Is scuba diving dangerous? Awareness and management

Those who have never scuba dived often ask a legitimate question: "But isn't it dangerous?" The honest answer is: yes, scuba diving involves risks, like any activity that takes place in an environment unnatural to humans. But the complete answer is another: modern recreational scuba diving is one of the safest sports of all, precisely because it has developed, over time, an extremely refined culture of risk management.

This post isn't meant to scare, nor to compile a macabre catalog of accidents. On the contrary, it stems from a specific idea: knowing the dangers makes them more manageable. Fear comes from the unknown; safety comes from understanding.

This post has two main audiences: those who have never tried scuba diving, are curious about it, but at the same time intimidated by the potential dangers. I want to reassure these people. What follows are some of the main dangerous events that can occur while scuba diving, and my goal is to inform and clarify what these dangers might be. The other audience I'm addressing is beginners: I'm actually one myself, but I've already had some experience and think I can begin to draw some conclusions. In my early years of scuba diving, I often asked myself, "How would I react if this or that happened? " and I've developed the understanding that closing my eyes, previsualizing the event, and thinking calmly about how to handle it is the best way to prepare for potential accidents. This type of training is partly provided during the courses leading to the various certifications, but in my opinion, not enough, so I think it's useful to focus on the most frequent accidents and, from the tranquility and safety of one's own armchair, reflect with one's eyes closed on the best way to manage these events.

I repeat: the purpose of this post is not to scare. The same approach can be applied to driving, skiing, hiking... the potentially dangerous activities are endless, and knowing their risks is the most prudent approach. If I were to write a post about the dangers of driving, I would start by talking about highway collisions, cars flipping over, falling off overpasses, and ending up in rivers. Anyone who concludes that driving is too dangerous would certainly be drawing the wrong conclusion, because the number of people who drive their entire lives without suffering injuries is negligible compared to those who are victims of a car accident. There are even people who continue to get married, despite the obvious dangers...

The method I'll use, therefore, is simple but powerful: for each potentially dangerous event, I'll ask you to stop for a moment and visualize the situation, as if you were actually experiencing it. Then we'll analyze what to do, calmly and rationally. This previsualization exercise is enormously valuable: if one day you actually find yourself in that situation, you will have already experienced part of it.

A fundamental premise: risk is not the emergency

Before going into the individual scenarios, a key point needs to be clarified.

Underwater:

• Risk is the possibility that something will go wrong.

• An emergency is when something has already gone wrong.

• The accident is when the emergency has been poorly managed

The vast majority of diving accidents do not arise from unforeseeable events, but from:

• distraction

• rush

• overconfidence

• underestimation

• lack of mental preparation

A safe diver is not someone who “never has problems,” but someone who knows how to recognize them early or manage them without panic.

To give you an idea of the frequency of these accidents, I've been scuba diving for five years and have logged about 150 dives, and I've witnessed many of these emergencies firsthand; no one has ever gotten hurt because, on each occasion, the person involved has handled the problem as best they can, thanks to their training and skill: knowing the risk has prevented the accident.

Nautical accidents

I'll begin by mentioning a category of accidents that, fortunately, I haven't experienced firsthand, but it happens relatively often: dive boats sink, catch fire, or capsize. If you compare the number of divers who have somehow been victims of this type of accident with the total number of divers who dive each year, I think it's a decidedly rare event in a diver's life, but the experience must be terrifying enough to leave a lasting impression on anyone who dives, much like the possibility of being attacked by a shark terrifies anyone who enters the water, even though, based on the numbers, it's such a rare event that it falls into the category of fatalities. Without claiming to be statistically accurate, I believe the areas most affected by this type of accident are Egypt and Indonesia, on which I've already written two posts, to which I refer. Here I limit myself to mentioning the category of accidents for the benefit of those who, not practicing scuba diving, are wondering what the potential dangers are, because I believe it would be complex and presumptuous to give advice on how to manage a shipwreck, even if I have already written something about it in the post on cruises in Egypt.

