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The Smith Diving News is a monthly E-newsletter which provides news and information of interest to scuba divers. The newsletter is not just a listing of events and specials. You can find that kind of information here on the web site.
We will cover new developments in the scuba world, book reviews, information about dive sites and throw in some fun facts too.
Use menu to the left or scroll down this page for s of selected articles from past issues of the newsletter.
Earlier this season one of our manufacturers asked me to take some of their new equipment out for an evaluation dive. We do this from time to time, and whenever possible if we're going to add a new product to our line-up. So I took a new regulator and B.C. out to Square Lake for a Tuesday Evening Fun Dive. While the rest of you we out chasing fish I was poking around in shallow water putting the gear through it’s paces. It didn’t take long to realize there were some serious drawbacks to this new gear. We weren’t able to find any exciting new products for you that day. While I was under I did make an even bigger discovery though, I was having a great time. I was sitting in 10’ of water in Square Lake, a place I’ve been diving a few hundred times before, and I was still having fun. I’ve been thinking about the experience I had that day and have reached what I think is a fairly significant conclusion, the reason I dive.
There are lots of reason why people dive, but there's one that stands out for me. That reason also seems to be the biggest motivation for some of the best divers I know. I'm going to share that reason with you, but first let me share with you some of the things that don’t motivate me to continue diving.
My first night dive was just north of Big Island on Lake Minnetonka. I was a fairly new diver so my anxiety level was right up there. The fact that my wetsuit was too tight and everyone else seemed to know exactly what they were doing made me think “this is supposed to be fun right‘. :20 into the future - I’m kneeling on the bottom with my dive light trained on the dorsal fin of a sleeping walleye. I have become completely distracted and relaxed. Slowly I move my light at an angle and the fish begins to tip sideways. After a few minutes I’ve got this poor fish practically on it’s side, it wakes with a start and flashes away from us (no doubt to share his close encounter story with the rest of the school). This ended up as a great and memorable dive, but I don’t dive today just because it’s fun to tip fish over.
When I attended my Advanced Diver Course (then called Open Water II), our Instructor, Dick “Grumpy‘ Hagen took us to Wirth Lake in Minneapolis (as we still do with our current Advanced Classes). Wirth Lake is well known for both it’s history and it’s lack of visibility. Many divers have a real problem with low visibility. Wirth visibility (0’’) makes many divers feel claustrophobic and anxious. My reaction was slightly different. I froze. At 20’ in the lake I had to constantly remind myself that there was a buddy at the end of my buddy line, (I could see neither buddy, line or my own hand). The visibility was so bad that I had to cup my hands around my face to see which way the bubbles were going, to locate the direction to the surface. In my case the anxiety over the inability to see was so bad that Grumpy ended up diving with me, holding my hand the whole way. As you will soon see I got over my feelings about low vis. And now actually love to dive by feel, but I don’t dive today because I love no visibility diving.
It’s 7:30 in the morning a few years later and I’m on the bottom of another Minneapolis lake (Calhoun) with Will Hastings (another Smith Instructor). Here we are “mucking‘ along the bottom in near black-out conditions on the site of the old Cedar Lake Ice Company and we’re having a great time. Each of us add an occasional “treasure‘ to our mesh bag. The dive is about :35 old when we stumble across an old wooden sailboat, it’s around 22’ long and is one our best finds yet. That was a great dive, but I don’t dive because I now love low visibility treasure hunting.
2004 - We’re in Cozumel and I just finished a dive with my wife and our two sons. Our two daughters are on the dive boat and between dives we spend our SIT time skin-diving. I look over and see our 4 year-old snorkeling non-stop, rushing from one “dory‘ fish to the next. She’s followed by her big sister and brothers who are having a hard time breathing through their snorkels because they’re laughing so hard. The sun was shining and we were floating on the surface of the Caribbean. That was a pretty good day, but I don’t still dive today because it creates unforgettable memories for my family.
I don’t dive to see critters. I don’t dive because it’s the closest thing to weightlessness this side of outer space. I don’t dive for practice or to see ship wrecks. I don’t go to be surprised by a diving loon or to swim through coral canyons, or to study the crystal formations under the winter ice. I don’t dive to explore the last frontier on earth. I don’t even dive for the peace and quiet, or the distraction from everyday concerns.
I dive because it’s still amazing to me that I can go underwater into an alien environment and stay there. Simply put, I dive to dive. All that other stuff is just icing on the cake. But the icing is pretty good too.
Did you know that the Smith Diving Instructor staff has more than 125 years of experience teaching scuba? The nine active Smith Diving Instructors represent a great resource of knowledge and experience, that’s a combined logbook of more then 12,000 dives! We’re very proud that they provide such a caring and important service to our students.
