First off this is the first step on the professional scuba courses and professionalism  is of paramount, so after paying my course fees!  it was a new drysuit neck seal,  new set of  regs, crew pack  so not an inconsiderable sum, but necessary to start on my journey.

Week one:  Friday the fifth, all day from 10.30am in the classroom with Chris my instructor and fellow Divemaster trainee Paul we went through every knowledge review that we had home studied the previous week into great detail, we were then thrown in at the deep end and asked to prepare a dive site map and present a dive briefing to four other instructors, a quick visit to the toilet and ten to 15 minutes later, calm had been restored and my legs had stopped shaking, but I had a sense of achievement and the de-brief was nothing but constructive and informative,

4:30pm  Student would be arriving soon for a pool session  so out of the classroom  and get everything prepared for the van to take the equipment to the pool  Phew !

Paul and I were briefed on what we would be doing and it was a skill circuit  of  every skill you have ever done and more  from Giant stride entry to controlled emergency swimming ascent, all done to demonstration quality and all marked on a scale of 1-5 with the onus put on improving all the time . One hour 16 minutes later were out of the water both my calves had cramped and were refusing to loosen , but no let up yet  de kit, put everything back onto the van  back to dive shop unload  and debrief .  I got home about 9:45pm exhausted   but let me tell you fully fulfilled in what we had all achieved in a long day.

So in summary  It was everything and more  I had hoped for  and I am looking forward to tomorrow 11/02/10  another long day  in the classroom this time Physics, Physiology and Equipment, Happy days,  next instalment soon.

Nick

OR

Adiabatic Compression, as it applies to scuba divers.

Why does my instructor get excited? What exactly is adiabatic compression and why do I need to know about it?

Your instructor gets excited because of the possibility of fire or explosion! Adiabatic compression is defined as a process where high-pressure gas flows at or near sonic velocity toward the low-pressure end of a piping system with a major restriction, such as a dead-end, a down sizing, or an abrupt turn. The likelihood of a reaction (ignition) increases with increases in the rate of gas compression and gas temperature.¹

So let us break that down into terms that are understandable and apply to scuba diving and let you the diver understand why it is important. We all use compressed gas, usually air, to scuba dive with. Some divers use enriched mixes called nitrox. This is a compressed gas with a higher concentration of oxygen than air or a PO2 greater than 21%. There are also divers who use 100% oxygen (O2).

As you know, when a gas expands (decompresses) it cools. When a gas is compressed, it heats (also known as heat of compression). In a closed system, scuba unit, filling bank, etc… you are allowing the gas to move from a compressed state to a expanded state then back to a compressed state. Most people have seen and felt this when their scuba cylinder is filled rapidly the sides heat up. This is compression of the gas. If you allow the gas to flow freely from the cylinder valve, it expands rapidly as the pressure reduces and there is a decrease in temperature at the valve. It can be so great as to have frost form on the valve. This is expansion of the gas.²

When compressed gas flows from high to low pressure, it can quickly reach a very high velocity, especially at constrictions, valve seats, regulator poppits and angular fittings. In these instances, flow velocities exceeding 148 feet / sec. (45 m / sec.) are considered to be dangerous. There is even greater danger when the speed of the gas flows at or near sonic velocity (speed of sound is approximately 1,125 feet per second at 68o F). When speeding gas strikes an obstruction, it is instantly recompressed and the ambient temperature instantly skyrockets because no heat is lost to the surrounding materials (instantly in this case is not instantaneous but rather very, very fast). The higher the initial pressure, the greater the temperature generated.³ High temperatues can cause auto-ignition of containment material.

With 2,000 psi oxygen (PO2 100%), temperatures well over I,500°F can be momentarily produced. This is sufficient to ignite even such inert substances as Teflon and stainless steel. To state it simply, an uncontrollable fire can ignite and burn, hoses, metal and YOU.

This phenomenon, similar to diesel ignition, is called ADIABATIC COMPRESSION. Great care must be taken to control adiabatic compression.

Scuba cylinders are frequently filled, pressurized and depressurized by the diver. The potential for danger exists with concentrations of oxygen greater than that found in air (PO2 21%) and incomplete understanding of Adiabatic Compression.

