6 Tips for Conserving Your Breathing Gas

There are many factors that can help a diver at any level conserve breathing. The following are six basic suggestions that may help you reduce your gas consumption.

Transitioning from Sport to Tech

You must want to learn more, and take the time to become more proficient in order to remain safe, but you must always make the step into the technical world for the right reasons.

The Top 3 Finning Techniques and When to Use Each One

A diver should be able to move through the water using their fins as the exclusive means of propulsion to increase efficiency and minimize the impact to the environment.

4 Things I wish I’d Known Before My First Tech Dive

by Sean Harrison:
Tech dive

As I look back on the days when I first started tech diving, two things come to mind that have had significant changes – equipment and logistics. There have been such dramatic changes in equipment it is hard to highlight them all. The early tech equipment was nothing more than standard equipment that was reconfigured to meet our needs, it was not specialized, light weight, easier breathing at deeper depths or made of special metals. And we certainly did not have rebreathers, those did not come ‘til the late 90’s. Logistics, on the other hand, has gotten better but can still be a little tricky. My tech diving started in the mid-Atlantic states of the US where there were several boats that would take us to deeper wrecks and allow us to stay a little longer in the water. We also had a hard time getting the gas fills we needed for the planned dives. Things have gotten better in this aspect but here is a list of things to be aware of if you are considering getting involved in tech diving or have recently learned to tech dive.

1. Boats – not all boats are created equal. Dive boat operators as a general rule rely on the number of divers they take out per day, pretty simply math – the more divers they take out, the more money they make. When boat operators take out tech divers they will usually reduce the number of divers on their boat (space for additional equipment) and stay out a little longer to allow for decompression or rebreather divers – this means you may pay a little more to do tech dives off of boats. This also means you need to speak with the boat operator and make sure you can do the dives you want to do off their boats. Mixing tech divers with sport divers normally does not produce good results.

2. I have to go! – tech dives are not always deep but they are almost always longer than your average sport dive. Longer dives means better exposure protection (even in warmer water) read: dry suit, which means no peeing in the water, or does it. TDI recently released two good articles on this:

The P-Valve Struggle »
Girls Pee, Too »

The short version of these articles is, it is important to stay hydrated while diving and with hydration comes nature’s call. Lots of options to manage this situation so do your research before your next long dive.

3. I’m hungry – anybody that knows me knows I love my food and after a few hours in the water, I surface ready to eat! Diving burns calories and the colder the water the more calories burned. Tech diving from boats in many places also means longer boat rides, so getting back to the dock is not going to happen as fast as it does on sport dive boats. Bring along some good snacks or a sandwich to get you back to the dock. If you have a good snack on the boat ride back, you will be able to get started on the monster nap sooner.

4. Bring on the gadgets – not so fast. Tech divers are certainly gear geeks but they also tend to be minimalists and only bring what they need. A big part of what allows us to tech dive and stay underwater longer is minimizing air consumption; carrying more gadgets means not being as streamlined and increases air consumption. As you select gear, think about what kind of diving you will be doing, cave divers don’t need what wreck divers do and cold water wreck divers don’t need what warm water ocean wreck divers do. Also think about where it is going to go on your body or configuration. Too many things stacked on top of each other means you may not be able to access it when you need it.

If you are a planner or someone that likes to work through scenarios, technical diving is right up your alley. Plan out your dives, call the boat operators or local stores (if you can do the dives from shore) and find out what sort of support they can provide. If you will be diving from a boat, make sure you are clear with the operator what kind of dive you want to do and see if they will do it. Planning ahead is critical when it comes to rebreathers and traveling, not all locations support all rebreathers. Make an equipment check list and go through it before every dive/trip, with tech diving comes more equipment which equals more things to forget. Make sure that check also includes a save-a-dive kit, and that the spare parts now include the ones you need for tech diving. Plan ahead and have fun. A spontaneous tech dive can result in a spontaneous disaster. If you have not yet taken a tech diving course, consider signing up for the TDI Intro to Tech Course. This course will give a great overview of what to expect and what you will need.

