TDI Diver News


4 Common Sense Rules You Can Apply to Wreck Diving

by: Joshua Norris:
wreck diving
As we all know, the scuba world is filled with many different types of diving. There are caves to explore, reefs to play on/near (don’t touch anything for God’s sake), diving in springs or a quarry to relax for a while, and almost anything else you can think of. Wreck diving has always been a popular activity. There are a few things to consider prior to entering a wreck in order to stay as safe as possible. However, this is not your normal “do” and “do not” list. These four discussion points are simply things to take into consideration. The ultimate decision is going to be left to you, the diver, and your buddies (if you have any). This brings us to our first discussion point:

  • – Personal responsibility

    The dive industry sometimes seems to be riddled with a lack of personal responsibility these days. When a dive pro is quick to take a picture of someone making a mistake, but never engages with the individual to perhaps shed some light on the problem, the entire industry looks petty and foolish. The old saying of “praise in public, and punish in private” has seemingly gone out the window. Instructors speaking poorly of other instructors, divers pushing their limits far beyond what is actually safe based on nothing more than something they read about on social media, and that feeling of “I forgot to bring X, but that will be no problem,” are situations that many need to do a better job of fixing.

    If you ever find yourself with the opportunity to dive down to a 150 feet on a wreck, but you have not been certified to that depth or given proper instruction on decompression procedures, should you continue with that dive? Well why not, right? Normal air is good to “180ish” feet and your buddy may just throw you an O2 tank and you can decompress at 20 feet until your computer clears itself. With that knowledge, what is the issue? You went out on a great dive, got an adrenaline rush because you broke the rules like a badass, and came home safe at the end of the day. No harm no foul… The issue with this is that the minute one little thing goes wrong your personal decision to go have a little bit of fun has successfully put the lives and jobs of both yourself and others at risk. Take some personal responsibility and explain to others your personal limits and perhaps you do not feel comfortable diving beyond that limit. Unlike prom night, you should not attempt to go as far as you can with everything in life.

  • – Forgot your computer, no big deal

    How many times have you forgotten your dive computer? For those of you who would never do such a thing and feel the need to explain with no less than 500 words how stupid someone must be to “forget” their computer, please feel free to do so in the comments section. To all of the others, like me, who have arrived at a site and discovered that they were missing something fairly important; this is for us. There is seldom a worse feeling than to be arriving at a dive site and realize that you have left something at the house. Now what do you do? You likely are not going to drive all the way back to retrieve it. You may be on a plane heading towards that vacation you have been waiting on all year. In any event, the fact remains that you have not properly packed your bag in some way. The best outcome for you is to admit defeat and find a suitable replacement for your missing item while conducting your dive(s). There is no reason to put yourself at risk simply because you do not want to rent a computer for an extra $20. If you happen to find yourself in a location that does not have that option, should you scrub your entire dive based on not having that particular item? I guess that just depends on what that the item is and what diving you would like to do. Again, as a diver you should do your best to take personal responsibility and remember that the safety of yourself and your dive buddies is paramount.

  • – It’s pretty much like cave diving in some ways

    Like many of you, I think I just heard all of the heads in Cave Country explode as a collective. Think about it though. If you are going to penetrate a wreck, it may be a great idea to carry extra gas, reels, lights, etc. This goes hand in hand with cave diving. The point is that if you don’t know what you are doing and are not fully prepared to enter the wreck; simply do not do it. Poke your head inside and look around if you like, but don’t go so far that you turn around and no longer realize just what you have done to yourself. There are a few videos online of folks lucking out and finding an exit. This is what we call, “one time learning”.

  • – Don’t over think it

    It happens all of the time. A group of new students will be standing, waist deep in the water, to do their very first open water dive. You and your buddy, a bit more experienced, see them in the water discussing their dive plan as you two are assembling and testing your gear. As you walk by them in the water, they continue to outline their plan in more detail than The Lord of the Rings. You conduct your 45 minute/1 hour dive and return to the entry point. What do you find? The same group of students discussing the same dive plan. Fast forward this into wreck diving and you will likely find some of the same attitudes, but perhaps in a different way. Meticulous planning of the wreck dive itself is not a bad thing at all. The problem comes when those who planned the dive with such great detail run into a situation for which they did not account. Perhaps the wreck moved since the last time you were there. Hurricanes have a tendency to blow things around a bit. Perhaps you had an equipment malfunction and did not plan for each and every thing to go wrong. From there, the horrible tradition of problems compounding themselves may begin. Just remember to plan your dive out, but also just go with it. Diving is not unlike other things in life in that curve balls will be thrown from time to time, and you must learn how to adapt quickly to potentially terrifying situations in an overhead environment. Educate yourself on how to deal with issues and practice until you can remain calm and take corrective measures when necessary.

These are some of the common sense approaches to take when preparing for a wreck dive. Things will go wrong, computers will fail, your buddies may call the dive leaving you in an awkward situation; just don’t be the diver that goes in and doesn’t come back simply because you rushed into it. I can guarantee that no one will care if you missed the wreck dive in five years. If you injure yourself or someone else though, that scar may never fade away.

– Joshua Norris, Air Hogs SCUBA


What’s Your Life Worth?

by Sean Harrison:
water rescue
In a previous life when I did not have as much at stake, an opinion that did not make my parents very happy, I road motorcycles… any kind of motorcycle. After a number of years of riding used motorcycles, I decided it was time to buy my very own, brand new, road bike. While picking out my bike and looking at all the other goodies that could go along with it (can’t have a brand new bike and a bunch of old accessories) I looked at the helmet display. Up until this point I thought a helmet was good for keeping the big bugs and rain drops from hitting my face, just hearing the splat on my face-shield was proof enough they would hurt. Near the display I saw a sign which had a very powerful message from a company named Shoei and it read, “If you have a five dollar head, wear a five dollar helmet”. Now, even in my early 20’s, that message struck home. In pretty much every course I have taught in the past 20 plus years, I have found a way to use this line. Not very hard really, helmets are a safety device; dive gear is life support… close enough. The point is, when it comes to your life or the life of a loved one, don’t take the cheap route.

