse on landing.

Fortunately I was alone in the cockpit so I could come to grips with what I was about to do without the distraction of worried passengers. I announced my intentions to land, and on my last circuit of the field I saw the crash rescue truck and fire truck pulling into position along the runway. That was a sight no pilot ever wants to see.

As I turned towards the runway I reviewed the landing checklist one last time, and then I was ready. As I turned final it was time to get it over with. Whatever would happen would happen, and there was nothing more I could do about it.

Approaching the runway and ready to land, my mind was focused on only one thing — making the landing as smooth as possible.

The main wheels squeaked as they touched the concrete, ever so gently, and with steady back pressure on the yoke I kept the nose high, sparing the nose gear as long as possible as the plane slowed.

When gravity overcame the aerodynamic lift on the nose, the wheel settled to the runway — and rolled.

My first word to the tower was, “Thank God!”

“Indeed”, they replied. They had been holding their breath as well, as they later told me.

The next day when the mechanics drove in, it only took them five minutes to adjust a tab on the nose gear down-lock switch. Such a simple fix for such a lot of drama.

Now that I’ve had time to reflect on the incident, I’ve come to appreciate the valor of the silver-suited firefighters who approached me after the landing, the firefighters who are prepared to thrust themselves into the flames to rescue those whose sojourns have gone awry. I was also appreciative of the calm-voiced air field controller whose only weapon against calamity was the calm tone of his voice.

Calm is a good thing when you’re trying to land a plane with all the tenderness of putting a candle on a birthday cake.

The Siren’s Call of Rebreather Oxygen Sensors

In Greek mythology irresistibly seductive female creatures were believed to use enchanted singing to beckon sailors to a watery grave.

Why this myth endured through the centuries is difficult to say. However, my theory is that it helped explain to grieving widows and mothers why ships sometimes inexplicably disappeared, taking their crew with them, never to be seen again. By the reasoning of the time, there must have been some sort of feminine magic involved.

The oxygen sensors in closed-circuit, electronically or computer-controlled rebreathers are a magic device of sorts. They enable a diver to stay underwater for hours, consuming the bare minimum of oxygen required. The only thing better than a rebreather using oxygen sensors would be gills. And in case you wondered, gills for humans are quite impractical, at least for the foreseeable future.

I have written, or helped write three diving accident reports where the final causal event in a rebreather accident chain proved to be faulty oxygen sensors. So for me, the Siren call of this almost magical sensor can, and has, lured divers to their seemingly blissful and quite unexpected death.

Those who use oxygen sensors know that if the sensor fails leading to a hypoxic (low oxygen) state, loss of consciousness comes without warning. If sensor failure results in a hyperoxic state (too high oxygen), seizures can occur, again leading to loss of consciousness, usually without warning. Unless a diver is using a full facemask, loss of consciousness for either reason quickly leads to drowning.

EX19 — EX 19 rebreather (U.S. Navy photo)

Due to the life-critical nature of oxygen control with sensors, three sensors are typically used, and various “voting” algorithms are used to determine if all the sensors are reliable, or not. Unfortunately, this voting approach is not fail-proof, and the presence of three sensors does not guarantee “triple” redundancy.

In one rebreather accident occurring during the dawn of computer-controlled rebreathers, a Navy developed rebreather cut off the oxygen supply to a diver at the Navy Experimental Diving Unit, and all rebreather alarms failed. The diver went into full cardiopulmonary arrest caused by hypoxia. Fortunately, the NEDU medical staff saved the diver’s life, aided in part by the fact that he was in only 15 feet of water, in a pool.

In two more recent accidents the rebreathers kept feeding oxygen to the diver without his knowledge. One case was fatal, and the other should have been but was not. Why it did not prove fatal can only be explained by the Grace of God.

The two cases were quite different. In one the diver broke a number of safety rules and began a dive with known defective equipment. He chose to assume that his oxygen sensors were in better shape than the rest of his rebreather. If he had been honest with himself, he would have realized they weren’t. If he had been honest with himself, he would still be alive.

