Thursday, September 29, 2005

Ascent Rates

Recently I wrote about a fellow instructor who is considering becoming a commercial diver. He mentioned that the ascent rate that they had to keep to during commercial diver training was 30 feet per minute or less. Some training agencies teach recreational divers to ascend at a rate no faster than 60 feet a minute.

With commercial diving, making a slow ascent after every dive is critical, since diving is one'’s source of income and you would not want to run the risk of decompression illness. The advantage that commercial divers have over recreational divers is that they are usually supplied with air from the surface. Slow ascents and elongated safety stop are therefore not influenced by remaining air supply as with recreational divers.

All this talk of various ascent rates might seem a little esoteric and theoretical. However, I would contend that safety should always be in the mind of the recreational diver. Even though we are not required to do safety stops for certain dives, a responsible diver will make a safety stop as a matter of habit. The same could be said for a slower ascent rate.

The real issue with ascent rates is the amount of nitrogen dissolved in the diver'’s blood. A slow ascent rate will give the diver'’s body the time necessary to "off gas"”. As the ambient water pressure decreases, so the excess dissolved nitrogen will be breathed out by the diver. The advantage of a slow ascent rate (and a safety stop) is that you are giving your body enough time to get rid of the excess nitrogen safely.

Divers have come up with all kinds of techniques to ensure a proper ascent rate. For example one technique that I read about is breaking the dive up into 10 foot segments. If your ascent rate is 30 feet per minute, then you should take at least 20 seconds to ascend 10 feet. If you exceed your set rate, stop at the 10 foot mark and wait until the time "catches up" to you. Another technique is obvious - counting slowly in your mind as you watch the depth gauge. Each foot increment should take 2 seconds (one thousand and one, one thousand and two). With practice one should be able to keep to a fairly consistent and safe ascent rate.

However, most divers, myself included, use their dive computers as a rate guide. My dive computer starts beeping loudly if I ascend too fast and I find this a useful feature when working with students, since I cannot watch the student and my computer at the same time. Additionally most computers will also give you a visual warning if the ascent rate is fast.

Ascents do not have to be boring. Since I am one of those people who really enjoy being in the water, I love every part of the dive. The ascents give me the time to practice buoyancy skills by releasing just the right amount of air from the BCD to slow down the ascent rate. The ascent also gives me time to do a little more sightseeing and take stock of what I saw on the dive.

A slow ascent is vital to safe diving and should not be rushed (unless you are running out of air or have some kind of medical emergency). Learn to enjoy every part of the dive and you will never find slow ascents and safety stops boring.

Tuesday, September 27, 2005

Thanks to those who led the way

One of the instructors that I regularly work with, has decided to add new skills to his resume’ and recently completed a commercial diving course. It was interesting to listen his perspectives on the training and different insights that he gleaned from his course.

The course that he took was very demanding with long days of classroom, pool and open water training. The equipment that commercial divers use is quite a bit different to what we use in recreational diving.

Some of the greatest differences were that they were supplied with air from the surface and used helmets as opposed to masks. He explained the various techniques that they learned to clear the fogging on the inside the helmet and what they did to equalize their ears.  

It was fascinating to listen to his tales of how they learned how to weld underwater, how to recover cars etc. with lift bags and how to survey underwater structures. As one would imagine, commercial divers perform their work under exacting rules and procedures. The team concept is vital to safety for commercial divers.

Recreational diving is a very different animal to commercial diving. However, both recreational and commercial diving share a common ancestry.  We owe a huge amount of gratitude to the great inventors, scientists and explorers who blazed the way – Haldane, Cousteau, Buhlman and others.  These pioneers paved the way for us to be able to conduct safe recreational and commercial dives. The decompression theories formulated by Haldane and the decompression algorithm devised by Buhlman et al, have enabled generations of divers to dive safely. The equipment originally invented and refined by Cousteau and others have enable millions of recreational divers to explore the vast and wonderful marine world all around us.