Smith Diving Instructors are available for speaking engagements. If you know of a corporate, school or other group that would like to take advantage of this resource give us a call at the shop.
Number of Smith Diving led exotic trips - 6
Number of divers on Smith Diving led trips - 91
Number of divers attending Smith Diving led local fun dives - 269
Total number of Smith Diving led dives in 2005 - 1250
During 2006 we will begin a diver mentoring program for those individuals interested in continuing on towards NAUI or CMAS Leadership level training. As part of the mentor program, past Advanced and Master Diver students may join Instructors for the open water portion of the Scuba Diver, Advanced Diver and Master Diver Courses. Also all Divers enrolled in the Master or 2-Star Diver Course will be matched with an Instructor or Divemaster who they can call on for advice or help with homework or skill development. If you are interested in Divemaster or Instructor level training please contact us for more information.
If it’s been a while since you’ve been diving, or if you’ve never been diving in Minnesota before we recommend that you attend some kind of refresher training before you head out to the lakes this spring. Our Refresher Class is open to any certified diver regardless of agency affiliation. Simply bring your c-card and logbook to the class. The class is a one evening session consisting of 2 hours of classroom and 2 hours of pool. Supervised pool only sessions are also an option if simply want to brush up or try out some new gear.
For those of you that have dived in Minnesota, you’ve experienced the hardest part of California Dive’n; the water temperature. Contrary to what many people think, the water temperature off the coast of California is in the 60’s not the 80’s, so a full wetsuit, hood, gloves, and booties are a must. I learned to dive in the kelp forests off of Monterey Bay and recently had the opportunity to re-visit my old dive sites. Monterey is about 1.5 hours dive south from San Jose. There are many places to stay in Monterey ranging widely in price or if you have friends in San Jose as I do, it’s easy to spend the evening visiting and then get up leisurely the next morning and drive to Monterey for a couple of dives.
“Why travel to dive cold?‘ you may ask. Well, I’ve been to a number of dive locations all over the world and have yet to see anything like the diversity of life in the California kelp forest. The nutrient rich cold water is ideal for supporting the kelp. Kelp is an algae not a weed. In the summer it grows up to 3 feet per day and reaches heights of 70-100 ft. Although there are structures called ‘hold fasts’ at the base of the kelp that look like roots, they do not provide any nourishment for the plant, they simply hold the kelp fast to the reef. There are ‘balloons’ on the leaves of the kelp that pull the leaves to the surface. So, what you end up with are kelp stalks that grow straight up to the surface and than form a leaf canopy that spreads out on the surface. In fact, diving in kelp forests are often compared to walking in the North Woods. One can easily move in and around the kelp stalks and explore the forest at one’s leisure. Instead of hiking on a path, one swims among the branches and ‘tree trunks’.
Another key aspect of the kelp forests are the reef structures. They not only provide a critical anchor for the kelp but also provide myriad cracks and crevices in which critters like crabs, eels, gobies, brittle stars and shrimp can hide. There is also a never ending surface on which other plants and animals thrive. A close look at the surface of the reef in the kelp forest reveals that every square inch is covered with life, from orange and blue encrusting sponges to barnacles, corals, mussels and starfish.
A notable benefit of diving in Monterey is that there are a number of very accessible beach entries within an easy swim of the kelp. The bay is well protected so the waves are relatively small making the beach entries about as easy as they get. Dive sights with names such as ‘The Breakwater’, ‘Copper Roof’, ‘Butterfly House’ ‘Macabee Beach’ and ‘Lovers Cove’ are right off the main street and provide a number of dive opportunities for many different weather patterns. That is to say there is rarely a day when there is no diveable location. On the rare occasions when the weather is such that there is no decent diving in the area or on the day before flying home, the land attractions in Monterey should not be missed. The Monterey Bay Aquarium is a must see. It features a kelp forest tank as well as an open ocean tank plus a number of smaller very informative exhibits. It would be easy to spend an entire day just wandering around the aquarium.
Given the unique life in the kelp forest as well as the relative ease of beach access, Monterey is an excellent yet often overlooked destination.
Last month this page contained part one of this article and showed some ways in which you as a diver could help improve the safety and enjoyment of the diving public. This month we present information that is geared toward the diving professionals in our area. We present this information here, not to blow our own horn or to cast blame, but to help educate the diving public. We believe that if the public is well educated about safe diving procedures and training practices it can only help to raise the bar for all divers.
