Aluminum 80s versus larger steel tanks

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Midge907

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Messages
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Location
Hot Springs, South Dakota
# of dives
200 - 499
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I don't really understand the hype with the whole 120cf tanks, to me they are a crutch for inexperienced divers in a place where 80cf tanks will give you 70min bottom times.

If all you want is a 70 minute dive.....

Personally I find nothing wrong with a couple of 85-90 minute dives separated by a nice relaxing shore interval. So I'll take the 120's. :D
 
I don't really understand the hype with the whole 120cf tanks, to me they are a crutch for inexperienced divers in a place where 80cf tanks will give you 70min bottom times. Just my .02

You know I often wonder is 70 minute bottom time is like so many inches? I am not the best, but I typically am in the top 3 out of 8 in our groups and I typically am getting high 60s to low 70s. So are ALL the people I dive with in Coz inexperienced air hogs? Am I still in that category too?

I mean we do ordinary high 70s to low 80 ft dives. Might dip down to 85, but that is about it. And on second dives, sure I more regularly go past 70, but really you are a bad diver if you can't suck 70 minutes out of an 80cf?
 
I don't really understand the hype with the whole 120cf tanks, to me they are a crutch for inexperienced divers in a place where 80cf tanks will give you 70min bottom times. Just my .02

I doubt that the majority of divers will get that time on a 80 cf tank. Throw in deeper dives and that goes out the window. Exclude women who may consume less air. Exclude those divers who just use less air.

I suspect that I am far more experienced than Midge but would not be surprised if I use air at twice the rate that she does. Such is life.
 
I don't really understand the hype with the whole 120cf tanks, to me they are a crutch for inexperienced divers in a place where 80cf tanks will give you 70min bottom times. Just my .02

You're female so you would almost positively be diving a steel 100 not a 120, as females already generally have a SAC advantage over males and you'd be diving for 2 hours on a steel 120 not 70 mins.

Two other things about them, is safety margin for all divers, making deeper dives safer such as the Devil's Throat and such and steel vs aluminum also has a weighting advantage and a non-buoyancy issue toward empty that aluminum doesn't offer, which is minor in the scheme of things, the real reason of course to use them is for extending your bottom time, plain and simple.

I'd stay down for 3 or 4 hours if I could so to me anything that extends my bottom time is a no-brainer for me, and of course since they come attached with diving with Aldora what more is there to ask for? If there is a steel120 tank next to an aluminum 80 tank and I have a choice, I'm always taking the 120, why wouldn't I???
 
I suspect that I am far more experienced than Midge but would not be surprised if I use air at twice the rate that she does. Such is life.

You're female so you would almost positively be diving a steel 100 not a 120, as females already generally have a SAC advantage over males and you'd be diving for 2 hours on a steel 120 not 70 mins.
Did either of you guys look at Midge's profile? She's a he.

That said, there are a lot of factors besides gender that affect a diver's air consumption. For instance, I insist on shooting macro in the currents of Cozumel. Because of that, I necessarily spend more time than most divers kicking against the current to stay still. I'm pretty sure that, and basic physiology, are why my air consumption may be higher than others on the same dive who are smaller and shooting wide-angle or carrying no camera at all. I really doubt it's my lack of experience.

When I did a Aggressor photo class liveaboard trip with "Mike and Mike", I noticed my air consumption (with camera) was just about identical to if not slightly better than Mike Haber, who is slightly smaller than me. Perhaps he just needs more experience too?
 
I don't really understand the hype with the whole 120cf tanks, to me they are a crutch for inexperienced divers in a place where 80cf tanks will give you 70min bottom times. Just my .02

That is certainly one opinion but it is not always true; In fact it's a bit of a mixed statement. Simply stated, yes they can be used as a crutch for inexperienced divers thereby allowing them to enjoy longer dives. However, in the hands of experienced divers it becomes a very valuable tool especially on deeper and longer multiple level profiles. I also prefer to have more gas than I actually need to increase my safety margin.

Not getting into a pissing contest over SAC rates but I can easily get 70 min bottom times on AL80s however I can easily get 80-90 minute bottom times on HP100s/HP120s. Also comparing AL80s to HP120s is kind of pointless if the profile is not mentioned. I imagine most people can bang out an 80 minute bottom time on an AL80 at Colombia Shallows.
 
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LOL, yes I am a male, man, dude, etc. not a chick. I wasn't trying to put down those who choose to use the 120 tanks while in Cozumel, just that I didn't (don't) understand why its always brought up. I have a shiny new set of HP100's in my garage right now that I will be using while drysuit diving where I also carry a 19cf pony. So its not like i'm saying that big tanks are taboo, and if I were living in Hawaii I would use them for my own shore diving. But again it was just a statement on how 120cf tanks are always being brought up for Cozumel diving. I think if I were diving a LP steel 120 in Cozumel I would be WAY overweighted in my gear configuration, so that would be more of the issue. Hope that clears it up. My profile picture is from my first warm open water dive (dive 15 or so) a few years ago, I am relatively green to most of you with only 115 dives in the three years I've been diving, but when you live in Alaska, WELL???? :)
 
I didn't (don't) understand why its always brought up.

Because they are an awesome option! I wish they were an option in more places, as I always check where ever I'm diving and unfortunately the old aluminum 80 rules the diving world in almost every location. Going to Cozumel AND having the option of steel 120s is awesome.

Would so love to get ahold of 120s in Bonaire. It's not unusual to do a 80-90 minute dive there on an al 80, with a steel 120, I'd need people to bring food to me on my dives, I'd be a wrinkled prune by the end of the week.
 

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