For the past 15 years a big part, and not the best part, of my job has been reviewing and analyzing diving accidents and fatalities. These reports span the globe, and cover all ages, genders, and disciplines of diving. Two unfortunate themes are reoccurring: basic skill failure and cutting corners on servicing.

Basic skill failure transcends all levels of diving from the basic open water diver to the best trained diving professional. This is a problem that boggles my mind because there is an unlimited amount of resources out there to prevent this from happening. A term was recently coined “Normalization of Deviance” and it is very fitting for what I have seen in diving. In short, and this is a very abridged interpretation, there is a correct way of doing something, but if you deviate from that correct way and nothing goes wrong, you find yourself continually deviating. This, in time, is going to catch up with you. Basic skills should be practiced on every dive, and at bare minimum a refresher should be conducted every year for divers not diving regularly. You may be asking – what kind of basic skills are you talking about? I am referring to: turning on a cylinder, removing a weight system, monitoring your gauges. Sound basic? They are, and taught in every open water course, but have seriously injured many and claimed the lives of even more.

Going cheap on servicing is another one that gets me. Most equipment can be serviced for less than $200 per year; the more sophisticated the equipment, the higher the cost. This is of particular interest when it comes to rebreathers. I have at this point, lost count of the number of accidents that have involved out of date cells, and scrubber canisters with expended scrubber materials. I am grouping scrubber medium in with servicing since it is an expendable item that needs to be “serviced”. O2 cells can be, and must be (by most manufacturers) replaced every year, for around $300.00.

So what are we talking about here? Depending on what type of equipment you are diving and how actively you are diving, $200 – $700 per year. Is your life worth less than that? I don’t think so and neither do your loved ones. The really sad part here is that you won’t realize the cost and the value until it’s too late. No, diving is not an inexpensive sport but it pays itself back many-fold by the places you go, the people you meet, and things you get to see that few others have or will. Just the therapeutic value alone is worth thousands!


Girls Pee, Too

by Shirley Kasser:
drysuit female

“You just need to get some adult diapers.”

Huh? Seriously? Before the advent of the She-P, such was the extent of the advice to female technical divers facing longer and/or colder dives who didn’t want to, or just couldn’t, hold it. Like many others, I had no desire to stew in my own juices, so to speak. In addition, I had my doubts about the capacity of those things. I pee a lot. Listening to the guys complain about their cath removal woes garnered zero sympathy from me. At least they could go!

While still diving wet, I began to do some research. Some products on the market for female hikers looked like possibilities, with some modifications. The solution seemed to be just there, dangling off into the middle distance. Yeah, I said “dangling.” Feel free to snicker.

Then, out of the blue, well… out of some wonderful Dutch folks, came a new term to our tech diving vocabulary, “She-P.” Looking a bit like a tubby black stingray after a trip to the country buffet, this little gizmo was the answer to all of those cross-legged, wiggling-dance prayers. My order for a new drysuit was placed on the same day as my order for one of these beautiful new pieces of art.

Having read lots of advice from the inventors and their then soon-to-be North American distributor, Laura, online, I was ready when the package arrived. I’d already installed my p-valve and completed the necessary landscaping. It was time to pee!

Now, let’s not skim over that landscaping bit. This device covers a wide swath of your girly bits. You think waxing sounds painful? Try ripping off a nicely glued She-P without having done the necessary hair removal preparation. Paramedics may be required. Have fun explaining things to them.

Shaving, and the stubbly regrowth, is nearly as bad as diving in a wet diaper. Waxing leaves a nice result, but if you’re diving a lot, the needed regrowth of hair before being able to wax again leaves much to be desired (refer to the previous paramedics note). Laser hair removal is the trick. It’s expensive, but worth every single curly-hair-removing penny.

With landscaping done and p-valve installed, we are ready for arts and crafts time. Get out the glue. There are multiple types of glue available, and some fairly detailed videos, so we aren’t going deep into detail here. However, like anything you want to be good at, you have to practice. Glue that baby on and slug down a Big Gulp. Depending on where you live, go outside and pee on a tree. Write your name in the snow. Or, if you live in the city, you might just want to practice in the shower.

Be patient with the gluing process. It takes practice and is no place for shyness about your body. The spray adhesive works, but I’ve found that the brush-on glue allows for easier repositioning when I miss. Did I mention, be patient? Ask questions, but ultimately, you have to experiment to find the right positioning for your body. Once it’s properly glued in place, I often forget it’s there. It warms up and becomes a part of me. It’s best to get glued up before heading to the boat or dive sites, but I’ve successfully glued up standing in the corner of a truck door. Practice makes perfect. Complacency and hurrying make for leaks. Don’t rush this bit.

This beauty attaches to a standard p-valve with no modifications required. A barbed fitting or quick disconnect work great. The choice is yours. Most kits come with tubing for you to cut to size. Keep in mind, you’ll be peeing out of that tube whenever you’re not suited up, so make it long enough to comfortably hit your target and connect into your p-valve. A bonus is that you can now use the urinal in the port-a-potties instead of having to drop trou and hover above that disgusting seat.

But wait, there’s more! Really need to pee but do not want to go to the marine head after that burrito-eating beer-drinking buddy has just had his morning constitutional down there? She-P makes peeing over the rail or into a bottle a breeze! Hiking the woods searching for that one special cave? Take a spot at a tree next to the guys without having to come out of your suit. The world is now your urinal.

