You’re Invited to Meet the Agency

What can SDI™-TDI™-ERDi™ do for you…?

You're Invited to Meet the TeamInternational Training’s agencies, SDI™-TDI™-ERDi™ will be at the Tacoma Dive & Travel Show from April 21st through the 22nd. We have so many exciting things that we want to talk to all Pro Members, Associate Members and non-members alike about. Be sure to meet with Shawn Harrison, Regional Manager for the northwest at booth #101 and say, “Hello.” We would love to hear from you!

For more information on what SDI™-TDI™-ERDi™ can do for you as a diver or a professional member, come see us at 12pm on Sunday, April 22 where we will have a presentation called, “Meet the Agency.” A lot of exciting changes have been made at International Training including our HQ move to Florida, a new website and the launch of TDI™ programs online.

Come and see what your next step in scuba training may be based on your interests and needs. Looking for a deep diver course? Interested in rebreathers? Do you run a dive team with your local fire department? Want to advance your career in scuba as a professional? We may have what you are looking for in the recreational realm, technical side of scuba and/or in public safety diving and training.

We are excited to be attending the Tacoma Dive & Travel Show from April 21st through the 22nd and hope to see you there. Contact Shawn Harrison at (888) 779-9073 or email for more information.

To learn more about the training options available visit today

Show hours are:

Friday April 20, Industry Only & Exhibitor Pack-in begins at 8 am with an Industry Social at 6 pm

Sat. April 21 from 10 am to 5 pm and Sun April 22 from 10 am to 4 pm

For 50% off your admission, print out this discount offer.

For a full schedule of events, please visit

Need a Dive Buddy?

Why not create one!?

Need a Dive BuddyIf like Santana’s infamous song you find yourself humming …”I aint got nobody that I can depend on…no tengo a nadie”… this is not a good place to be for a diver. You need to launch a plan to get a Dive Buddy…right now!

Chances are you have half heartedly tried to recruit a friend to your favorite past time, SCUBA. You may have had some luck and some failures.

Here’s a plan: invite your friends to go diving, NOT just go take a class on it. Have them come along on a trip and actually be part of the fun. Arrange for their involvement, a spot on the boat, on the beach or water’s edge. Maybe, just maybe, if the opportunity lends itself, arrange for them to snorkel above the dive group so they can see firsthand what you are up to. Chances are that if you contact your local SDI™ facility and ask them if you can bring a friend down to a pool session to have them splash around and maybe try SCUBA, they will be more than happy to accommodate you.

One thing is for sure: if you don’t ask, you won’t get! So quit humming already… you are starting to scare the person beside you…don’t look now!

Simply contact for the facility nearest you or give a call 207.729.4201.

Stay Ready to Dive by Keeping a Fin in the Water

A refresher course and continuing education will keep you ready to dive!

We all do it and we are all guilty of it….we get busy, sometimes we’re actually busy and sometimes it’s all just in our minds. But there is something else we all share…we are never too busy to go DIVING!

This is where the potential problem lies; we have all heard the discussions of qualified versus certified. For example, I maybe be a certified diver but not qualified for cave diving…get the idea?

Well this time of year many of us get ready to make our trek back to the water’s edge and in doing so we need to remind ourselves that we have to get our qualifications back up to speed! If you have stayed active and maintained your “diving rhythm” you are to be congratulated and a bit envied. Now for the rest of us, there are considerations to undertake…

As we approach the diving season, not only should your equipment be ready, but so should you! If you have found yourself in an extended period of diving inactivity, a refresher course may be called for. During the refresher course you will review the basics of equipment and important skills that will improve your comfort in the water. You can easily arrange a refresher course with an SDI™ Instructor; to find one near you simply visit

For just a short absence from diving, an SDI™ specialty course may be the perfect way for you to get back to diving. The specialty programs are also conducted by SDI™ Instructors and the same link above can be used to plan your course. The specialty will often incorporate the review of skills as well as acquiring new ones, all along improving your comfort in the water.

Specialties also open up possibilities of different dives and travel areas; particularly, you will find that many centers will incorporate specialty courses in conjunction with trips and even host a “pool equipment shake down” to make sure everything is “just right” before you embark on the adventure.