    

Saturday, September 24, 2005

Soap Box

Sadly a student on a night diving course disappeared in Hout Bay South Africa (see report on CDNN). It would seem that diver and buddy felt that the seas were too choppy and aborted the dive and made their way back to the boat. The one buddy made it back onto the boat, but the other buddy apparently drifted away from the boat. An intensive search was launched, but as of the time of writing, the diver has not been found.

Please read the rest of my comments in the light of the fact that I do not know exactly what happened on the dive, do not know the instructor or anyone related to the incident etc.

One aspect of the report on CDNN that bothered me was that there was a indication that the diver was lost in "another" PADI course. I know that there is friendly rivalry amongst instructors from the various training agencies and we like to gently rib each other about each other's agencies.

However, there is also a group of people who are malicious and do not like to see anyone or anything be successful. I call this the crab effect. The crab effect is explained by this story. There was an old man catching crabs and he put them in an open basket. A kid walked by and asked the old man if he was not afraid that the crabs might climb out of the basket and escape. The old man replied that as long as there was more than one crab in the basket, the other crabs would drag down any crab that tried to escape. I think that as humans we sometimes try to drag down anything that is more successful than we are.

It is well known that PADI trains more divers than the other agencies combined (in the USA). It is also well known that PADI does a lot of marketing and has changed the diving training to make diving more accessible to the general public. However, it would not be correct in my view to say that PADI had dumbed down diving to the point of saying that PADI divers are "unsafe at any depth".

The key difference to any course is how the instructor conducts the class. Think of how teachers are trained. School teachers receive generally the same training to be licensed yet there is a vast difference of the teachers who you remember and who made an impact to your life and the teachers who were just going through the paces. I think it is fair to say that SCUBA instructors could be seen in the same category. Some instructors are passionate, caring and very competent, and some are just going through the paces.

At the same time one could argue that it is up to every instructor to ensure that he or she conducts safe diving courses. I cannot believe that the average instructor trained by PADI would be less concerned about student safety than the average instructor trained by agency X. The training agencies can only do so much to prepare and train instructors.

Sometimes I have conducted courses and felt that I was herding cats. Even in highly structured military environments, you cannot completely control how people react. In recreational diving, we do not treat people like military recruits. We cannot completely control how people think, react and respond to conditions. You can brief people till you are blue in the face and you will find that some will do whatever they want no matter what you say. Under stress, people forget what you say, or remember only a part. Some people treat dive briefings like airline passengers listening to the preflight safety briefing.

I am aware of a volunteer firefighter who unfortunately died during a night diving class this year. It so happened that the course was a PADI course, but the person had a medical condition and his death had nothing to do with PADI. I cannot believe that PADI should be responsible for sudden unexpected health emergencies.

Before every course, students have to complete a medical questionnaire. However, I know that there are people who are macho enough to answer the questions with ignorant bravado just to get the "paper work out of the way". I am not saying that this was the case with the unfortunate firefighter at all. I am just relating my observations of students that I have worked with.

Saying that someone died or was injured on another PADI course (as opposed to another agency) is like saying that traveling by bus is safer than driving a motor car since MORE people are injured in car accidents than in bus accidents. Obviously this statement is not valid since many more people drive in motor cars. In the same way, since more people are trained by PADI than the other agencies combined, it is inevitable that on average PADI will be mentioned more than the other agencies when there is an incident.

What I am aiming for with this post is a call for objectivity. If there are concrete things PADI and the other training organizations can do to improve safety we should and must talk about those things and incorporate them into our training courses. Lets drop the rhetoric and pointless blame game and work together to make diving safer for the divers we train.

Thursday, September 22, 2005

The new mask

Recently I changed masks. The mask that I had was getting really old and the silicon had started to discolor from being in pool chlorine too long. Buying a new mask is one of the parts of buying new equipment I do not enjoy. Normally, I get excited about a new piece of equipment and usually cannot wait to try it out.

Masks and buying masks have been challenging. It would seem that I have a face that is not a standard shape. As many people know who have purchased masks at their local diving store (LDS), there is a fairly standard way of fitting masks for seal and comfort. I will not go into the various methods here, except to say that the stores do as much as possible under the circumstances to find well fitting masks for divers.