Who’s problem is it? There are three entities responsible for creating and upholding diver training standards:
The system of standards for training can (and does) break down with any of these entities. This month I will address issues related specifically to dive shops since this is the area I can most directly affect and am familiar with. I noticed an advertisement the other day that proclaimed “Less is More‘. I forget what it pertained to, but it made me think of diver training. It seems to me that some dive shops have embraced the less is more motto. Many scuba students at all levels of training are required to perform less skills with less mastery, over less time than ever before. We have all seen news accounts of diving tragedies, some local and some that have reached the national spotlight. More often than not these tragedies are a result of something unexpected and generally out of any ones control. A diver suffering a heart attack while diving is a tragic thing, but is often unforeseen and blame cannot be placed for an event such as this. On the other hand diving accidents have happened (and are waiting to happen), that could and should be prevented through proper education and the use of safe diving practices.
The biggest diver training problem that dive shops face is one of their own making. As with so many other things, training problems stem from economics. Many of you are already aware of the fact that dive shops generally lose money on their diver training programs. The amount of money generated by a dive class is almost never enough to cover the expenses involved. When dive shops are faced with this economic reality they do one of 3 things; they raise prices for their training (rarely), they continue to lose money on their training, or they cut corners in an attempt to save money. It is this third option that should frighten us all. One of these shortcuts is very imaginative. In an effort to save time and money many shops have gone to the one tank/two dive procedure. The students enter the water and make a surface swim to the skill area, then descend where they perform their skills, ascend and wait on the surface for 10 minutes so when they descend again they are making a second dive. There is a lot of good training and learning that happens when students are required to take the time to exit the water, change their tanks, sit down and fill out logbooks and use dive tables. This also provides the best time for Instructors to talk about what happened during the dive and make suggestions or corrections. In addition to the lost surface training time, these students are getting very little (if any) real dive experience during their open-water training. Students (customers) who endure this assembly line style of teaching are being cheated out of a thorough education and the money they paid for it.
One obvious way to cut the cost of diver training is simply to have larger class sizes. Believe me this is a very tempting idea for dive shop owners. In the short term larger classes save us money. It is obviously more cost effective to “share‘ the expenses out between 10 students as opposed to 6 or less. While this idea may help the dive shop in the short term it definitely hurts the students chances of getting a complete education. Large class sizes are a disservice to the student who has paid a lot of money to learn to dive. For many of these students the dive training experience actually turns them off from diving before they even get started. When dive students are crowded in to the pool, or complete their certification at the lake with a class of 12 other divers, I question how much those divers have really learned. If the new diver has not learned enough to be comfortable diving on their own they are much less likely to keep diving (or buy equipment).
In the past couple of years many dive shops around the country have reduced the hours required for diver training courses. This is done for two reasons:
A prospective scuba student usually has no idea what they need to learn, let alone how long it should take, so it’s easier to sell them on a 3 day weekend course than a 6 day course. These customers simply do not know what questions they should be asking. Dive professionals have an obligation to educate these prospective students about what they really need to learn and how much time it takes to learn it. With each year that passes, diving equipment and procedures are refined and improve. Those improvements often mean that more education is required. Dive computers are a good example. Computers have become a standard piece of dive equipment and time for training about computers should be added to the course curriculum. It is essential that dive shops make the effort to educate the diving public about the need for complete training.
Diver training problems go far beyond the basic scuba certification course. It is true that there are some legitimate differences of opinion about how best to train divers, and each certification agency has it’s own take on the standards and procedures used for training. In fact most dive shops and instructors agree on what should be included in training and many of those agency standards are pretty universal. Major problems arise when Instructors and dive shops focus more on the bottom line than on their responsibility to the diving public. The list of cut corners seems to grow longer each year.
I believe it is time for us all to say ENOUGH. Less is not more, more is more.
If you have purchased all of your own scuba equipment you have made a substantial investment. That investment may be a risky one if you don’t carry insurance on your equipment. Most homeowners policies provide coverage for theft or loss due to catastrophe, but that insurance policy probably won’t cover your equipment if it’s damaged on a dive boat or if the airlines drop your dive bag. Many insurance policies specifically exclude some high value specialty equipment. Call your insurance company to find out. They may require a special rider for your gear. Some of us at Smith Diving have our equipment insured through Sean, Marsh and Roland, LLC. (This company is associated with Divers Alert Network). You can get a quote for equipment insurance on the web site simply by filling some information about your gear and it’s value. There is a deductible and a few exclusions, but the next time you flood that $1200 camera you won’t feel quite as bad. We’ve found the insurance to be reasonably priced, we were quoted a premium of around $270.00 to cover $5400.00 worth of equipment.
