200' on air for 5 min bottom time?

[Stoo]

In this new and modern age of voodoo gasses, there is absolutely no viable reason to use air at a depth of 200'. Nitrox is better and trimix is what you really need.

Ummm, virtually any nitrox mix would be fatal in all likelihood...

Am I reading the OPs question correctly? Is there something happened to tables, that they are no longer available? This is a question and OW certified diver should be able to sort out in about 10 seconds... isn't it???

 

[AfterDark]

Ummm, virtually any nitrox mix would be fatal in all likelihood...

Am I reading the OPs question correctly? Is there something happened to tables, that they are no longer available? This is a question and OW certified diver should be able to sort out in about 10 seconds... isn't it???

I don't think todays OW divers even know there are tables that go below 130'.

 

[lamont]

Congratulations. What did you get, Meg or Pathfinder?

Meg. mCCR for now, standard can, radial scrubber. BOV for it should be in the mail today or tomorrow...

 

[PfcAJ]

No, helium is not available everywhere. Some places on this planet just don't have sufficient demand to keep a supply of helium on hand for the occasional trimix diver. And those places usually have transportation and import regulations that make it functionally impossible to get helium.

You are programmed for trimix below 30m, and that is a good, conservative approach that will keep you well within your personal safety envelope. But out in the wilderness, there are some places deeper than 30m worth diving that don't have a supply of helium. My buddies and I will dive them; you can enjoy yourself on the beach while you wait for your helium to be air dropped by your industrial gas supplier.

Those sites are few and far between. You can get it in most places, if you try. Theres just no excuse in places like North America where helium is super easy to get.

 

[rjack321]

Those sites are few and far between. You can get it in most places, if you try. Theres just no excuse in places like North America where helium is super easy to get.

Sort of...
You realize there isn't even a gas plant in Alaska? Even O2 is shipped in from the Seattle area by barge.

Nevertheless, its easy to track down He with some phone calls, but heavy to haul it along with you in any kind of quantity. Compressor 175lbs minimum. 300cf helium, another 150lbs+. Then you still have to put the tanks in the truck. Yes I did just have to replace some rear shocks for $340.

 

[PfcAJ]

Some friends of mine made it happen in rural China. That's a tall order and just proves that its possible. USS Atlanta project is another example. Idk much about Alaska, but Dive Alaska fills trimix. An RB can really help with the logistics, too.

Possible. Not always easy, sure, but usually possible.

 

[Tortuga68]

Ummm, virtually any nitrox mix would be fatal in all likelihood...

Considering that people have/do dive air well beyond 330'/100m (PPO2=2.31) it would seem logical that you could dive any 'recreational' EAN mix to 200'/60m with a reasonable chance of surviving. I don't know WHY you would do it, and I wouldn't, but EAN wouldn't necessarily be fatal on a short bounce dive like the OP mentioned.

(By the way I think Dsix36 recanted on his nitrox recommendation later in the thread, after a convoluted attempt at justifying it)

 

[Kevrumbo]

Some friends of mine made it happen in rural China. That's a tall order and just proves that its possible. USS Atlanta project is another example. Idk much about Alaska, but Dive Alaska fills trimix. An RB can really help with the logistics, too.

Possible. Not always easy, sure, but usually possible.

For the WWII Aircraft Carrier wreck HMS Hermes in Sri Lanka 2009, in two weeks we used up the entire country's retail supply of Helium diving on Standard Bottom Mix & Deco Gases.
(http://www.asiadivers.com/tech/images/techasia_diving/expeditions/Hermes_MoreInfo.pdf)

Some real objective costs here:

For the upcoming Bikini Atoll Trip later this month June, Oxygen costs will be $0.06/litre and Helium $0.20/litre (That's $1.70/cuft for O2 and $5.66/cuft for He).

I plan on doing nearly 20 dives over 11 days on the M/V Windward Liveaboard (multi-place Recompression Chamber included onboard, but not DAN approved), using Eanx50 & Oxygen for deco gases --and Deep Air & 20/20 Trimix and Standard Bottom Mix as needed for penetrations at 45m and deeper.

"Guesstimate" Open Circuit Total Gas Costs to be over $3k.

 

[PfcAJ]

sounds badass. I like it.

 

[Tortuga68]

I was going to do the Hermes trip (on normoxic trimix) this year, but work got it the way

IIRC someone's spools are still inside the engine room from the last trip, because they also ran out of He on the last day and when he went to recover them on the final (air) dive he couldn't find the way in...