Fundamentally, I think that there must be better way to find well fitting masks. Perhaps the manufactures can try wider skirts around the outside of the mask. Perhaps the answer lays in the design of the masks. Perhaps manufacturers should rethink how masks are designed and sold.

For example, some clothing manufacturers have started experimenting with taking full body scans of people and then custom manufacturing garments based on the specific body of the client. Would it be complete over-kill if we could come up with something similar for making masks?

Alternatively, how about if the manufacturers came up with standard sizing templates that could be fitted to one’s face that will indicate which mask would be a better fit?

Having a comfortable, well fitting mask makes a huge difference to one’s dive. There are few things that annoy me as much as a leaking mask.

Tuesday, September 20, 2005

Twenty Questions

While this blog is meant to be a forum where I ramble on about whatever happens to pop into my mind concerning my SCUBA obsession, I thought it would be interesting to find out if there are regular readers who would like me to cover any specific subjects.

To that end I created a special email account where you could send in your suggestions for topics or general questions about SCUBA diving. I will do my best to answer any SCUBA related questions.

So send in your questions and suggestions to bwraf.comment at gmail.com

Monday, September 19, 2005

The adventure continues

Occasionally I run into students who were in one of my classroom and pool sessions. This weekend, two students who were in the first class that I taught were diving in the same area that I was. It was fun to catch up on their various diving adventures.

In the classes that I teach, I try to convey my passion for diving to the students. When we teach students we never really know how much diving the future divers will be doing. People get into SCUBA diving for various reasons. Adventure, travel, making new friends and so on are just a few of the reasons that people start SCUBA diving.

A fair number of my students are middle-aged people who are trying new adventures. Some of these folks have a list of things to accomplish – for example, sky diving, bungee jumping, SCUBA etc. I guess of these, SCUBA has the most rigorous training before one can participate. SCUBA is also the one sport that you can do in many exotic locations around the world.

Some divers become very passionate about diving and they arrange their vacation times around diving. The couple I mentioned earlier have spent every vacation diving all over the Caribbean. Sometimes I speak to divers who have been on three or four diving trips on one year!

Although this post might sound a little like an advertisement for diving, it really is not. Personally, it is wonderful to see how my students have progressed. I felt like a proud father watching my ex-students conduct their dives safely and skillfully. At least I had a small effect on their lives and hope that they will have many, many safe and adventurous dives ahead of them.    

Saturday, September 17, 2005

Reality check

My dives today did not turn out be so much fun after all. The problem was that I was using all kinds of new equipment and it took the entire first dive to get the problems taken care of. In a way I am glad that I had a difficult time. It made me realize how the new students must feel on their first dive. It is not that I forgot how my first dive went. For me, my very first open water dive went well with no real problems. However, today I experienced a number of problems that I have noticed that some of my students have.

This situation had me thinking of a documentary program that I saw about how some new doctors are trained. Somewhere in their process of becoming doctors, the students were "admitted" as patients and had all kinds of procedures performed on them. Not only that, they were subjected to many of the mundane hospital routine type things, like being waken at 4 am for a sponge bath and to have the sheets changed. The purpose of this immersion into the world of patients was to help the fledgling doctors understand what it feels like to be a patient - and obviously to try to get them to treat their patients with respect and understanding. I do not know how widespread this type of immersive training is in medical school, but it seems like a novel idea that might have a good effect.

New divers, have a lot of task loading going on. New equipment, unfamiliar surroundings and trying to remember everything that was learned in class and pool. Sometimes it is good for an instructor to have a bit of reality check to be able to better identify the stresses that new students experience.

Friday, September 16, 2005

My turn to have fun

For a change I will be diving just for my own pleasure this weekend. On a whim, I decided to take a SCUBA class that I have been meaning to take for a while and we will be diving this weekend as part of the class requirements. It might seem strange to some that taking a class could be fun diving.