How do you prevent mishaps? With careful design and operation of gas flow and filling operations and specific education about gas pressurization and depressurization. Several O2 fires have occurred during the preparation of diving gas mixtures due to lack of understanding and a inappropriate attitude toward adiabatic compression. Mishaps include oxygen hose fires where Teflon-lined hoses with stainless steel over-braid have detonated and burned , throwing molten particles about. Other accidents have included the neck of a scuba cylinder being blasted open and launching the valve.⁴

To prevent accidental detonations, always open O2 cylinder valves very slowly and pressurize systemic components as “gently” as possible. Design your system using slow-opening globe or needle valves that contain seats made from oxygen-compatible polymers. Transfer oxygen gas slowly to prevent excessive heating. The maximum transfer rate for pure O2 is 200 psi / minute and rates during mixing are usually 50 – 70 psi / minute. And lastly, open your scuba cylinders slowly, gently pressurizing the system.

Charles law states: “For any gas at a constant pressure, the volume of the gas is directly proportional to its absolute temperature”⁵ or more simply put “when a gas is compressed, temperature is raised”.

So remember, when working with compressed gases, always open the valves slowly. Gently pressurize systems. Transfer pure oxygen at 200 psi per minute or slower. And if you are involved with mixing gases, do not exceed rates greater than 50 – 70 psi per minute.

It can save your life!

For more information on Adiabatic compression and gas mixing consider taking a Mixed Gas Blender or Oxygen Service Technician course.

Some additional definitions of Adiabatic compression.

Adiabatic compression is a process where there is not heat transfer to or from the system, and all supplied work is added to the internal energy of the gas, resulting in increases of temperature and pressure. Adiabatic compression or expansion is favored by good insulation, a large gas volume, or a short time scale (high power level). In practice there will always be a certain amount of heat flow, as to make a perfect adiabatic system would require perfect heat insulation of all parts of a machine.⁶

Adiabatic compression is a chemical or mechanical process in which there is no exchange of heat with the surroundings (no heat entering or leaving the system). It is applicable to enclosed systems.⁷ The relationship of pressure and volume when a gas or other fluid is compressed or expanded (with no loss or gain of heat) is that compression causes an increase in temperature and expansion a decrease in temperature.

¹ Neal, Jan and Morrissette, D.. (1998). Mixed Gas Blender And Oxygen Service Technician. p. 11. Daytona Beach, Florida: Underwater Dynamics, Inc.

² Taylor, Larry “Harris”, Ph.D. Adiabatic Expansion. A Gas Laws Primer. 9 Mar 2010. http://www-personal.umich.edu/~lpt/primer.htm .

³ Boyd, Richard, Dr. and Kent, Greg. Inherent Hazards Of Pressurized Oxygen. Engineering Nitrox Partial Pressure Blending Systems © 2002 . GMC Library. Global Mfg. Corporation. 9 Mar 2010. http://www.gmcscuba.com/pdf/engineering%20nitrox%20partial%20pressure%20blending%20systems.pdf .

⁴ Boyd, Richard, Dr. and Kent, Greg. Inherent Hazards Of Pressurized Oxygen. Engineering Nitrox Partial Pressure Blending Systems © 2002 . GMC Library. Global Mfg. Corporation. 9 Mar 2010. http://www.gmcscuba.com/pdf/engineering%20nitrox%20partial%20pressure%20blending%20systems.pdf .

⁵ Heine, John, Bookspan, J. and Oliver, P.. (2000). Diving Physics. NAUI Master Scuba Diver. p.89. United States of America: NAUI.

⁶ Adiabatic. Temperature. Gas Compressor. Wikipedia. 20 May 2007. http://en.wikipedia.org/wiki/Gas_compressor.

⁷ Adiabatic. Chemical Molecule Library- Glossary. 9 Mar 2010. http://www.ch.ic.ac.uk/vchemlib/mol/glossary/ .

Dive Safe!

Dean

Sooner or later with enough dives something will happen, it probably will be something minor but are you prepared? Consider getting some training as a Rescue Diver.

Rescue training is sometimes referred to as the “ultimate dive buddy training” because you learn to become a self-reliant, and competent diver. The main focus of training is to learn how to deal another diver in the event something goes wrong.  Remember back to your basic scuba class you were taught to “stop, think and then act”.  Did really understand the “act” part?  Rescue training will teach you the “act”: locating a missing diver, surfacing an unconscious diver and providing in-water resuscitation, getting the victim back to the boat or shore and accident management.  You also learn to be prepared for other problems, how to plan for and how to prevent problems from occurring.