WARNING: This device has been known to turn middle aged professional women into 6 year old boys, considering anything and everything a potential target for their new skill. You have been warned.

Have fun. Be patient with yourself. Ask questions. Keep trying. And DIVE DIVE DIVE!

Go to and for information, education, entertainment, and dealer locations.

– Shirley Kasser –


The P-Valve Struggle

First things first, if you don’t know exactly what a P-valve is, it’s pretty basic. Essentially, it’s a tube that has a valve on one end that vents to the outside of your dry suit that allows liquids to pass from the inside of the suit to the outside.


Cave diving 101: Avoiding Entanglement

by Steve Lewis:
cave diving 101
Scuba diving seems to make an appearance on just about every sports writer’s list of the most dangerous recreational activities; and my guess is that when asked, every single one of the men and women compiling those lists would rank cave diving the most dangerous form of scuba diving. For example, Forbes, the venerable business magazine famous for listing things like the world’s richest person, most expensive car, or blingiest wristwatch, puts cave diving right up there with bull riding, base-jumping and surfing monster waves. With respect – and with a nod of the head to the personal bias resulting from being an avid cave diver – I feel we should temper any belief in the accuracy and relevance of these lists with the knowledge that they are put together by writers happier conforming to uninformed generalizations, than researching primary data and supportable statistical evidence… but let’s not go there right now.

Let’s say instead that although cave diving presents divers with an alarmingly long list of potential risks, those risks are well-managed and suppressed to a perfectly acceptable level by following a few quite simple rules. Sure, cave diving has the potential to be dangerous, but when we follow best-practice guidelines, the stats reflect a totally different perspective: in short, the level of danger is inversely proportional to how closely we stick to well-established guiding principles!

Paramount among these principles is having the relevant instruction, up-to-date experience and practice with the appropriate kit and skill set, and staying within personal limits.

For example, let’s consider entanglement… and the steps cave divers learn to reduce the dangers entanglement present.

Even if you have never been inside a cave, you may already know, those dived on a regular basis have a network of permanent lines and navigational markers in them. These lines (usually color-coded kernmantle), are fixed in positions that make them easily seen, and not easily tangled in fins or other gear. This helps to make getting snarled up in them unlikely: especially compared to divers who penetrate wrecks, which often have a horde of cables, nets, wires, and ropes ready to reach out and grab at passing dive gear. But cave divers are also taught a few skills to further ensure any interaction with lines is visual only.

The first step in the process of managing entanglement risk is to streamline one’s personal dive gear. This is part of the process that every Cavern/Intro Cave/Full Cave student is walked through with his or her instructor usually well BEFORE diving in an overhead environment.

Chief culprits are the “danglies”: any accessory, any piece of harness, any clip, reel, spool, light, or regulator second stage not tucked away either out of sight in a pocket or pouch or “hidden” making contact with permanent lines improbable.

Another step in the streamlining process is to “trim the fat” from one’s dive gear. This means to take only what’s needed, and to leave behind what’s not. For example, some divers like to adorn themselves with every piece of kit they can pick up and carry to the water. It’s not unusual to see divers (even cave divers) with five or six additional reels and assorted spools attached to their harnesses. Make no mistake, every member of a cave-diving team MUST at all times carry a safety reel or spool, but taking “three or four or five extras just in case” is overkill. Especially when the dive plan calls for no deviations from the main line or gold line. OTT (Over-The-Top) accessorizing is unnecessary and encourages the Christmas Tree approach to kit configuration!

With this in mind, we can segue to the topic of “line traps”, places on a diver’s kit or person that a line might get pushed into, making removal difficult, time-consuming, or darn right dangerous. Classic line traps include manufacturer’s standard fin and mask straps (which are either taped or replaced with better options); swing-gate boat clips (which are sometimes called suicide clips and typically replaced with bolt snaps); anything behind the diver’s back such as a doubles manifold or a tangle of reels and spools clipped to the diver’s butt; or a side-slung stage, bailout or decompression bottles (which should be pulled in tight to the body’s lateral line a la sidemount configured tanks). Most of these can be managed or eradicated completely using a little creativity, judicious gear selection and editing, and common sense, but some simply have to be accepted as inevitable (the behind the head paraphernalia for anyone diving backmounted doubles or a rebreather for example), and dealt with accordingly.

And this brings us to what is perhaps the most important skill, and certainly the one most difficult to acquire: positional and situational awareness.

Cavern and cave diving students learn that they should strive to develop complete control of their buoyancy and the ability to maintain their body in an attitude best suited to the conditions: often, but not always, horizontal trim. As these skills begin to develop and become finely tuned, a diver’s awareness expands to provide them uncanny feedback regarding the exact position of their hands, feet, fins, body, equipment, accessories, etc. relative to their environment. This makes it possible for them to maneuver through restrictions, glide past snags, over, around and under lines without coming into contact with anything.

Most of all perhaps, the seasoned cave diver understands the Zen-like concept of being in the moment… and being in no rush to get anywhere. Yes, the most common mistake made by new cavern and cave divers is to behave like a puppy at the beach… or perhaps more like a bull in a china shop. Slowing down, taking one’s time will certainly be helpful, and will help avoid entanglement. And in the cases where something does become snagged, the Stop, Think, Act response taught in basic SDI open water classes, remains the best advice.

So, go out there and have fun, and if you should bump into that writer from Forbes, take the time to explain that cave divers are not nutcases with a death wish!


March 2015 Instructor Trainier Workshop in Israel

by Ilan Berkovich:
ITW IsraelIt took some time, effort, and commitment (about 15 years worth) to become an Instructor Trainer Evaluator within the International Training family, and I was finally able to conduct the first ever Instructor Trainer Workshop in Israel. This program started on March 8th and was completed on March 15th 2015. During this time, the Instructor Trainer candidates covered many topics such as methods of professional instruction, the role of the instructor trainer, standards and procedures and evaluation techniques.