So no matter what route you should decide to take it is imperative that first and foremost you remember your limitations! Ease back in and do all you can to be one of “the lucky ones” that plan and dive year-round to continue to advance their diving skills, never “slowing down” for refreshers…instead taking in adventure after adventure!

To learn more about Specialty Programs available from SDI™ please visit or simply give us a call 207.729.4201 or 888.778.9073

Is Being a Dive Instructor Something You Enjoy?

Then becoming an Instructor Trainer MUST be at the Top of your Bucket List!

Becoming and InstructorBeing an ITW can be heaven-sent for most Instructors, giving them the ability to often combine travel adventures with training

Isn’t it time you started taking your dive career in that direction?

Are you ready for the challenge? Are you ready for an IT? We have selected the following dates for the ITW which will be held in Jensen Beach, Florida; April 23rd-30th.

Just 30 miles north of Palm Beach you will find the new TDI HQ. With the Gulfstream in our backyard, the diving is good and warm year-round!

Become an SDI TrainerWe are extremely pleased with our move, and now it is time to continue business as usual with our 1st ITW located in our new office at Jensen Beach. We know many people are eager to further their professional levels in education as a leader in scuba and enjoy the Florida sun at the same time.

For more information, please contact Cris Merz ( at HQ or your Regional Manager for details.

Visit for general information or call us at 207.729.4201

Gas Management Techniques for Sport Divers

Some fun facts about the “pony bottle”

Gas Management
With the rising popularity of sidemount diving, semi-closed and fully closed-circuit rebreathers, and of course the ubiquitous popularity of traditional North Florida Cave diver’s kits (doubles, manifold, backplate and wing), it’s sometimes easy to forget that the majority of divers still manage to have plenty of fun underwater wearing a single cylinder! A single cylinder is simple, comparatively light-weight, easy to set-up and operate and is without a doubt the most common kit configuration among scuba divers around the globe. But as popular as it is, a single cylinder does have one huge drawback, and a growing number of recreational sport divers recognize the short-coming and have opted to do something about it.

Chances are good that if you are a graduate from an SDI Solo Diver program, or if you came up through the University of Hard-Knocks, you probably already know that one huge drawback is that the diver has very limited options when Murphy tags along as a dive buddy. For example, with only one regulator first stage, the only backup life-support system is your buddy’s octo. A massive free-flow really gives little alternative but to share air and get outta Dodge.

Options are even more limited if your buddy is way over there not paying attention to anything but the critter in his viewfinder. A free-flowing regulator can empty a freshly filled cylinder in minutes, and the deeper you go, the faster it drains. Swapping regs and heading to the surface may be the only course of action open to you… unless you count reaching BEHIND your head and feathering the valve on your single tank; turning off your air to fix a free-flow is definitely not something you’d want to try as an emergency ad hoc drill anyway. The truth is that without pool practice and, at the very least, a donated octopus (backup reg) attached to your buddy’s tank in your mouth, a sport diver should never turn off his gas.

The simple alternative is to carry a redundant gas source, and the most functional and practical for the average single-tank diver is a “pony bottle.”

Time for a not-so-simple definition. Just about everyone who has lounged around the aft-decks of dive boats for a season or two will have heard the term Pony Bottle to describe a variety of small scuba cylinders – all a sort of perfect copy of a full-sized cylinder but looking as though they were put through a hot wash and dry cycle and shrunk – and used for a variety of tasks.

Other names for these mini-cylinders include sling bottles, stage bottles, buddy bottles and a half-dozen or so more equally descriptive names. As with so much that has to do with scuba (for example, what IS the definitive definition of technical diving, these days?) there are few unbendable rules when it comes to words and phrases describing pieces of dive gear. A classic example is a pony bottle. I like to tell people that it can only be used for a small cylinder used as a backup air source… exactly what we are talking about here. Of course, that is not absolutely true, but between us, let’s make it so.

Now let’s assume that we have decided that having a backup source of gas is a good plan and that the most practical way for us to carry that gas is to use a pony bottle; there are three more questions we need to answer.