The Divers Alert Network's Project Dive Exploration (PDE) is a research program developed to collect information from individual divers about their dive profiles and personal information. DAN’s project hopes to use this information to gain a better understanding of the causes of and prevention methods for DCI (decompression illness). The DAN Research Department began PDE in 1995. The observational study analyzes dive profile data as recorded by a depth/time recorder (computer) for each dive, and compiles data on behavioral and health aspects associated with recreational diving in an effort designed to make dives safer. It notes each diver's individual characteristics, such as age, sex and weight. The diver's health status is also verified 48 hours after exiting the water. Petar Denoble, M.D., D.Sc., DAN Senior Research Director, said 100,000 is a magic number indeed for his department's dive study needs. "The data set of 100,000 dives is large enough for us to evaluate the dive profiles for their risk of decompression sickness and to learn more about risks in multi day repetitive diving," he said. The Suunto line of dive computers available at Smith Diving can be used to contribute to DAN’s PDE.
I would like to be very careful here, I don’t want to sound like I’m preaching - Oh who am I kidding, of course I’m preaching. As you read this, please remember that I know that I’m preaching to the choir, but maybe some of this will get filtered out to the diving public and to those who really need to hear it. There is an old saying in scuba that goes, “If you can dive in the Midwest - you can dive anywhere‘. This is true to a great extent, after all if you can control your buoyancy while staying with your buddy and pulling a dive flag, in 65 degree water with 10 feet of visibility - well you must be doing something right. If you dive locally, and have been on vacation to some warm-water location, you’ve probably been complimented on your skill and comfort level in the water.
So we’re all greate divers - what’s the problem you ask. The problem is that this level of skill and comfort are eroding. There has been a definite decline in the past few years. There are 2 main causes for this decline:
I will address the first cause here and revisit this topic next month to deal with training problems as I see them.
Diving Frequency - This has been a problem since there have been divers, and it’s not likely to go away soon. Many divers get certified in order to dive on a warm water vacation, and that’s great, but these divers seldom dive locally and if they do their dives are sporadic at best. Divers with little experience don’t realize the benefits to diving more often. People who dive more frequently have a greater comfort level, use less air, usually need less weight and can respond more quickly if something should go wrong. In other words they would be safer and have more fun. One simple way increase the number of dives and decrease the time between dive outings is to divide the year in half. If a diver could get 15-20 dives in from January through the end of June and another 15-20 dives in from July through December, that diver would be a lot safer and would enjoy diving a great deal more.
We all know there are divers who simply don’t want to dive locally. We’ve all heard it - “why would I dive in Minnesota, you can’t see anything‘, or “the fish don’t do anything‘, or “the water’s too cold‘, and “you’ve got to where too much stuff‘. These all seem like reasonable arguments for someone who doesn’t know what it’s like to cruise through a forest of trees in the Crosby Pits, or know the feeling of the first sight of the Madeira off in the distance. “The wonders of the deep‘ are not exclusive to warm waters and we in the dive industry need to do a better job of promoting local diving, but you can help too. The next time you’re talking to a diver who isn’t sure about diving around here, invite them out with you (or just send them to us). We are all looking for an extra buddy from time to time, this would be a great way to create one. If you’re not sure where to take them or don’t want all of the responsibility, bring them out to one of our fun-dives. We’ve got enthusiastic and helpful dive masters who know just how to assist divers who haven’t dove here before.
Those of you who have taken Smith Diving’s Excellence in Buoyancy Course understand just how important good buoyancy is to a diver. Buoyancy control affects nearly all aspects of diving. According to Divers Alert Network statistics, the majority of all dive fatalities are caused either directly or indirectly by buoyancy control problems. Most divers understand that good buoyancy control is essential to keeping us safe when we dive, but mastering buoyancy will also make our diving much easier too. Lets take a look at two common buoyancy problems. These problem divers are purely fictitious and any resemblance to real divers is coincidental.
Diver #1 - JOE DIVER - spends most of his dive either at the surface or on his way to the surface. Joe just can’t seem to get underwater even though he just did a weight check and he’s actually a little heavy. When he finally manages to make it down he needs to look around quick because after a couple of minutes he’s popping back to the surface. There can only be 2 causes for Joe’s problem. 1) He’s got (too much) air in his B.C., or 2) He’s kicking himself to the surface. This kicking is actually a fairly common problem for divers who are anxious about diving. If you notice this have the diver cross his ankles as he descends. Joe’s problem is too much air in the B.C. And this is also a common problem for newer divers especially. The solution is simple. Joe needs to really learn how to use his dump valves. Choosing which dump to use seems fairly obvious to experienced divers, but a new diver may need to be reminded that the air will come out easiest if his dump valve is the closest thing to the surface. Even experienced divers should practice using the various dump valves that are available on their B.C.
