call it “High

(NAUI, PADI, etc.), as no-stop scuba diving with air, to 40 meters, or 130 feet. Many more experienced divers By R.W. Bill Hamilton, PhD. push beyond that envelope, either by new category of doing longer bottom times that re­ diving is taking quire decompression stops or by shape in the recrea­ going deeper. Although there are tional diving world often some definite objectives for that sparks consider­ these dives, they are nevertheless able controversy, being done for fun, so it still comes 1 and is a cause of under the "recreational" label. It does great concern. This, in general terms, not, however, fit within the "tradi­ is diving deeper and staying down tional" definition. A new term is longer than the traditional limits. Al­ needed. though by no means new, for many The training agencies discourage years it was a cause for concern more the use of the term "sport diving" than controversy. There was general because it implies some sort of agreement that it was surely competition. A colleague mentioned dangerous, was not approved by that he saw two young divers anyone, and one could say with a holding onto the bottom with their clear conscience, "Don't do it." Now BCUs inflated, then letting go and methods are coming along that, for racing to the surface. It is appropriate the price of extra effort, make it to discourage that sort of competi­ possible to extend both depth and tion, just as it is the equally risky bottom time with what is regarded practice of seeing who can swim the by some as an acceptable degree of farthest underwater in breathhold risk, and in comparison with older dives. Certainly advanced divers can methods, some tempting efficiencies. practice their sport without This article describes the new dangerous interpersonnal competi­ technolog, setting the stage for tion, so the word "sport diver" does future articles that explore some of not meet our needs. Competition is these methods in more detail, but it indeed a motivation, not so much for also contains a serious caveat about the depth and time records—since all this: It has to be done properly, or nowadays they are limited to those it should not be done at all. willing to make exceptional efforts— Limits of Traditional but to be the first in an unexplored Recreational Diving cave, or the first to look into a virgin Recreational diving is defined by wreck. "Sport" does not fit the bill the so-called "training agencies," the here. organizations of diving instructors Two other names seem to be 6 Tech’ ’ Diving

suitably descriptive. One is the Some of the most experienced leaders in possibly overused term "advanced" the scuba world are dead set against recreational diving, which already releasing information—let alone encouragement—on the diving methods has many specific meanings, but is under discussion here. perhaps valuable for its ambiguity. Bill Hamilton This applies to a diver working outside the no-stop, 40 meter (130 feet) limit, regardless of the technique used. The other, "high tech" diving, relates to the new methods but does not include all situations, since the traditional limits can easily be exceeded with standard gear. The task of picking a single all-inclusive term can be left to others; for now, I am calling dives outside the traditional limits "advanced," and those done outside those limits using equipment other than standard wetsuits for thermal protection, as "high tech." ■his includes the use of The Need For Competence involved. Something that may ■dive computers and Considering the unforgiving involve just a little extension beyond new decompression nature of mistakes in diving, just standard limits, if it seduces a diver techniques, dry suits, talking about advanced and high- into running out of air at depth, can scooters, multiple or tech diving has to be done with be a great deal more risky than trying overpressurized tanks, caution, lest it lead innocent lambs to a flip on skis. Divers do these things. as well as special gas the slaughter. Therefore this general Therefore, allow me this bit of mixtures. Use of dry suits and dive topic has to lead off with a note on preaching on competence. computers within the traditional competence. We cannot proceed Many things can be done with depth and decompression limits can without such a caveat. acceptable risk, even flips on skis, by be considered traditional diving, al­ Somehow it seems unnecessary someone competent to do them. But though some special training is to warn a novice skier against trying in advanced and high-tech diving needed. While some of these "high an intentional head-over-heels flip there are many things that seem easy tech" items are relatively new to (some of us do them occasionally and indeed are easy for experts, but recreational diving, many of the without intending to, but that is which can involve unacceptable risk terms are old stuff to commercial another matter). But novice divers, it for ordinary divers. The bottom line divers. seems from the accident reports, do is: divers must become competent in equally risky things, apparently new diving practices before sticking without recognition of the risks their necks out. 7 The need for proper knowledge Familiarity with one's equipment is build, or maintain your own dive and training is not a new idea. When also critical—how it works, how to gear, you do need to know how to numerous commercial