Take Your Tech Diving Skills to the Public Safety Sector

by Dr. Thomas Powell:
erdi diver
Scuba diving is a sport in which a person can always grow and learn. Anyone who has looked at the list of available classes out there can understand that the sky is the limit when it comes to scuba education. Similarly, there exist multiple types of diving around which a diver can focus education, skill progression, and experience. The reality of the various educational pathways is that they all have the potential to build upon one another.

Public Safety Diving is a type of diving based upon the training divers receive along a pathway. First, public safety divers are trained as open water scuba divers. From that point, they may venture directly into the public safety realm or move on to learn more about technical or recreational skill sets. Like any other subject, increased education and experience often leads toward an improved level of overall performance. Essentially, the more a diver gets wet, and the more that diver tries to learn, the better he or she may have the potential to become as a public safety diver.

Public safety diving is one of the most dangerous realms within scuba diving. Divers often enter the water not knowing bottom terrain, currents may be present, and the visibility may be nil. Similarly, the technical diving realm is one in which divers work to better understand physiology, gas switches, safety precautions, and bailout procedures. Many of these activities are practiced without a mask while maintaining neutral buoyancy. Each of these subjects has a direct correlation to public safety diving. Imagine that a diver is in zero visibility, stuck in an entanglement hazard, and low on air. Technical training can better prepare that public safety diver to handle gas switches and emergency procedures while blind.

Similarly, technical divers tend to focus on streamlining equipment, exposure protection, moving items for convenient placement, neutral buoyancy, launching buoys and bags, and equipment redundancy. Again, each of these actions can also be found within public safety diving. First, public safety divers often carry lots of equipment and wear bulky garments. This equipment must be streamlined to prevent entanglement issues and moved around as needed for easy access in zero visibility. Second, public safety divers often spend time on the bottom doing hand searches for missing items. The problem with settling on the bottom is that the diver may accidentally move, cover, bury, or miss an item. The diver may also further “muck up” the environment for secondary searches. Finally, public safety divers often carry lots of redundant items for safety. Many of these items may be marker buoys or even lift bags.

Technical training may be a perfect baseline for any public safety diver. Technical training can teach a diver to perform tasks while close to the bottom but maintaining neutral buoyancy, and move excess items around on the body in a fashion that helps streamline equipment and reduce the effect on diver trim. Essentially, technical training may allow a public safety diver to better understand how to carry equipment, use equipment, reduce any effect on bottom terrain, and avoid the development of foreseeable problems. Every Technical Diving International class also teaches divers to launch buoys and bags. Every public safety diver must be proficient at launching marker buoys and working with lift bags. Again, this is technical training that can help any public safety diver become more proficient at his or her trade.

In regard to overhead environments, technical training may also include cave training. Cave training teaches divers how to be safe and proficient in overhead environments when visibility may change in a quick fashion. Cave divers learn to lay lines that can be followed back to an exit while working in a confined space and as a team. Again, each of these actions is something valuable to a public safety diver. Almost any environment may be considered an overhead environment for a public safety diver. If the diver cannot see, he or she may not know what is overhead or if there is an obstruction between the diver and the surface. Training to lay lines and understand how to properly backtrack can help a public safety diver remain safe in an unknown environment. Similarly, a proper education on laying lines can help a diver or dive team return to a known location in an efficient fashion, mark specific positions, and do so while maintaining a tight continuous line with minimal extraneous hazard developments. Finally, cave divers are trained to deal with tight spaces. Imagine a public safety diver entering a wrecked school bus in an effort to perform a recovery. That diver must be able to act and react in a proficient fashion with minimal space to move. This is something that cave classes teach.

Technical training is something that can help any public safety diver become more proficient at necessary skill sets. The current problem is that many public safety divers begin public safety training and do not have the personal time or resources to take on technical programs. As excess or secondary training opportunities, technical classes should be considered by public safety dive teams to help provide growth and development opportunities for divers. Education and time in the water is something that can help any diver. The first big step is to inquire about training opportunities and to decide for yourself how it can help you or your team.