Diver #2 - JILL DIVER - Jill has an even more common problem and if you’ve spent any time boat diving in the Caribbean you’ve seen your share of Jills. Jill and her buddy listen attentively to the dive briefing when the Divemaster tells the divers that the dive will start at the bottom in 65’ of water. All divers are told to meet the Divemaster on the bottom at 65’ and when everyone is there he’ll start leading the dive. Jill and her buddy enter the water and, not wanting to waste any good dive time, fall to the bottom with all of the grace of boulders falling from a cliff. But hey, no problem, Jill & her buddy stay together and can equalize just fine. When the dust settles after their impact with the bottom, the buddies take a look at their consoles and see that they’ve reached the bottom - at 85’! Maybe the current took them off course, or maybe the Divemaster was just wrong about the depth. Whatever the reason Jill is 2 minutes into her dive and the profile is already blown. This descent “technique‘ can lead to further problems. Following touchdown, Jill needs to add A LOT of air to get neutral. It is very easy to add too much air and Jill starts to go up too much, so she dumps and ends up back on the bottom, up and down turns Jill into a human Yo-Yo. The bottom line - add or dump air a little at a time. Try to keep yourself either neutral or almost neutral all the time. That way you’ll always be in control of where you are and you be a safer diver.
Since the Orca Edge (the first commercially available dive computer) came on the market in 1983 more and more divers every year have come to rely on their computer to keep them safe and track their dive history. Dive computers have become so dominant that some certification agencies no longer require their basic level divers to learn dive tables at all. So how do those computers work? Very simply, your dive computer contains a small pressure sensor (similar to a depth gauge) which converts pressure (psi) into an electronic signal which your computer displays as feet or meters of depth. The computer then uses that depth information, along with time at depth and change in depth, to calculate the body’s nitrogen absorption. These calculations are based on an algorithm (a computational procedure) which is specific to each computer brand or model. Most dive computers make a nitrogen loading calculation every 5-20 seconds during the dive. This constant analysis of information allows the dive computer to create a very accurate picture of the average divers nitrogen absorption. By definition, we can’t all be average (fortunately), so even when you are diving with a computer there can still be a risk of DCS. Almost all dive computers these days allow the diver to make an adjustment of their computers “conservativeness‘. The computer manual will list some specific personal factors which may increase a divers risk for DCS/DCI. These factors generally consist of: level of physical & dive fitness, age (divers over the age of 50 are at a statistically greater risk for DCS), fatigue, cold water exposure, pre or post-dive exercise, heavy work load or stress during the dive, over heating (no post-dive hot-tubs), and of course dehydration (see related article). If some or a few of these conditions exist, the personal factors setting on your computer should be adjusted. The algorithm used in a computer attempts to predict how quickly your body’s tissue will be completely saturated with nitrogen. These formulas actually separate your body into several tissue types or compartments. This definition of compartments is require because the various tissue types absorb (and release) gasses at different rates. The most current decompression theory (Reduced Gradient Bubble Model or RGBM theory), used in Suunto brand computers, defines 9 different tissue types in the body. It is the saturation rate of these different compartments that create a maximum time (nitrogen load) for a particular time/depth calculation. Because we generally do repetitive dives, a dive computer must calculate not only gas absorption, but off-gassing as well. The computer uses it’s algorithm to determine how quickly our tissue releases nitrogen both during the dive and during SIT times. These calculations get very complex and must take into account ascent rates, stop times, and Henrys Law (of equilibrium) which shows that even though we may be ascending, at the end of our dive, we are still adding new nitrogen to our tissue all the time, even on the surface after the dive. The dive computer has certainly made our diving easier and safer, but many divers have come to rely too heavily on their computer. It is important to remember that a dive computer cannot take the place of good dive skills, experience or safe diving practices. Nearly all divers will use a dive computer at some point. When you decide to use a dive computer it is essential that you read and understand the instructions provided with that computer and then pay attention to the computer as you dive.
At Least We Hope So. A well hydrated diver is a safer diver!
