Nitrox in doubles ?

[gbray]

Ok, I'm convinced. I'm having the tanks doubled with 200 din and an isolation valve. They will be O2 clean and filled with EANX32 for the first fill. I plan on practicing within the NDL table limits to get accustomed to using doubles and one day hopefully continuing my training into wreck and/or cavern diving. The cost of The O2 clean and fill is insignificant however just as in technical diving... every detail counts and why wast any effort/money on something unnecessary? I am going for it. Can hardly wait to try it out.

One last question. Without taking an extremely involved and expensive intro to tech course (which I am not presently prepared for), is there a basic introduction to doubles class available? I have read quite alot about setting up and using doubles but would sure like some instruction. I don't currently dive with anyone who uses doubles. A quarry near me (Mermet Springs) is trying to get SSI to sanction one but is as of yet unsuccessful.

Thanks to all for your input. Diving and scuba board are my top two passions.

 

[StreetDoctor]

First thing is to make sure they use the right bands for the tanks. You need 7" or 6.9" bands (good luck finding 6.9") or they won't fit. O2 cleaning won't hurt but is almost certainly unnecessary. The nitrox fill is a nice; I suspect that eventually EAN32 will be the standard gas for most recreational diving. You're not required to keep nitrox in the tanks, just fill them with air when you want. Most places have grade E air these days which does not contaminate your O2 clean tanks/valves, but then again you don't need O2 clean tanks for nitrox (under 40%) use unless you're getting partial pressure fills which you almost never see.

If they're saying you need O2 cleaning to get nitrox fills then they are either using an outdated means of filling nitrox (Partial pressure) or they're ignorant about nitrox requirements or they're just trying to get you to spend some extra money.

I doubled my 72s for about $220 if I remember, and that was new 7" bands and a blue steel 200bar manifold from piranha dive gear. You get the vis first, ask the LDS to put only a hundred PSI or so in the tanks, then when your bands/manifold arrive you empty the tanks, take off the valves, assemble the doubles (which is easy) then head right back to the LDS for a fill. If you do it right your tanks will only be exposed to ambient air for a few minutes, and then empty for an hour or so.

Nice post! First grade E air is not considered O2 clean, you need modified grade E. Secondly there is only one place I know of within the Chicagoland area that does anything BESIDES partial pressure fills. For myself, I would have them cleaned. Doubles gives you longer bottom time, if you really want to take advantage you should probably be diving nitrox.

-Nick

 

[StreetDoctor]

Ok, I'm convinced. I'm having the tanks doubled with 200 din and an isolation valve. They will be O2 clean and filled with EANX32 for the first fill. I plan on practicing within the NDL table limits to get accustomed to using doubles and one day hopefully continuing my training into wreck and/or cavern diving. The cost of The O2 clean and fill is insignificant however just as in technical diving... every detail counts and why wast any effort/money on something unnecessary? I am going for it. Can hardly wait to try it out.

One last question. Without taking an extremely involved and expensive intro to tech course (which I am not presently prepared for), is there a basic introduction to doubles class available? I have read quite alot about setting up and using doubles but would sure like some instruction. I don't currently dive with anyone who uses doubles. A quarry near me (Mermet Springs) is trying to get SSI to sanction one but is as of yet unsuccessful.

Thanks to all for your input. Diving and scuba board are my top two passions.

If you're willing to travel a little bit there is an excellent instructor up here that does an Intro to Tech course for $250 over a weekend and you'll be sure to learn a LOT, not only about your doubles but about proper gas management, planning, and other skills necessary to pursue technical diving. I've been recommending the class to those that aren't even interested in going the technical route as it makes you a better/safer diver. Much better than taking an AOW class IMO. I've yet to hear anyone that was disappointed. He might even be willing to travel as you aren't that far away.


Duane Johnson @ Precision Diving - The Great Lakes and Chicago Premier SCUBA Dive Training

 

[Nemrod]

I have just taken two lp72's in to be doubled. This will be my first set of doubles. I am on a budget so my LDS is rebuilding a used manifold to put on my tanks. They quoted me a package price for the manifold, bands, O2 cleaned and EAN 32 filled. It came out to be a little higher than I had originally figured. I also had not considered O2 cleaning. My question is ...is it worthwhile to have them o2 cleaned? My intent is to practice using doubles to possibly move into more tech stuff in the future, such as wreck or cavern. I made my first dive to over 100ffw this weekend and loved every minute of it. My concern is having nitrox as my primary gas may limit my depth. I don't plan on any deco dives just yet but don't want to push my limits with nitrox. Am I being over concerned ? should I let them o2 clean my tanks?

Are you planning on setting up camp on the bottom?

N

 

[adamd]

Ok, I'm convinced. I'm having the tanks doubled with 200 din and an isolation valve. They will be O2 clean and filled with EANX32 for the first fill. I plan on practicing within the NDL table limits to get accustomed to using doubles and one day hopefully continuing my training into wreck and/or cavern diving. The cost of The O2 clean and fill is insignificant however just as in technical diving... every detail counts and why wast any effort/money on something unnecessary? I am going for it. Can hardly wait to try it out.

One last question. Without taking an extremely involved and expensive intro to tech course (which I am not presently prepared for), is there a basic introduction to doubles class available? I have read quite alot about setting up and using doubles but would sure like some instruction. I don't currently dive with anyone who uses doubles. A quarry near me (Mermet Springs) is trying to get SSI to sanction one but is as of yet unsuccessful.


Thanks to all for your input. Diving and scuba board are my top two passions.

is mermet putting the tanks togther for you? i work there and dive doubles all the time currently there is no class realy for doubles the way i learnt was got with some guys i work with and they more less taught me to dive them. if you are wanting some one to dive with you who has some experince in doubles come on down to mermet just pm me or somthing and let me know ill dive with you and help you get started.

 

[DevonDiver]

I think nitrox and doubles is a great combination - especially for wreck diving, where you will be on a pretty square bottom profile.

Twin '80s and 32% is a lovely combination for a leisurely dive on a 30m wreck - with the added benefit of redundancy and sufficient air to employ a 'rule of thirds'.

 

[Slonda828]

Ummm ... am I missing something? You can get a "best mix" with banked nitrox assuming that your "best mix" has an O2 % less than the highest mix available. All it takes is a bit of maths and the same basic theory that goes into PP blending. The only difference is that the tank still never sees an O2 % over 40.

You are missing something, but you answered your own question. Most places that bank nitrox bank NOAA-I and NOAA-II right? You cannot get a best mix of 37% or higher with banked 32% or 36%. There's plenty of shallower diving around here, and if you fill a 72 or an 80 with a higher nitrox mix (say 40%) then you can stay down forever with a good SAC rate. Plus you have the extra margin of safety if you are a little bit older and you either dive your computer or tables for air. People do it.

 

[gbray]

is mermet putting the tanks togther for you? i work there and dive doubles all the time currently there is no class realy for doubles the way i learnt was got with some guys i work with and they more less taught me to dive them. if you are wanting some one to dive with you who has some experince in doubles come on down to mermet just pm me or somthing and let me know ill dive with you and help you get started.

I was there last weekend, Boy was it crowded. I actually live 4 hours away but will look you up next time I am there. hopefully in about two weeks. I appreciate the offer. Mermet is a great place to dive.

 

[adamd]

im there about every weekend and yes it was a very busy weekend had over 200 people reserved in the pavilons plus probaly 50 others both days. just let me know a few days before your coming down n i will most likely be there.