The program was very intense and brought them to the proverbial finish line of understanding their role as the future educators and ambassadors to the next generation of professionals for SDI, TDI, and ERDI. The program was a great experience and was a fantastic success.

I would like to take a moment and share the overview of the course with you. We started the first day in the classroom at a new facility in the International Training family, Manta Dive Center – a beautiful facility on the Red Sea. After the paperwork and introductions were made, their first classroom session began and the candidates started to understand and embrace the expectations of the course. In the following days, the candidates conducted numerous presentations covering many levels of instruction (and some non-diving related hilarious stuff) allowing others to hone in on their evaluation techniques at various levels. Many discussions were had on the evaluating process, along with brainstorming sessions on improving their techniques to the point where they all understood their roles and what they needed to achieve when preparing future instructors. Candidates always contribute many new points of view and great ideas that make these programs an ever evolving process.

The final two days were spent in the lovely waters of the Red Sea using Deep-Siam (International Training Regional Office) utilizing the amazing beaches for in-water and rescue skills, and confined/open water sessions during the water part evaluations. The program was completed with great success and I am proud and confident knowing these Instructor Trainer’s have so much knowledge to pass on to new professional members and will continue on developing the next great generation of educators for the industry as a whole.

For more information on the next Instructor Trainer Workshops, follow this link,


Are You Ready for Trimix? – Students VS. Instructor Perspective

by Instructor Trainer: Jon Kieren and Diver/Student Jordan Greene:
trimix diver

Instructor Perspective

Jon Kieren:
Day one of a TDI Trimix Course can be intimidating. It usually includes an evaluation dive with your instructor to ensure your skills are up to par before proceeding, as well as an academic review session to evaluate where your dive planning and emergency procedures skills are at presently. While this evaluation day is not typically a go/no-go situation, it gives the instructor an idea of what (if any) remedial work will need to be completed before moving forward. How do you know if you’ll be ready?

The first step will be to determine if the TDI Trimix Course is the appropriate next step for you. This is a personal decision that you need to make on your own, but your TDI instructor can be an excellent resource when trying to decide what your next step is. Do the dives you want to do regularly require trimix training? If not, maybe you should focus your dive training efforts on something that will more directly benefit your diving goals. If they do, then you’re on the right path.

Are you willing to make the investment? Yes, trimix diving is expensive, but it is also time consuming. Many divers have no problem coughing up the cash for the gear, gas fills, and training, but then fall short on making the time investment to keep their skills fresh. Are you willing and able to commit to diving at least once or twice a month? Are you willing to dedicate most of your dives to shallow water practicing skills? If not, your skills can quickly deteriorate after your course leaving you with an expensive plastic card.

Next up, are you mentally prepared for trimix diving? Trimix diving involves depths reaching 100 meters/330 feet and decompression obligations ranging from 30 minutes to several hours. Any emergency must be handled in the water, failure to do so can almost certainly result in serious injury or death. These situations are stressful for just about anybody, but if you are not mentally prepared to be in those situations, you will likely not be able to handle them. How do you handle stress? Can you solve multiple equipment failures in limited to zero visibility without panicking? Your TDI Trimix instructor will teach you techniques to cope with these types of scenarios, but you have to be mentally prepared to be put in those situations before you even get in the water.

Finally, are you a good enough diver? This is difficult for most divers to answer honestly. By now you’re a certified technical diver, at a minimum TDI Advanced Nitrox and Decompression Procedures certified, and you have made at least 100 dives. You’re a pretty experienced diver by this point. Whether your skills are where they need to be to begin TDI Trimix will be a decision that ultimately your instructor will make, but it’s important to be honest with yourself as well. We all want to think we’re the best divers in the universe, but this is typically far from the truth. A buddy with a GoPro camera filming you practice can be a great tool to help you evaluate your own skills. Some simple drills can be done to quickly evaluate your current skill level:

  • Valve Drills- How quickly can you identify shut down a malfunctioning regulator/valve? At trimix depths, mere seconds count when gas is hemorrhaging, and being able to isolate and control the situation will be critical in your TDI Trimix Diver course.
  • SMB Deployment- While the practical use of this skill varies drastically from environment to environment; it is ALWAYS an excellent test of a diver’s ability to handle a complex task quickly and efficiently.
  • Fin Kicks- Modified Flutter Kick, Frog Kick, Back Kick, and Helicopter Turn; can you perform each of these efficiently and without sculling your hands?
  • Stage/Deco Cylinder Handling and Gas Switches- Can you remove and replace your stage/deco cylinder and make gas switches effortlessly without skipping a beat? Trimix training will begin adding additional stage/deco cylinders making basic cylinder handling skills extremely important. These dives also often require up to 2 or more gas switches on a dive, additional gas switches means more opportunities to make a fatal mistake.
  • AND MOST IMPORTANTLY- can you perform all of the above while hovering within a 1 meter/3 foot window and in proper trim? How about without a mask?

At this level of training, all of your basic technical diving skills need to be second nature in order to ensure you will be able to handle the additional task loading of more complex dives as well as equipment failure and other emergency scenarios appropriately. Your TDI Trimix Instructor will help you refine many of these skills and help you with managing emergencies; however, taking an honest look at yourself and your current skill level will greatly help you prepare for your class.

Once you have decided that the TDI Trimix Diver Course is the next logical step, have committed to making the time and financial investment to both the training and keeping up your skills, determined you are mentally prepared to conduct trimix dives, and have made an honest self assessment of your skills, it’s time to get in touch with your TDI Trimix Instructor and start planning your training. Use our Instructor Locator Tool to find an instructor near you.