The first is, “how much backup gas is enough?“

Well, the short answer is, “enough to get us back to the surface.” But how many litres or cubic feet is enough? Let’s do some basic calculations using an average consumption rate and an ascent speed that will keep our personal dive computers happy as clams. Let’s also pick a depth that is on the fringe of recreational sport diving: 40 metres or about 130 feet.

We start with a gas consumption rate of 15 litres/0.5 cubic feet per minute. (By the way, the imperial and metric measures used in this example are NOT a direct or exact conversion. Close, but rounded for convenience). Let’s also say that if we have to “bailout” to our pony bottle at depth, we are going to be a bit freaked out – Murphy does that to divers – and therefore our consumption rate is going to be doubled. So we can use 30 litres or one cubic foot per minute.

Our depth has a direct relationship to the density of the gas we breathe so at 5 bar/ata (40 meters or 130 feet) we will use about 150 litres or five cubic feet per minute!

Also, let’s make some allowance for fiddling around at depth for a couple of minutes before we start heading back to the surface. How many minutes exactly is tough to guess, but it would be a mistake to think that we would start to head up immediately we detected a problem and bailed out to our pony. It would be nice to think that’s the way things would unfold but the truth is it takes time to get our buddy’s attention, get ourselves calmed down, sort out our gear and start the swim home. Initially, let’s calculate that we stay at depth for three minutes.

Three minutes at our depth and stress adjusted consumption rate requires 450 litres or 15 cubic feet of gas. (Wow that immediately rules out one of those Barbie-sized tanks. doesn’t it?)

Now we can look at the ascent itself. In an emergency, the hard-wired, natural response that kicks in is the aptly-named flight, fight or freeze response. In diving, we have to resist flight – forget about freeze and fight – to remain controlled and panic-free. As such, our ascent rate must be unhurried and moderate. My personal computer is a fourth generation model controlled by a later version of the VPM algorithm, and as such, the controlling ascent speed is about 9 metres or 30 feet per minute. Let’s use this speed to get ourselves from 40 metres / 130 feet up to six metres or 20 feet for a five-minute safety stop, which is once again a conservative choice. This gives us a smidge less than a four-minute travel time. We can round up again and make this a full four minutes. (In fact my computer would serve up a variable ascent speed causing us to slow down to about 3 metres or ten feet per minute for the last few metres approaching the safety stop. But we can ignore that in these calculations; I will explain why later.)

Gas ManagementTo establish how much gas we will get through during that four-minute swim from depth to the safety stop, we have to know our average depth. The halfway point between 40 metres/130 feet and six/20 feet is 23 metres/75 feet which gives us 3.3 bar/ata. From this we can calculate our gas needs as: 30 litres X 3.3 bar X four minutes; or 5 cubic feet X 3.3 ata X four minutes. That’s around 400 litres (396 rounded up) or 14 cubic feet (13.2 rounded up).

So far, we need 450 litres at depth and 400 litres to swim to the stop, which adds up to 850 litres. For the imperial crowd, the required gas volume is around 30 cubic feet (actually 15 + 14 for 29 cubic feet. A note: if you are doing actual calculations to translate from imperial to SI or metric on the fly, there is some slop in the numbers quoted here because of rounding errors and soft conversion values. The differences though are moot and the principle message remains the same).

Now we have to spend five minutes at the safety stop. Using our base consumption rate as a guideline, our diver will use around 240 litres or eight cubic feet, and we can round those numbers up to cover the slow ascent from the stop to the surface. (The numbers are 1.6 bars / ata X 5 minutes X 30 litres / 1 cubic foot.)

Looking at our total gas requirements from the bailout at maximum depth then, we have:
450 litres / 15 cubic feet on the bottom; 400 litres / 14 cubic feet for the swim up; 240 litres / 8 cubic feet for the safety stop. This adds up to 1090 litres (let’s call that 1200) or 37 cubic feet.

Before moving on to touch briefly on some issue that fallout from discovering just how much gas we should think about carrying, let’s make a couple of things clear.

In the calculations used here, we have been conservative with the baseline per minute consumption figure. At least half the divers reading this article would use less than 30 litres or one cubic foot per minute as a working surface rate. However, the other half would probably use more. (And by the way, these numbers do work better if you plug in your personal SAC (Surface Air Consumption) and a factor modifying that volume to account for stress based on your abilities and needs, but frankly, our conservative baseline is a REALISTIC average).

