A Letter to a CyberFriend About To Embark On Cave Diving TrainingIf you are cavern trained, and are thinking about progressing on to some cave diving classes, you may find some of this interesting.NOTE: For those experienced cave divers reading this (why are you bothering?), don't cringe too much at some of this... I wrote it when I only had about 12 months of experience... I know better, now, about some of this... (This letter was written as an answer to many of Michael's questions. Often, I would include part of his question [which start with ">>"] to make the answers a bit easier to understand.)
Michael -
Glad to help, but for every 100 cave divers, you'll get 150 opinions
(a lot of them change their minds in mid-sentence
It sounds like physically and mentally, you're in shape. I wasn't
in very good shape physically, but still made it, so that part will
be a breeze for you.
>> I've heard that Lamar is humorless, but he also has an excellent
Absolutely true, he is very good. And he's not humorless... it's just
that he has to deal with all those dumb intro-to-cave students!
>> Can you tell me why a swift dump is important when exiting a cave?
The high flow caves will want to PUSH you out... in certain caves like
Devil's Ear, out means UP, so you either have to grab on to some
piece of limestone and keep pressing the purge valve until you're "flat",
or have a fast purge. The purge on my drysuit is slow, so I've learned
(the hard way) to think ahead, find a place where I won't be in the
flow and out of everybody else's way, and dump a lot of the air out of my
wings, purge as much air from my drysuit, then brace myself for a swift
exit. It's fun!
>> Transpac/metal backplate/wing size, etc. hmmmmm. Cost is about $ 500.
Renting is good, too, especially if you're not going to dive very often.
The Divers Supply price for a backplate/harness/pouch/z-knife combo is
about $350 or so. Prices from the NACD and NSS-CDS BBS's are even
less. (I picked up my spare kit for about $150.)
>> Again, understand that most cave divers use ScubaPro or Poseiden.
Some use the US Divers Conshelf, the Mares Abyss, Dacor Extreme, and
some even use the Beachat VX-10. So, although Poseiden and SP seem
to be your only choices, they aren't really. The theory, though,
goes like this: if several minor things have gone wrong in a cave,
that tends to make even more things go wrong; the more things that
go wrong, the more likely the diver will start to stress out; everyone
has that point-of-no-return where the stresses cannot be resolved;
if you have anything but a really good breathing regulator, you may
"add" to the stresses by deciding that you can't breathe, that
something is wrong with the regulator. There are documented cases
of cave divers spitting out a perfectly good reg, with tons of air
in the tank: asked later, they state that they couldn't get any
air out of the reg. That sort of situation is not physical, it's
psychological. That's why I made my statement about, having a
good reg is one less thing to worry about.
>> I am intrigued with the new Poseiden Trident...
Sorry, no. It's a Poseiden, but it's not up to the rigors of cave
diving. If you purchase Poseiden, get either then Odin or Cyklon 5000.
>> I am now thinking of waiting on many (all) of these purchases until I
Boy, then you'll be REALLY confused!
>> Would you have a phone number for Ralph Hood?
>> Think DR manifold use slip in O-ring quick connects rather than screw
I'll admit that I'm no expert on any manifold except the one I own, and
I KNOW it's got limitations!
>> I've arranged to rent double 104's from Wings with manifolds.
Good choice. I'd love to be there the first time you have to walk to
the spring!
>> Good advice; might just stick with my Datamax Sport for now, until I
Like you, I already had a dive computer when I decided to cave dive, but
unlike you, it was an Aladin Pro. Does the Datamax Sport provide for
deco stops? You'd better check. If not, then you'll have to use tables,
and THAT will leave you in the water for quite a while (use DCIEM tables
if you can get them).
Although I don't have a back-up computer, I do have a Citizen Hyper-
Aqualand, which records depth and bottom time (and provides for some
neat downloaded profiles, later). With the HyperAqualand and the
tables in my pouch, I can get out of the water bend-less if my computer
does go haywire.
>> Good point. Tho I don't have a regular CD partner......I'll have to
Yeah... I read Robbie Osman's message to you about not buying any tanks
at all, and doing your diving in Akumal. Pretty good advice; but you
might ALSO want to start a Christmas account and save up for some nice
104s. I use my 104s for deep diving, too, so they can come in handy
for more than just the occasional Florida trip. And, I've heard about
some u/w caves in the Idaho, Wyoming, Utah area... could be, with your
skills (rock climbing, dry caving, etc.), you could have some major
finds if you go poking around! Then, of course, you'd need the tanks!
>> Not so much my legs; rather those three slowly degenerating lumbar
Okay, dude, here's my secret. If you tell anyone, I'll have to kill you.
In 1977, I had back surgery: herniated disk. Like you, carring around
heavy weights is mucho terrible'. But here's the GOOD part: since I
started cave diving, my back has gotten BETTER! It's not documentated,
but I have lots of anecdotal evidence that every dive is like a hyper-
baric O2 treatment, especially if you use pure O2 on the 20 and 10 foot
stops. These "treatments" have cured lots of ills, as told to me by
many, many different cave divers around the world. So, IMO, the short hike
to the springs with 125# of cave kit WILL be compensated for by your
60 minutes of higher PPO2, and maybe then some. And, of course, nitrox
dives are even better than air.