The other dive was being run by an organization with a reputation for being extremely safety conscious. Nevertheless, errors of omission were made regarding oxygen sensors which almost cost the experienced diver his life.

In the well-documented Navy case, water from condensation formed over the oxygen sensors, causing them to malfunction. The water barrier shielded the sensors from oxygen in the breathing loop, and as the trapped oxygen on the sensor face was consumed electrochemically the sensor would indicate a declining oxygen level in the rig, regardless of what was actually happening. Depending on how the sensor voting logic operated, and the number of sensors failing, various bad things could happen.

During its accident investigation, when NEDU used a computer simulation to analyze the alarm and sensor logic, it found that if two of the three sensors were to be blocked (locked) by condensed water, the rig could lose oxygen control in either a hypoxic or hyperoxic condition. Based on a random (Monte Carlo) sensor failure simulation, low diver work loads were more often associated with hypoxia than higher work rates, even with one sensor working normally.

We deduce from this result that “triple redundancy” really isn’t.

The white circles at the top left of this scrubber canister housing are the three oxygen sensors used in an experimental U.S. Navy rebreather.

When the accident rig was tested in the prone (swimming) position at shallow depth, after 2 to 3 hours sensors started locking out, and the rig began adding oxygen continuously. The computer simulation showed that the odds of an alarm being signaled to the diver was only 50%. The diver therefore could not count on being alerted to a sensor problem.

Unfortunately in this near fatal case the rig stopped adding oxygen, the diver became hypoxic and the diver received no alarms at all.

After NEDU’s investigation, the alarm logic was rewritten with a vast improvement in reliability. The orientation of the sensors was also changed to minimize problems with condensation.

Today what is being seen are divers who extend the use of their sensors beyond the recommended replacement date. Like batteries, oxygen sensors have a shelf-life, but they also have a life dependent on use. Heavily used sensors may well be expended long before their shelf-life has expired.

the-siren — The Siren, by John Williams Waterhouse.

Presumably, the birthing pains of the relatively new underwater technology based on oxygen sensors have now passed. Nevertheless, those who use rebreathers should be intimately familiar with the many ways sensors, and their electronic circuitry, can lead divers ever so gently to their grave.

Like sailors of old, there are ways for divers to resist being lulled to their death by oxygen sensors. First among them is suspicion. When you expect to have a great day of diving, you should be suspicious that your rebreather may have different plans for you. Your responsibility to yourself, your dive buddies and your family is to make sure that the rebreather, like a Siren, does not succeed in ruining your day.

The best way to ward off sensor trouble is through education. To that end, Internet sites like the following are useful. Check with your rebreather manufacturer or instructor for additional reading material.

http://rebreathers.es/celulas%20o2/celulas%20o2.htm

http://www.rf30.org/

http://www.deeplife.co.uk/or_files/DV_O2_cell_study_E4_160415.pdf

Margin of Safety

A diver’s breathing equipment, helmet, gas bottle, umbilicals and buoyancy compensator lie stretched out on the grey concrete floor. The diving gear has a look of sadness about it. Perhaps that equipment will tell a story of why its owner is dead, but usually it does not.

3477572378_fa6d16e282 — Storm clouds from 30,000 ft. Photo by Wendell Hull.

In another part of the world the NTSB catalogs the fragments of an airplane shredded by the elements and thrown in a heap back to earth. The only good thing to come from an aircraft accident is that usually there are enough clues from wreckage, radio recordings, radar returns and weather reports to piece together a story of the end of life for pilot and passengers.

It’s always the question of “Why?” that drives any investigation.

Perhaps it is the knowing of how death comes, so unexpectedly to surprised souls, that makes it just a little bit easier to make the mental and emotional connection between an interesting moment and a deadly moment. If that is true, and I believe it is, then the telling of such macabre stories can be justified. It is not a telling through morbid interest, but a sincere belief that by examining death closely enough we can somehow force it to keep its distance.

That may be foolish thinking, but humankind seems to have a hunger for it, that esoteric knowledge, so perhaps it is a truism. Perhaps we sense instinctively that the knowing of something makes it less fearsome.