Engines and propellers: a real, often underestimated danger

This is a situation I've experienced firsthand. We were in Egypt, doing a negative-weight dive from a Zodiac. Essentially, all the divers on a dinghy enter the water simultaneously at a signal, and must have adjusted their trim so they have no buoyancy and sink immediately and rapidly after entering the water. This type of entry is typically done where there are strong currents, so they can immediately descend as a group to depth, where the current is expected to be weaker than at the surface. On that occasion, one of the divers on my dinghy, while getting dressed before boarding, had forgotten to put on his weight belt. As a result, as soon as he entered the water, he found himself under the dinghy with the engine running, unable to reach any depth. Fortunately, the dinghy's driver immediately recognized the emergency and stopped the propeller.

It's a classic example of how a simple, routine act (putting on a weight belt), if underestimated, can lead to potentially fatal consequences, and how the buddy check must always be performed scrupulously, even if it seems obvious and boring.

In general, propellers and boats represent an undoubted danger for divers, and the danger can arise both due to errors on the part of the diver, who makes mistakes in managing the trim, or who chooses the wrong point or method of entry and exit from the water, or due to reckless behavior on the part of those driving the boats.

As I said, I have 150 dives under my belt, a paltry sum compared to someone with thousands of dives under their belt, yet I've already experienced at least three times seeing a motorboat pass overhead, which shouldn't have been there and should have been alerted to the reported presence of divers. Personally, I've always made sure I was deep enough when I heard a motorboat's engine approaching, and the whole thing has resolved itself by me summoning from the depths some curse on the ancestors of careless sailors. But if I were to list the potential dangers of diving, boat accidents would certainly be on the list. From this perspective, I don't have much advice to offer other than to stay calm as soon as you hear the sound of a propeller approaching, descend to at least ten meters, maintain your trim, and unleash your barrage of curses.

Currents: When the Sea Takes Decisions for You

Currents are one of the most misunderstood phenomena by beginners. They're not "bad," they're not an anomaly: they're an integral part of the marine environment.

Stories of divers swept away by strong currents and lost in the vast ocean are among the most frequently told to child divers around the bonfire on Halloween nights. During my last cruise in the Red Sea, I was told of a young diver who was separated from her group during a dive on the Thistlegorm and, after a whole night in the open sea, was rescued the next day near Hurghada (70 km to the south), alive and well, but clearly shaken by the experience. The film Open Water, based on a true story, attests that these incidents don't always have a happy ending. Strong currents are a constant feature of the world's most renowned dive sites, from the Galapagos to French Polynesia, from the Maldives to Indonesia. The intensity of an ocean current is difficult to describe to anyone who has never experienced it firsthand; the most effective way I find is to compare it to a veritable river in flood crossing the sea. Evidently, this is a force that cannot be resisted in any way, but only accommodated; the first thing to do is avoid losing contact with the group. However, if separation occurs, for example because the other members of the group were quicker than us to find shelter behind a reef, while we, distracted by taking a photo of a jack fish, get swept out to sea, the first thing to do is not panic and immediately throw an SMB (or signal beacon) to signal your position, so you can surface safely, while also signaling your position immediately to those on the surface. Personally, although I hope to never have to experience being lost at sea, I always carry several signaling devices in my BCD: a whistle, a strobe light attached to my first stage, an EPIRB (satellite beacon), and a small mirror for light signals, in addition to the SMB, of course; but as I said, I hope to never have to use them.

In terms of emergency foresight, I suggest imagining a situation where you're with a group and notice the current suddenly increasing. The key things to focus on are: stop whatever you're doing (such as taking photos) and focus solely on staying connected with the group, seeking the shelter of a reef if possible. If you get separated from the group, first launch the SMB, remain calm, and then terminate the dive. Once you reach the surface, do everything possible to signal your position.

Marine fauna: between myth, ignorance, and real dangers

The danger posed by marine wildlife is, in my personal opinion, relatively modest. From this perspective, I believe it's much better to be in the middle of the sea than to spend a night in the African savannah or the Amazon jungle.

I'll get straight to the point, because it's one of the most frequently asked questions about scuba diving: sharks aren't dangerous. I've already discussed the dangerousness of great white sharks in another post, and naturally, the possibility of finding myself in the water with one doesn't reassure me. But, numbers in hand, the chances of suffering a fatal shark attack are little more than statistical noise, especially in scuba diving, considering that almost all shark attacks involve surfers and swimmers. For a long time, it was thought that shark attacks on humans were errors of judgment by sharks mistaking the surfer or swimmer for that of their usual prey, such as a seal (the "mistaken identity" theory). Today, this theory tends to be questioned. It's true that if a shark sees something floating on the surface, it tends to attack it, or at least bite it. It tends to keep a cautious distance from a diver, which is usually not an inanimate object floating on the surface, but a strange object at the same depth as the shark and emitting a strange trail of bubbling bubbles. Searching YouTube, you can find some very rare cases of more or less aggressive interactions between sharks and divers; the most striking case that comes to mind is an attack by an oceanic whitetip shark that bit a diver's calf at Brothers Island in the Red Sea in 2018. Among the comments on the video, you can read many cases of interactions between divers and sharks, which in my opinion document curiosity rather than the sharks' aggression.

