HeliAir - Pros and Cons

Ivon · 17th February 2007, 20:40

I've just received my PSAI Trimix manual for my course next week and it seems geared toward using HeliAir over Trimix. The reasons are set out in the maual, and I can agree with most of them but what are peoples thought on using HeliAir, say 10/52 over 17/40 or 15/55 in the unit and for bail-out?

seaturtle · 17th February 2007, 21:13

10/52 is my choice diluent for dives to 300'. Easy to fill and calculate ppo2 on the fly.

scu8astu · 17th February 2007, 21:39

Hi Ivon

you should have a look at the pdf link below

PHP Code:

  heliair

and you would'nt use heliair as a bailout its just not practical, its really only used in rebreathers, i have only used trimix on my mod 2/3 courses apart from that i only ever use heliair.

stu

Quote: (Originally Posted by Ivon)

I've just received my PSAI Trimix manual for my course next week and it seems geared toward using HeliAir over Trimix. The reasons are set out in the maual, and I can agree with most of them but what are peoples thought on using HeliAir, say 10/52 over 17/40 or 15/55 in the unit and for bail-out?

AndyMumford · 17th February 2007, 21:41

Hi Ivon,
Heliair has its uses easy to blend being the most obvious, in my OC gas diving days 90% of my dives were on Heliair as I had many pre-cut tables from 12/43 though to 19/9.
With the breather I still use Heliair mainly for the 50ish metre range (16/24) however I am a firm believer in the right mix for the diving depth and not just following the 10/52 crowd.
This also applies to bailout gases, say I plan a 2hour run time, I will try and match the bailout gases to give an overall run time as close as I can to the 2 hours planned for the original profile.
Of course this is providing I can carry the amount of gas required for the bailout and deco.

We can have a chat in more detail on the subject next weekend at Stoney.

Ivon · 17th February 2007, 21:52

Quote: (Originally Posted by AndyMumford)

Hi Ivon,
Heliair has its uses easy to blend being the most obvious, in my OC gas diving days 90% of my dives were on Heliair as I had many pre-cut tables from 12/43 though to 19/9.
With the breather I still use Heliair mainly for the 50ish metre range (16/24) however I am a firm believer in the right mix for the diving depth and not just following the 10/52 crowd.
This also applies to bailout gases, say I plan a 2hour run time, I will try and match the bailout gases to give an overall run time as close as I can to the 2 hours planned for the original profile.
Of course this is providing I can carry the amount of gas required for the bailout and deco.

We can have a chat in more detail on the subject next weekend at Stoney.

Thanks for the replies guys, Andy I'm currently messing with deco software and taking in the manual but I'm sure I'll have plenty more questions for you by the weekend.
My thought was that 17/40 would be the gas that I would use most often for normal stuff and it shaves 20 minutes of deco off compared to 10/52 on a 25min 75m dive so other than been easy to blend and calc. ppo2 was finding it hard to see any other benefits to diving it. I'm glad you say to use the correct gas though for the job, makes sense to me.

AndyMumford · 17th February 2007, 22:05

Ivon,
In my opinion there are many people diving 10/52 off the stake of it, fine if 10/52 is the best gas for the diving depth then great!
But in my experience many of these people are only diving 10/52, regardless of the depth....
Something people don't consider or maybe just don't no is that, we as humans are not design to breath 3 different gases at the same time, so why put our body’s under increased strain for no good reason other then all my mates dive 10/52 so I'm going to....

Anyway if you got any questions regarding the course at the weekend either email me or give me a call.

Ivon · 17th February 2007, 22:11

Quote: (Originally Posted by AndyMumford)

Ivon,
In my opinion there are many people diving 10/52 off the stake of it, fine if 10/52 is the best gas for the diving depth then great!
But in my experience many of these people are only diving 10/52, regardless of the depth....
Something people don't consider or maybe just don't no is that, we as humans are not design to breath 3 different gases at the same time, so why put our body’s under increased strain for no good reason other then all my mates dive 10/52 so I'm going to....

Anyway if you got any questions regarding the course at the weekend either email me or give me a call.

Cheers Andy, if I have any burning questions I'll give you a call. See you at the weekend.