Student Perspective

Jordan Greene:
trimixWhen technical diving was introduced to me, the TDI Trimix Course stood out in particular more than any other course. Not to undermine the magnitude of any other courses or to discredit the knowledge and skill each one built upon my dive education, it was something about the science of it. The idea of using a gas not commonly or naturally utilized in human physiology for the purpose of exploring a deeper reach, a manipulation even was fascinating to me. This course and type of diving seemed so far-fetched when I started my first tech course (TDI Intro to Tech), it was something I saw as intimidating. Learning the fundamentals of technical diving and being exposed to new types of equipment, configurations, skill sets and understandings made a Trimix course seem mountains above my ability at the time. Building up to performing decompression dives to depths of 100 meters/330 feet (TDI Advanced Trimix) would become a long, hard, time consuming (and expensive) dedication; one that I would happily pursue over time. A Trimix course is by no means a weekend course and requires a great amount of focus and dedication, whether your just starting technical diving or you have accomplished your prerequisites to this course (Advanced Nitrox, Decompression Procedures , 100+ logged dives), honestly ask yourself if deeper diving on mixed gasses is a path you would like to follow. Do you have the time and dedication to learn and maintain skills? Do you have the mental ability to apply the knowledge? Can you handle emergencies scenarios in stressful situations while maintaining a clear train of thought? Are you ready for a Trimix course?

These were my initial thoughts when starting out in my technical training and actually still remain as my thoughts today, though the intimidation and fear factor has been greatly replaced with confidence, understanding and ability. As I mentioned before, a trimix course does not happen over a weekend or week, many months of preparation and experience must be built up prior to starting a trimix course. As with any education or skill, a strong foundation must be built to ensure a sturdy structure can stand. Without a strong understanding of what trimix diving entails, one might not be as thoroughly physically and mentally prepared; training and building upon your current skill set should be routinely enforced before entering into your trimix course. Ultimately it is the student’s decision to move onward to this course, and with the advice of your trimix instructor, it may be determined whether you’re ready or not. As a student, you should be well versed and confident in the practices of your Advanced Nitrox/Decompression Procedures certification including physiology, gas planning, labeling, analyzing, switching and application of corresponding skills. These skills can quickly deteriorate, so it is very important for a student to constantly refresh them in shallower water environments often. Work closely with your instructor for evaluation and areas of improvement; take advice with an open mind. Emergencies can arise at any moment and the more practice a student can have mapping and executing these drills, the better. Valve drills, assortments of fining and kicks, deco cylinder drills, gas switching, low/no visibility comfort, strong current comfort and SMB deployment all need to come natural at the point of entering your trimix course. If one point could be greatly enforced and underlined, it would certainly be to follow your instructor’s guidance for planning, skills assessment, and knowledge development. Your instructor will truly be your greatest asset in determining if this is the right course for you. Ultimately, you should appreciate any advice given, even if it isn’t what you would like to hear. After all, diving is supposed to be fun and your instructor wants you (and themselves) to preform these complex dives as safe as possible. The time commitment and financial investment in a TDI Trimix Course is significant, but remember, the payoff is just as great if not more. The reward will be more than just exploring a deep wreck or over head environment. The discipline and confidence the training and course provides can be applied throughout your diving career and applied to many future courses. Contact your TDI Trimix Instructor and discuss your thoughts on moving forward with this course, be honest with yourself and your instructor about your skills and ability to determine if this is indeed the right course for you.

Related Articles


Looking Back On Innovating Decompression Protocols to Expedite Water Exits

by Bret Gilliam:
Bret Gilliam
The era of dive tables as the only method of calculating dive plans is one that is largely forgotten by many in the “modern” world of electronic diving computers and the plethora of algorithms and deco models that now are available.

I have long been an advocate for embracing innovation and new technologies, including being a prominent spokesperson for transitioning to dive computers, nitrox, mixed gases for deep diving, and rebreathers beginning in the late 1980s.

But my first involvement with deviations from standard practices was back in January of 1971 working on an experimental Navy deep diving project where we were assigned to film fast attack submarines in the open ocean at depths that eventually took us past 500 feet. At the time, all Navy diving was done on dive tables and there were very few choices.

We had “standard” single dive exposure, “repetitive” multi-dive exposure, “exceptional” exposure, and “heliox” that employed helium with oxygen to manage both narcosis and O2 toxicity issues. Of course, there were also tables to default to in the event of omitted decompression due to contingencies. But it was a short menu.

For the most part, these tables served us pretty well. One thing that is interesting to note is that the standard maximum oxygen partial pressure then was a PO2 of 2.0 ATA. This allowed air diving to 300 feet. Later the PO2 limits were reduced to 1.6ATA but that was derived from NOAA protocols that determined that some of the population could not tolerate higher PO2s.

In military diving when I came into the project, the governing protocols tended to be determined by the priority of the project as this was during the height of the Cold War era and making fast attack submarines as undetectable as possible was right at the top of the list. So we were encouraged to innovate as necessary to get the job done. In retrospect, it’s also worth noting that our dive team was probably considered to be “expendable” in the pecking order of achieving the outcome and we were very much aware of that in short order.

Most Navy divers were tethered and on surface supply breathing gas then except for shallow scuba work and some one atmosphere 100% O2 rebreather projects. (Of course, Sea Lab’s saturation project preceded us but the divers were basically confined within a restricted swimming range of the habitat.) We were some of the first teams that would work untethered, on self-contained multiple cylinder equipment packages and without the benefits of removal from the ocean for surface decompression. There is much to be learned from a variety of the departures from standard practice and some of the internal controversies that ensued, but the “bottom line” was the priority of the mission to get us below the deep scattering layer of ocean thermoclines (typically first encountered in the Caribbean below 500 fsw) and get the film work done for evaluation that would drive changes in nuclear submarine design to make them quieter and undetectable to the Soviets.