One of the leading contributors to instance of D.C.S. is dehydration. Most divers are diving at a severely reduced level of hydration. This is especially true of divers traveling to a warm-water dive destination. It is a fact that the dryer your body tissue is, the faster that tissue will absorb gasses (nitrogen). So, what makes your tissue dry? Many things. The most obvious answer is the air in your cylinder. Air in a tank is dried intentionally as part of the filtration process. High moisture content is very hard on scuba cylinders and can cause growth of bacteria or oxidation on the inside of tanks. Starting off with dry air in our tanks compounds our problems. As we breathe the dry air our bodies try to moisturize the air as it passes through the mouth. This process dehydrates our bodies. On top of that, many divers come to the dive site dehydrated. Temperatures in tropical climates make us sweat and many divers don’t drink enough water to replace that lost as the body tries to cool itself. Some of the things that we like to drink cause us problems too. The alcohol in that Cervesa and the caffeine in that morning coffee, or the cokes on the dive boat are diuretics (they dry us out). This is often why divers need to get out of their wetsuit so quickly after a dive and visit the head. All of this dehydration is increasing the risk for D.C.S.. Some medications (like anti-histamines) are designed to dry us out. Take a good look at the label if you plan to take something before you dive. The solution to this problem is really simple. Be aware of what you’re putting in your body and drink a lot of water or juice before and after dives and try to avoid the things that dry you out.
Just a year or two ago most divers had never heard of the term deep stop. If you have taken a class from us any time in the past two years you already know what deep stop means. The term refers to a part of a diver’s ascent and safety stop procedure. The rule of thumb for deep stops is as follows; for all dives in excess of 40’, divers should make their first stop half-way to the surface for 1 minute, then ascend to 15’ and make the balance of their safety stop for an additional 2-4 minutes. So a dive to 70’ would require a deep stop at 35’ for 1 minute and a stop at 15’ for 2-4 minutes. For dives shallower than 40’, the diver simply completes his/her stop at the standard depth of 15’ for the entire 3-5 minutes. The deep stop has actually been in practice for many years among technical divers. Deep stops present another tool in a diver’s toolbox to help reduce risk of D.C.S.. The theory behind deep stops (explained thoroughly in the NAUI Master Diver Class) describes the relationship between changes in pressure gradients underwater and the formation of nitrogen bubble micro-nuclei in body tissue. Very simply put, it is easier for nitrogen to come out of solution (not turn into full blown bubbles) if the diver changes pressure in stages on his/her ascent. The deep stop creates an opportunity for these bubble nuclei to revert to an absorbed state allowing greater off-gassing of nitrogen both during the ascent and at each stop. Deep stops have become required procedure for all Smith diving training dives in excess of 40’. Many other agencies and organizations are now recommending deep stops for all recreational divers, and computer manufacturers are beginning to build this procedure into their new models.
Smith Diving has been offering nitrox fills and certification for close to a year now, and we are surprised and encouraged by the number of divers who have decided that nitrox can increase their safety. For those of you not familiar with nitrox, look around you, the air that’s surrounding you right now is essentially nitrox with an oxygen content of 21%. To help alleviate some common confusion, nitrox is often referred to as EAN (Enriched Air Nitrox), or EANx (the x stands for the percent oxygen in the mix). Nitrox is actually a mixture of nitrogen and oxygen where the oxygen percentage of the mix is boosted to a higher level than air. The two most common mixes of nitrox available are nitrox 32 (Enriched Air Nitrox with an oxygen content of 32%), and nitrox 36. Smith Diving stores nitrox 32 and will fill any “custom‘ mix up to 40%. Mixes with an oxygen content above 40% require more stringent equipment requirements and create special problems related to filling of cylinders and dive depth/time limits. Nitrox has several dramatic and obvious benefits over normal breathing air. The risk of D.C.S. Can be greatly reduced using nitrox, this is especially true when making multi-day, repetitive dives. Divers generally feel less tired and lethargic following dives using nitrox, and nitrox allows for longer no-stop dive times and shorter sit-times. There are a few special procedures required when diving nitrox. One common myth regarding nitrox is, that it is a “deep‘ gas. Actually the depth limits for nitrox are shallower than for air and these limits must be followed closely.
The NAUI Nitrox Certification Course is the most complete nitrox course available to recreational divers. The course includes 2-four hour classroom sessions where students learn about the physics of mixed gas diving, nitrox equipment requirements, gas analysis, the benefits and hazards of nitrox, and planning for nitrox dives. Unlike many other nitrox classes, this course requires all students to plan, analyze for & perform, two dives using nitrox. These dives can be combined with another Smith Diving course or trip you may have planned.