Being a student of diving and diving accidents, I know full well how unexpected events can make you question what is real and what is not, what is normal and what is abnormal. Without practiced calm and reasoning, unexpected events can induce panic, and underwater, panic often leads to death. That is also true for aviation.

The best preventative for panic is a realistic assessment of risk. Risks are additive. For instance, flying in the clouds is accompanied by a slight degree of risk, but with a properly maintained airplane, with a judicious use of backup instruments and power supplies, and with recent and effective training, that risk can be managed. In fact, I delight in flying in clouds; it is never boring, and I know that I am far safer than if I had been driving on two lane roads where the potential for death passes scant feet away every few seconds.

Flying at night is another risk. If something were to go terribly wrong, finding a safe place to land becomes a gamble. On the other hand, seeing and avoiding aircraft at night is simple because of the brilliant strobe lighting which festoons most aircraft. For me, the beauty, peace and calm air of night flight makes it well worth the slight risk.

41xhiFRnOJL — Garmin NEXRAD Weather display.

Technology has made weather flying safer and, I have to admit, more enjoyable. The combination of GPS driven maps and NEXRAD weather has made it almost impossible to blunder into truly bad weather. During the daytime, my so-called eyeball radar helps to confirm visually what NEXRAD is painting in front of me. If it looks threatening, it probably is.

Unlike aircraft weather radar, virtually every pilot can afford to have NEXRAD weather in the cockpit. And unlike aviation radar, NEXRAD can see behind storms to show the view 100 miles downrange, or more. Having often flown in stormy weather without benefit of NEXRAD, I truly rejoice in the benefits of that technology.

I routinely fly with not only NEXRAD, but also a “Storm Scope” that shows me in real time where lightning is ionizing the sky. Those ozone-laced areas are off-limits to wise aviators. But sometimes even a Storm Scope is not enough to keep the willies, or as some call it, your spidey sense, from striking. (Presumably spiders are not particularly cerebral, but they are pretty adept at surviving, at least as a genus and species.)

I was recently flying around stormy weather, carefully avoiding the worst of it, and maneuvered into a position that would provide a straight shot home with yellow tints showing on the weather screen, suggesting at most light to moderate precipitation. I had flown that sort of weather many times; it usually held just enough rain to wet the windshield.

However, my internal risk computer made note of the following factors: we were in the clouds so if weather worsened I wouldn’t see it. Night was approaching which markedly darkened the wet skies we were beginning to enter. The clouds and darkness conspired to make useless my eyeball radar. In addition, the Storm Scope was unusually ambiguous at that moment. I thought it was confirming a safe passage home, but I could not be 100% certain.

On top of that, the FAA recently warned that NEXRAD signals can be considerably more delayed than indicated on the weather display. The device might say the data is 2 min old, but the actual delay could be 10 minutes or more. In other words, the displayed image could be hiding the truth.

Airborne_weather_radar_NASA — Aircraft weather radar.

Planes have been lost because of untimely NEXRAD data. For that reason there is a philosophical difference between NEXRAD and true radar. On board weather radar is said to be a tactical weather penetration aid, and NEXRAD is a strategic avoidance asset. My gut told me that at that moment in airspace and time the boundaries between those two uses, tactical and strategic, were getting fuzzy.

It is times like that when an awareness of the slim margin between a safe flight or dive, and a deadly flight or dive, becomes a survival tool. In this case, I and many other experienced pilots have made the call to turn around and land. Unfortunately, the record and the landscape is littered with the wreckage of those who chose otherwise.

They forgot just how thin the margin of safety can be.

Capture — The flight (green line) from Cobb County Regional (KRYY) to Panama City (KECP) was interrupted by a stop at Montgomery AL.

Carbon Dioxide – The Diver’s Nemesis Pt. 1 (Meduna’s Mixture)

Of all the gases humans excrete, the most bountiful, and arguably the most deadly, is exhaled carbon dioxide.

There is a forgotten bit of American medical history that reveals the bizarre features of the toxicity of carbon dioxide. In 1926, before the advent of modern psychiatric medications, some American psychiatrists began experimenting with the use of inhaled carbon dioxide for the treatment of schizophrenia and psychoses. At the time, there were no effective treatments other than electroshock.

