Shallow water heliox diving

cstmwrks · 27th September 2007, 01:12

Has anyone out there regularly engaged in using heliox for dives less than 150' ?
Bill

doug allen · 27th September 2007, 03:40

Perhaps because of the cost of He?

Just a guess.

matti_anttila · 27th September 2007, 07:09

Quote: (Originally Posted by cstmwrks)

Has anyone out there regularly engaged in using heliox for dives less than 150' ?

I used Heliox 50 when I test dived my IDA-59 in max. 60ft.
The only "good" reason why I used that gas was that it was easier
to fill. In that occasion, we had O2 and He in our gas bank, but all
N2-based gases came from the compressor. And it's irritating to use
a big compressor with EANx/Tx stick to fill IDA's 1-litre cylinder. The
diluent cylinder is full even before the gas mixing is settled. So it was
relatively easy to whip O2+He into the cylinder without even touching
the compressor. (Of course I could have used an EANx bank, lazy me..).

Anyway, no diving benefit, just filling (still have to think about O2
cleanliness!).

cstmwrks · 30th September 2007, 22:01

Just wondering.. Had a few visits with Brad Gilmore who made the atomox helium analyzer for on the fly tri mixing some years ago. He was sold on trimix for dives even at 60 feet as I recall. OC must make for a pricey dive but on a rebreather it would not be much of a cost increase. I have navy tables for heliox diving and have studied the no deco time factors with some interest.
If one screws up and gets a "hit" diving helium are you in even worse trouble than from nitrogen?

Bill

***ScubaDadMiami*** · 1st October 2007, 02:19

Helium hits tend to involve the central nervous system. This can cause a more serious hit with worse permanent after effects.

Mdemon · 1st October 2007, 06:47

My feeling is that you need to be more precise in your stops. The speed of helium going in and out is faster than N2 so you have less margin for error (IMVHO). I also think the same as SDM above. Gut feeling rather than based on evidence though.

lizardland · 1st October 2007, 09:01

I don't know that I'd go to the effort of diving heliox for shallow dives but I do use 18/40 for anything up to 60m, mainly because I can keep one gas in my bank and it's good for big chunk of my diving.

One thing I've really noticed is fatigue is reduced massively. I don't know if it's because it's easier to breathe or if it's something on a deeper physiological level but I don't feel tired after a day's diving. For <40m diving I dive it on an air computer with pyle stops chucked in on the fly with a SP of 1.2 then pure O2 at 6m.

As for being careful with stops and ascents, that should be a basic skill for any rebreather diver.

Cheers,

Stuart

Dutchy · 1st October 2007, 09:25

Quote: (Originally Posted by lizardland)

One thing I've really noticed is fatigue is reduced massively. I don't know if it's because it's easier to breathe or if it's something on a deeper physiological level but I don't feel tired after a day's diving. For <40m diving I dive it on an air computer with pyle stops chucked in on the fly with a SP of 1.2 then pure O2 at 6m.

Funny I could have written every word of the above passage myself had I been an equally eloquent writer

The only difference is that I use 21/35 and a 1.0 SP.

Crazyduck · 1st October 2007, 13:06

what about bailout?

Jumping from Heliox to what? 'bailout heliox' and then O2?
I would not want a massive nitrogen shift... of going to air or nitrox.

Andrew

27th September 2007, 01:12	#1 (permalink)
cstmwrks The old ways still work. Current Rebreather/s: Home Build Other Rebreather/s: Not Bought Yet Home Build Join Date: Sep 2006 Location: Boise Idaho Posts: 238	Shallow water heliox diving Has anyone out there regularly engaged in using heliox for dives less than 150' ? Bill __________________ Why you ask... well it's not like I have anything better to do.
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27th September 2007, 03:40	#2 (permalink)
doug allen New Member Current Rebreather/s: Optima Other Rebreather/s: Optima Join Date: Sep 2007 Location: Asheboro, NC Posts: 32	Re: Shallow water heliox diving Perhaps because of the cost of He? Just a guess.
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27th September 2007, 07:09	#3 (permalink)
matti_anttila New Member Current Rebreather/s: Other CCR Other SCR Other Rebreather/s: Other CCR Other SCR Join Date: Aug 2006 Location: Finland Posts: 16	Re: Shallow water heliox diving Quote: (Originally Posted by cstmwrks) Has anyone out there regularly engaged in using heliox for dives less than 150' ? I used Heliox 50 when I test dived my IDA-59 in max. 60ft. The only "good" reason why I used that gas was that it was easier to fill. In that occasion, we had O2 and He in our gas bank, but all N2-based gases came from the compressor. And it's irritating to use a big compressor with EANx/Tx stick to fill IDA's 1-litre cylinder. The diluent cylinder is full even before the gas mixing is settled. So it was relatively easy to whip O2+He into the cylinder without even touching the compressor. (Of course I could have used an EANx bank, lazy me..). Anyway, no diving benefit, just filling (still have to think about O2 cleanliness!).
(Offline)

