Some Manifold Questions!!! Please!!!

[manumenzella]

Hi.
While I was surfing the web, i started looking for manifols. I have some questions, though:
1- When using doubles with manifold, you end up with 4 second stages, right? (2 main second stages, and 2 octos)
2- I dont understand why, when, for example, you close valve A, how are you still getting air from that tank?

Thanks!!!!!!!!!
Manuel

 

[Jimmer]

Manuel, you only have 2 second stages when you dive manifolded doubles. A primary first and second stage, and a backup first and second stage. Now as for the other question, the valve knob only limits the gas in the tank from going out the opening of that valve. The side of the valve that connects to the manifold crossover is open the tank pressure all the time, regardless of if that valve knob is open. Which is why we have the isolator valve in the middle to cutoff access to one tank from the other completely.

 

[manumenzella]

Hi Jimmer. I got it. Thanks!
Do you guys think it is worth the extra money and weight if i am just into 90-100 feet diving and perhaps in the future some wreckege??
Thanks again, and sorry for my english!!!!!
Manuel

 

[mikerault]

usually with a single 80 CF (10L?) tank I have to call the dive before I hit NDL (depending on depth) I am looking at doubles to extend bottom time for my dives.

Mike

 

[Jimmer]

Manuel you're welcome, and your english seems pretty good to me. I dive my doubles all the time in that range, and on wrecks, since I'm fortunate enough to live near a huge selection of wrecks. I like my doubles for no deco diving in that range because you automatically have a fully redundant air source, simply by closing the isolator knob on the manifold. I'm also in the process of getting my decompression training, but I do think that doubles are useful for no deco recreational diving too.

Jim

 

[Jorbar1551]

i dive doubles and they are wonderful. it can get a little heavy at times, but underwater, they are very stable, and you always have that extra air just in case you see something really cool and your nitrogen level allows it.

i dive primarily in the 45-70 foot range, but i bought them because i plan to do tec diving in the future.

if you post in the tec' wreck forum, i think a lot of guys prefer doubles with a 7 foot long hose for the always important "just in case"

 

[The Chairman]

When you need doubles it will become apparent. Until that time, I would just enjoy diving with a single!

 

[capeofstorms_pierre]

usually with a single 80 CF (10L?) tank I have to call the dive before I hit NDL (depending on depth) I am looking at doubles to extend bottom time for my dives.

Mike

Morning ,have you given thought to a larger cylinder like a12l or 15l 232 bar before going twin.

For my deeper diving i have a set of twin 7l 232 bar steel which gives me redundancy and enough air should a buddy or student need sum.

looking at doing myadvanced nitrox so willbe twinning upaset of 12l 232 steel.

 

[capeofstorms_pierre]

PS manifolds make nice carry handles hehehe

 

[manumenzella]

Thanks for all the help!!!!!!!
I think i will try to get a manifold for my 80's and i also need another regulator
I don't think i could have made my desicion without your help !!!!!!! ;;
Thanks again
Manuel