One of the most successful of these researchers was Dr Ladislas J. Meduna, a Professor of Psychiatry at the University of Illinois College of Medicine in Chicago.

High levels of carbon dioxide (CO₂) did in fact have some success in treating schizophrenia, but it also produced Out of Body (OBE) and seemingly spiritual experiences. The following text is quoted from a book called Carbon Dioxide Therapy. A Neurophysiological Treatment of Nervous Disorders, published in 1950 and authored by Meduna.Meduna administered by mask between 20 and 30 breaths of a gas mixture of 30% CO₂, 70% O₂. From pg. 22 of his book we find,

“Any attempt to define the sensory phenomena during CO₂ anesthesia, in terms of dream, hallucination, illusions, etc., would be futile. The actual material would support any hypothesis. Some of the sensory phenomena would direct us to define them as hallucinations. Some of these phenomena are felt by the patients as “real dreams”; others obviously are dreamy repetitions of real events in the past or of past dreams. I believe therefore that any classification of these phenomena in terms of dream or hallucination would be not only meaningless, but directly misleading; the patient is not “sleeping” in the physiological sense, nor is he in the state of consciousness which we usually assume to be present in true hypnagogic hallucinations.”

“One subject, after 20 respirations of the gas, reported seeing a “bright light, like the sun.”

“It was a wonderful feeling. It was marvelous. I felt very light and didn’t know where I was. For a moment I thought: ‘Now isn’t that funny. I am right here and I don’t know whether I am dreaming or not.’ And then I thought that something was happening to me. This wasn’t at night. I was not dreaming. And then it felt as if there were a space of time when I knew something had happened to me and I wasn’t sure what it was. And then I felt a wonderful feeling as if I was out in space.”

“After the second breath” — reported a 29 year-old healthy female nurse who had taken a treatment – “came an onrush of color… then the colors left and I felt myself being separated; my soul drawing apart from the physical being, was drawn upward seemingly to leave the earth and to go upward where it reached a greater Spirit with Whom there was a communion, producing a remarkable, new relaxation and deep security. Through this communion I seemed to receive assurance that the petite problems or whatever was bothering the human being that was me huddled down on the earth, would work out all right and that I had no need to worry.”

“In this spirituelle I felt the Greater Spirit even smiling indulgently upon me in my vain little efforts to carry on by myself and I pressed close the warmth and tender strength and felt assurance of enough power to overcome whatever lay ahead for me as a human being.”

Meduna summarized that preceding case by stating, “In this beautiful experience we can discern almost all the constants of the CO₂ experience: (1) color; (2) geometric patterns; (3) movement; (4) doubleness of personality; and (5) divination or feelings of esoteric importance.”

Meduna went on to admit that “Not all of the sensory phenomena experienced by the patients are of celestial beauty and serenity. Some of them are horrifying beyond description.”

In 1971, Chris Lambertsen, M.D., Ph.D., from the University of Pennsylvania School of Medicine, and considered to be the father of special warfare diving by Navy SEALS, published a careful examination of the physiological consequences of the Meduna mixture. He found that inhalation of 30% CO₂ in oxygen would cause unconsciousness and convulsions within 1-3 min. The precipitating event for loss of consciousness seemed to be a catastrophic increase in the acidity of the blood due to the large amount of carbonic acid produced by the CO₂ inhalation. This raises the possibility that the experiences noted by Meduna were caused by pre-convulsive events within the brain.

Since then the medical community has deemed carbon dioxide “treatments” as not only dangerous but ineffective compared to modern psychiatric medication. Meduna’s mixture is no longer used.

While at the Naval Medical Research Institute, I was my own research subject in a study of the effects of rebreathing CO₂ concentrations up to 8%. That was a carbon dioxide concentration that some Navy SEALS had claimed could be tolerated without impairment.

