On my last dive to 400 Ft...

[ghostdiver1957]

Oh dear,

that makes me a technical diver too.

AFAIK, a technical dive is is an overhead dive either real (cave, wreck, ice) or virtual (deco).

Given the above definition, would a "tech" dive be planned for a group of recreational divers - including a 14 year old that is on his first ever ocean dive?

True Story: In Roatan Honduras there is a site called Bears Den. Some of you may know it. I'm not sure of the exact depth of the dive... but I believe it to be at just about 60 feet. Bears Den is an enclosed Cave... it starts as a long narrow tunnel that opens up into literally a cave. There is one way in and one way back out. While there is some natural light along the tunnel... there is none in the cave. It is dark in there and cramped for a group of 8 -10 divers. There is no direct ascent availability. A dive leader from a resort there lead a group of divers (including about 4 divers with less than 25 dives and a 14 year old) into the cave. They all made it back out... but now I'm wondering... can they all now call themselves tech divers?

What do you think of a PADI DM (Dive Guide) leading such a group into such a dive? Opinions...

 

[mmadiver]

Just reminded me of a picture I saw of tech divers on the manta industries www site doing deco after a 600 foot dive. Now THAT'S a lot of tanks.... The guy with the RB looks like he's got multiple scrubbers and tanks hooked up.. waaaay to complicated for me.

D.

Perhaps I dont know enough about the subject but what exactly could you do at 600fsw. I'd think youd be so narced out that you would be pretty useless at that depth. A final test that navy divers have is the assembly of a piece of equipment at 300fsm and I know they practice constantly before the test so that their hands litterly memorize the movements. I belive they do that dive on air...I suppose I just don't know enough about deep diving. Anyone care to educate me?

 

[MikeFerrara]

Perhaps I dont know enough about the subject but what exactly could you do at 600fsw. I'd think youd be so narced out that you would be pretty useless at that depth. A final test that navy divers have is the assembly of a piece of equipment at 300fsm and I know they practice constantly before the test so that their hands litterly memorize the movements. I belive they do that dive on air...I suppose I just don't know enough about deep diving. Anyone care to educate me?

Helium is the answer to narcosis.

600 ft is deeper than even most technical divers dive. the gas requirements for OC are huge and even bail out gas for a rebreather diver would be a bunch. 400 ft dives are fairly common and 300 ft is even more common. 200 ft is an every day day thing and most technical divers wouldn't even think of it as being very deep (not based on depth alone).

My deepest dive to date was done with an END of about 70 ft which means that I was less narced than your average vacation diver on a reef dive in Cozumel. I also had larger gas reserves and more redundancy and was with other divers who had the same. I proabobly even exited the water with with a significantly lower inert gas load than a vacation diver doing a couple repetative dives following a computer.

There is always risk but if you take a look at how many technical dives are done...the procedures, skill level of the divers and equipment you might see that they have more safety margin than many dives that divers are doing every day at resorts that are far shallower and more casually approached.

Now, single tank AOW divers, doing swim throughs (or so they call them) at 130 ft in Cozumel is flat out insanity. The divers that are doing it just don't know it.

 

[dbush]

My definition of a tech diver is somebody who meets all the criteria below:

1. Trained to do it. Either by class or by mentorship.
2. Outside recreational limits
3. Requiring decompression

I think just because somebody violates their NDL doesn't make them a tech diver.

Just my thoughts.

 

[brianstclair]

...with an END of about 70 ft...

Mike, forgive my ignorance - what do you mean by "END"? I'm assuming that's a technical term and that you're not referring to the deepest point of your dive?

Brian

 

[ianr33]

Mike, forgive my ignorance - what do you mean by "END"? I'm assuming that's a technical term and that you're not referring to the deepest point of your dive?

Brian

END is Equivalent Narcotic Depth. i.e. the partial pressure of nitrogen(and the degree of narcosis) is the same as it would be at the stated depth of 70 feet, even though the actual dive may have been to 400 feet . The narcosis and END is reduced by adding Helium to the gas mixture. This is called Trimix (3 main gasses,oxygen,nitrogen and helium)

 

[TheRedHead]

Now, single tank AOW divers, doing swim throughs (or so they call them) at 130 ft in Cozumel is flat out insanity. The divers that are doing it just don't know it.

Thousands of divers dive Devil's Throat every year. They're all insane?

 

[brianstclair]

END is Equivalent Narcotic Depth. i.e. the partial pressure of nitrogen(and the degree of narcosis) is the same as it would be at the stated depth of 70 feet, even though the actual dive may have been to 400 feet . The narcosis and END is reduced by adding Helium to the gas mixture. This is called Trimix (3 main gasses,oxygen,nitrogen and helium)

Got it. I figured it was something like that. Thanks.

Brian

 

[Hank49]

Having said the above, I must say that in my opinion, outside of an ego trip, diving deep isn't a great idea. but why, outside of a specialty profession such as geological study of under water caves structures, would you want to?

$$$$$$ is a good reason. I have a friend who did North Sea oil rig diving for a few years and he saved enough to invest in a nice bareboat charter business.
But what amazes me is that he doesn't seem real knowledgable about the mixing of gasses etc etc. I get the feeling that the companies that hire guys for this just figure "you do the diving, we'll do the mixing". He says he did over 600 feet a few times but this was out of a habitat at 300 or something like that. And he has that "war vet silence" about it too. He doesn't talk a lot about it and still does 200+ feet, single tank air dives.

 

[Rick Inman]

Thousands of divers dive Devil's Throat every year. They're all insane?

When I was swimming through the Devil's Throat, packed between divers in front and behind me, I remember thinking, if something goes sideways here, it won't be pretty. That was on the second tunnel. On the third one - the one that empties out at around 130' - I went first and the DM went last in line.

There's a clue there somewhere. eyebrow