Another incident documented on YouTube occurred in Fiji in 2019; a huge tiger shark meticulously explored the instar of a tourist attending a shark-feeding show. Things could have gone terribly wrong, and the decisive intervention of a guide likely averted the worst. In my opinion, however, while keeping quiet about the practice of shark feeding, which only fuels sharks' nervousness and the risk of accidents, this incident also demonstrates the curious, rather than aggressive, nature of sharks.

Of all the hundreds of shark species that exist, there are some you are more likely to encounter while diving; the probability of encountering a great white shark, as mentioned, is extremely remote; oceanic whitetips are the superstars of Red Sea diving, and in particular, those taking a cruise along the Brothers-Daedalus-Elphinstone route have an encounter with one as their primary goal. These sharks can become dangerous (Jacques Cousteau considered them the most dangerous of all), but as mentioned, the incidents represent infinitesimal numbers compared to the millions of encounters in which the shark has proven harmless. Another exceptional protagonist of scuba diving is the hammerhead shark, essentially shy and harmless, it can be encountered from the Red Sea to the Galapagos, passing through Bimini or Japan: if you are lucky enough to encounter one, enjoy the show. Then there are tiger sharks and bull sharks: both are potentially dangerous species, statistically responsible for the greatest number of attacks on humans; A dive guide who accompanied me on dives to Mafia Island and regularly met both of them in the waters of Chole Bay, called the former "sweet and loving" and the latter "sons of bitches"; my recommendation is to always choose the guides who accompany you on dives with tiger sharks and bull sharks carefully, because never like in these cases does the competence and professionalism of a guide make the difference between a memorable experience and reckless and potentially risky behavior. Another magnificent shark that can be encountered from the Red Sea to the Philippines, totally harmless, is the thresher shark. In many tropical seas you can encounter sharks such as blacktips, whitetips, grey reef sharks, nurse sharks... these too are all fundamentally harmless.

Bottom line: shark accidents can happen, have happened, and will happen again, but the numbers are so small that they aren't statistically significant, especially when compared to the millions of divers who enter the water every year. Therefore, to summarize: sharks don't pose a danger to divers, but rather one of the most beautiful spectacles you can witness while diving. There are circumstances in which sharks can become dangerous, but these are mostly exceptions, often caused by reckless behavior on the part of divers. Even in this case, my recommendation is always, first and foremost: study, study, study. Understanding shark behavior is essential for diving with them safely and avoiding dangerous situations; but in general, sharks don't pose a danger to divers.

Sharks aren't the only potentially dangerous marine life; I'll skip over potentially dangerous but essentially harmless species, such as barracudas, moray eels, stingrays, and titan triggerfish. Anyone who cares to watch my YouTube channel will find numerous videos of these animals, noting that simply avoiding disturbing them is a safe way to admire them up close.

Ultimately, I believe the species that pose the greatest danger can be divided into stinging and venomous species. In the first category, I would highlight specimens such as the fire coral and the fire urchin, as well as numerous varieties of jellyfish, some of which can even be potentially deadly (such as the infamous irukanji ). As for jellyfish, I believe that fatal cases involving divers are limited to very rare episodes good for tabloid news stories, while the risk posed by stinging species such as fire coral is concrete and frequent but easily inhabitable: just respect the golden rule of "never touch anything." As for venomous species, the marine environment is indeed quite prodigal with dangers: from the geographic cone to the stonefish, from the blue-ringed octopus to the devil fish and the lionfish, the sea (particularly in Southeast Asia, but also in the Red Sea) is full of animals with stings that inject very powerful poisons. All these species, however, have in common the fact that they use these extremely powerful weapons only for defense. The author has on several occasions floated within a few dozen centimeters of stonefish or blue-ringed octopus without running any risk; the important thing, I repeat, is to never touch anything. Among these venomous species, in particular, the stonefish, the blue-ringed octopus, and the geological cone are often depicted as potentially deadly in major marine zoology textbooks. In my brief experience, a diver from my group inadvertently put her hand on a stonefish during a night dive in Hurghada; on that occasion, the cruise crew loaded the unwary victim onto a dinghy and quickly took her to a medical station in Hurghada. The next morning the girl was sipping coffee on board while recounting the incident of the previous evening, and I had the impression that the poison hadn't been that lethal. This led me to the impression that these poisons are potentially lethal only for highly sensitive individuals, such as the venom of a common wasp, while in most cases they are "simply" very painful, but I'm not a marine biologist or a toxicologist.