I was assigned to a team working in the Virgin Islands Trench, over 10,000 foot depths, while other teams were doing similar work off Andros Island in the Bahamas. Those teams included such pioneers as Jordan Klein who was also known for his Hollywood movie work on such films as “Thunderball” that featured Sean Connery’s secret agent James Bond in diving adventures.

When we learned that we would be deployed from surface vessels and would conduct our dives and subsequent long decompressions in the open ocean this initially did not raise any particular warning flags to our team. However, once we began operations we encountered a completely unexpected hazard that was off our “radar”. Everyone is probably aware of the prolific population of oceanic white tip sharks, a pelagic species known for their aggressive behavior. What we didn’t know then was that their aggressiveness was amplified by low frequency sound projections we introduced into the ocean caused by both the instruments used to calibrate various sonar devices and by the subs themselves with their own systems.

It wasn’t until many years later that the relation of low frequency sound, and other stimuli such as the noise made by sinking ships as the hulls and compartments collapsed and aircraft that crashed into the ocean, tended to drive the sharks into far more excessive threats and virtually ended any ability to thwart their aggressive attack behavior. At times, we would enter the water for routine dive system drills and encounter 10-15 oceanics and have virtually no problems with them other than curious close approaches that could be dealt with by a bang on the snout or similar actions. However, once low frequency sound and other stimuli were introduced, both their numbers and aggression tended to go off the scale.

Instead of a few sharks that generally behaved, we would now be faced with scores that could escalate into hundreds at a time. And all seemed hell-bent on biting anything they encountered. They bit the ship’s props, the prop shafts, equipment that was lowered into the water, cables that were deployed, and just about anything that entered their ocean universe. From our rather selfish perspective, we were not particularly concerned about rushes to bite the boarding ladders. But we did care about their tendencies to want to bite us… fins, tanks, camera housings, and most importantly: body parts.

There were times when it was necessary for the deck crews to hang over the working dive decks on the vessel’s sterns to push away the sharks with boat hooks just to make a “hole” in the ocean that we could jump into. It was not for the faint of heart. Once our descents were initiated, we found that the sharks would lose interest in the divers as we passed about 80-foot depths and return to abuse the vessel and its equipment. But when we came back up from deep exposures, we entered long decompression cycles that forced us into a constant war of evasive protective behavior that was more than a bit nuts.

So we began to experiment with anything that would get us out of the water faster without compromising our inherent risk and tolerance of inert breathing gas uptake that dictated our long decompression hangs to out-gas. The first thing we did was initiate contact with some civilian physiologists in Canada at a company called BioLab that were fascinated to have human subjects to beta-test some of their theories about the then largely unproven methods of changing decompression by innovations in usage of both pure oxygen and what they called “oxy-air”. This gas would later become known as “nitrox” or “enriched air”. Hell, they could have called it “magical mystery” gas as far as we were concerned if it got us out of the water faster and away from the munching predator sharks that never ceased trying to eat our equipment… and us… during the long hangs.

The first deviation from Navy protocol was to begin switching to oxygen as deep as 60 feet… a PO2 of 2.8 ATA. That exceeded the allowable maximum oxygen exposure for working divers but was exactly the same as what divers breathed if removed to the safety and comfort of a decompression chamber. We adopted a practice of as little physical exertion as possible to minimize carbon dioxide production (CO2) that was known to be a triggering influence for O2 toxicity and seizures. Our methods worked and that cut our deco hangs by as much as 50%.

The next innovation was to switch to “oxy-air” or nitrox mixes in deeper depths while adjusting the PO2 levels to our tolerance. This even more dramatically cut our deco times.

Also remember that this was January 1971, over 44 years ago. There were no cell phones, no Sat-Phones, barely any land phones on St. Croix and calling Toronto in Canada was absurdly expensive. There was no email or fax to quickly communicate the results of our daily dives and deco results so sometimes our dialogue was accomplished by “snail mail” and it could take weeks for our feedback and BioLab’s suggestions to be exchanged.

On occasions when we could get access to phones, we’d call in following a new beta-test of a suggested aggressive deco schedule and when the phone would be answered on the other end we’d detect obvious surprise that we had somehow managed to survive. But that quickly moved on to a conversation about the next suggested evolution. It was an interesting process but ultimately effective. It laid the foundational groundwork for major changes in diving.

But most importantly to our dive teams, it got us out of the water faster and away from our antagonist shark partners that we shared the ocean with.

Later, NOAA picked up where we left off and when the first generation of computers allowed algorithmic experimentation on deco models using early electronic “real time” diving computers, the revolution really took off. Much credit is owed to the late Dr. Bill Hamilton in the U.S. and the late Dr. Albert Buhlmann in Switzerland for their pioneering work in underwater physiology and deco modeling. I was pleased and proud to have known both men as friends and professional colleagues. Their work forever changed how we dive today.

Looking back on how we arrived where diving technology is today is revealing. For our dive teams nearly 45 years ago, it was prompted by adaptions aimed at self-survival and the methods worked. That’s a “bottom line” that increased our “bottom time” at depth while dramatically reducing our “hang time”.

I’m sure the oceanic white tip sharks missed us. But we were not missing our prolonged time with them…

Bret GilliamBret Gilliam was the founder of TDI and the other agencies of International Training. He began diving in 1958 and his professional diving career in 1971 with the Navy project. Since then he has been involved in every segment of the diving industry including retail and resorts, military and commercial operations, filmmaking, publishing, manufacturing, diving ship and liveaboard design and operations, as well as legal consulting in litigation procedures. Along the way he has logged over 18,000 dives. He was inducted into Diving’s Hall of Fame in 2012 by the AUAS as the Recipient of their NOGI Award for Diving Sports/Education. After nearly 25 years of living in the Caribbean and equatorial regions of the world, he now makes his home in Maine and travels internationally on diving projects.