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

4 Tech Diving Questions You Should Ask, But Never Do

by: Dr. Thomas Powell
tech diver with doubles
Scuba diving is a sport that a person can enjoy for an entire lifetime and never truly reach the end of training or educational opportunities. As the scuba community has expanded, many sport divers have started asking more and more about the world of technical diving and the opportunities that it has to offer. Technical diving is a realm that many new or long-standing sport divers often look at with awe, excitement, and desire. As technical instructors make educational opportunities available to a larger group of potential students, many unique and interesting questions often get asked. These questions are often critical to aid in the education of newly-minted technical students. When questions do not get asked, a student or a new technical diver may choose to test certain ideas that may lead to problematic situations or even injury. The desire to go deeper, see new things, and venture where few have gone before can cause individuals to become complacent about sensible actions. For that reason, the technical community has been a tight-knit and supportive group for many years. Understanding why answers to certain questions are important to know, but not to “test,” can go a long way toward helping a student become a more competent diver who builds a trusting relationship with his or her educator.

There are many questions that show an eagerness to learn but deviate from the tried-and-true standardized educational path. Of those questions, here are four examples with illustrations as to why knowledge is essential when partaking in the “advanced” levels of scuba diving:

How many dives do I need at the bare minimum to jump to the next course and training level?

We all want to learn more, grow as divers, and push some sort of limit in our individual sports, hobbies, and activities. Otherwise we would not grow at doing what we love. The problem is that becoming a better diver is not about the card, what course you have jumped into, or how high you can go within a hierarchy. Instead, scuba education is about getting more proficient, learning tricks that make diving easier and more enjoyable, and more than anything, PRACTICE. The point behind taking a training course is to learn how to perform certain skills and how to do new things (or become more skilled at certain things). The job of an instructor is to ensure that a student can safely complete tasks and perform as a competent diver. This does not mean that every diver who completes a new course is the best diver in the world at that particular training level. The education provides a diver the means and knowledge he or she needs to – go out and safely continue working to become better. Some divers may be ready to jump to the next level of training, while others may desire, need, or even be encouraged to continue diving and practicing. Similarly, participating in too many courses in a row may create an overload of information for a student. One of the best practices out there for any student is to partake in a class, and then GO DIVE! Once the student feels like he or she is ready, the next educational step should then be taken. Training should never be based on a baseline minimum number of dives, but instead on the readiness and preparation for a new program. A diver who looks at scuba education as a race to the finish may not take the time to learn the things he or she needs to know to stay safe and efficient in the water. The best way to make the determination regarding a person’s readiness for the next step in education is to ask the instructor and follow his or her guidance. The goal of any instructor from Technical Diving International (TDI) is to train and prepare divers to be competent enough to dive and be partners with his or her own loved ones. For this reason, a good instructor can help a diver make quality decisions about what steps to take and when, in regard to scuba education. Once a diver knows in his or her own mind that he or she is ready, and the associated instructor agrees, then it is time to safely take that next step.

Can I get by with my current equipment? Do I really need to spend money on something so similar to what I already have? I can cut some of this cost out, right? Why does my computer have to be replaced? Those things are expensive.

Technical scuba diving can be an equipment-intensive world within the overall realm of scuba diving. Many divers get into diving with fun new equipment geared toward sport activities. Depending on the type of diving a person is learning, new equipment may be needed. The best way to view equipment in scuba is to relate it to something else. If you were running a marathon would you rather wear your dress shoes in the closet at home, or would you rather wear a fitted set of stable and comfortable running shoes that would not blister your feet? Or, if you had a loved one who was in a medical emergency, would you want the ambulance coming to get that person to have quality modern life-support equipment or hand-me-down equipment from twenty years ago? Sometimes “it might work” is not the way to approach gear needs, especially involving life support equipment. A technical diver does not necessarily need the most expensive and newest top-of-the-line equipment, but he or she does need quality life support equipment that is both dependable and reliable. A technical student must remember that he or she may be venturing into colder waters, darker waters, soft ceiling scenarios, or even hard ceiling overhead environments. These situations call for redundant gear items and equipment designed for that type of diving. Similarly, many sport computers do not have the capability to plan for the use of mixed gas or decompression needs. Again, the job of an instructor, following the standards of TDI is to ensure that during training, a technical student learns about what equipment a diver at each training level needs in order to dive at that level in the safest way possible. Sometimes gear can be recycled for technical diving use, but money should not be the determining factor behind diving in a safe or unsafe manner. Instead, quality equipment should be obtained when possible, and learned (in regard to use) prior to partaking in advanced and potentially more complex diving activities.