Many additional skills are gained that make you a better overall diver.  For example you will become more observant of other and your “global awareness” will improve.  Recognizing pre-dive stress in others and how to best handle those situations is a key skill on the prevention side of the equation.  As your awareness increases you will understand common causes of diving incidents and more importantly, how to properly deal with them correctly.

Every diver will benefit from this training for the simple fact of understanding physical demands of rescuing another diver, especially in the ocean.  Think of your regular dive buddy, could you tow them a couple hundred yards while simultaneously providing in-water resuscitation?  Now add a little current, get the picture?

Diving is a safe and fun activity.  Serious accidents are rare, but an underwater adventure can turn to tragedy in a flash. Rescue training helps you develop an awareness to anticipate potential problems before they strike. The ability to recognize and prevent problems is a very valuable skill, one that could save a life.

So as you think back to the beginning, put yourself in the picture and ask yourself ‘If something were to go wrong am I prepared, am I confident in my rescue abilities?  If your answer is anything but an enthusiastic “yes” contact your local dive shop and get into the next rescue course.

The old saying goes:

“An ounce of prevention is worth a pound of cure”

To learn more about rescue training visit www.NAUI.org and learn more about the author visit www.scubajax.com

Don’t let this be the end of your diving education. There are still more things that you can learn and also more things that you can offer people as a diving educator. For instance have you ever thought about being able to teach the things that interest you? Do you have a particular passion for wreck diving or perhaps underwater photography? Would you like to be able to teach other divers these things so they can join you in your interests? Maybe you just want to be able to teach something that you have real enthusiasm for or something particular to your local environment. It also means that there is less repetition for you. Let’s face it teaching the same courses day-in-day-out might become a little tedious so the ability to be able to go and teach something else once in a while can provide a nice break plus adding different teaching experiences for you. Either way you might want to think about becoming a PADI Specialty Instructor.

Look at all the options that are available to you. There are over 25 PADI Specialties and that is not including the Distinctive specialties written by instructors that apply to interests of theirs. There is so much more that you can offer your students and your potential dive centre employers.

This is also not something to be sniffed at. If you can teach more then you can offer a potential employer more value as they can obviously utilize you more. The more things you can add to your ‘Instructors Quiver’ then the more valuable you can be to a dive operation. It can also help you to move up the PADI Instructor ladder to Master Scuba Diver Trainer and beyond.

These ratings past the Open Water Scuba Instructor rating denote instructors with a lot of experience and thus give you a large amount of credibility. Once you move onto ratings such as IDC Staff Instructor as well you are starting to help in the PADI Instructor Development process assisting Course Directors in shaping the future diving instructors. Wouldn’t you like to be a part of this process in changing people from divers into guys who can teach diving? Be a part of that life changing experience for someone else. Continue your diving education and this is certainly possible plus it again makes you even more useful within the dive industry. My own experience as a Staff Instructor took me to a whole new perception in the way I looked at teaching diving and the way that I could work with people. This was pretty much the best transition I made in diving and only encouraged me to go further up the ladder to Course Director.

This might all; be quite a lot to take in just following your gradation from the IDC/ IE which obviously was such a great achievement in itself. But why not build on what you have learned and thus make yourself a more rounded dive professional. Going through the Continuing Education process will also allow you to carry on working with experienced instructors and seeing their methods of teaching which will allow you to build your own style by working with and observing many others. Even now I still learn from watching other diving instructors at work as no one has completely the same way of teaching and working with people.

This is not to say just focus on your con-ed but still get on with teaching the ‘bread and butter’ PADI courses. Just recognize what con-ed can offer you and what you can use it for. Teach those things that really interest you and your enthusiasm for your subject can rub off on your students. There are also little things like teaching certain Specialties can enhance you knowledge to make teaching other courses better such as the PADI Divemaster course.

The point that I am trying to make is that you shouldn’t just think that now you have passed your IE that that is the end of your education. There is so much more that you can learn and so much more that you can offer in the dive industry both to the benefit of your students, and yourself. The PADI system offers so much more for you as an instructor and you should take the opportunity to use it to its full potential and realize your full potential.

