26 replies to this topic

[Diverbrian]

True,

But let's see...

Five minutes of bottom time on the tables means exactly that. I don't have my IANTD tables handy, but I was trained to take a minute or so away from that. That knocks it back to three to four minutes bottom time. Factor in narcosis (slow reactions to everything) and descent time, you will be in decompression if you are doing an honest dive. I don't know of too many people that are willing to pay a boat to take them out to do a dive with four minutes of bottom time. So, for literal purposes it is possible to do the dive on air to 140 and not violate NDL. For practical purposes, it is not likely. You had better be planning on deco.

The minute that you go into deco, the diving mindset changes from "if worse comes to worse, I will safely ascend and be safe" to "underwater problems MUST be solved underwater". This affects required redundancy of gear and the mindset of the diver.

Hence, below 135 ft., one should be thinking about being trained for staged deco. At some point in there (and most divers will agree that it is before 165 ft.), one should seriously consider tri-mix training as well because the narcosis will be a large factor.

[Diverbrian]

Funny how certain words can crystallize a concept for me. Brad's & Brian's use of the term "overhead environment" really brings home the fact that there is always deco when diving to the depths that are being discussed- not that I wasn't aware before- I'm not that :marvel: but, putting it in those terms provided me (& perhaps others) with a terrific visual that can really bring home the necessity of the deco obligation.

Marvel,

Actually, my limit for serious, no-fooling deco diving is 100 ft. Let me explain that, if I dive below 100 ft., typically I am diving on a lean EAN mix (such as EAN32,EAN28 or EAN26 depending on planned depth) to buy a little distance from NDL's and stay within 1.4 PO2.

My ascent will be done on EAN50 as I pass 70 ft. and do proper stops on the way up. I don't play games with these things even if I planned and executed the dive to stay within NDL's. I will take any advantage to help keep that nitrogen down by that point.

Obviously, below 120 ft. to 135 ft., I plan those as a staged deco dive to start with. You are obviously seeing the reason that I am buying the gear to get into tri-mix. Hopefully, my tech instructor will be free to teach me the course within the next year.

[WVMike]

If travel were not a concern, and certifying agency not a concern, and money was, of course, to be a factor, what agencies and courses would you guys recommend for tek training? I have had a few recommendations to consider the cavern/cave training, which seemingly would benefit all divers. (Thanks again!)

Mike, as has been said and I totally agree, it is much more the instructor than the course. Then comes the student!

I would look into DIR training based on your question, concerning the ultimate with no time, money, or travel constraints. Especially if you have a buddy who is as passionate as you and can do all the training with you.

[BradfordNC]

Five minutes of bottom time on the tables means exactly that. I don't have my IANTD tables handy, but I was trained to take a minute or so away from that. That knocks it back to three to four minutes bottom time. Factor in narcosis (slow reactions to everything) and descent time, you will be in decompression if you are doing an honest dive. I don't know of too many people that are willing to pay a boat to take them out to do a dive with four minutes of bottom time. So, for literal purposes it is possible to do the dive on air to 140 and not violate NDL. For practical purposes, it is not likely. You had better be planning on deco.

The minute that you go into deco, the diving mindset changes from "if worse comes to worse, I will safely ascend and be safe" to "underwater problems MUST be solved underwater". This affects required redundancy of gear and the mindset of the diver.

Hence, below 135 ft., one should be thinking about being trained for staged deco. At some point in there (and most divers will agree that it is before 165 ft.), one should seriously consider tri-mix training as well because the narcosis will be a large factor.

exactly.

you could go to 190fsw on air and spend no time and then come back up.

but what would the point be??? other than to check an ego block and say, "I went to 190fsw on air."

if your looking at going deep because you want to ckeck out the wrecks and other sites that the majority of recreational divers will never see, then look into the training.

a responsible dive to greater depths is going to take advanced training, which will include the whole deco bit.

and on a sidenote: the deco training isn't just for deep dives. there are several wreck divers around here who do deco dives in less than 80fsw. they stay down for a loooong time looking for artifacts.