Also, we have maintained the “high” per minute consumption rate for the whole of the swim to the safety stop as well as for the safety stop itself. In all likelihood, a diver who has him or herself under control would begin to “breathe easier” as they arrived at a shallower spot in the water column with their circumstances starting to brighten. Using a stressed consumption rate throughout the dive has resulted in a high total gas volume requirement. However, we have not factored ANY gas for a swim back to an ascent line at depth; we have factored nothing in for holdups while ascending, and nothing for blimps in procedures.

We have also opted for a slow ascent, followed by a five-minute stop at six metres or 20 feet. We could just as easily have computed a faster ascent speed and a stop at three metres or 10 feet for three minutes. The resulting consumption figure would have been slightly less. However, I believe that a controlled normal ascent and a five-minute stop provides a better edge against decompression stress in this scenario.

Finally, we have worked out all these numbers based on a dive at the very fringe of sport diving. A 40-metre or 130 foot dive is the maximum sanctioned for a sport diver with special training. Not all sport dives go this deep. However, in more than 20 years teaching divers about the basics of dive planning, — and being downright lazy –I’ve discovered that using a pinnacle dive (one that’s at the far boundary of what’s best practice for your experience and the maximum for your training) to calculate contingency needs follows perfectly the axiom of calculate once, use many times. In other words, if we follow these guidelines and then bailout from a shallower dive, we should have more than enough gas, all else being equal.

Clearly, the default sized pony bottle would be something that can hold this much gas. A decent choice in my opinion is a 6 litres / 40 cubic foot aluminum bottle. There are a couple of companies making this sized tank and they are relatively easy to find in local shops. Also, this tank has pretty good buoyancy characteristics in the water, is easy to handle with a little pool practice behind you, and is simple to carry with you in the water. The important thing is that fully charged, it carries ample gas for the purpose it’s being used for. There is the whole issue about whether to have it piggybacked on one’s main cylinder, carried as a sling bottle (classic North Florida Cave Diver rig) or as a side mounted bottle (my personal favorite because it is out of the way but accessible), but let’s leave that debate for another article. Instead, let’s look at what type of gas would be the best to carry and why.

The simplest and most straightforward choice would be to always carry in your pony bottle EXACTLY the same gas that you have in your main cylinder, but this does require us to be wary of a potentially fatal mistake. For example, last week, hypothetical diver Jillian was diving a wreck on which an EAN38 was perfectly suitable, and she had her main cylinder and pony filled with a nitrox 38. Everything on her dive was perfect and the pony stayed unused. She does not bother to drain it. This weekend, she and her buddy are going to dive a reef and intend to take a photo of an Elephant Ear Sponge at around 40 metres or 130 feet. At that depth, her pony bottle mix is hot, delivering an oxygen partial pressure of 1.9 bars / ata. This is problematic.

A simple fix is to have the pony filled with a gas that CAN be breathed on a pinnacle dive. For Jillian, or for the rest of us non-hypothetical divers for whom the specter of oxygen CNS toxicity is a real one, this would be a mix containing 28 percent oxygen, which delivers a ppO2 of 1.4 bar / ata at depth.

The principle of diving with a bailout bottle or redundant gas source is a sound one. Many divers opt to follow the practice. It gives a diver – and that diver’s buddy – options when things go pear-shaped at depth, and allows for a controlled, independent ascent (by which I mean an assent where we are not tethered to our buddy by their octopus).

As with ANY procedure that’s outside the classic stuff taught in most open-water sport programs, there are a few “good to know” knowledge nuggets focused on pony bottles:

  1. Have the valve and hand wheel within reach, and practice breathing from the reg while feathering the valve.
  2. Fit the regulator with a full-sized SPG and check it before every dive.
  3. Pre-breathe the bailout regulator before every dive.
  4. Drill bailouts often until the process becomes natural and fluid.
  5. Mark the cylinder contents and check MOD before every dive.
  6. Have the hose for the pony bottle second stage long enough to reach your mouth (and your buddy’s) easily. A 40-inch hose is a good start, longer is usually better.
  7. At least a couple of times each season practice complete ascent breathing from your pony bottle.
  8. Splurge on a good quality regulator for your pony bottle. It has to perform when you may be under stress.
  9. Treat your pony bottle system as life-support. Get the components serviced and checked on exactly the same schedule as your main cylinder and reg.
  10. NEVER, NEVER, NEVER use the gas volume in your bailout bottle or pony in the gas calculations for a dive. In other words, do not plan your dives around the 1200 litres or 38 cubic feet you have in the pony. That gas is a RESERVE and should be ignored in one’s principle dive plans.