diving use it, how it should be maintained, tell when it is—or is not—right. fatalities swept the early days of and what to do when it malfuntions. ■he last item on this list offshore oil exploration in the North Next is practice. And I offer this ■is planning, but it may Sea, a number of regulations were is­ as the proverbial Catch-22: before be first in importance. sued that addressed proper equip­ doing a new and dangerous thing, All modern divers get ment and procedures. But they had one must be highly experienced in it. some training in dive no great impact on the safety record. The way around this double-bind is planning, and let us The thing that brought about a sharp practice, something one can do at hope that they all use reduction in fatalities was an any level of experience. An aspiring it. Planning a high-tech dive is no dif­ emphasis on competence. Although advanced diver should practice all ferent in principle, but it can be a this is hard to define, it was followed the various steps that are required, great deal more complex. Not much by specific requirements for training, from reading a table to connecting ap more needs to be said here, just be certification, and updating of divers paratus. Practice things in parts, then sure to make planning a fundamental and their supervisors. And it has link them together. Practice first with part of every dive. worked. Many of the early accidents everything right, then with some vari Getting The Technology were human error, and while it is dif­ ables different and finally with some It is one thing to instruct new ficult to legislate that people must things out of order. And take small high-tech divers on the importance not make mistakes, it is possible to steps; perhaps it is best not to try to of learning, it is something else to ensure that they at least know—and provide the necessary information. know well—the right way to do risky Likewise, preaching about "the things. Considering the right equipment" does not make it All this is merely a prelude to a unforgiving nature of available, nor does it define what is difficult task: to discuss what is needed. How does one go about happening in advanced, high-tech, mistakes in diving, just getting the information—the recreational diving without encourag­ talking about advanced knowledge—to do advanced and ing people to try things they are not and high-tech diving high-tech diving? prepared for and thus to lead them There is no easy way. Some of into situations they cannot handle. has to be done with the most experienced leaders in the So in very general terms—you caution, lest it lead scuba world are dead set against heard it here—don't do it if you do releasing information—let alone en­ not know what you are doing. innocent lambs to the couragement—on the diving Training, and Then slaughter. methods under discussion here. And Competence they are right. The word-of-mouth What does it take to be prepared network that gives someone just stage bottles and oxygen in the water for high-tech diving? Knowledge, enough information to get started the first time you use your new dry practice, the right equipment and but not enough to do it right, is suit. Consider thepilot of a high per­ good planning. extremely dangerous. formance jet; it may take only a few ■ irst, a diver should Proper textbooks and courses are months of around-the-clock training B have knowledge of the hard to come by for several reasons. to learn to fly it, but this practice obvious hazards to life First, most recreational divers must go through many stages before and health that may shouldn't consider advanced, high- real proficiency is achieved. What exist in the high-tech tech diving because they cannot—or some world-class divers do is every diving environment. will not—get the necessary bit as challenging as flying "Top In addition to knowing knowledge and training to do it Gun"; divers have a different task, when an oxygen mix can be expected safely. Second, those who train divers but they will be just as dead if they to explode, this includes an under­ as a profession don't want to add to screw up. standing of the body's physiological their own woes; and the average Much of the high-tech in high- limits, first in the classic "black and instructor seldom has the specialized tech diving has to do with white" limits, but also in the duration knowledge anyway. Third, the scien­ equipment. It need not be the most of exposure as well as other environ­ tific diving community, who, while expensive, but it has to be right for mental and physiological factors. diving professionally, generally use the job. Know that it is right, and Necessary knowledge includes the recreational diving practices; they are know that it is working and in good procedures and practices to be used— not eager to see an excess of recrea­ shape. Pilots may not take their own not just what they are but what they tional diving accidents threaten their planes apart, but they do have to mean, the consequences of deviation, programs. A final point is perhaps know when the aircraft needs fixing. and how best to proceed when things the most important, things are not Likewise, whether or not you design, are not going according to plan. well enough developed that a crisp 8 textbook can be written; we basically enterprise. Like anything else, the generally lacking, the principle holds. do not