When I am teaching a class I can never really relax and enjoy the dive. Like many of my friends, I really enjoy being in the water. However in a class situation where I am responsible for students, my focus is on the students and their safety.

J. one of my first instructors is teaching the class. He is an awesome instructor and I am still learning from him. For example, I was very impressed with the way he conducts the class and even how he handles the mundane stuff like doing the paper work (liability releases, medical statements etc.). In future classes that I teach, I am going to copy his method of handling the paper work.

Carrying on the theme that I recently wrote about that an instructor should always strive to be a good role model; it is good to sit in on a class once in a while to keep your skills current and to learn from other instructors. Every time I work with another instructor or sit in on a class, I try to learn at least one or two things from him or her.

For example last year, I worked with an instructor who gave an awesome briefing on how to use a compass for navigation. With his permission, I shamelessly copied his method of teaching the compass to rave reviews. Thanks J.

Thursday, September 15, 2005

Being a role model

In my view, it is important to cultivate good habits in divers early on. Instructors use various techniques such as multiple repetitions of key concepts so that we cement certain behaviors and concepts in the students’ minds.

Part of being a good instructor is being a good role model. Often more is caught than taught in instructing students. Students carefully observe the instructor and will subconsciously adopt certain behaviors and habits from their entry level instructors. I remember thinking about how gracefully my entry level instructor moved through the water and it was my goal early on in my SCUBA diving to move as gracefully as he did. I can clearly remember how he instructed my class on how to set up the SCUBA gear. I still use the same method and teach it to my students.

Even though the most important rule in SCUBA is never hold your breath, for instructors, the most important rules could be to always be a good role model and help instill good habits in your students.

Tuesday, September 13, 2005

Most important rule - part II

The most important rule in SCUBA is never hold your breath.

In the classroom and pool sessions that I teach, I always tell the students that by the end of time we have together they will have heard me talk about the most important rule in SCUBA more than twenty times. I do this so that they will focus on what the words mean. By the end of the second pool session they recite the answer to the question loud and proud.

During the past weekend, I had to work with students who were trained by other instructors. When I asked what the most important rule in SCUBA is, some answered that "you should always breathe".

The problem was that at the time we were talking about regulator recoveries. Of course I made light of that answer since it is very inadvisable to breathe underwater while the regulator is out of your mouth (just so you know, I meant this as humor).

Some people might feel that there is a distinction without a difference between “never hold your breath” and “always breathe”. In other words, some people think that the two terms mean the same thing. I do not agree.

Always breathe implies that you will always have a source of air available. However never hold your breath indicates to the students that they should always keep their airway open. The concern is that a diver could suffer lung overexpansion injuries when holding their breath upon ascent.

Sunday, September 11, 2005

Can you see me?

An article on CDNN sadly reported that a diver was accidentally killed in Hollywood Florida by a hit and run boat accident. Police thought that it was possible that the people in the boat did not realize that they had hit a diver. The divers did have a dive flag (diver down flag) with them.

This past weekend, Navigating Phenom, I and another instructor were doing open water certifications in a local body of water that allows all manner of small boat traffic.

We witnessed a Jet Ski pass right over a group of recreational divers (we knew this from watching where the air bubbles were coming up). Fortunately nobody was injured in this incident. However, the divers did NOT have a dive flag with them as required by local regulations. Clearly the divers were not taking their own safety seriously.

These two events had me thinking about boat traffic and diver safety.

My initial reaction is that divers must be proactive about their safety. I do not know what happened in the tragic event with the diver in Florida and do not even want to start to speculate about the cause. However, in the case of the divers that I witnessed, it was clear that the divers did not take boat traffic into account when they started their dive (not to mention local regulations).

My second reaction is a question as to whether boaters are sufficiently made aware of what dive flags mean. Locally boat traffic is required to stay at least 150 feet (50 m) from dive flags. I am not familiar with what licensing is required to be able to operate a boat or a Jet Ski. From what I have heard it would seem that just about anyone can hop onto a Jet Ski and tear up the water.