Although not the law, the best general advice for ANY single-tank diver who wants the assurance and personal “cushion” that comes from carrying a pony bottle is that they would do well to get some face-to-face time with a good mentor or instructor familiar with the kit and the procedures governing its use. An excellent certification course on this score is the SDI Solo Diver Certification.

A similar version of this article was first published in issue 24 of Underwater Journal, An Underwater Adventure Magazine, the official publication of SDI™ & TDI™. To learn more visit underwater journal magazine

Written by Steve Lewis

Steve Lewis ( is an active instructor-trainer with TDI/SDI and has written scores of articles on dive safety and skills development and is a regular contributor to several online magazines and discussion groups. He occasionally dives “open-circuit with a single aluminum 80” but never without a pony bottle by his side filled with a lean nitrox. His best-selling book called “The Six Skills and Other Discussions” is available at select dive stores and through onLine stores such as Amazon and Create Space eStore via:

Do You Know SUDS? …You Should!

All of us at SDI™, TDI™ and ERDI™ ask you to please learn more and get involved!

Soldiers Undertaking Disabled Scuba (SUDS) at Walter Reed National Military Medical Center (WRNMMC) in Bethesda, MD is designed to help improve the lives of injured service members returning from Iraq & Afghanistan. By training the warriors in a challenging & rewarding activity it can help facilitate the rehabilitation process & promote mobility. Offering this venue provides the service member with a sport they can enjoy throughout their life. SUDS is a 501 (c) 3 non-profit organization & a chapter of Disabled Sports USA.

Suds Diving

The SUDS organization has been training wounded warriors to dive as part of their rehabilitation since February 2007.

During this time SUDS has worked with over 200 injured veterans. The scuba instructors are American Red Cross volunteers and active or former military and all the training utilizes SDI™ & TDI™ training certifications.

The SUDS group runs several trips per year to complete the injured veteran’s scuba certification to a variety of great warm water locations.

In December 2011 they ran a trip to Turks and Caicos with six injured veterans from across the country to do continuing education. So far in 2012 SUDS has run its 5th trip to Rincon, PR where four men from WRNMMC (Walter Reed National Military Medical Center ) in Bethesda, MD and two men from the NMCSD (Navy Medical Center ) San Diego participated working towards their Rescue Diver certifications.

SUDS Diving Scuba

The SUDS program continues to offer open water certifications at WRNNMC at Bethesda to our American heroes, and several of these men and women move on to advanced certification.

Follow SUDS on Facebook, Twitter and join the SUDS Newsletter by visiting their web site.

While you are at see how you can help. Divers like you are needed to help Heroes like these!

To learn more about SDI™ please visit

SDI™ Introduces “HOW TO” on YOUTUBE

Just one more time…QUIET ON THE SET!… TAKE # 187535498496498749

YouTube Scuba DivingIf you have recently visited our NEW and we believe BETTER and IMPROVED you have seen a myriad of new features that lead to GREAT opportunities. So since our Pro Members and Facilities have been fielding questions from Associate Members just like you, we decided to make using the site even easier than before. Although we have already built an extensive help section on the website, we recognize that videos are easier to follow for many, while reading is best for others; now you both can have it your way – hold the lettuce!

Visit and check out our first shot.

We will be developing multiple videos over the coming weeks, so keep checking back to see what has been updated.