Is my depth limit associated with the course a requirement or is it just a suggestion? I can go deeper if I feel prepared right?

Depth limits have been established by TDI with safety in mind. Instructors have been trained to show students why depth limits are important, and often depth limits are associated with gas, physiological reactions, and physiological needs. For instance, why would a person go to a certain depth if they could stay twice as long and dive more safely on a gas mixture different from air or nitrox? The person who wishes to push that limit without knowing a good answer to that question is not taking his or her time to either answer the question in an effective fashion, or is only entertaining technical scuba for the thrill of the moment rather than the love of the sport and the desire to do more. Similarly, TDI Instructors are required to take advanced students to specific depth ranges to complete many of the courses within the technical program. Technical students will get the chance to go “deeper” during training and not just simulate depth as an exercise. Pushing depth limits without knowing how to be safe, monitor physiology, or be prepared for problems can lead once again to injury or even death.

Can I use my shiny new gear to go straight into tech? I bought this yesterday and I am ready to roll!

Many new technical students do make the decision to purchase new equipment to support the needs and activities related to technical diving. These purchases may include new regulator sets, buoyancy compensation systems, dry suits, wet suits, masks, lights, and even fins. The problem is that many new students may be jumping into gear that they are not yet able to use in a confident manner. Once again, if you pay for one hour of training time at the gym, do you want forty-five of those minutes to be spent learning how to use the equipment? When a diver buys new equipment at any training level, that gear needs to get wet. The diver needs to strap it on in a safe and controlled environment and work out the bugs. Not knowing how to use or configure new equipment may lead to problems, a lack of focus, or a dislike of diving activities. For this reason, prior to starting any technical program, a diver should go to the water with his or her gear and do some sport dives to make sure he or she is ready to learn and enjoy a future class. The only time this type of situation does not come into play is during a program such as TDI’s Intro to Tech Course during which a diver may be trying new equipment and diving methods for the first time, and a lack of preparation may be considered part of the educational environment surrounding the course.

One other question that is often asked by new technical students revolves around training. New students, old divers, and anyone getting wet should remember that skill practice has a purpose.

I was doing these things long before this class. I already know this stuff so can we skip these steps and move on?

Many individuals have partaken in “technical” scuba activities over lifetimes of underwater adventures. Every dive shop knows old salty divers who went deep long before technical scuba was organized under TDI and other agencies. Similarly, many technical classes require that basic tasks be performed that sport divers have learned over time. These tasks may include the deployment of a lift bag, buoyancy skills, or basic physiological reaction tests underwater. Students may consider repeating old skill sets redundant and desire to move forward at a faster pace (eliminating skill steps). The problem with this request is that basic skills may not be the same in the technical realm of scuba. For instance, the diver may know how to deploy a lift bag, but can he or she deploy that lift bag while hovering in a neutral fashion next to a vertical wall at depth with gloves on? Technical instructors are often looking for more than basic single-skill competency. Instead, they are looking at how the diver handles his or herself while enduring various complicating factors. What was once a simple skill in warm Caribbean waters during an SDI Advanced Adventure Course may not be so easy in deeper and colder waters while wearing a redundant equipment load. Technical students must trust that skill sets have a purpose, and once again practice is a good thing. Working through skills and trying to become more competent at what someone may consider a basic task is what makes a diver “better.” So while a diver has the attention and time of an instructor, the best value is to do everything he or she can, new and old, in the hopes of establishing a better understanding or receiving possible advice from someone who has done it countless times.