>> Got it; is Diver's Supply at Ginnie?
There are several towns that have a Divers Supply, but the closest to
Ginnie is in Gainesville (a 25 minute drive). However, you should call
them (800-999-3483) and have them send you a detailed catalog, so you
can start dreaming and salivating. I meant to mention before that
you should dedicate 1 entire day toward acquiring gear. For me,
my 9 days was 9 FULL days, and I didn't have time to go get anything.
>> (Another hint: dial up the NACD and NSS-CDS bulletin boards. There
NACD BBS: 912-246-3280
NSS-CDS BBS: 813-648-9400
>> Wow again; never thought of scooters as dangerous!!! Thought they
I got the Peacock rangers mad at me for doing a scooter dive "too soon."
They'd like to see 100 dives or more before anyone does a scooter dive.
But, I knew Peacock really well, felt comfortable on the scooter, and
knew I could swim out at any time with no problems, so I did it. It
was fun. I would have preferred more experience, but I didn't have any
problems and ya gotta start somewhere!
>> "cave divers often relocate, changing jobs and domiciles, in order to
I think about it.... A LOT!
FWIW, the two most common problems cave diving students have during
their "9 days" (based on my own experiences, and experiences shared
by others) are:
1: your kit will be A LOT heavier than you're used to, and changes
happen much slower. You'll need more air in the wings than you're
used to putting in your b.c.. You can be going through a tunnel
that you think is level, but it's slowly descending, so before you
know it, you're negative. And, of course, the opposite is true.
The one TRUE test is, stop swimming, stop moving, and see what
happens. About 59% will start rising, 39% will sink, and 2% will
stay where they are. Constantly adjust your trim, but don't worry
about it for the first few days (you'll have LOTS to do).
2: Line awareness is much more than simply watching the line, or
"knowing" that it's "over there, somewhere." The problems occur
when you're tooling along, thinking that everything is hunky dory,
you're right OVER the line so you can't possible mess up, and
you really are starting to enjoy the dive rather than see it as
a series of tasks to deal with... then, something distracts you
for a second, you waver, look for the line, find it and start
following it again. Trouble is, it's the WRONG line! You don't
even know to ask yourself "am I sure this is the right line" because
you NEVER SAW what happened. This scenario happens more frequently
than you'd imagine, and has killed divers. It happens when you
haven't looked at the line in a while, get distracted for a moment,
and/or waver away from the line for a moment, look down or around
and see an *off-shoot* line and don't question that that is INDEED
the correct line, and follow it dutifully off into the cave.
Problem #1 has happened to me twice during my training, and only gets better
if you dive a lot. The first time, my instructor when off somewhere
to do something and I was waiting, and it wasn't long before I found
myself near the ceiling of a large domed room. When he came back,
I tried to look nonchalant, like "hey, I *meant* to do that", but
John knew better and laughed. (Yes, instructors know how to laugh
underwater... irritating bastards!
Problem #2 I've done twice, once during training, and once on a dive not too
long ago. During training, I was hovering at the jump between the Peanut
line and the Crossover tunnel in Peacock, waiting for John to retrieve
the jump reel, and I got distracted... I looked up, saw the line and
started swimming. After about 5 kickcycles, I stopped and realized
that this was "not right". Almost immediately, I saw John's light
flashing and turned around sheepishly... I was heading futher down
the Peanut line. After that, he told me he watched me go and wanted
to see how far I'd get before I noticed. It was a good lesson, and
I passed! The other time was on a dive with 2 other fellows, and
I was swimming, but looking behind me, looked up, saw the line and
followed it. It was an off-shoot... Again, I noticed almost immediately
that it was wrong, but the other guys bragged later than they had to
"go get me"... wrong, but I let them brag...
Both #1 and #2 occurred during my training because I got distracted,
and the main thing that distracts you during training is your kit.
You look down, your eyes focus on something inches away, so you loose
your peripheral vision of the cave, and loose any reference points
that will tell you if you're sinking or rising, loose track of the
concept of "where you've been" and "where you're going" so running
off in a different direction is possible. So, this emphasises how
important familiarity with your kit is... if it distracts you, then
in essence, that's just one more task to deal with that can quickly
add more tasks.
By the way, I've since learned that the sense of "where you've been"
and "where you're going" differs with each individual. Some divers
can go into a cave once and "know" it (although this is pretty
rare, and virtually impossbile during training since you're paying
attention to so many other things). Others take 2 or 3 dives in the
same cave before it seems familiar (this is me). Yet others seem
to never catch on to cave landmarks and layout (you don't want to
dive with these types leading!). So, during your training, you
may find that you've finished your dive and don't have a CLUE what
the cave looked like. This is not unusual, but you can be sure the
instructor won't miss the opportunity to slam you for it.
One of the big thrills for me now, is to go into a cave that I've
been in twice before and feel that first-time sense of "knowing" what
the cave is like. Really a neat feeling. Some day when you've got
45 minutes, I'll tell you about my Waterhole dive.
Well, I guess I should get back to work! Feel free to ask more
questions, if you have them.
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