Bottom line: marine life is rarely aggressive and rarely dangerous to humans; ignorance and recklessness are the main dangers.

traumas

Having cleared the field of the remote dangers that most frequently capture the imagination, we come to the more concrete and real dangers.

The risk of fractures, sprains, and crush injuries is a very real one. This danger is especially real aboard boats and dinghies. A fully clothed diver, equipped with fins, wetsuit, BCD, weights, and a tank, carries between 30 and 40 kg of equipment, moving in unstable and uncomfortable conditions on a boat that rocks on the sea, often in confined spaces filled with obstacles.

In this case, I'd say that, no matter how cautious and prudent one may be, in diving, traumatic events of varying severity are virtually inevitable. A particularly dangerous phase is climbing back onto a boat in rough seas; grabbing the ladder of a boat bobbing on the waves at the end of a dive, carrying 35 kg of gear, can be an experience akin to a rodeo on a runaway thoroughbred, as can transferring from a large cruise ship to a small, eight-person dinghy. One of my instructors still recalls with some apprehension how, while transferring from the boat to the dinghy during a dive in Sudan, the boat was lifted more than a meter by an unexpected wave, causing him to fall face-first into the dinghy, his chest miraculously avoiding the row of tanks lined up in the dinghy. In my own small way, with 150 dives under my belt, I already have a dislocated thumb, sustained while climbing back onto the boat while holding onto the railing. The boat rocked due to a wave, and I tightened my grip to keep from falling backward (perhaps onto some diver behind me waiting to board after me), and my thumb twisted 180 degrees, pivoting against the railing. My wife nearly sprained her ankle when, still crossing from the boat to the dinghy, the latter was lifted by a wave, crushing her foot between the dinghy and the base of the tank dangling from her back. And I could go on; in my opinion, orthopedic injuries are part of the folklore of diving and the price you pay for enjoying the wonders of the underwater world; in the life of a diver, I think that sooner or later, a fracture or sprain is inevitable. As I said, I believe the greatest danger is when you're getting back on the boat; a series of common-sense rules apply: always try to have at least one hand free, move with caution, avoid reckless movements, and anticipate the boat's movements.

Decompression sickness

Let's get to the real, primary danger of scuba diving. Statistically speaking, decompression sickness is by far the most common cause, and although it's far less terrifying in the collective imagination than a shark attack, it's by far the most real danger. Among the potential dangers, those who begin scuba diving likely fear drowning. In reality, while drowning accidents due to running out of air can occur in technical diving, which frequently involves diving in caves and wrecks, in recreational diving, which typically takes place within 30 meters of depth and in open water, the risk of drowning is virtually nonexistent because the possibility of a rapid resurfacing is almost always present. The real danger of recreational diving isn't falling into the depths and drowning, but, paradoxically, failing to stay at depth and surfacing too quickly, victims of an uncontrolled ascent. This is why recreational divers dive with weights, and why proper weighting is an essential element of diving safety. To put it simply, during a dive, you breathe compressed air, composed of nitrogen bubbles whose size decreases the deeper you dive (and therefore the higher the pressure). These tiny gas bubbles diffuse into your tissues, and must be slowly eliminated by your body. If you ascend too quickly from a depth of, say, 30 meters, without giving your body time to eliminate these absorbed gases, the gas bubbles in your tissues expand rapidly as the depth and pressure decrease, causing a series of physiological damages to the respiratory, circulatory, and neurological systems, which in the most serious cases can even be fatal. This type of accident is statistically by far the most common and the most subtle danger of diving.