Jet Skis are fun and I have absolutely no issue with people enjoying their boats and Jet Skis. My concern is that boaters and Jet Ski operators are not aware of what our dive flags mean, or give sufficient clearance to the area where a dive flag is.

Locally we are required to have a dive flag for every four divers. The dive flags that we use here in the USA are red with a diagonal white stripe (some other countries the dive flags are a different color and design).

Perhaps it is time for a dive flag education campaign by dive training organizations, SCUBA equipment manufacturers and other interested parties aimed at small recreational craft operators.

Please follow your local regulations concerning dive flag usage. Even if you do not have local regulations that require dive flag usage, take a proactive approach and use a dive flag or other signaling device that will make boat traffic aware of your position. For example if you will be surfacing or diving shallower than say 15 feet (5 m) in an area that is prone to boat traffic, take extra precautions.

Do not take any unnecessary risks or assume that boaters will see your dive flag and avoid the area that you are in. The question is not whether you can see the boat traffic, but whether the boat traffic can see you and know that you are in the water. Take your own safety very seriously.

An example of local dive flag regulations:
  • Scuba divers must display a warning flag when
    diving.
  • The diver’s flag must measure at least 15 inches horizontally and 12 inches vertically. Both sides must have a red-colored background bisected diagonally by a three-inch wide white
    stripe. There is also a blue and white diver’s flag authorized under the federal rules of the
    road.
  • No more than four divers shall dive under one flag.
  • Divers must remain within 50 feet (measured horizontally) of the warning flag.
  • If a group of divers is using a contained area, the perimeter of the area must be marked. The area must be outside the normal area of navigation. These markings must consist of the official diver’s flag and must be placed around the perimeter of the diving area at intervals of not more than 150 feet.
  • Do not place a diver’s flag where it will obstruct navigation.
  • The diver’s flag may be displayed on a watercraft or float or be anchored to the bottom. The top of the flag must be at least 30 inches above the surface, however.
  • Boats not involved with the diving operation must remain 150 feet away from a flag. Persons who dive at any time from sunset to sunrise must carry a diver’s light visible when above the water for a distance of 150 feet.

Thursday, September 08, 2005

Heavy breather?

Most dive training organizations have some kind of swimming and water treading requirement for certification. Often students will ask why it is that they need to be able to swim 200 meters to be certified to do SCUBA diving. The reasoning goes that since we will be submerged while SCUBA diving what is the point of doing a 200 meter surface swim?

As some of the veteran divers will remember, the entry requirements and training for SCUBA were much more stringent in the “early days”. Recreational SCUBA diving training was largely based on Navy training methods. Navy diver candidates should be able to swim, tread water and do many other very challenging things to be Diver qualified.

Anyone who has seen TV programs on how Navy Divers are selected and trained will probably remember seeing student divers doing many physically demanding and challenging drills and exercises that might not seem to be directly related to SCUBA diving. The physical training is partly due to the candidates are being physically conditioned and partly due a weeding out process.

Recreational diving has changed substantially since the “early days”. Diving is becoming more and more popular as people are spending more on leisure and adventure travel. The training regime and entry requirement for CERTIFICATION has changed with the times. The certification requirements now more closely mirror what a recreational diver needs as opposed to what a combat or salvage diver needs.

Often students will think that the swimming requirement and water treading is a hold-over from the military heritage of SCUBA diving. Personally I do not think that this is an accurate view.

Most divers will compare air consumption after a dive and sometimes students will ask why their air consumption is so high compared to their buddy’s. The answer is of course that there are many factors that affect air consumption, but one of that factors that is easy to change is the diver’s fitness level. The fitter divers tend to use less air than those who are not. Think about a fit and a non fit person walking up a set of stairs. The out of shape person will be most likely breathing heavier than the fit person. The website divefitness contains many great articles and tips on how to improve your air usage and fitness for diving.

SCUBA diving is inherently a physically challenging activity. The tanks, weight belts and other equipment are heavy and just getting to the water and setting up your gear can be a mini workout all by itself.