30th September 2007, 22:01	#4 (permalink)
cstmwrks The old ways still work. Current Rebreather/s: Home Build Other Rebreather/s: Not Bought Yet Home Build Join Date: Sep 2006 Location: Boise Idaho Posts: 238	Re: Shallow water heliox diving Just wondering.. Had a few visits with Brad Gilmore who made the atomox helium analyzer for on the fly tri mixing some years ago. He was sold on trimix for dives even at 60 feet as I recall. OC must make for a pricey dive but on a rebreather it would not be much of a cost increase. I have navy tables for heliox diving and have studied the no deco time factors with some interest. If one screws up and gets a "hit" diving helium are you in even worse trouble than from nitrogen? Bill __________________ Why you ask... well it's not like I have anything better to do.
(Offline)

1st October 2007, 02:19	#5 (permalink)
*ScubaDadMiami* Moderator Current Rebreather/s: Optima Other Rebreather/s: Join Date: Sep 2005 Location: Florida, USA Posts: 2,138	Re: Shallow water heliox diving Helium hits tend to involve the central nervous system. This can cause a more serious hit with worse permanent after effects. __________________ Howard Packer IANTD CCR Instructor Miami Beach, Florida CCRDiveTraining.com
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1st October 2007, 06:47	#6 (permalink)
Mdemon SiegeEngine II Current Rebreather/s: Inspiration Classic Home Build Other Rebreather/s: Inspiration Classic Home Build Join Date: Feb 2007 Location: SWUK Posts: 1,931	Re: Shallow water heliox diving My feeling is that you need to be more precise in your stops. The speed of helium going in and out is faster than N2 so you have less margin for error (IMVHO). I also think the same as SDM above. Gut feeling rather than based on evidence though. __________________ www.southwestmafia.com "small minds talk about people, Average Minds Talk About Events, GREAT MINDS TALK ABOUT IDEAS!" The WRONG Attitude will get you killed. "Once the agenda-monkeys and perfect-worlders have moved on, perhaps we can do some diving?"
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1st October 2007, 09:01	#7 (permalink)
lizardland Yak Current Rebreather/s: MK 15.X Home Build Other Rebreather/s: Classic Kiss Home Build Join Date: Mar 2005 Location: North... Posts: 1,303	Re: Shallow water heliox diving I don't know that I'd go to the effort of diving heliox for shallow dives but I do use 18/40 for anything up to 60m, mainly because I can keep one gas in my bank and it's good for big chunk of my diving. One thing I've really noticed is fatigue is reduced massively. I don't know if it's because it's easier to breathe or if it's something on a deeper physiological level but I don't feel tired after a day's diving. For <40m diving I dive it on an air computer with pyle stops chucked in on the fly with a SP of 1.2 then pure O2 at 6m. As for being careful with stops and ascents, that should be a basic skill for any rebreather diver. Cheers, Stuart __________________ Can you imagine drifting along in the sea with your mouth open and a load of f***ing plankton going in? You'd like it, would you? www.westons-cider.co.uk Azerbaijani Association of Technical Divers Publicity Officer and Goat Wrangler
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1st October 2007, 09:25	#8 (permalink)
Dutchy Rene Warries Current Rebreather/s: Sport Kiss Other Rebreather/s: Join Date: Apr 2006 Location: Nieuwegein (The Netherlands) Posts: 763	Re: Shallow water heliox diving Quote: (Originally Posted by lizardland) One thing I've really noticed is fatigue is reduced massively. I don't know if it's because it's easier to breathe or if it's something on a deeper physiological level but I don't feel tired after a day's diving. For <40m diving I dive it on an air computer with pyle stops chucked in on the fly with a SP of 1.2 then pure O2 at 6m. Funny I could have written every word of the above passage myself had I been an equally eloquent writer The only difference is that I use 21/35 and a 1.0 SP. __________________ = This post is environmentally friendly. It is composed of 100% recycled electrons only. =
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1st October 2007, 13:06	#9 (permalink)
Crazyduck Underwater Mechanic Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Mar 2005 Location: TEXAS, Dallas/ Ft.Worth Posts: 712	Re: Shallow water heliox diving what about bailout? Jumping from Heliox to what? 'bailout heliox' and then O2? I would not want a massive nitrogen shift... of going to air or nitrox. Andrew __________________ Howdy Senor- What’s Happening! Rob Davie April 2005- Presently in a state of transition from Open Circuit to Closed Circuit. "You will not be punished for your anger; you will be punished by it." - Buddha.
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