Under what circumstances can an excessively rapid and uncontrolled ascent occur? The typical case is poor buoyancy management; buoyancy management is the primary skill taught during certification courses for the most important divers. It can be said that a properly trained diver should have sufficient buoyancy control to avoid losing control and ascending uncontrollably. However, anecdotes of uncontrolled ascents in which the diver, losing control of his buoyancy, rockets to the surface are relatively common. In most cases, this is due to errors made by the diver who panics and makes trivial errors in buoyancy management, such as inflating the BCD instead of deflating it as soon as he realizes he has become too positive. To this case, various circumstances can be added, all attributable to panic and a lack of clarity. There might be an inexperienced diver who panics when he spots a shark and decides to flee, fleeing to the surface; or someone who spends the entire dive focused on their GoPro and suddenly realizes they're out of air; or someone who, in poor visibility, loses contact with the group and, once again, panicked, thinks only of ascending, skipping the safety stop. Generally speaking, these are all episodes of panic and a lack of clarity. While perfect buoyancy is a skill that develops with experience and hundreds of dives, the minimum buoyancy management necessary to avoid accidents is generally part of the knowledge base of any certified diver, so an uncontrolled ascent shouldn't be a major concern. Yet these are statistically the most frequent accidents, so the recommendation can only be the same as that consistently recommended during all training courses: should any event occur, "stop, breathe, think, act" strictly in that order.

Returning to my personal experience, in the few dives I've done to date, I've witnessed a divemaster who, while diving with novices, had carried excess weights in his BCD to distribute to his dive buddies in case of emergency. Seeing a diver who had dived with too few weights and was struggling to manage his BCD, he approached the diver, following a downward trajectory, headfirst. The Velcro on the BCD pockets must have been a bit loose, and the weights began to fall off the BCD, immediately making it positive, and within seconds they were both rocketing to the surface. The dive had only been underway for a few minutes and the maximum depth hadn't exceeded 10 meters, so the greatest damage was to their pride, but it's a good example of how many unimaginable events can occur, and for which it's always wise to plan ahead and plan for possible emergency management.

Regarding my personal experience, I happened to dive the Thistlegorm without my weight belt; I realized my mistake only after some time inside the wreck, noticing that my buoyancy wasn't as expected. Since the entire Thistlegorm dive takes place at a constant depth of 30 meters, I was able to complete the dive aided by the pressure (on a dive at an average depth of 15 meters, it might have been more difficult) and manage the ascent by paying greater attention to managing the inflation of my BCD. In conditions that could have potentially caused an uncontrolled ascent (as I ascended, the lack of a weight belt could have made me feel too light at any moment), I simply kept calm, preventing emotion from taking control and managing my buoyancy with doubly careful attention.

Again, on a recent dive in the Red Sea, my wife and I found ourselves in a group with a reckless Chinese boy who blatantly ignored the most basic rules of dive profile management. He spotted a tuna at 50 meters and rushed to photograph it, then within seconds returned to -15 meters. At the end of a dive, with about ten minutes left, our guide decided to move away from the reef and spend a few minutes "in the blue" to see if there was a chance of spotting a shark. The unwary Oriental man indeed spotted a tuna at -50 meters and rushed in; my wife, faithful to the principle of sticking with her group, followed him, and we found ourselves at -40 meters, at the end of the dive, with little air remaining in our tanks. As we moved away from the reef, we were caught in a strong current that, while we were attached to the reef, we hadn't noticed. And now, a dive that had been perfectly routine up until that point was becoming potentially risky in a matter of seconds. We began finning toward the line of the boat we were supposed to attach to for the safety stop, but we were at -40 meters, struggling due to the strong current. The more we finned, the more we struggled, consuming more air, and the deeper we went, the greater our air consumption became. Without visual references and focused only on the goal of pushing to reach the top, we began to end up at -42 meters, -43 meters... and therefore, with even greater air consumption... my wife began to panic, fearing she'd run out of air. Eventually, we managed to reach the top, but while I held onto the line and began to slowly ascend following my computer's indications, my wife, not quite clear-headed, seeing the pressure gauge drop to 30 bar, quickly ascended along the surface, much faster than I did. Everything went smoothly, but it's another example of how irresponsible behavior and a lack of clarity could have led to a decompression sickness incident. The rule: don't be responsible for other people's mistakes; stop, breathe, think, and act.