but the main thing is the deco obligation, even with no wreck penetration, you are now in an overhead environment. and some people don't understand that, they just think, "oh wow, deep diving with deco procedures, thats cool."

but even out in open water, if you have a required deco, you are in an overhead environment, and all problems in the water must be handled under the water.

ok, lets see how much flak this gets.
IMHO, if you realy want to wrap your brain around it without taking the whole series of deco classes, first try out one of the cavern courses. it will help you "visualize" exactly what the OE is. just before christmas, saw a cavern class do their first dive, as they started towards the cavern zone, one of the students turned around, surfaced, and got out of the water, game over.

if you enjoyed it, take the next step, Intro to Cave. now your doing full cave dives, which will stress bouancy and other skills. the first time you do a lights out drill, you'll see just how dark, dark can be. when all natural light is gone, you realy come to grips with the fact that if there is a problem, natural happy air is a long swim away, and you can't surface, you need to solve the problem in place.

but thats just me.

hope it helps.

[peterbj7]

ok, lets see how much flak this gets.

Why flak? Sounds pretty reasonable to me. But I think the decision point comes even sooner. It isn't when according to some relatively arbitrary algorithm you're "in deco" that things change, but as soon as you're so deep that you wouldn't have a realistic chance of getting to the surface on one breath and still being in good health. To me and I believe most divers that's a long way short of 135', and probably short of 100'. I'd like to see all scuba training beyond introductory teaching self-help skills, and including in-water stress management.

[Diverbrian]

ok, lets see how much flak this gets.

Why flak? Sounds pretty reasonable to me. But I think the decision point comes even sooner. It isn't when according to some relatively arbitrary algorithm you're "in deco" that things change, but as soon as you're so deep that you wouldn't have a realistic chance of getting to the surface on one breath and still being in good health. To me and I believe most divers that's a long way short of 135', and probably short of 100'. I'd like to see all scuba training beyond introductory teaching self-help skills, and including in-water stress management.

Thanks Peter,

I do agree with that wholeheartedly. At the recreational level, these skills do not tend be taught.

Brad,

I have done planned deco dives to 80 ft as well. Normally for me this is the second dive of the day with the first dive to 100 ft. or deeper. Both dives in that event will likely turn into planned staged decompression, but not always.

Cavern training doesn't happen in my neck of the woods or I would say that it is a good idea. We have plenty of Cave divers around, but they tend to train in Central Florida and I don't have the vacation from work to do that training.

[BradfordNC]

I suggested taking a cavern course because it is a relatively inexpensive way to get an introduction to an overhead environment, so a diver can see if they are comfortable with it, and get a feeling for just what that means.

nothing like several million tons of solid earth between you and air to make you realize the seriousness of the diving.

i say relatively inexpensive because the alternative is to either take the full series of course to become deco or full cave certified.

the full deco route is often times done in calm, crystal-clear water. and with some of the dives being "theoretical deco." when all is happy happy and you can see the sunlight on the surface, it might not sink in that the surface isn't an option. so you'd spend a lot of time and money to eventualy figure out, "hey, this isn't for me."

the same with full cave certification. there are agencies out there that laugh at cavern training, and claim it has no usefull purpose, that you are either full cave or nothing.
ok, fine, go on with your bad self then.
but those full cave classes cost a lot of money, and of course require more dives than i have fingers (i was born in DC, not in NC).
it sure would suck to spend all that money and time to find out on the first dive that maybe the overhead environment is a bit to much for you.

cavern training lets you get a little taste of it, introducing you to the skills you need. and most importantly, letting you get comfortable with what future training is realy going to entail.

and you can stop at that level and call it a day. or move on to the next steps in either cave or deco.


Brian,
taken seperately, Cavern and Intro to Cave are both 2 day courses. If taken together, they can be combined into a single 3-day course.
i think your in water skills are good enough to where you could do that option.
a lot of people will initially schedule a combo course, but then the instructor ends up halting it after cavern, sometimes without even granting a cavern cert.

Edited by BradfordNC, 06 January 2005 - 10:32 AM.