DaveP · 18th February 2007, 09:05

Quote: (Originally Posted by Ivon)

Thanks for the replies guys, Andy I'm currently messing with deco software and taking in the manual but I'm sure I'll have plenty more questions for you by the weekend.
My thought was that 17/40 would be the gas that I would use most often for normal stuff and it shaves 20 minutes of deco off compared to 10/52 on a 25min 75m dive so other than been easy to blend and calc. ppo2 was finding it hard to see any other benefits to diving it. I'm glad you say to use the correct gas though for the job, makes sense to me.

Hi Ivon,

On a 75m dive I would use 10/52 dil. Using ddplan a 25min bt would give total rt of 1hr 52m on 10/52 against 1hr 44m on 17/40 - a differance of only 8m. The main advantage to me of using 10/52 is the END of 28m against END of 37m when using 17/40. Also you would find it very hard to flush an O2 spike on the bottom using 17/40.

Regards

Dave

AndyMumford · 18th February 2007, 09:33

DaveP,
The point I was trying to make is that 10/52 is not the be all and end all of gases.

Out of interest what do you carry as your bailout for the dive you mentioned?

DaveP · 18th February 2007, 10:02

Quote: (Originally Posted by AndyMumford)

DaveP,
The point I was trying to make is that 10/52 is not the be all and end all of gases.

Out of interest what do you carry as your bailout for the dive you mentioned?

Hi Andy,

I agree 10/52 is not to be used for all dives . My bail out carried for a 75m dive is 7l 18/40, 7l EANx50, and 12l EANx 80 drop bottle.

Regards

Dave

17th February 2007, 20:40	#1 (permalink)
Ivon Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Feb 2006 Location: Hull, East Yorkshire, England Posts: 313	HeliAir - Pros and Cons I've just received my PSAI Trimix manual for my course next week and it seems geared toward using HeliAir over Trimix. The reasons are set out in the maual, and I can agree with most of them but what are peoples thought on using HeliAir, say 10/52 over 17/40 or 15/55 in the unit and for bail-out?
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17th February 2007, 21:13	#2 (permalink)
seaturtle RebreatherWorld Sponsor Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Jan 2006 Location: Montauk,NY USA Posts: 35	Re: HeliAir - Pros and Cons 10/52 is my choice diluent for dives to 300'. Easy to fill and calculate ppo2 on the fly. __________________ *Diving off the deep end on a regular basis* *www.seaturtlecharters.com*
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17th February 2007, 21:41	#4 (permalink)
AndyMumford New Member Current Rebreather/s: Megalodon Other Rebreather/s: Megalodon Join Date: Apr 2005 Location: Kent, UK Posts: 81	Re: HeliAir - Pros and Cons Hi Ivon, Heliair has its uses easy to blend being the most obvious, in my OC gas diving days 90% of my dives were on Heliair as I had many pre-cut tables from 12/43 though to 19/9. With the breather I still use Heliair mainly for the 50ish metre range (16/24) however I am a firm believer in the right mix for the diving depth and not just following the 10/52 crowd. This also applies to bailout gases, say I plan a 2hour run time, I will try and match the bailout gases to give an overall run time as close as I can to the 2 hours planned for the original profile. Of course this is providing I can carry the amount of gas required for the bailout and deco. We can have a chat in more detail on the subject next weekend at Stoney. __________________ Cheers Andy Mumford TDI Megalodon Instructor www.megalodon-uk.com www.deepdiving.co.uk
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17th February 2007, 21:52	#5 (permalink)
Ivon Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Feb 2006 Location: Hull, East Yorkshire, England Posts: 313	Re: HeliAir - Pros and Cons Quote: (Originally Posted by AndyMumford) Hi Ivon, Heliair has its uses easy to blend being the most obvious, in my OC gas diving days 90% of my dives were on Heliair as I had many pre-cut tables from 12/43 though to 19/9. With the breather I still use Heliair mainly for the 50ish metre range (16/24) however I am a firm believer in the right mix for the diving depth and not just following the 10/52 crowd. This also applies to bailout gases, say I plan a 2hour run time, I will try and match the bailout gases to give an overall run time as close as I can to the 2 hours planned for the original profile. Of course this is providing I can carry the amount of gas required for the bailout and deco. We can have a chat in more detail on the subject next weekend at Stoney. Thanks for the replies guys, Andy I'm currently messing with deco software and taking in the manual but I'm sure I'll have plenty more questions for you by the weekend. My thought was that 17/40 would be the gas that I would use most often for normal stuff and it shaves 20 minutes of deco off compared to 10/52 on a 25min 75m dive so other than been easy to blend and calc. ppo2 was finding it hard to see any other benefits to diving it. I'm glad you say to use the correct gas though for the job, makes sense to me.
(Offline)