DSCN7464 — The simplest scrubber canister in the simplest rebreather, Ocenco M20.2

I was not under water, but riding a stationary bicycle ergometer in the laboratory, simulating breathing on a closed-circuit underwater breathing apparatus (in diving vernacular, a rebreather.) Although oxygen was being added as I consumed it, there was no carbon dioxide scrubber (a container of carbon dioxide absorbing material), so the test was examining what happens when a scrubber canister is no longer functioning properly. At 7% inspired CO₂ I stopped the exercise, feeling a little abnormal. However, I was surprised at how unimpaired I seemed to be; that was, until I attempted to dismount the ergometer. I almost fell and needed help removing myself from the bicycle to a chair.

The single-minded and simple-minded task of exercising had hidden a growing central nervous system impairment. Like someone intoxicated with alcohol, I could not judge my level of impairment until a task requiring some coordination was required.

So we see that high levels of carbon dioxide intoxication can lead to profound disturbances of the central nervous system. In upcoming posts we’ll see how elevated carbon dioxide levels and the control of respiratory ventilation can interact to put rebreather divers at risk.

Much of the above is from a nonfiction book project currently under review. The working title for the book is “Collected Tales of the Spiritual and Paranormal.”

Children of the Middle Waters

Children of the Middle Waters (working title) is a science fiction/thriller that has been completed and is being submitted today for consideration by Tom Doherty Associates, New York. My friend and mentor, the writer Max McCoy, has provided literary criticism and encouragement for the manuscript. Max, who works primarily in the Western genre, wrote a diving-related thriller called The Moon Pool, which happens to involve in its closing chapter the Navy Experimental Diving Unit, and someone a lot like me.

Below is a blurb briefly describing Children of the Middle Waters.

In the deep-sea canyons and trenches of the Earth lie thousands of alien spacecraft and millions of their inhabitants who have to leave soon or risk being stranded forever, or being destroyed. Due to their physiology they have been unable to directly contact humans, but they are adroit at mental contact and remote viewing, when it suits them.

They need the help of two humans to assure their safe escape, an experienced Navy scientist and a beguiling graduate student. But introductions through mental means are slow and suspect, as you might imagine.

The U.S. government is well aware of this deep sea civilization, and is desirous of the weapons the visitors possess, which puts the two unsuspecting scientists in the middle of a conflict between powerful
military forces and powerful intergalactic forces. Things could get messy.

Even worse, jealous friends turn on the unlikely duo and put their lives at risk.

Children combines two separate Native American beliefs and legends with current events. It is a complex thriller with science fact and science fiction mixed in with military action and government intrigue. Also revealed are romantic possibilities that far exceed the capabilities of the mundane, everyday world.

Early American Indian beliefs create an ending for this story that no one could anticipate. It is an ending that causes the protagonist to realize everything he has held dear is wrong, in one way or another. At the same time he discovers a reality that is the greatest blessing that man can receive.

Divers In Space

Signs of flowing water have been found on Mars. http://www.nytimes.com/2011/08/05/science/space/05mars.html?_r=1

That of course makes Mars even more tantalizing than it is already.

Now Mars has been added to a growing list of bodies in our solar system that are believed to have water, and in some cases entire oceans. Let me be so bold as to pronounce, where you have water, you will eventually need divers.

I once attended a joint NASA – Diving Conference at Disney World in Orlando. It was largely devoted to discussions of the science and engineering that would be required to send men and women to Mars and to sustain them in a colony. I was presenting a diving related talk at the invitation of one of the editors of the Life Support & Biosphere Science journal, a short-lived scientific journal that reported on the science conducted in Biospheres and other life-support systems.

After hearing a number of fascinating NASA accounts, I talked about a rather arcane subject: A Priori models in the testing of diving life support equipment. That work was published in 1996. At the end of the talk, a NASA engineer asked, somewhat smugly I felt, how diving had anything to do with space.

Well, that wasn’t at all the purpose of the meeting, or the reason why I was talking. The organizers believed, correctly, that sojurns in space and underwater share elements in common; namely, people and breathing equipment. We could, and should, learn from each other.