Accreditation and Experience – Does your Course Director have the education and experience to train you proper. Just like in the Dive master course, a big part of the IDC is for the CD to share his/ her experience. If somebody does not have that, then it comes down to “teach you to pass the IE”. Also remember that if the CD has been around for a while and has trained a lot of Instructors in the area, you will get lot’s of valuable info outside of just the IDC. Such as local issues/ concerns and probably also advise on future work opportunities. Before signing up with “the cheapest deal” do a bit of research and find out what other people in the area has to say about your potential choice. Happy customers are usually a good indication that the CD cares about the candidates. If needed, ask for references of students from all skill levels that you can contact. Does he/ she offer programs on a regular basis or do they just have a few per year?

Compatibility – It is your responsibility to insure that there is a fit between you and your instructor on all levels, personality type, mutual goals, and your instructor’s ability to relate to your individual needs. Learning to dive is supposed to be fun, so learning to be an Instructor should also be fun then. Not a military training camp! If the CD is a “boring” speaker it can turn into pretty long days. Yes, you will spend a lot of time in the classroom, so having a person in front that can be entertaining as well as knowledgeable will be very important. Some have ego’s bigger than the dive store and that gets to be a bit boring after a few days.

Facility – Where will the program be conducted and does the CD know the facilities well? Are the classrooms air conditioned (in tropical climates)? How far from the classroom to the pool or confined water? How far to open water site? If things are slowed down by difficult logistics, such as long travel between class room to pool or open water site this will interfere with learning. Also your days will then be very long. Since you have to do preparations every night for the next days action, it makes sense to be able to get out of class at a reasonable time every afternoon. Relaxing and catching your breath before homework and dinner. Remember; never hold your breath! Check if all diving is done from the beach or if boat is an option if the beach “blows up”. It often saves time to go from the beach, but if conditions are bad, then that is an issue. If they would not teach an open water course at the site, then they should not teach an IDC there either. Can they help with fixing equipment as well as help with booking hotels, advice on restaurants etc. Having some surround support will help make the experience less stressful and way more fun too. Check what schedule the course will have. Is it a squeeze with cramped in study over the bear minimum of time or is it laid out perhaps with a “study/ relax” day in the middle. Is there any room between the IDC and IE for maybe some extra stuff or remedial training?

Follow-up Communication – Your CD should be willing to help out with answering questions after training has been completed. You are going to be a brand new Instructor, and sometimes may get a little stressed. Being able to call or email and get some good advice will make life less stressful.

Let’s face it; diving is not rocket science or brain surgery. By asking simple questions before taking instruction, you will insure that you will invest your time and money wisely, as well as maximize your learning curve.

——————
The following article was submitted by
Bent Posejpal – PADI Course Director
Siam Dive n’ Sail, Phuket, Thailand
Tel: +66(0)76-330 967; Fax: +66(0)76330 990
Cell: +66 (0) 81 892 0643
Email: bent@igotbent.com
Email: igotbent@gmail.com

http://igotbent.com

http://siamdivers.com

http://indodivers.com

Like you, I to had what some would call a “real job” some 18 years ago! I had real clothes that I always spent money on to make sure that they were the most fashionable of the time. I drove nice cars that were mostly financed by the banks. My jobs over the years involved working in the publishing business, farm work, every aspect of the restaurant business and even a short time at a large retail outlet.

Back then internet wasn’t around but there was no shortage of newspapers and magazine articles that gave you a glimpse of various exotic locations. I too worked hard to save my money in order to visit these wonderful places when vacation time rolled around, and like yourself I always thought, wow, wouldn’t it be great to live here!

I would experience the cultures of far away countries and hidden tropical islands. I learned to dive and experience mother natures beauty in creating this extraordinary ocean playground. I encountered the turtles, various species of sharks and eels, the manta rays, Eagle rays and the Southern Stingrays. Every location was a sea of dreams painted over a moving canvas.

When holidays were over and I was stuck in my office cubical, it was the rich vibrant colors of the corals and tropical fish, the diverse terrains and the abounding sea life that would all play a major roll in my quest to live my dream.

It all seemed fantastic to me living on a tropical island, lounging by a pool sipping on refreshing cocktails, sleeping in every morning after partying into the wee hours of the night, just diving and living my dream and not a care in the world.

Wow!!!!! What a wake up call when I entered into the world of being a dive instructor living and working in paradise.

