Tank selection for Fundies

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The 119s are not unmanageably negative at -2 empty, and they aren't unmanageably tall. I don't know anyone who dives them, so I can't speak to how they trim.

Ehem, seriously? I have a set of HP119s and a set of PST lp95s (which are actually heavier). I dive both but...

But I'm very much in the minority in our GUE community locally -- most of our divers go on to doubles and dive nothing else. I'm almost 60 years old and acutely aware that I have the only back and knees I'm ever going to get, so I do single tank dives with . . . a single tank!

I am 44 years old and going into my second lumbar surgery in 2 weeks. Tanks this big (or worse 130s) are really unnecessary unless you're pretty far along (or diving caves). I can do 2 GUE Tech1 dives on them with ample reserves. You don't need them and carrying them around "for practice" is silly.

I'd go with faber lp85s. They are long but narrow. Enough gas for Tech1 and even many Tech2 dives and easy to trim out. I fill mine to 3600psi and they are passing their 3rd or 4th hydro no problem. If you can't get 3400+ fill in "LP" tanks try another shop or go for the hp100s, they are a little shorter but still light enough that pretty much anyone can trim them out easily.
 
I'm going to throw in a vote for some double LP50's if you're not looking to go into tech or cave right away but would like the redundancy of two manifolded tanks & first stages, these are a good choice. They trim out well, you can add a V-weight if/when needed, they are light as feather compared to HP100's. They can be overfilled and give you 130 cf of gas for possibly two dives (depending on depth). You could talk to an instructor about adding a stage which would be great practice for T/1 (mock deco tank). If you know you're going into T/1 get the bigger AL80's or HP100's. FWIW I own all the tanks mentioned in this thread (50's, 80's, 100's, 130's) and my go to tanks for most dives under 140' are the HP100's.
 
Thanks for your input. I actually see T1 in the near future so bigger tanks are needed. I pretty much settled for big fat 119's so I can get 2 long rec dives with plenty of gas left. With choice in mind, I could easily see myself move through T1,T2 and possibly Cave1 in the next couple years with the same setup.


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Thanks for your input. I actually see T1 in the near future so bigger tanks are needed. I pretty much settled for big fat 119's so I can get 2 long rec dives with plenty of gas left. With choice in mind, I could easily see myself move through T1,T2 and possibly Cave1 in the next couple years with the same setup.


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If you're wanting to dive in Florida, 104/108/112/130's are about all that's used for backmount cave diving with the occasional set of 85's for short dives, and Al80s are all there is in Mexico.

For cave 1/2 dives I would use 104/108/112/130's in FL, AL80's in Mexico.

For T1/T2 dives I would use AL80's or LP85's jacked to 3600 with a stage or two.
 
Are you saying that if I show up in Ginnie Springs, I'll get weird looks with HP tanks or is it because it's harder to get partial pressure fills on a HP tank in Florida?

Am I missing something here...

If you're wanting to dive in Florida, 104/108/112/130's are about all that's used for backmount cave diving with the occasional set of 85's for short dives, and Al80s are all there is in Mexico.

For cave 1/2 dives I would use 104/108/112/130's in FL, AL80's in Mexico.

For T1/T2 dives I would use AL80's or LP85's jacked to 3600 with a stage or two.
 
Are you saying that if I show up in Ginnie Springs, I'll get weird looks with HP tanks or is it because it's harder to get partial pressure fills on a HP tank in Florida?

Am I missing something here...
No, I'm saying that those tanks are about the only tanks used in North FL. Anything else will result in weird looks. LP104 is about the same volume as a HP130.
 
Deg;

Allow me to give you a practical example on tank volume and usage. My buddy and i just finished Full Tech cave this past month. I dive LP108s he dives HP100s. Through out the whole set of training dives.

Based on calculated SAC rates and gas matching between the different tanks i was force to turn the dive at 700PSI in due to diving thirds. The farthest we made it in even on a staged dive was 500ft into the devil system. Just past the jump on hill 400.

This past weekend he dove LP108s for the first time. since we were diving the same tanks we could actually dive our thirds. With 1 stage we went from 500ft penetrations to 1100ft.

If your going tech get either LP108s or HP130s. If your doing your training in florida cave country you can always rent the 108s for the training from the local dive shops as an option.


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Edit : unrelated comment
 
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Are you saying that if I show up in Ginnie Springs, I'll get weird looks with HP tanks or is it because it's harder to get partial pressure fills on a HP tank in Florida?

Am I missing something here...

Are you actually thinking of driving your tanks to Ginnie? Why?

I think you should take Fundies in whatever tanks you are going to be using at home. If you are currently using a single tank, use that. If you are buying doubles specifically to take Fundies in them... you are setting yourself up to get a provisional or not pass at all and have to redo Fundies later.

All this talk about what you'll need 2 years from now is just a distraction. By the time you are doing Cave 2 ("full cave") you WILL undoubtably have multiple sets of doubles for different purposes and to hold onto different gases for different dives.
 

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