[Diverbrian]

I suggested taking a cavern course because it is a relatively inexpensive way to get an introduction to an overhead environment, so a diver can see if they are comfortable with it, and get a feeling for just what that means.

nothing like several million tons of solid earth between you and air to make you realize the seriousness of the diving.

i saw relatively inexpensive because the alternative is to either take the full series of course to become deco or full cave certified.

the full deco route is often times done in calm, crystal-clear water. and with some of the dives being "theoretical deco." when all is happy happy and you can see the sunlight on the surface, it might not sink in that the surface isn't an option. so you'd spend a lot of time and money to eventualy figure out, "hey, this isn't for me."

the same with full cave certification. there are agencies out there that laugh at cavern training, and claim it has no usefull purpose, that you are either full cave or nothing.
ok, fine, go on with your bad self then.
but those full cave classes cost a lot of money, and of course require more dives than i have fingers (i was born in DC, not in NC).
it sure would suck to spend all that money and time to find out on the first dive that maybe the overhead environment is a bit to much for you.

cavern training lets you get a little taste of it, introducing you to the skills you need. and most importantly, letting you get comfortable with what future training is realy going to entail.

and you can stop at that level and call it a day. or move on to the next steps in either cave or deco.


Brian,
taken seperately, Cavern and Intro to Cave are both 2 day courses. If taken together, they can be combined into a single 3-day course.
i think your in water skills are good enough to where you could do that option.
a lot of people will initially schedule a combo course, but then the instructor ends up halting it after cavern, sometimes without even granting a cavern cert.

I see your point on the cavern course. Actually we agree on the full cave concept. There is a lot to that course of action and I don't have the time away or money to do that and the wreck diving that I love to do in the summer. Choices, eh?

I wasn't aware that the Cavern/Intro to Cave program was that much shorter. I am looking into finding a mentor and a class to start teaching me line work. I will let you guess the reason. I may have to start looking into that as a beginning point. It's difficult to find in the immediate area where I live. Of course, I wish that the water up here was crystal clear, LOL.

[BradfordNC]

I wasn't aware that the Cavern/Intro to Cave program was that much shorter. I am looking into finding a mentor and a class to start teaching me line work. I will let you guess the reason. I may have to start looking into that as a beginning point. It's difficult to find in the immediate area where I live. Of course, I wish that the water up here was crystal clear, LOL.

yeah, i hear ya on the crystal clear water part.

but i think viz is relative to comfort.

i've realy gotten to enjoy some of the lower viz diving. (but not Cooper River mud diving)
on night dives, i shut my light off for most of the dive.
and in a cave, the water may be crystal clear, but your only gonna be able to see as far as the next wall. lol

the NSS-CDS and NACD have pretty much merged the way they do business. and you pretty much just choose which agency you want your certification filed with.

they have come to realize that more divers would be interested if it could fit into their schedule. and if your married with children, and have a weeks vacation, your going to take the family to disneyland, not spend the week learning to cave dive.

you only have a limited amount of vacation time.
but weekends, you've got one every week.

so the full cave certification is broken down into 4 courses, each building upon the skills taught in the prior course, with new equipment added along the way.

each of the 4 courses is a 2 day event, each with a minimum of 4 dives.

Cavern introduces you to the community, teaches line skills, gas management, and gets you under the rock.

Intro to Cave builds on that, with the introduction of redundant regs, the 7-foot hose, lost line and lost buddy drills.

Cave Apprentice takes it a step further with double tanks, more line work, jumping gaps, and more advanced dive planning.

and finaly full cave.

a person can get the training in little bites, and see how they like it, and decide if they are ready to move to the next level. you can stay at whatever level you like, and continue diving at that level.

of course, it also lets you pay for that training, and the upgrades in equipment for each level, over time. easier to pay for it all when it's spread out over several months or a year.

**note: this post is just an fast overview, and is not all inclusive of the skills taught at each level of training. the views expressed belong to me, but feel free to adopt them as your own.

[MadManMike]

Groovy, love all the info.

Where would you guys recommend the Cavern course, taking distance from Key Largo as the major consideration.

Also, knowing a LITTLE about the specific gear requirements of the cavers, are there any gear requirements for the cavern course? Or do you start the new gear purchases at the next step?