My stylish wardrobe changed immediately and now consist of a half dozen board shorts, a dozen t-shirts, half of which are company issued, no more having to choose which shoe’s I’m going to wear, it’s either bare feet or sandals. As a Dive Instructor it’s unlikely that you’ll ever have a loan for a new sports car, your new mode of transportation is now navigating the local bus system along with the chicken and goats, walking the beaches to work, riding a bicycle, scooters or motor bike. Sure some dive instructors have cars, but it’s no longer a status symbol. There are no sipping cocktails by the pool in a lounge chair; they are all reserved for the paying tourist. No time for that, we are all busy behind the scene working preparing boats, filling tanks and signing up guests in order for them to experience the dynamic diving that we have grown to love. As a dive instructor, you will work hard. It’s unlikely that you will get rich, but you will make it rich with life’s experiences.

You need to be prepared to accept the culture and values of a foreign country, the long distance travel involved in seeing family and friends. In many tropical location the food will be a new adventure in itself. Mother Nature does bring in some nasty weather from time to time. You need to be aware of the occasional tropical storm or hurricane. Be sure to check out the local health care system, and you want to make sure that your choose a destination that is safe and typically crime free.

There are companies out there that will combine your dive training with other activities such as surfing, wake boarding, kite surfing and kayaking that will give you exposure to a variety of sports. You’ll have the opportunity to meet people from all corners of the globe and make life time friends. As an instructor it’s easy to pick up a second language. So start living, unshackle yourself from your office cubical and become an instructor.

Once you choose to become a dive instructor, you have the ticket to travel. After all, it’s a Lifestyle, and when life becomes a Beach, then live it!

Contributed by: Ash McKnight
PADI Course Director
www.goprocayman.net

I am often asked (again just today) “How old does my child need to be to dive?”.   NAUI has a minimum age requirement for open water scuba diver, it is 15 years.

NAUI does have a Junior certification for ages 12 – 14 years.  Some courses (open water) allow a conditional Junior Certification. This Junior certification can be issued to persons age 12 – 14 years.  Junior Certification carries several restrictions.

* The parent or guardian and Junior diver agree that the Junior diver will dive with a certified adult (18 years of age) diver of the parent’s or guardian selection.

* The parent or guardian and Junior diver agree that the Junior diver will limit diving depth to 60 feet or less.

* By signing the Junior certification card, the parent or guardian agrees to be responsible for the selection of the certified adult buddy and the limitation of the diving depth.

* To remove the Junior cards conditional requirements, a new card must be requested by an active-status NAUI Instructor, parent or legal guardian one the Junior attains the age required for full certification. “Junior” divers may directly request from NAUI a full certification in the event that they have reached the age of majority.¹

Teaching children is not for everyone. Just as scuba diving is not for everyone. All parties involved have to be in agreement. For me, the joy is seeing that young person safely and enjoyably scuba dive. Nothing can replace the wonder seen in a young persons eyes, when they are exploring the beauty of the undersea world.

I teach at Scuba Steve’s Aquatic Adventures (http://scubastevesadventures.com/) in Tyler, Texas.

Dean Pennington II
NAUI Instructor Trainer
16 November 2009

¹NAUI Standards and Policies Manual (Tampa, Florida: NAUI, 1996), page 2.9.

Is PADI the best?
It is hard to argue with 70 percent of the trained divers yearly.
PADI History: Let take a look

In 1966 in Illinois, John Cronin, a scuba equipment salesman for U.S. Divers, and Ralph Ericson, an educator and swimming instructor, were concerned about the scuba diving industry. They felt that the current scuba certification agencies were unprofessional, didn’t use state of the art instruction and made it unnecessarily difficult for people to enter the sport. And the equipment was not suitable to the civilian population. John and Ralph knew there had to be a safer, easy way for people to learn to breathe underwater.

After several meeting in restaurants in Morton Grove and Niles, Illinois, they decided it was time to start a scuba training organization. John insisted that the word “professional” be in the name of the company. Ralph wanted an “association of diving instructors.” Soon, the acronym
PADI was born:

The Professional Association of Diving Instructors (A nonprofit corporation)

Purpose
PADI exists to develop programs that encourage and fulfill the public interest in recreational scuba diving and snorkeling worldwide.

Vision

PADI intends to be the world leader in the educational development of scuba diving professionals and enthusiasts.

Slogan
PADI – The Way the World Learns to Dive.

Mission
We want to teach the world to scuba dive.