One of the key rules of underwater photography is to get close. When you think you’re close enough, get closer. It is imperative to get as little water as possible between the lens and your subject. Think about everything that’s in the water around you, plankton, algae, sand, minerals etc. Your camera is looking through all of this stuff to see the subject. Common sense tells us, if we get closer, we minimize the amount of stuff between the lens and our subject, and that will result in a clearer picture every time. So how do we get close enough without spooking the subject? Very carefully. Most large animals such as turtles, sharks and rays spook easily and should be approached timidly. Slow your breathing and approach at an angle trying not to look directly at the subject. If you swim straight for a critter, they may take that as an aggressive action and simply swim away. Make yourself as small as possible, and keep the camera close to your body. For smaller creatures, the best strategy is to wait for the shot to come to you. Watch the environment for a few minutes from a distance and you should be able to identify the best spot to set up for the picture. Look for repetitive behavior in the fishes, compose for background, framing and light, then relax and hover in position. Before long the best shot will present itself.
To zoom or not to zoom ... A common recommendation is to fill at least half of your frame with the subject. This can be accomplished in two ways, either by getting close or with the zoom. In most cases you should avoid zooming to fill the frame. Using the zoom generally allows too much water between the lens creating a cloudy or “dirty‘ shot. Try to get closer and use the widest angle of the lens, this will also allow the flash to improve color quality. The zoom is used most effectively to capture macro objects or to focus on a specific area of a critter for those artsy shots.
It’s white outside and the water is now hard. Time for all of us good Minnesotans to demonstrate our time-tested techniques for driveway clearing and WVM (Windshield Visibility Management). If you plan to spend any amount of time outside in the weather, or under the weather (ice diving), you should take a few minutes to refresh yourself about the hazards of winter weather. As you may remember from your Rescue Diver class, hypothermia is a potentially life threatening condition caused by a decrease in the core temperature of the body.
Hypothermia is a condition that requires immediate medical attention! If you suspect hypothermia, provide first aid by
Avoid rubbing or abruptly moving the victim; this can cause an erratic heartbeat. Trying to re-warm the victim too aggressively can increase the risk of shock and heart failure. Remember that all dives are made in water that is colder than our body temperature. As new divers, we all learned in our training that water conducts heat approximately 25 times faster than air does. This increased loss of body heat creates the possibility of hypothermia in practically any diving situation. It is essential that divers ensure adequate thermal protection even in tropical waters.
You can make your old grungy mask look new again. Simply clean the skirt (inside & out) with dawn dishwashing liquid. Rub the undiluted soap into the silicone. Use a toothbrush to get into the edges and crevices. Rinse thoroughly and then scrub the inside of the glass with toothpaste (not gel). The toothpaste will remove silicone gas that has leeched out of the skirt. This silicone gas bonds to the glass causing your mask to fog up easier.
The term “Free Diving‘ is used to refer to many different kinds of breath-hold diving, from simple snorkeling to extremely deep competitive events. There are 3 basic categories of competitive free diving:
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Additional competitions include Static and Dynamic Apnea contests, which are simply breath-holding while either lying still in the water or swimming horizontally. For more free diving information, check out the links page of smithdiving.com
According to the National Oceanographic & Atmospheric Administration (NOAA) web site, “red tide is an event caused by a large bloom of harmful algae. Harmful algae are single celled plants that live in the sea. When conditions are just right these algae grow very fast and accumulate in dense patches which are visible near the surface of the water. The term red tide is a misnomer as these blooms are not associated with tides. Most scientists now prefer the term harmful algae bloom (HAB) to refer to a bloom phenomenon that contains toxins, or that cause a negative impact. The red coloring occurs occasionally due to the bloom of certain phytoplankton species which contain red pigment causing the water to be “stained‘ red. These blooms are not always harmful, in fact the more harmful species may bloom, but not reach a high enough density to “color‘ the water. A small number of species produce neurotoxins which can enter the food chain and eventually cause food poisoning in humans.
According to my old pile of National Geographic magazines, Chironex Fleckeri - Australia’s Box Jellyfish is the world’s most venomous creature. This jellyfish, which can grow to the size of a basketball, inhabits the northern coast of Australia from Queensland to central Western Australia. Box Jellyfish, like other Jellys, affect mainly swimmers but it’s hatch is closely monitored and warnings are posted in most locations. This square bodied jellyfish can have up to 60 tentacles that grow to 15’ in length. While an anti-venom is available, a skin sting can kill a human in as little as 4 minutes.
Divers will be glad to learn that at least some of their tax dollars are spent underwater. Several years ago, a few of us at Smith Diving were treated to a special VIP tour of NASAs Neutral Buoyancy Lab (NBL) at Johnson Space Center in Houston, TX. The tour was one of the highlights of my dive career and of such interest that its worth reviewing again here.
