1 Comment

Good Enough for Today, Not Yesterday

This blog brought to you by Jonathan Bernot:

Let me be clear, I see two distinct levels within this sport.  There doesn’t have to be.  In fact I wish that those at all levels would strive to emulate and be as precise and competent as the upper level.  I do however see a line within the sport where when you cross it, you are now at the top of the food chain.  You are at a level in the sport where there is very little room for compromise, very little room for error.  Cave diving in my opinion, certainly falls into this upper end of the sport.  As a cave instructor it pains me to see divers that come into the sport, or are already in the sport, who do not seem to understand the importance of certain key concepts.  I could expand indefinitely on this but I am limiting this to a single focus, and that is gear choice.  As a diver at the top end of the sport, in a segment that holds inherent risk potentially higher than that of the lower recreational levels, equipment decisions should not be taken lightly.  If a diver is going to be at this level they need to take the sport seriously. They need to take their equipment choices seriously.  Good enough doesn’t cut it!  You need to seek out the best available now, not what was the best when you were certified 10 years ago or what your instructor bought 10 years ago,  and certainly not what is just as good as what you started open water with 10 years ago.


Technology evolves; a diver at this level needs to choose the best equipment available today. Part of what allows us to continue to save ourselves heartache and problems is evolving technology.  We owe it to ourselves to take advantage of it.  Regulator choices need to be taken seriously.  There are many regulators I would not criticize the newly minted Open Water Diver for choosing to dive with, but I would simply not allow a cave student to use in my class.  A quick example are any of the “slimline” octopuses.


One of the areas that is paining me more and more in recent years has been lighting choices.  I am hearing divers talk about lights at the dive site and what they deem as great deals.  The 10 Watt HID of 10 to 15 years ago were absolutely fantastic lights at the time.  It was one of my first canister lights.  It is absolutely true there are many lights out there brighter than this one that are in current production.  However, we must ask ourselves whether or not it is really the best available now and is it appropriate to our needs as true technical and cave divers.  What is built as a backup light today is just that, a back up light.  It doesn’t matter it has the lumens of our canister lights of old.  First we need to discuss burn time.  A Light that only burns for 1 to 2 hours is in my opinion not an appropriate light for this side of the sport.  Forgetting the fact you will outgrow it at some point, it does not have the adequate burn time in the event of problems that may lengthen the dive itself.  To answer by saying I will simply carry two of them is also not acceptable in my opinion.  Get the correct burn time for the job and get a light you can run on the power you want.  Running on a candle because to run on high would not get you your appropriate burn time is not the answer either.  Build quality, or lack thereof, is still a true concern for the vast majority of lights being produced in the Far East.  I will give you an example of a method of production that I have seen in a number of “dive lights”.  An LED module is inserted from the front and then a stainless or aluminum bezel is screwed down over the lens.  At depth the pressure reduces the tightness of that bezel, it can then begin to spin, and while in most cases the lens is held in place by pressure at depth, it is then allowed to flood at the very end of the dive in shallow water or on the surface when the pressure is relieved.  I am seeing Goodman handles being molded from plastic and breaking.  I am seeing corded lights with very questionable cables that truly appear to be more suited for my laptop than for diving in a harsh environment.

I never understood the mentality of, “well they have great service, I had a problem and they sent me a brand new light”.  You should not be having routine problems to begin with.  Yes when you do, service is important, but just recently on one of the forums I saw these exact statements.  Good service should not be viewed as quick replacement of the faulty product.  It should be deemed first and foremost by not having to deal with the service department at all, and then on the rare occasions you do, you should be met with prompt service usually in the form of a speedy repair at an acceptable price.  It is rather hard to do that when the manufacturer is overseas.  Yes there are lights in Europe I would probably dive if I lived in Europe.  Right now as a serious American cave diver I see there only being 4 true manufacturers of dive lights that have high build quality, acceptable burn times with acceptable light outputs, and on those small occasions where it is needs, prompt and good service, within the United States market.  Light Monkey, Halcyon, Underwater Light Dude, and Dive Rite are the most popular lights in the cave diving scene for a reason.  I am sure others will emerge, just as those four have continued to evolve their manufacturing in order to stay relevant in this industry.  Don’t be cheap.  Lights are part of the kit you are taking into a very unforgiving environment.  Make your choices carefully.