5 Best Wreck Dives in North Carolina’s Famous “Graveyard of the Atlantic”

by Thomas Powell:

Around the world, divers and dive professionals will tell you that different areas have some of the best diving available. The desire to find new and exciting places to dive often leads to the development of “best dive location” lists that get printed in various publications. Many of these lists often include dive sites off the coast of North Carolina.

The North Carolina coast is one laden with a rich maritime history beneath the waves. If you have ever had the pleasure of diving the North Carolina coast and its famous “Graveyard of the Atlantic,” you know that there are hundreds of wrecks that range from wooden-hulled sailing vessels to modern artificial wreck structures. The wrecks sit at depths from 60 foot recreational limits to depths beyond the reach of standard technical diving methods. Each one of these fascinating structures lay in blue waters with a feel and visual display much different from traditional tropical settings.

When divers ask North Carolina natives what the best dive sites are off their coast, very rarely is the same answer provided. For that reason, I have chosen to list five favorites that are only a small portion of what North Carolina waters have available.

1. The U-Boats (U-352, U-701, U-85)
North Carolina is lucky to have three scuba-accessible World War II era U-boats beneath her waters. Those vessels represent a unique era in American history. The U-352 is one of the most famous wrecks off the North Carolina coast and she sits in 110 feet of water. Various charter groups offer trips to dive her on a regular basis and crowds from all over the planet come to partake in this experience. In truth, the U-352 is the wreck that first draws many divers to the North Carolina coast. Conversely, the U-701 and the U-85 are more difficult to visit. Temperature changes, currents, and visibility also make these dives a bit more difficult. Despite an increased level of difficulty to visit, these wrecks have the benefit of experiencing fewer divers, making the sites less disturbed by human intervention, each year. Many divers seek to dive all three of these U-boats and over time many have achieved this accomplishment. Diving the North Carolina U-boats is a historical experience as well as an exciting experience.


USSAeolus” by US Navy – Transferred from en.wikipedia to Commons by User:Magnus Manske using CommonsHelper.. Licensed under Public Domain via Wikimedia Commons.

2. Aeolus
The Aeolus is a wreck that was sunk off the North Carolina coast for the sake of developing an artificial reef system. She is 400 feet long, sits in 110 feet of water, and is broken into three major pieces from the hurricanes that often hit the North Carolina coast. Once a cable repair ship, the Aeolus is now a wreck famous for it’s abundance of sand tiger sharks. Divers often experience them in large groups, and they are mostly found in and around the wreck. Any diver who ventures out to the Aeolus will always remember an incredible dive that can rival almost any “shark dive” out there today.

3. USS Indra
The USS Indra was once a landing craft repair ship that was sunk as an artificial reef. She is 338 feet long and is a common dive location visited by the various North Carolina charters. The site has little current, remains largely intact, and offers dive depths from 30 to 60 feet making the wreck a fantastic place for new divers or a place to complete training programs. Similarly, she is close to shore and easily accessible throughout the dive season. The USS Indra is one of the wrecks more commonly visited by divers off the North Carolina coast and is perfect for any type of diver to get a “first taste” of what North Carolina coastal diving is all about.

4. Proteus
The Proteus was once a luxury passenger liner that sank in a collision in 1918. This makes the vessel a true wreck sitting in roughly 120 feet of water. Though she is old and maintains a large debris field, she still has the appearance of a ship, and items that would be found aboard a luxury liner are still being recovered from this site. The water surrounding this site is often warm and clear due to Gulf Stream currents and the structure still provides enough coverage to allow reprieve in the event that a current is present. The Proteus is also a hot spot to encounter sand tiger sharks and various other types of marine life such as large sting rays. On some occasions, divers have even reported sand tiger shark numbers in the hundreds on this site. Diving the Proteus is an incredible experience that will leave any diver wanting to experience more of the blue Carolina waters.

5. Normannia
The Normannia is a pleasant wreck to dive and often described as “pretty.” She is 312 feet long and was once a passenger ship and freighter. She is easy to navigate with the bow, stern, and boilers somewhat intact; but time has caused the wreck to fall into itself to a large degree. The wreck sits in roughly 100 feet of water and the Gulf Stream currents often provide a warm and clear environment. Many of the normal North Carolina fish are found on the wreck of the Normannia, but again, Gulf Stream waters have had an effect and caused many fish species often found in southern tropical waters to take up residence on the wreck. The Normannia is a perfect blend of east coast experiences combing wildlife from southern waters with that of the central east coast.

Each of these wreck sites offers a wonderful and exciting experience to a diver visiting the North Carolina coast, but a diver who is interested in the “Graveyard of the Atlantic” dive sites should contact the coastal charters and go diving. Diving the various available wrecks is the only way to decide for yourself what site is really “the best.” Having been diving around the world, I believe the North Carolina coast and her “Graveyard of the Atlantic” is truly a wonderful diving experience that is different from most places people venture. The only way to understand why it is different is to test the waters and give it a try.

– Dr. Thomas Powell
Owner/Instructor Trainer – Air Hogs Scuba, Garner, NC


Why You Should Invest in Visual Inspection Training

by Don Kinney:
high pressure cylinder
There are many reasons to invest in formal visual inspection training. The best reason is safety; to keep everyone out of harm’s way from a cylinder failing while under pressure, or a compressor failing to work properly. There are also other reasons, even financial reasons, to invest in such training.