Now, regarding the question: I can ad lib with the best of them. Knowing that Jupiter’s moon Europa was believed to be hiding a large ocean beneath its icy surface, I responded that someday astronauts will be carrying a dreadfully expensive piece of hardware to an alien moon or planet with water, and that priceless tool will get dropped — into the water. It happens all the time on Earth.

Now what? You can’t go on-line, order a replacement, and expect an overnight FedEx shipment. That is when a space diver would be worth his Earth-weight in rhodium.

enceladus-large — Saturn's moon Enceladus

Since that time, we’ve learned that Saturn’s moon Enceladus jets water from its south pole. As reported in the journal Icarus, that suggests that, like Europa, there may be a liquid ocean beneath the moon’s icy crust.

My suspicion is that long before we’ll need cowboys in space, we’ll need divers in space.

So divers, keep your diving helmets oxygen clean. You may get the call any day now.

Outsmarted by an Octopus

Jim Duran and I started a night dive in about sixty to seventy feet of water several miles off the beaches of Panama City, FL. I was wearing double 80 tanks, held a collecting bag and lights, and fully intended to capture an octopus, alive.

At the time I was working in an invertebrate physiology laboratory at Florida State University, under the mentorship of Dr. Michael Greenberg. I had been impressed by the reputed high intelligence of the octopus and was also interested in the effects of high pressure. The Navy base at Panama City had a new high pressure chamber, capable of simulating deep-sea pressures. Since I was in training in the combined Navy and NOAA program called the Scientist in the Sea, it seemed logical to me to catch an octopus and study it to see if it would be a suitable candidate for testing in the Navy’s giant hyperbaric chamber.

Navy Experimental Dive Unit, Panama City, Florida

It sounded like a reasonable plan to me, and Jim Duran was willing to follow along as my assistant critter catcher. And to begin with, the plan worked. We spied our quarry only a few minutes into the dive. The gray-brown octopus was crawling over the sandy bottom and initially seemed unaware of our intentions. But as the two of us closed in on him, specimen bag flapping in our self-generated current, he sprang off the bottom and squirted away.

But we were strong swimmers, and our quarry was in the open, maybe eight feet off the bottom. He had nowhere to hide – silly thing. Keeping our lights on him, and stroking like mad, I began gaining on him, at which time he let loose with his ink. I was prepared for that, and continuing to kick I soon caught up with him and got my hands on him, trying to stuff him into my bag. But he would have none of that.

Off we went again. What we didn’t realize was that the clever invertebrate was constantly turning to our right. We of course were too intent on capturing him to notice his strategy. And besides, invertebrates were incapable of strategic planning – or so we thought.

Apparently, the octopus was determined not to be touched again, or else we were tiring, for we never quite caught up with him. So close, and yet so far away.

And then a curious thing happened. He collapsed his tentacles upon themselves, streamlining his body shape, and shot like a rocket from our depth to the sandy bottom. Once on firm ground again, he spread his tentacles as wide as he could, and his entire body turned white. I froze in shock.

In another instant, before I could recover my senses, he collapsed his body down to the width of an apple and slithered into his hole in the sea floor.

He was gone.

It didn’t take long for us to realize that the chase had started near his home, and he had led us at a furious pace in a large circle, which ended precisely where it had begun. He had maneuvered us to within striking distance of safety.

Humbled, and now growing low on air, and embarrassingly empty-handed, we headed back to the off-shore platform where our dive had begun.

It had seemed like such a good idea. Who knew that two graduate students would be outsmarted by an invertebrate.

Below is a link to a video showing an octopus’ ability to disguise itself, and some of the defensive behavior we witnessed.

Purple octopus photo by Diane Picchiottino on Unsplash

My Top Three Diving Sites: The Red Sea Pt. 2

I was one little inch away from BIG trouble.

Twenty kilometers north of Sharm el-Sheik are four current-swept reefs that attract Red Sea divers and bountiful sea-life alike. We left for the dive site from Ras Nasrani, heading for Thomas Reef, in the middle of the current-swept Straits of Tiran.

