Tank Purchase Help

[jgaryclark]

Need to buy my wife a "light" tank...she has some lower back problems and I'm wondering if there is a lighter weight alternative to the kinda standard aluminum 80s that we use. I've found these with a search http://www.carbondive.com/en/single-cylinders but can't find any pricing info on them. Any suggestions?
Thanks.

 

[Scott]

I don't see anywhere on their website that the cylinder is DOT approved. Unless you have a home fill station, you're not likely to get that one filled.

Whatever weight is removed from the cylinder would have to be added someplace else ie: BC weight pocket, wet belt to achieve proper weighting.

There is a composite cylinder, Divator on www.interspiro.com that I believe is DOT approved but the site is down. It was a doubles set if I recall. Not sure if they have a single cylinder.

 

[Marie13]

How is her air consumption? An AL63 might work.

Is she walking long distances geared up? There are strategies to get around carrying heavy gear on her back depending on how/where you dive.

 

[tbone1004]

I do not believe composite cylinders to have safe for in water use. I say that as a composites engineer who has worked on the design of said cylinders. They are fine as disposable items, but not for regular use. There were some big threads and posts with lots of information on why a few months ago after the add helium debacle.

Aluminum tanks are poor choices for weight:capacity due to buoyancy characteristics and the square foot on the bottom. I.e. an al80 has 77cf of gas, weighs 32lbs empty, and requires 4lbs to sink. Total weight of 36lbs for 77cf of gas *not including the gas itself*. A HP100 has 100cf of gas, weighs 34lbs, and is just over a pound negative. 5lbs lighter on land, 25% more gas.
A FX80 holds 80cf of gas, weighs 28lbs, and is about 3lbs negative. So on land you have a net advantage of 4lbs for the tank, and 7lbs for the buoyancy for the same gas capacity. For women they tend to work better as well since they are 10" shorter than an AL80.

These tanks are not going to be available when travelling. You will have availability of AL63's and AL80's. I have to disagree with @Marie13 on an AL63 being an option due to air consumption because it removes your reserve capacity for air sharing. It also only saves about 5lbs so isn't that significant of an advantage and there may not be availability when travelling.

If you do most of your diving locally, then I'd find some HP80's and go that route. You take 10lbs of weight off and don't sacrifice gas capacity, and you get a length advantage. If you do most of your diving abroad, then I would recommend going to a single tank sidemount system where there is no weight on the back at all

 

[Bob DBF]

I believe they are european tanks, so you won't find them here. I didn't notice any buoyancy specs, usually if you have a really light tank you have to add weight on the belt.

Look into AL60 and AL63 as the buoyancy is good and you do shave off some weight.

Good Luck

Bob

 

[Marie13]

OP's wife needs to investigate other ways of handling her gear. If she can gear up totally in the water, wheeling her tank down to water's edge, that's one possibility. Or if they only dive via boat, doffing in the water and handing it up, to avoid climbing the ladder geared up.

 

[hilljo88]

It sounds like you are looking for some compromise on tank weight vs material and performance. But if your wife needs to be additionally weighted as almost everyone does, the weight you save on the tank will have to be made up with lead on a belt or in integrated pockets, and you are back to the same weight load on her back. So I second Marie13's post. Try to find a way to get her into the water first, then you or a DM carry the gear and help her into it if needed. this is not that uncommon for divers with bad backs or bad knees.

 

[tbone1004]

It sounds like you are looking for some compromise on tank weight vs material and performance. But if your wife needs to be additionally weighted as almost everyone does, the weight you save on the tank will have to be made up with lead on a belt or in integrated pockets, and you are back to the same weight load on her back. So I second Marie13's post. Try to find a way to get her into the water first, then you or a DM carry the gear and help her into it if needed. this is not that uncommon for divers with bad backs or bad knees.

that makes absolutely 0 sense, please explain

 

[2airishuman]

Need to buy my wife a "light" tank...she has some lower back problems and I'm wondering if there is a lighter weight alternative to the kinda standard aluminum 80s that we use. I've found these with a search http://www.carbondive.com/en/single-cylinders but can't find any pricing info on them. Any suggestions?
Thanks.

tbone speaks my mind. Tank wise the best choice would be an HP80 if that fits her well. The alternative is to gear up in the water. It is not necessary to switch to sidemount to do this. I gear up in the water with my ordinary backmount setup when I'm diving from a canoe. I use a BP&W, which makes it more difficult, a jacket BC is easier for most people.

 

[hilljo88]

that makes absolutely 0 sense, please explain

Assume the OP's wife is positively buoyant as most people are, then she currently needs some added weight to dive. If she gets a lighter weight tank, whatever weight she saves from the tank swap, she will need to replace in lead to get back to (slightly) negative buoyant. She will still have the same weight load to deal with. So looking at alternative tanks wont solve the problem. One solution is to don and doff the inflated BCD in the water, on the surface. We've done this often for people with bad backs or bad knees. The diver in this case does not ever have to bear the weight of the unit.