A properly trained individual will understand the allowable damage on a specific style of cylinder, the workings and proper operation of a compressor, and they can help develop safe filling procedures for a facility. There are a great number of people who have been around for a long time and have experience in these areas, but when was the last time they had a refresher course, listened to new ideas or developed new techniques? Taking a formal inspection training course can help a novice understand the nuances and dangers involved and can also give new ideas and techniques to the seasoned veteran.

Here are but a few reasons to take a formal training program:

Protect your investment in your equipment (cylinders, valves and compressors)

A company or person has invested hundreds, thousands or even millions of dollars in the cylinders they use recreationally or for business. These cylinders are quality pieces of equipment that can withstand specific uses and/or environments. There are times that the uses or environments exceed the design of the cylinder. The cylinder can then be exposed to factors that may weaken it due to corrosion and stress.

Many of these conditions can be reduced or eliminated as long as the cylinder is properly maintained.
An example of such a circumstance is a steel storage cylinder sitting on concrete with no barrier. The bottom of the cylinder is in direct contact with an environment where it is exposed to moisture. If this condition goes unchecked, it could lead to damage which may render the cylinder useless due to the level of corrosion. With proper training a person charged with the maintenance of the cylinder may prevent such an occurrence and keep that cylinder in service for its intended service life.

When a cylinder becomes damaged it must be determined if the damage exceeds an allowable limit. Simply having damage does not render a cylinder unsafe to use. Most cylinders are designed with a certain amount of damage expected and are designed to withstand that damage. The person maintaining the cylinder must know the allowable limits and understand how to gauge the amount of damage. When looking inside a cylinder and corrosion is detected, how can the inspector measure the damage and make an assessment? Proper training will give the inspector hands on knowledge with a trained professional.

The same principle holds true for the valve on the cylinder. The valve has moving parts and components designed to retain high pressure gases. Constant use, as well as infrequent use, can have an affect. Over-use or over-tightening the valve can affect the high pressure seating material. No use, with the addition of contaminates, may cause the valve to seize or not work as designed. With proper maintenance and care, a cylinder valve should have a long serviceable life. Proper training can cover common issues and proper maintenance tips to ensure a long service life.

If a person or organization has invested in a compressor, it is likely one of the most expensive pieces of equipment in their high pressure arsenal. The compressor is a complicated piece of machinery with numerous moving parts that must work in unison to achieve its rated service pressure. Small particles, not enough oil, too much oil or wearing seals can cause very expensive, unexpected repair bills. The compressor must be maintained, parts replaced and it should be on a scheduled, budgeted maintenance procedure. It is when the compressor is neglected or ignored that the maintenance costs become problematic. Proper training can help the staff develop a maintenance schedule and keep the compressor running as intended.

With a compressor working properly the compressed gas needs to be filled into a storage cylinder. How can this be accomplished safely? The compressor will likely handle pressure well above 207 BAR/3000 PSI. Even much lower levels of pressure, in the hundreds, is enough to go through skin and cause life threatening injuries. The person operating a high pressure fill station must understand these risks. The person filling a cylinder is also the most likely person to notice a safety issue with a storage cylinder and prevent a problem by not using a specific cylinder until it is properly inspected and found safe to use. The fill station can be one of the most dangerous assignments, and that person needs proper training to keep themselves and the facility safe.

Keep yourself safe – hazards from noise to explosions

Working around cylinders and compressors exposes a person to noise and other dangers such as air embolisms and possible failures of the valves or ruptures of cylinders. Care and maintenance of the cylinders and machinery is one step in preventing these issues. But a more critical step is training the person or employees to be safe around the hazards. Simple training tips, such as wearing hearing protection, how to properly move the cylinder, or how not to handle a valve, can go a long way in protecting a person and property. A formal training program will help an organization develop a proper and useful training program.

Compliance with some countries hazmat laws

Because the person or facility is dealing with compressors and cylinders and there is a risk of rupture and damage, most areas and countries have rules in place to keep persons and property safe. Even if an area does not have a governing body, it should be the operator or owner’s responsibility to develop rules that keep themselves and everyone safe. Governing bodies may dictate what training is required or how frequently that training must be administered. However, if no rules exist for proper training, it is important for the organization or person to develop common sense training to keep persons and equipment safe. Taking a formal training course will help to make a person or organization compliant with local rules and regulations, or give the organization proper training if no governing body exists.

There can be no guarantee that if a person takes formal training and follows all the rules, that an issue wont develop. However, if steps are taken to train persons in allowable damage, the repair of valves, the workings of a compressor and the dangers involved when dealing with high pressure gases, there is a greater chance to reduce the threat. A formal training program goes a long way in keeping personal safety as well as a facility safe and preventing damage to the expensive equipment it has purchased and wants to maintain for a long service life.

Interested in International Training Visual Inspection Course?
Get more info here >

About the author: Don Kinney is the owner of Cylinder Training Services ( Don started formally working with and filling cylinders in 1991. With his background in public safety he continued to gain knowledge in the field of high pressure cylinders and began to develop training programs. He has developed programs for PSI/PCI including; Eddy Current testing (2003), SCBA, Fire Department (2004) and their Fire Safety Seminar program (2004). He went on to develop his own visual inspection program covering cylinders, valves, cleaning and compressors in 2011. At this time he realized that inspectors needed a source for affordable and high quality inspection tools. His tools are designed for the high pressure cylinder industry, and to assist them in determining damage and ensuring cylinders remain safe. In 2014 he developed an inspection program for International Training (SDI/TDI/ERDI) where he published a manual and developed an on-line training program. Don continues to dedicate himself to safety in the high pressure cylinder industries. He prides himself on understanding the client and their needs and coming up with a safe and useful training program designed to keep them safe and save them thousands of dollars.