Thanks again for all the great info/opinions.

mmm

[BradfordNC]

Groovy, love all the info.

Where would you guys recommend the Cavern course, taking distance from Key Largo as the major consideration.

Also, knowing a LITTLE about the specific gear requirements of the cavers, are there any gear requirements for the cavern course? Or do you start the new gear purchases at the next step?

Thanks again for all the great info/opinions.

mmm

Mike,

most instructors will tell you not to buy any new gear before the course, because you don't know anything about it yet, so can't make an informed decision.

for cavern, you can use your normal openwater set up. thats the beauty of the course progression.
you will need two lights.
you will also need a reel.

you can usualy rent the items needed, which allows you to try them out and see what you like, then buy with knowledge after the course.

the cavern reel will become your safety reel once you progress to Intro to Cave.

as for where to find instructors near you. i'm pretty sure there are some pretty close to south Florida.
i get all my instruction in the north Florida springs area. but there are some other training sites further south.
you can get on the NACD website for a list of instructors.

[bigblueplanet]

DSAT Tek Deep course is about training you to be a tech diver. The line was drawn at 165 for many reasons, most of them not practical with depth. It is about what is accepted worldwide already. 50M is accepted in Europe and other areas as normal. This class is not about the depth, but mindset and skill set development to be a technical diver. If you chose to dive deeper after course completion that is your choice. While dives in the course do not have to go as deep as 165. Those who choose to not dive air deeper have the room to stay near 130 with air, but as I have said in past and other posts, this stance is silly. Air and helium are tools. For all the "danger"of air below 130, I would say the use of helium by those unable to control ascent rates properly is more dangerous than air beyond 130.

The course has to be considered on its own. As a course, it is educationally valid and the course text actually teaches you what you need to know for the course. You learn a system for approaching the dives. At worst, the course is going to provide a structure to have hopes of ending up with solid skills for these dives.

It is about the instructor. A bad instructor in any system is going to produce crap. But, Tek Deep is going to provide a format that will make you a better diver. In the hands of a good instructor you will be good. If someone teaches for multiple agencies I would hope that the diver at the end of the day would be the same diver. It would imply that somehow one course was less professional than the other. I do not believe that an instructor is going to allow a diver to leave a course less capable simply because of the agency he chooses to associate with for that course. It is about what the diver is able to do on the bottom.

You will likely have a great course if you chose to particpate in a Tek Deep course. Just make sure you feel good about the instructor you will work with. The philosophy on the course is that you learn how to tech dive in Tek Deep. When complete you are ready to do the dives. There is a break now called Level One before you reach decompression dives. But, realistically, with any agency you are not a true tech diver until you finish all the courses that will then allow you access to all the components you need to do air dives with oxygen. So, Tek Deep is not all that longer than the rest, but does a better job in the approach.

If you want to compare, simply look at the course texts you will use in your courses. That will clearly show the difference in approach.

I am an instructor in IANTD, TDI and DSAT. Part of the reason I participated in the development of the Tek Rec courses is that I wanted something better than what we have before. I can say the course is very different and markedly better than the other courses available. I would not have kept my name associated with it if I did not feel it was. A student certifying in any agnecy with me leaves the same diver. But, what I add to the other agency courses is not present in the materials provided to me by those agencies. So, with the other agencies, if you have an instructor that doe snot add to their courses, you will receive much less.

DSAT's appraoch is that you have two levels of technical diver. You do not need several divisions in the process from the point of what the diver does with the training.

Tec Deep with those that are technical divers but use air and have the full capability to do so. Tec Trimix for those that want the use of helium and added depth. DSAT believe that when someone learns to use helium they should have the full ability to deal with it. There are many examples of divers taking a dumbed down helium course to only turn around and do the full trimix dives without the training. If you learn trimix you should have the skill set to use it. Recreational trimix is simply a political agenda. If a trimix diver wants to use helium shallow, then it is their choice to use the tool that way. Certainly we do not want to see divers using helium as a crutch to allow access to deeper dives they should not be doing.

Tec Deep is a good course.

Grant