17th February 2007, 22:05	#6 (permalink)
AndyMumford New Member Current Rebreather/s: Megalodon Other Rebreather/s: Megalodon Join Date: Apr 2005 Location: Kent, UK Posts: 81	Re: HeliAir - Pros and Cons Ivon, In my opinion there are many people diving 10/52 off the stake of it, fine if 10/52 is the best gas for the diving depth then great! But in my experience many of these people are only diving 10/52, regardless of the depth.... Something people don't consider or maybe just don't no is that, we as humans are not design to breath 3 different gases at the same time, so why put our body’s under increased strain for no good reason other then all my mates dive 10/52 so I'm going to.... Anyway if you got any questions regarding the course at the weekend either email me or give me a call. __________________ Cheers Andy Mumford TDI Megalodon Instructor www.megalodon-uk.com www.deepdiving.co.uk
(Offline)

17th February 2007, 22:11	#7 (permalink)
Ivon Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Feb 2006 Location: Hull, East Yorkshire, England Posts: 313	Re: HeliAir - Pros and Cons Quote: (Originally Posted by AndyMumford) Ivon, In my opinion there are many people diving 10/52 off the stake of it, fine if 10/52 is the best gas for the diving depth then great! But in my experience many of these people are only diving 10/52, regardless of the depth.... Something people don't consider or maybe just don't no is that, we as humans are not design to breath 3 different gases at the same time, so why put our body’s under increased strain for no good reason other then all my mates dive 10/52 so I'm going to.... Anyway if you got any questions regarding the course at the weekend either email me or give me a call. Cheers Andy, if I have any burning questions I'll give you a call. See you at the weekend.
(Offline)

18th February 2007, 09:05	#8 (permalink)
DaveP New Member Current Rebreather/s: Inspiration Classic Evolution Other SCR Other Rebreather/s: Other SCR Join Date: Jun 2005 Location: UK Cornwall Posts: 35	Re: HeliAir - Pros and Cons Quote: (Originally Posted by Ivon) Thanks for the replies guys, Andy I'm currently messing with deco software and taking in the manual but I'm sure I'll have plenty more questions for you by the weekend. My thought was that 17/40 would be the gas that I would use most often for normal stuff and it shaves 20 minutes of deco off compared to 10/52 on a 25min 75m dive so other than been easy to blend and calc. ppo2 was finding it hard to see any other benefits to diving it. I'm glad you say to use the correct gas though for the job, makes sense to me. Hi Ivon, On a 75m dive I would use 10/52 dil. Using ddplan a 25min bt would give total rt of 1hr 52m on 10/52 against 1hr 44m on 17/40 - a differance of only 8m. The main advantage to me of using 10/52 is the END of 28m against END of 37m when using 17/40. Also you would find it very hard to flush an O2 spike on the bottom using 17/40. Regards Dave
(Offline)

18th February 2007, 09:33	#9 (permalink)
AndyMumford New Member Current Rebreather/s: Megalodon Other Rebreather/s: Megalodon Join Date: Apr 2005 Location: Kent, UK Posts: 81	Re: HeliAir - Pros and Cons DaveP, The point I was trying to make is that 10/52 is not the be all and end all of gases. Out of interest what do you carry as your bailout for the dive you mentioned? __________________ Cheers Andy Mumford TDI Megalodon Instructor www.megalodon-uk.com www.deepdiving.co.uk
(Offline)

18th February 2007, 10:02	#10 (permalink)
DaveP New Member Current Rebreather/s: Inspiration Classic Evolution Other SCR Other Rebreather/s: Other SCR Join Date: Jun 2005 Location: UK Cornwall Posts: 35	Re: HeliAir - Pros and Cons Quote: (Originally Posted by AndyMumford) DaveP, The point I was trying to make is that 10/52 is not the be all and end all of gases. Out of interest what do you carry as your bailout for the dive you mentioned? Hi Andy, I agree 10/52 is not to be used for all dives . My bail out carried for a 75m dive is 7l 18/40, 7l EANx50, and 12l EANx 80 drop bottle. Regards Dave
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