Another anecdote based on my own indirect experience: a highly experienced diver I met in Hurghada, a scuba instructor, dive center owner, and highly experienced in shark diving, traveled to Mikomoto, Japan, a popular spot on Instagram for diving with huge schools of hammerhead sharks. He told me that he relied on an unscrupulous dive center that conducted the dive without even the slightest respect for basic safety measures. They entered the water in an area of very strong current with the goal (generally discouraged) of finning against the current to reach the spot where they were supposed to find the sharks. My friend, a hulking man of nearly two meters and weighing 120 kg, found himself finning alone in a swirling current, quickly using up most of his tank and unable to reach the agreed-upon spot, while the guides continued on, abandoning him. At one point he gave up, launched the SMB, and began the ascent, only to find himself completely alone, surrounded by a dozen or so gray sharks circling him. As I said, he's a diver who knows exactly how to handle a shark dive, but a good rule of thumb is to never find yourself alone with more than one shark and to stick to the largest, most compact groups possible. Even in that case, everything worked out for the best: my friend completed the ascent in the necessary time, managed to signal his presence, and got back on the boat (and I wouldn't have wanted to be in the shoes of the person who was on the boat when he resurfaced... I'd say being on a boat with a pissed-off Steve definitely qualifies as one of the dangers of diving), but in the same circumstances, it's likely that others would have run the serious risk of decompression sickness by ascending too quickly and in complete distress.

Equipment problems

Here too, the scenarios are very common, from the rented BCD with a malfunctioning button that forces you to inflate it orally the entire dive, to the regulator that goes into continuous flow, to the O-ring that suddenly gives way with a bang, causing a veritable hemorrhage of air from the first stage, to the buddy who only realizes once you've reached the bottom that he forgot his computer, to the diver who hits you in the face with his fin, causing your mask and/or regulator to fly off, and the list could go on and on.

Other fairly common problems aren't really equipment-related issues, but rather equipment management issues. I'll mention two in particular, which may seem trivial but can become dangerous: the first is entering the water with the tank closed (this can happen if the tank is opened and then closed, leaving some pressurized air in the hoses); the sensation of starting to sink and realizing the tank is closed and no air is reaching the regulator must not be the best; in these cases, while unpleasant, the important thing is—guess what?—not to panic; if your weight is correct, a few kicks of the fins will be enough to resurface and be out of danger, even if you're unable to inflate your BCD. Another similar situation is starting the descent without switching from the snorkel to the regulator; again (I've been there...) the feeling when you begin the descent and take that first unsuccessful breath isn't the best, but you just need to stay calm and resurface. However, if you examine DAN accident reports, you discover that some accidents were caused precisely by cases of closed tanks, which evidently were not managed with clarity.

The message I'd like to convey briefly, because this post has already become far too long, is that potentially every dive could hold an emergency, so much so that I myself, with relatively little experience, can attest to numerous incidents that could have turned into accidents. Methodical, meticulous planning is essential, even if it may seem tedious: accidents like descending into the water without a weight belt can be avoided with scrupulous supervision and a rigorous buddy check; the danger to be warded off is that after a while, you'll reach a point of illusory safety, causing you to underestimate routines that are nevertheless essential (such as remembering to check that your buddy is wearing a weight belt before entering the water). Redundancy is another important aspect: whenever possible, always try to have a plan B; carry two computers, if you have them; during a night dive, bring two flashlights, and so on... but above all, what I consider the most important point: don't panic; In the anecdotes I cited above, I've always systematically reiterated one concept: the first thing to do when an unexpected event occurs is not to panic; in recreational diving, if everything goes wrong, the escape route is always just a few seconds away: just launch the SMB and surface. Except for exceptional cases that are good for campfire tales, the sea voyage will always be just a daydream.

Conclusion: safety comes from calm

Scuba diving isn't for risk takers. It's for risk managers.

Every scenario you've read isn't a reason to give up, but a reason to prepare better. If one day you find yourself in one of these situations and think, "Wait, I've seen this before," then this article will have done its job, perhaps even encouraging you to put your imagination to work, trying to imagine ever-new emergencies and how to handle them before they become accidents.

Diving safety isn't the absence of danger. It's awareness and clarity in managing every situation. And if you know how to manage risk, what I've described in this post is the worst that can happen to you underwater, while you admire and explore wonderful worlds from which you'll never want to leave.