know as much about this as risk involved is directly related to the An Overview of Current we would like. Even so, "state of the style of the practice. Some High Tech Diving Practice art" does exist, and because high- automobile drivers go their entire For those who have paid their tech diving is here to stay and is lives without accidents, others have dues and bravely read the sermon, it going to continue to be used, books them all the time. Most of the factors is now time for a brief discussion of and courses will become available in that influence driving risk are well- what this is all about. As explained, time. Several university diving known, with attitude—the strong any proper diving outside the recrea­ programs are beginning to move into desire to drive safely—being the tional guidelines is "advanced." This advanced diving practice; standards most important item. Diving is the includes air dives in the range of 40 are being developed; and the same, and the consequences of an to about 60 meters (130 to 200 feet)— documentation is slowly taking accident—a loss of control—are just more or less within Navy and com­ shape. as serious as in driving. In a recent mercial limits, and those to greater Organized programs are another talk on fitness to divers, Dr. Fred depths, in some cases exceeding 90 approach. At present, virtually all of Bove said, "The first guy to be meters (300 feet)—which almost in­ the high-tech divers are individuals eliminated should be the one who variably carry too high a risk to con­ working alone. Each has his or her runs out of gas on the freeway." done. Deep air dives deserve further own equipment and procedures, Running out of gas is more serious in discussion, first to elaborate on the diving than in driving, but the point risks, but also to relate what has been was made. The guy who runs out of done. gas or suffers frequent fender The next methods are in a benders has no business in high-tech category best called "special-mix diving. diving," that is, dives done with gas here is no such thing as mixtures other than air. Of these, the perfectly safe diving, most common are two types of any more than there is "nitrox" diving. Nitrox, a mixture of a decompression table oxygen and nitrogen with a composi­ with a true zero-bends tion different from air, is for use in incidence. The only undersea habitats and has less way to be perfectly safe oxygen than air. This method offers underwater is to stick to coldcertain specific advantages, the main Tshowers. But diving can involve an one being access to the depth range acceptable risk. Recreational diving, of from 10 to 60 meters with very as currently practiced, has less risk long bottom times, and little or no maintenance, and planning practices; than many other activities, both sport decompression following excursions only when diving with partners will and occupational, and the risk is (depending on the depth of the he/she follow the same dive profile acceptable to most. Advanced high- habitat). as someone else. So in organized tech diving will involve a higher risk The term "nitrox" is also used groups, individual divers can follow than routine diving, but the risk can for a mixture of air and oxygen more the group's practices and can gain be kept within acceptable limits by properly called "enriched air nitrox." experience with risk reduced to the having the right attitude, and by This method, "EANX," is useful in practical limit. This is not widely following guidelines like those given the range from 10 to about 35 or 40 available yet, but it is coming. above. If you do not intend to do it in meters, and allows greatly increased Another tried and true way to a safe way, then for goodness sake bottom times with no increase in learn new tricks is from someone don't do it at all. decompression time. It is being used who already knows how. How do xperience deserves a by some university diving programs, you know when your expert is telling special emphasis here. is described in the NOAA diving you the right things? Obviously you Whether they be manual, and is beginning to be check his track record, find out how metallurgy or embraced by recreational divers. he got his training, and how he is medicine, practices There are two main hazards to EANX, regarded by the community. that work on both related to its oxygen content. Our contribution is to offer more numerous occasions Since excess oxygen is being specific details in future articles, in­ are generally regarded as breathed,"accept­ the possibility of toxicity cluding a review of the activities able."E This is certainly the way must be accounted for, and handling being carried out by high-tech diving decompression tables become mixtures rich in oxygen is a fire programs. validated, and other diving practices and/or explosion hazard. Risk might follow the same path. Decompression tables for EANX At some point, it is necessary to Although this is a complex issue, diving can be derived from existing discuss risk. Diving is a risky since real depth of experience is air tables by the "equivalent air 9 continued on page 50 High Tech experience a realm not previously Setting the Stage continued from page 9 accessible to humans. And there is continued from page 17 every reason to think—as our depth" calculation, but some research. I taught diving in the technology and knowledge advantages can come from