Thomas Reef is the smallest but most popular reef for diving. Because of the current, it requires a different diving technique than the simple but awe-inspiring wall dives at Ras Mohammed. Our dive boat with some diving professionals and tourists onboard anchored just off Thomas Reef and quickly had its bow swept into the current.

The plan was to enter the water from the stern, and follow the anchor line down to a point where we could kick like mad and make our way to coral encrusted rocks. From there, it would be a fairly short swim against the current, using the rocks for assistance, until we entered the calm water in the lee of the reef.

Thomas Reef provides a unique dive site due to the sea life attracted to the current. Because of that, it is well worth negotiating the heavy flow; rewards awaited the determined diver. In my case, a surprise awaited me as well.

As I let loose of the anchor chain, I could clearly see the steeply sloping bottom features of the reef, where I was headed. I spotted my target rock and kicked mightily until it was in my grasp. Now anchored, I had time to survey the beauty around me, and plan my next step. It was then that I noticed that an inch way from my naked right hand, the one firmly grasping the rock, sat not just another stone, but a stone with eyes.

It was in fact, something far more dangerous than a stone — it was a stonefish.

Stonefish are reputed to be the most venomous fish in the world. Had I grabbed it instead of its stony neighbor, glands at the base of its many dorsal spines would have flooded my bare hand with venom. The sting causes intense pain; with the affected body part swelling rapidly, potentially leading to death of tissues.

Just how bad the symptoms become depends on the anatomical location of the punctures, depth of penetration and the number of spines involved. The effects of the venom are muscle weakness, temporary paralysis and shock, which, if encountered during a scuba dive in a strong current, could make a safe return to the dive boat somewhat difficult. If not treated, the incident could prove fatal.

The emergency treatment required is much more than is likely to have been available on a chartered dive boat. As breathtaking as a Red Seas trip promises to be, you might stumble across critters that can take your breath away, literally. So a check of the closest and most capable medical facility should be high on your pre-dive checklist.

No doubt about it, if I had grabbed the wrong “stone” I would have been in a world of hurt; and probably in a lot of trouble with my dive buddies as well since that trip would have been brought to a sudden and exciting conclusion.

Oh yeah, once I overcame my surprise, and moved on, ever so carefully to the lee of the island-like reef, the experience was everything I had come to expect from the Red Sea.

Highly recommended!

My Top Three Diving Sites: The Red Sea, Sharm el-Sheik

I’ve read a couple of books lately where the author, critically injured in an accident, experiences what seems to be a visit to heaven, followed by a swift return to Earth. The most recent such book was Flight to Heaven, by CAPT Dale Black, a plane crash survivor.

A common theme in these books is that the author finds colors in Heaven to be much purer and vibrant than any colors seen on Earth. Well, I know a place just like that, and for a diver it must indeed be heaven on Earth. It’s called the Red Sea.

Sharm el-Sheik and Ras Muhammad are located on the southern tip of the Sinai Peninsula, where the Gulf of Suez and the Gulf of Aqaba meet the Red Sea. On my first dive at Ras Mohammed, as I sank below the water’s surface I saw a wall of color that defied description. The phrase, “a riot of color”, is a cliché, but that is what I saw. It was as if every inch of the reef was shouting for attention, clamoring to be the most colorful, the most interesting piece of rock ever created. I was stunned — in sensory overload from the beginning to the end of that dive.

At Ras Muhammad, the coral encrusted wall dropped at a dizzying angle, headed for depths of 3000 feet, 1000 m, a very short distance from shore. I had planned a dive to no more than sixty feet, where the natural light was bright enough to show off the colors cascading downward, towards what seemed to be a bottomless abyss. But at sixty feet I saw a never ending waterfall of fauna, just a few feet below me, and then below that, even more. The colors were still spectacular even at that depth, defying all the laws of physics as I understood them.

When I realized I was twenty feet below my planned dive depth, a curious thing happened. I stopped searching for the next most beautiful thing, stopped my descent, but for a few moments I had an almost overwhelming desire to throw rational thought aside and continue down into the abyss.