Tasks, Goals and Purposes
PADI strives to be the world’s most respected and successful organization in recreational scuba diving and snorkeling. PADI is committed to product and service excellence, the professional growth and security of PADI Members and employees, healthy competition and partnership within the dive industry and to providing training and opportunity for all who seek to enjoy and safely explore and protect our planet’s oceans, lakes and waterways.

At the start PADI recruited other instructors, many of these who believed in PADI’s philosophy of diver training came from NAUI and YMCA. They submitted for review and PADI approved the curriculum of their submitted courses. Certifications were given throughout the 60s and early 70s. PADI was the first to introduce the positive identification card (PIC) with the diver’s photo. In 1975 PADI introduced their first Instructor Training Course (ITC) in the Philippines in Oct 75. This course turned out so well that PADI instituted it worldwide to train their instructors.

They hired Nick Icorn from the U.S. Divers’ engineering team, who worked with Erickson to develop a modular training program for the PADI Open Water Diver course, the first of its kind. PADI’s unique training methods started to catch on.

In the late 1970′s and early 80′s PADI began creating its own integrated, multi-media student and instructor educational materials for each course. They developed the specialty continued educational courses. This development spawned an incredible growth period for PADI and made it unique from other agencies.
PADI was the first to have its courses approved for college credit in the USA.
PADI was the first diver training agency to be allowed to teach the Medic First Aid course. And now the Emergency First Response course which was designed by PADI.

In 1984, to insure consistency in all the Instructor Training Courses, PADI revamped their instructor training to allow course director to develop the candidate and then PADI staff examiners was sent out to do the final evaluations. In 1984 PADI also became profit making and continues to give away several thousand dollars annually in grants.
Today PADI certifies over 70 percent of the divers in the World. They issue over 1 million certifications yearly.

PADI has worldwide offices and are recognized in over 183 countries.

So why is it important to be able to swim underwater while holding your breath? I think we all can think of several reasons. Some of them would include comfort underwater without scuba, more comfort when skin diving and while snorkeling. There is also the added benefit of preparing the diver in the event of an out of air emergency while on scuba. Granted, the diver will not hold their breath while doing an emergency swimming ascent, but the diver does become accustomed to not breathing while underwater.

The first time swimming the length of the pool underwater can be a daunting task. It is uncomfortable and you think you are going to die or drown. Here I will insert a WORD OF CAUTION.

Any breath hold training must be done with supervision. The supervisor must be aware of the inherent dangers of breath hold diving. All breath hold diving Should Not be done with hyperventilation due to the risk of shallow water blackout. Strict attention must be payed to the diver while swimming underwater.

Underwater swimming while holding your breath is easy, say for ten seconds. Almost anyone healthy can hold their breath for thirty seconds. It is when you hold your breath and begin exertion that the problem arises. It is exactly that, a rise in the level of  CO₂(carbon dioxide) in your blood stream that triggers the desire to breath. Your bodies sensors are very sensitive to change in the levels of CO₂. These sensors are called carotid bodies.

The good news is that like many things associated with your body, you can train it. Training your body to gradually accept greater levels of CO₂ takes practice.  Ideally this will be done in the water with supervision. In addition to training your body you must train your mind. As a reader here on Scuba Jedi, certainly you will understand the need to train your mind! I will not delve to deeply here but instead will say that you must calm your mind and your body. Excitement stimulates your heart to beat faster.

If your heart beats faster, then your body uses more oxygen. If your body uses more oxygen it in turn produces more carbon dioxide. When CO₂ reaches that critical value, you have a incredible urge to breath.

So four steps to help enable you to successfully swim 25 yards underwater in one breath include:

1.  Supervised practice
2.  Gradual increase in time underwater
3.  Calm mind and calm body
4.  No Hyperventilation!

Let us not forget neutral buoyancy. If you float or are wearing thermal protection you will need to offset this with a minimal amount of weight. Another consideration when swimming underwater is streamlining and remaining hydrodynamic. Stretch out and remain level while swimming and do not forget to glide!

Swimming underwater while holding your breath is exciting, especially if you can see that you are making progress in your distance. If you follow the simple steps outlined you will be touching the wall at 25 yards in no time!

Dean Pennington II

NAUI Instructor Trainer

8 November 2009

¹NAUI Standards and Policies Manual (Tampa, Florida: NAUI, 1996), page 2.27.
²NAUI Standards and Policies Manual (Tampa, Florida: NAUI, 1996), page 2.73.