No question is a bad one. Education and understanding is essential to safe diving practices and learning programs. Instructors should be ready to answer questions or at least find information for students as knowledge is requested. It is always better to ask and learn rather than push the unknown within a community that may have sensible answers already developed based on experience and knowledge. Technical diving is about learning the complex nature behind advanced scuba diving activities while developing independent proficiencies; so ask questions and then take the time to enjoy and use what you learn.

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

Technical Diving Resources

by Jon Kieren:
tdi divers researching

Books – The texts listed are all excellent resources for any active technical diver, or anyone who is interested in beginning their technical diver training. Some of the titles are instructional manuals, while others are non-fiction stories of exploration.

  1. Advanced Wreck Diving Guide – Gary Gentile
  2. Basic Decompression Theory and Application 3rd Edition – Bruce R. Wienke
  3. Basics of Rebreather Diving, The – Jill Heinerth
  4. Beyond the Deep: Deadly Descent into the World’s Most Treacherous Cave – William Stone, Barbara A.M. Ende, Monte Paulsen
  5. Blueprint For Survival – Sheck Exley
  6. Cave Divers, The – Robert Burgess
  7. Caverns Measureless to Man – Sheck Exley
  8. CCR Cave “Almost Simplified” – Dr. Mel Clark
  9. CCR Trimix Simplified – Dr. Mel Clark
  10. Deco for Divers – Mark Powell
  11. Deep Descent: Adventure and Death Diving the Andrea Doria – Kevin F. McMurray
  12. Deeper into Diving, 2nd Edition – John Lippmann and Dr. Simon Mitchell
  13. Diving in Darkness: Beneath Rock, Under Ice, Into Wrecks – Martyn Farr
  14. Diving into Darkness: A True Story of Death and Survival – Phillip Finch
  15. Diving Physics with Bubble Mechanics and Decompression Theory in Depth – Bruce R. Weinke
  16. Diving Physiology in Plain English – Jolie Bookspan
  17. Essentials of Cave Diving – Jill Heinerth
  18. Fatally Flawed – The Quest to be Deepest – Verna an Schaik
  19. Introduction to Technical Diving – Rob Palmer
  20. Last Dive: A Father and Son’s Fatal Descent into the Ocean’s Depths, The – Bernie Chowhury
  21. Mastering Rebreathers – Jeffrey E. Bozanic
  22. Mixed Gas Diving: The Ultimate Challenge for Technical Diving – Tom Mount and Brett Gilliam
  23. Physiology and Medicine of Diving, 5th Edition – Alf Brubakk and Tom Neuman
  24. Rebreathers Simplified – Dr. Mel Clark
  25. Shadow Divers – Robert Kurson
  26. Shipwreck Hunter: Deep, Dark & Deadly in the Great Lakes – Gerry Volgenau
  27. Sidemount Profiles – Brian Kakuk and Jill Heinerth
  28. Six Skills and Other Discussions: Creative Solutions for Technical Divers, The – Steve Lewis
  29. Staying Alive: Risk Management Techniques for Advanced Scuba Diving – Steve Lewis
  30. Technical Diving from the Bottom Up – Kevin Gurr
  31. Technical Diving in Depth – Bruce R. Wienke
  32. Technical Diving Handbook – Gary Gentile
  33. US NAVY Diving Manual
  34. Wookey Hole: 75 Years of Cave Diving & Exploration – Jim Hanwell, Duncan Price, Richard Witcombe


    • The SDI/TDI/ERDI website provides student divers direct contact with their local TDI facilities and Instructors via the Dive Center/Instructor Search Tool. You can also search hundreds of articles about technical diving on the TDI Blog. The Course Description Page gives potential students access to complete descriptions as well as the Standards and Procedures of almost all TDI courses offered.
  2. Rubicon Foundation:
    • The Rubicon Foundation Research Repository is a free digital archive of over 8500 searchable references on topics ranging from Diving Accidents and Fatalities, Decompression Sickness, Hyperbaric Drug Interactions, In-water Recompression, Oxygen Toxicity, and much more! This is by far the largest collection of diving references, and the foundation actively undertakes projects that:
      • Contribute to the interdependent dynamic between research, exploration, science and education;
      • Improve the available resources for students, professionals and the general public; and
      • Preserve the valuable natural resources that are vital to future endeavors.
    • The Rubicon Foundation is a non-profit organization, they accept donations to help support their projects HERE.