Here are a few videos we are currently working on for Associate Members and site visitors:

  1. How to create a user account
  2. How to recover your username and password
  3. How to get started with my eLearning course – both by using an access code and without using an access code
  4. How to adjust my settings when using IE 8 or 9 to use the site
  5. How to get a replacement card
  6. How to verify my dive credentials
  7. How to send feedback to the site
  8. How to find a dive center
  9. How to sign up for an additional eLearning course
  10. How do I update my profile
  11. How do I affiliate or un-affiliate with a Dive Center

Let us hear back from you at and tell us what you would like to see next. After all, by now you must realize….special orders don’t upset us!

TDI™/ SDI™ at the London International Dive Show (LIDS)

Do not miss this provocative and thought provoking discussion

Solo Diving – Coming of age

London International Dive ShowSDI™ was the first agency to launch a Solo diving course and to emphasize the importance of Self Reliance. Although still a controversial topic, many other agencies are now following SDI’s lead and launching courses aimed at creating more self-reliant divers. Don’t miss TDI™ / SDI™ Instructor Trainer Mark Powell’s perceptive take on the subject. If you are an instructor, photographer or just dive with a variety of buddies, you will want to hear what Mark has to say on this topic.

LIDS will be held on the 31st March – 1st April at the Excel Centre, London.

For more information visit

For more about SDI™ programs, and to schedule your own Solo Course, please visit

Know Where All of Your Dive Buddies Will Be on March 23-25th?

At “Beneath The Sea” in the New Jersey Meadowlands Expo Center!

Beneath The SeaIt’s that time of year again… Beneath the Sea is here, and TDI™-SDI™-ERDi™ will be looking forward to meeting with you once again to share with you what is “new and improved” with our agency.

Last year we kicked off with the BTS & TDI’s Tech party. This time around, we would love to do it all over again and ask that you join us. Join Brian Carney, President of TDI™, and the rest of the gang at the Embassy Suites at around 7pm on Friday 3/23 for drinks and light appetizers. But hurry! It is first come first serve, and after all this IS a hungry and thirsty dive crowd!

Invest just an hour of your time, and you will be pleased with the return you get from either of these informative seminars.

  • Members Update- Sponsored by TDI™-SDI™-ERDi™- We will also be doing a Member’s update at La Quinta, just steps from the Expo Center on Saturday at 3PM, if the weather requires a shuttle, we will wisp you away from the Expo Center to La Quinta.
  • Rebreathers in 2012- Sponsored by TDI™- Don’t miss the latest in the industry buzz – rebreathers. Join our seminar “Rebreathers in 2012” and learn all about courses you can take for fun or if you are looking for the right path to become a rebreather professional instructor. This seminar will be at La Quinta, just steps from the Expo Center on Sunday at 1PM. Same shuttle plans are also in place.

To reserve a spot at either of these events, stop by our booth and tell us “I’ll be there!” For more information, contact Cris Merz at

We look forward to seeing you at BTS. For more info about the show, visit:

For more about TDI™-SDI™-ERDi™ visit

There has never been a better time to join the TDI™-SDI™-ERDi™ family, ask us how!

Your UWJ Magazine is Ready!

Underwater Journal - ScubaUWJ Issue 23 is ready for download. If you’re not yet a subscriber, simply sign in and create an account with your email address (takes about 3 minutes and it’s FREE).

Your winter issue of The Underwater Journal has some great features – from finding the little stuff with photog Mike Bartick to Capt. Gary Mace’s gripping story about decompression sickness. We’re starting 2012 with something for everyone. This issue covers it all: gear, photography, marine life, advanced diving and adventure travel.

Steve Lewis gives us another pragmatic view in his column Nitrox, Voodoo Gas No More, but Still Misunderstood. His discussion focuses on the details of using this gas that many of us don’t fully understand.

Jump into the icy waters of the Antarctic Peninsula with Eco-photo Explorers Mike Salvarezza and Christopher Weaver. Learn and look at South Florida’s amazing wrecks from our Editor. And be sure to catch the DAN Column, Dive Safety Essentials, and get your dive year started off on a safe track.

There’s so much more to enjoy and learn, get your FREE magazine today. Don’t forget, UWJ is iPad compatible to download and save in iBooks.

This is YOUR MAGAZINE with lots of benefits. We appreciate your support and encouragement! Enjoy, and please let us know what you think.

Underwater Journal is the official publication of SDI/TDI/ERDI