The swimming requirement is not a weeding out process, but is a measure to determine whether the student is up to the physical challenges of recreational diving. Some people are better swimmers than other, but generally there is a good correlation between the people who are comfortable in the water (swimming, snorkeling, water treading etc.) and being comfortable underwater.

Your fitness level directly impacts your potential enjoyment of SCUBA diving. The fitter you are the easier and more enjoyable the dive.

Tuesday, September 06, 2005

By their signs shall you know them

I have been noticing a trend on some of the vehicles of divers and instructors. A number of divers have a dive flag sticker somewhere on the rear of the vehicle. A few have a license back plate that has some kind of dive flag design. A few probably have personalized license plates that advertise their love for SCUBA. I don’t remember seeing any creative and fun personalized license plates recently that refer to SCUBA but I am sure there must be a few around. For example SCUBA1, SCUBADVR etc.

Then there are some folks who tend to be over-achievers in life. These folks have just about every SCUBA sticker known to man on their vehicles. Not only do they advertise their love for SCUBA, but will tell of their preference of equipment manufacturer, and for good measure the fact that they are an instructor.

As I derive a modest source of revenue from my SCUBA obsession, I am all for making diving as popular as possible. So I say, advertise away, just remember not to drive as if you were suffering from nitrogen narcosis!

Saturday, September 03, 2005

How deep is deep enough?

“What is the deepest that you have dived to?” This question comes up from time to time in my classes. Of course, I give a carefully qualified and truthful answer. The point really is, how deep is deep enough.

Open water divers should not be diving to deeper than 60 feet (20 meters) unless they are diving with a professional. With additional training (for example advanced open water) the diver could venture to 100 feet (30 meters). The absolute depth limit for recreational diving specified by most training organizations is 130 feet (40 meters).

Someone once said that there is nothing in the water that is worth to die for. His point is very well taken. So many times, we hear of divers who are injured or worse, due to deep dives that lead to complications. Often there is an equipment malfunction or a diver error that leads to tragedy.

On the other hand, there are divers who are very experienced, trained and equipped who venture to depths well below the recreational limit of 130 feet (40 meters). These divers are in a very different category than the divers that I train and the type of diving that I do. For the purposes of this post, let’s exclude these divers from my comments below.

The depth of a specific dive should be carefully considered based on the individual’s health, experience, training and of course the prevailing conditions. Some of the factors that should be taken into account are:
  • How well can you see at depth? (colors appear different at depth)

  • What will your bottom time be to explore? (the deeper you are the shorter the bottom time)

  • What are the conditions like? (current, marine animals, possible entanglements)
An article on DAN’s website cautions related to deciding on how deep to dive, “As with many things in life, one must balance the risks against the benefits and make a decision. However, it is essential to have a real understanding and appreciation of the risks.”

The DAN article goes on to caution:
It becomes obvious that there is no safe depth limit that applies to all divers all of the time. A diver’s ability to cope with depth depends on a number of highly variable factors. The depth of the onset of the effects of the exotic cocktail of elevated pressures of nitrogen, carbon dioxide and oxygen, coupled with the sensory deprivation and stress associated with diving, are not always predictable. A dive to 80 feet in cold, dirty water can be far more hazardous than a dive to twice the depth in warm, clear waters. Factors such as visibility, water temperature and diver experience and preparedness greatly affect a diver’s comfort and safety, rather than depth alone.
There is no single answer to the question of how deep is deep enough. However, in recreational diving, one should always dive to well within your training and ability while taking the prevailing conditions into account.

Thursday, September 01, 2005

A great gift idea

In every open water class that I teach there will be at least one couple who are about to get married and are planning to go diving on their honeymoon. The idea of Scuba diving on your honeymoon is wonderful.

Sometimes we get students who received the training as a gift from their parents or other loved ones. Once we even had students who received the training as part of their company’s program on promoting fitness and education.

If you are hard pressed for a gift to give to someone special in your life, perhaps giving him or her a gift that will lead to a lifetime enjoyment from the wonders of Scuba diving will be best thing you can do. This is truly one of those gifts that keep on giving.