Forums – Forums and discussion boards can be an excellent source of information from active technical divers and instructors. It is important to use caution whenever you are taking advice from someone on the internet, however.


Don’t Be Intimidated By Tech Diving

by Bob Meadows:
tech diverBack when diving was perceived as dangerous and intimidating, a small group of divemasters (DM) and instructors asked me to go diving in some springs and caverns in what was considered my back yard at the time. That place was Ginnie Springs in High Springs, Florida. This weekend adventure is still fixed in my mind, like that first car you owned! These early “tech” divers invited me into their world, when I was only just a kid with some good buoyancy skills.

They were fantastic mentors, providing me advice and training on how to use a reel, lights, communicate through light signals, air sharing, the importance of buoyancy in a cave (to not disrupt the bottom), and how to calculate air consumption. Three days came and went, leaving me hooked and excited to dive in places where few could, or even wanted to. All because a few of the DMs and instructors I was with at that time thought I had good buoyancy skills.

Those early mentors of mine contributed to the great passion in my love of diving; not just to dive pretty reefs, but they encouraged me to ask questions such as, where did that ship sink and why? Where does all the beautiful spring water come from? They enabled me to have a lifelong passion for diving and it all started at a far away time in Florida, and has literally taken me around the world since.

Diving has it cast of characters for sure. The better divers and mentors are not judgmental or arrogant in any way. They are genuine, they inspire, and they instill a sense of passion for learning, even when one does not know it. Yours truly, might not have become a technical diver without the early invite from mentors guiding me through their non-intimidating instruction.

Most divers today have the ability to efficiently technical dive once they receive the training and have the requisite experience under their belts. There are plenty of instructors and divers from all backgrounds to teach and mentor technical divers, while the truly good ones do not beat their chest over their accomplishments to the world. These divers instill and inspire the next generation of divers to be the best diver they can be; whether it’s on is a 10 metre/30 foot reef dive or a wreck in 60 metres/200 feet.

As a community of divers we should always be learning and evolving. We should represent our community, whether sport or technical endeavors, with the same understanding and empathy needed for one learning how to dive. There are plenty of instructors with varying degrees of experience that do a great job of that – taking a student and instilling confidence and passion for diving in their life.

On the other hand, the elitist attitudes of some have pushed away potentially great divers over the years. On several occasions I have witnessed divers stating they cannot start a technical dive course because their instructor requires 500+ dives, perfect buoyancy skills, and jet fins for training. These are great opportunities for mentors out there to guide divers in the right direction, foster the basics, and allow the diver to learn, grow, and gain more experience along the way – not just the right amount of dives or fins. Arrogance is the last thing our dive community needs, everyone should be working together towards promoting our sport and all that it encompasses whether it is shallow dives, long cave dives, deep dives on a wreck, or an exploration on a virgin reef.

Sport and technical diving have differences, such as going deeper and staying longer. Most people who are curious or want to technical dive shouldn’t be discouraged by bad attitudes. There are a lot of dive facilities and instructors that will help turn their desires into realities. Technical diving isn’t for everyone, but everyone should have an equal chance at exploring options and not be discouraged by chest beating scuba super heroes. Every mentor in the dive community should inspire confidence, passion, and a willingness to learn and do better in every diver they encounter. Technical diving takes commitment, training and an open mind to new ideas that emerge.

The moral of the story is, there are a** holes everywhere, but there are also plenty of empathetic, caring, encouraging divers out there to help the new aspiring divers along the way. Whatever level we’re at in diving, we should always be mindful of our attitudes and encourage a mentoring type relationship to bring up divers to come.

– Bob Meadows
Instructor Trainer
Owner – World of Scuba, Boca Raton, Florida

The Secret Sauce for Surface Marker Buoy (SMB) Deployment

This article focuses on one specific aspect of deploying an SMB: methods for inflating the SMB.