The NBL facility provides important pre-flight training for Extra-Vehicular Activity (EVA). Astronauts and technicians spend many hours (more then 23,000 hours of total bottom-time in 2003) underwater in order to simulate the dynamics of weightlessness in space and to work through simulated EVAs to solve any problems that may be encountered in space. Astronauts “dive‘ the lab in space suits which are fitted for surface supplied air. They are accompanied in the water by a team of support divers. The NBL is 202’ long by 102’ wide. At a constant 40’ of depth, the Lab accommodates life-sized mock-ups of portions of the International Space Station, Space Shuttle Cargo Hold, and other specific equipment that astronauts may need to deal with in space.
The NBL also acts as a test center for astronauts. Each shuttle team member must complete their assigned EVA activities in the pool before they are released to complete the actual space mission. These tests leave no room for error. If an EVA is going to last :40 minutes in space, the astronaut must perform that mission perfectly in the NBL for :400 (ten times the planned length of the mission.
Our tour of the 6.5 million gallon “pool‘ was conducted by 11 members of the NBL staff each with a very impressive dive resume. The NBL, like most scientific dive organizations rely on NAUI training and all NBL staff are NAUI certified Divers, Instructors or Course Directors.
Why don’t whales get DCS? Even though whales “breathe‘ from the surface rather than from compressed air, the gas laws that affect diving gasses would lead us to believe that whales could get bent due to the extreme depths to which they dive. Whales do not develop DCS because their ratio of lung volume to total body tissue is so small. Whale respiration is so efficient (due to a hemoglobin type cell that carries oxygen) that they need very little air to stay under water for extended periods of time. Because they use such a small amount of air there isn’t enough nitrogen to saturate that huge body mass. On ascent a whale has relatively little nitrogen to off-gas, so they don’t develop DCS.
The 2004 dive season brought the discovery of three new shipwrecks on Lake Superior. Shipwrecks in the Great Lakes have long been a passion of a select few divers who dedicate each new season to the discovery and preservation of these underwater historic sites and we are fortunate that Minnesota is home to the shipwreck hunting team of Ken Merryman, Jerry Eliason, Randy Beebe, and Craig Smith. Ken Merryman was kind enough to provide the following contribution for this month’s newsletter.
Our shipwreck hunting team has been patiently hunting for a number of specific wrecks for 13 years. Our search has covered well over 100 square miles of lake bottom in the process. For some reason Mother Superior found a reason to reveal three new wrecks to us in one year. I might add the wrecks we found are not the ones we were looking for.
Our June discovery was the Thomas Friant, a 96 foot passenger steamer - converted to fishing tug - converted to coastal steamer then back to fishing tug. This wreck is confirmed and lies in 305’ of water in perfect shape in mid-lake out of Knife River. The Thomas Friant was built in 1884 and sank in January of 1924.
In August, the discovery was a badly broken up schooner or schooner scow in a depth of the mid 200’s off Michigan Island in the Apostles. Our best guess at this time is that it is the Moonlight, a fairly significant or famous schooner. I would put the probability that this wreck is the Moonlight at about 60% based on location, cargo and type of ship. It could however, be an unreported sinking which there seem to be a lot of in the Apostles, but it did sink with a cargo of iron ore so we suspect it would have been reported. The Moonlight supposedly sank about seven miles further out in the lake, but given that it was in the 1800’s and just a barge at the time, the chances that they tried to tow it back to a beach, and that the news might not have bothered with that detail is a reasonable assumption. I for one wouldn’t yet stake my reputation on the identification of this wreck.
The November find we believe to be the badly broken up 230’ Benjamin Noble which sank in April of 1914. The wreck sits deep in the clay bottom in a trench shaped impact crater. Based on location, ship type, cargo, and ship structure we’ve seen on the drop camera, we are about 99% sure it is the Noble. We know of no other similar steel vessel that supposedly sank in this area. The only other thing it might be is some “went missing‘ steel freighter that for some strange reason ended up in this part of the lake. This wreck is located in mid-lake out of Two Harbors and lies in 300-500’ of water. The Benjamin Noble has long been the legendary “ghost ship‘ of the North Shore since it sank with all hands and few clues as to where it sank. We are excited at the prospect of finding it to say the least.
Ken Merryman is one of the founding members of The Great Lakes Shipwreck Preservation Society. The GLSPS hosts an annual ship wreck show in the Twin Cities called Dive Into The Past. Membership to the GLSPS is open to anyone.
Did you know that you can “dump‘ the logbook from your Suunto Vyper, Cobra, or Stinger computer at Smith Diving. For a fee of $5.00, we’ll hook your computer up to the Suunto Dive Manager software in the store and download your computer’s onboard history. We will then print out copies of logbook pages for each of your dives. These log pages show a graph of each dive and lots of other specific information.