I understood the consequences of that action, had I continued deeper, but the experience in that moment seemed to transcend my worth as a human being. The living communal organism, and all the life forms sustained by it, clutching close to the wall, seemed to have much greater significance in the whole scheme of things than I did. I felt a kinship, perhaps pointing to our theorized evolutionary beginnings, that made it seem that where I was, was where I belonged.

egypt-napoleon-wrasse — Napolean Wrasse - Egypt. (Photo credit - Sami Salmenkivi.)

My Top Three Diving Sites: The Great Barrier Reef, Australia

My Navy travels have afforded me the privilege of diving in some of the most interesting places. In this, and the next couple of posts, I list my top three diving destinations.

I’ve been diving on the Australia’s Great Barrier Reef on two occasions, both times departing for the reef from Cairns, pronounced like the first syllable in “Kansas”. The first trip was to the inner reef, a short boat ride away from the docks. That experience was OK, but not what I had expected. It seemed like the reef had been abused by massive diver and snorkler populations which had not treated the reef with the respect it deserved.

On my second trip to Australia on Navy diving business, I traveled with the Commanding Officer of the Navy Experimental Diving Unit, CDR (later CAPT) Jim Wilkins.

Scan20083 — Two NEDU Divers - Jim Wilkins and John Clarke (the short one)

From Cairnes we took a fast boat to a liveabord vessel anchored on the outer reef. It was a beautiful 140 ft. tall schooner, SV Atlantic Clipper. And that made all the difference.

During the diving season the Clipper is stationed on the outer reef, and shuttles divers to four diving locations; Norman Reef, Saxon Reef, Hastings Reef, and Michaela’s Reef. Each location featured different underwater vistas, showing an overwealming diversity of colorful reef animals. On a typical day we’d make three daylight dives of varying depths plus a night dive.

SV Clipper blog shot — SV Atlantic Clipper

After one memorable night dive we walked up the long gangway to the deck, shed, cleaned and stowed our dive gear, and then, attracted by commotion at the bow, found a cluster of divers feeding large fish while six or more Bronze Whaler sharks circled amongst the fish, which seemingly paid the sharks no mind at all. The fish knew where the sharks were at all times, and only the healthiest, quickest fish dared feed in such proximity to the large predator. The agile fish apparently felt confident they could dodge the far more cumbersome sharks, because while we watched, not a sinlge fish was taken.

I, on the other, was not quite so agile. And I admit that it bothered me a bit that while I had been swimming through the dark to a dive ladder on the port side of the vessel, near the stern, Bronze Whalers were circling alongside the port bow. But the ship’s crew assured me that the Bronze Whalers were “not particularly dangerous.” They had attacked spearfisherman and “bathers”, but the attacks had not been fatal.

Well, that’s comforting, I thought.

I have to say the most memorable series of dives were with the magnificent Green sea turtles. To observe such beautiful and docile creatures in their native environment was probably the highlight of the entire trip.

During one of the many dives I learned a valuable lesson about diving with diveboat gear. Through the years I’d been diving, since 1964, the equipment was either my own, or belonged to the Navy, and was always maintained in like-new condition. It may have looked battered, but mechanically it was pristine.

As Jim Wilkins and I descended through 60 feet on one dive, I noticed my regulator was becoming increasingly difficult to breathe. I checked my bottle pressure, and there was plenty of air – the dive was just starting. But whether I understood it or not, it was becoming harder and harder to breathe – by the second. I finally took action by grabbing my dive-buddy’s octopus regulator (a back-up regulator), and together we slowly ascended to the surface.

Back on the boat I discovered my tank valve was not fully turned on. Why not, I wondered?

Well, the valve was worn, and generated a considerable resistance before it was fully open. As I am accustomed, I had turned the valve until I met resistance and stopped. That is a good way to prevent damaging a well working valve, but that particular tank valve was not working as smoothly as it should. It fooled me.

Chalk one up to lessons learned.

Without a doubt, the series of dive made from the Atlantic Clipper were among the most memorable of my diving career. In upcoming posts I’ll describe Red Sea dives at Sharm El Sheik and Ras Mohammad, followed by a dive at Herod’s Port, in old Caesarea, Israel.