custom 1950s and the students common fear advance—that we will be able to table computation. was running out of air. With no pres­ push the envelope even further. Perhaps the most exciting of the sure gauge, an no BC to assist an Bill Hamilton, a physiologist with special mix methods are "trimix" and emergency ascent, this was under­ 25 years of specialization in the diving, heliox diving. Trimix involves the standable. In actuality, cautious use aerospace and environmental fields, has use of mixtures of helium, nitrogen, of air and spent much of his professional effort reserve valves avoided emergency as­ and oxygen that are appropriate for bridging the gap between the laboratory cents and most deaths were from diving in the range of 50 to 100 and the field. A resident of Tarrytown, drowning at the surface. I used to meters. At the deeper end of this New York, he is the principal in his emphasize to my students the idea range, a mixture of helium and consulting firm, Hamilton Research, that they not be dependant on their oxygen, with little or no nitrogen, is Ltd., where his work includes the Aqua Lungs. A partner of mine better. Trimix, or heliox diving takes development and assessment of twice made free ascents from 165 feet considerable operational planning commercial, institutional, and govern­ to demonstrate this. Even with what and preparation because of gas ment decompression procedures. we knew then, this was foolish. logistics problems and in most cases, Today, many hold the same view special decompression tables are with respect to shallow dives, while needed. Logisitics applies first at the Science continued from page 15 in deep water it is obvious that level of mixing which takes both skill procedures must be pre-approved by problems should be dealt with at and equipment, and later at the level the dive safety officer. depth, hence the use of pony tanks, of breathing, since all the gas needed 4) Sufficient air supplies must be Benjamin valves and other methods for a deep trimix or heliox dive available for each diver at the planned of providing back-up air supply. cannot normally be carried by the decompression stop depths. Over the last few years I've diver. 5) Each diver must carry a set of witnessed an alarming number of Still another special mix method decompression tables, calibrated emergency ascents. I am equally involves the use of rebreathers. These depth gauge, pressure gauge, and disturbed when I find myself with a supply gas to the diver in a closed, or watch. diver with a near-empty tank at the semi-closed loop from which CO2 is 6) A standby diver must be end of a dive and an alarming absorbed. They are not readily available at the surface to assist the number of divers routinely dive this available to recreational divers, but divers or supply extra tanks if way. When we have had problems some scientific diving programs are necessary. with dives on deep dives, in every beginning to use them, and they 7) A decompression chamber with instance they have employed—in have been used for years by many trained chamber operators must be one form or another—what might be navies. In addition to long in-water immediately available at the dive site. called shallow water technique, times, rebreathers offer the 8) Dives are generally limited to technique that a modern under­ possibility of optimal oxygen level to 130 feet or less. For dives greater than standing of diving physics should gain decompression advantages. The 130 feet, the above regulations are re­ suggest is not appropriate even for need for redundancy in the event of quired even for no-decompression shallow diving. Many of the ideas system failure is a problem in some dives. followed in deep dives are well-ap­ applications. Prior to 1978 scientific diving was plied to shallow dives. As mentioned, other high-tech regulated by OSHA, the Occupational As a group, we perhaps are items are having an impact on Safety and Health Administration. By thought of as daring to venture into diving. Dive computers make this time scientists at several univer­ the open water areas that we explore, variable depth diving (multilevel) sities had formed an organization and to be diving to the depth this and repetitive diving more called AAUS, the American Associa­ requires. In truth, I always argue accessible, albeit with meaningful tion of Underwater Scientists, and there is both dangerous and safe risk of decompression sickness had developed there own standards. diving in both deep and shallow unless certain precautions are taken. Because of their safety record and water. ✓ Dry suits are making all types of demonstration of independent self diving more comfortable, and with Malcolm Smith, a retired regulation, they were able to convince proper training this is probably with photographer, now spends his free the government to exempt scientific less overall risk. Dry suits are time capturing Monterey Bay's diving from OSHA's commercial essential for the long dives possible gorgonian population on film. diving standards. Currently 23 univer­ with special mixtures. sities and institutions including HBOI With all of these warnings are organizational members of AAUS. issued, and all of the described parameters met, advanced high-tech John Reed is the diving officer for diving offers the prepared, Harbor Branch Oceanographic knowledgeable diver a chance to Institute. 50