1 Comment


What Gradient Factor???

This is a question I get asked a lot.  In almost every single technical course I teach I am asked by the student which gradient factor should they set their computer to.  The next question : What gradient factor do you dive?  I hate this question for a couple of reasons.  First what I am comfortable diving is not necessarily right for that diver. From a liability standpoint if I tell a diver to run 35/85 and they take a DCS hit I don’t want to be morally or legally liable.  The only gradient factor I can suggest is the factory default.  But I am getting ahead of myself.  Which one is right? 

First people need to understand what those numbers are doing and I will put it in basic layman terms since that is the best way for us to understand it.  If you hold a technical degree and know more than I do and can expand in a way I will be able to understand I would love to hear from you.  You have a line, and that line is basically the point at which the vast majority of divers should be able to get out of the water and not have DCS problems.  Notice I say vast majority, not all.  That is that second number, in this case 85 if we are running 35/85.  So imagine that as a margin of safety at 15 since that is what is left when we assume 100 is that line.  Now the first number.  That 35 is going to dictate your first stop with 100 being the point to which you could ascend to and again most likely not have issues.  Keep in mind after a 300 foot dive that line that is the 100 may start at 150 feet.  So what we have is a low starting point and a merger up through your stops until that 85 is 0 feet of depth.  Now the diver needs to understand 2 things.  First there are many factors that play into decompression.  Your stop depths and times are only two of them.  Dehydration, mental, and physical stress, warmth, ascent rate, and general physical variants can all cause these profiles to work better or worse depending on the day.  The second is that this code and the various tables and computers used by divers are not all coming from a single source and a single code writer.  The author must create a starting point and incorporate the code and theory he has chosen into a useable format.  I will give an example.  I once did a dive on Open Circuit to 175 feet for 1 hour of bottom time.  I had two mixed gas dive computers from mainstream reputable companies.  With the exact same gradient factor on that dive I had a 20 percent difference in the decompression obligation between those two computers.  I continued to dive them both, not necessarily together, and had no significant decompression related issues from dives performed with either one. 

Now here is the important part.  I have known divers who got bent using gradient factors I would consider to be VERY conservative.  No I won’t say what they were.  I have also known divers who for various reasons aborted deco and suffered no decompression hit.  I have also completed my deco 25 minutes sooner than other team members on the exact same dive using the exact same gasses, gotten out of the water and was fine while they got bent bad.  So we are left with some very real facts.  First; stops and times are important but equally as important is the “Art of Diving”.  Ascent rate, hydration, relaxation at deco, staying warm.  These are all in my opinion as important as your stop depths and time. 

Next let’s look at risk.  Having told you that divers I know have gotten bent while using in my opinion quite conservative gradients do you still feel comfortable diving a gradient factor that leaves almost no conservatism and brings you up very quickly?  Are you diving it just because your instructor is diving it?  I have no problem doing deco.  I am much more comfortable in the water than in a dry chamber with IVs hooked up. I have no problem doing a little extra deco.  So why am I writing this?  First I want people to seek out education for themselves, not just blindly follow what someone else does because that very experienced diver may have 20 years of doing things a certain way, and that certain way might not be correct for you or even them for that matter.  I want people to evaluate the dive, assess the risk they can accept in terms of their dive profile and dive safely.  I have evaluated the risks and chosen my dive planning.  Have you? Or have you just plugged in numbers someone told you to use on the internet or in that video you watched about an exploration project.  Oh but if you are diving 100/100 or something very close to that, believe me you are wrong.  Safe Diving. -Jon B.