Info on large tanks

[claymore]

I am fairly new to diving and am a real hoover. I am assuming that my air consumption will improve with experience.

I am in the market for a couple of large tanks. I am looking in the 115 - 120 cu. ft. size probably in the lp pressure type.

I am wondering if there are any advantages to a certain manufacturer or type.
I know that the lp tanks tend to be heavier and larger but can supposedly be over filled to 3000 to 3400 psi range for even more gas.

I know that there are only two tank makes available now Worthington and Faber and
that the Worthington tanks are a newer design but am wondering what the differences are othere than tank finish.

I know that at some point this size tanks may become over kill for most rec dives
but I can afford them now and would rather have the capacity if I need it than buy smaller tanks that may limit my dive times even more.

Thanks for any information

 

[Papa_Bear]

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I would look at the LP95 steel! Great tank with good trim and you can drop 10bs from your hip!

 

[DA Aquamaster]

Here are a couple links to consider.

If it were me I'd go with a X8-100 long before I would buy an LP 108 unless you live in an area where you can get a cave fill for the LP tank. The HP 130 is similar in size (1 inch shorter and a few pounds lighter) but will hold 130 cu ft with a 3442 psi fill you can get in MSP. The LP 108 will hold 148 cu ft if filled to 3600 psi, but that does not do you any good if all you can get is 2640 psi. On average the HP 130 is a better way to go.


Scuba Cylinder Specification Chart from Huron Scuba, Ann Arbor Michigan

XS Scuba Worthington Steel Cylinder Specifications

 

[pasley]

What do you consider bad? Most new divers get about 20-30 minutes on a AL80 tank on a dive of 40 feet or less. With proper weighting, buoyancy control, SCUBA diving techniques and physical conditioning that will grow to 90 minutes or so.

If you air consumption is truly bad, the real solution is to solve the problem not the symptom. Why is your air consumption so bad?
IMHO the true issues to address are:
1. What is making you nervous? Solve the problem and remove the cause of your discomfort. Nervous about diving, dive more, practice skills more in the pool until you can do them in your sleep. Then you will calm down. You should not even be thinking about your breathing. Just breathe like you do sitting at your computer.
2. Get your weighting right. 500PSI holding 15 feet neutral with empty BC.
3. Learn how to put air in the BC, wait for momentum to be overcome and then if necessary ad more.
4. Quit waiving your hands around. Park them. If you need to scull your hands to maintain depth or keep off the bottom, you need to add a puff to your BC and get neutral.
5. Get off the couch and go run or bicycle or do some other cardio. Get physically fit.
6. Dive more often, it will help with Number 5
7. SLOW Down. If you move slow, you are not a threat and the fish will come to you. If you only see 5 square yards of the ocean, so what, you had a great dive and saw a lot of stuff most other people swam right past and look at all the fish that came over to check you out.

If you want a bigger thank the 3442 would be my suggestion. Remember those huge 130s will also increase weight, and drag and increase your air consumption rate a tad which may offset the added gas.

 

[Papa_Bear]

The steel 95 is rated at 95cubic ft of air at 2450psi so a 3000psi fill will give you over 110cubic ft! In a package about the same size as an 80cft tank and anyone, even a portable compressor can fill it! I understand the HP argument, but I like my stuff full! It is personal preference and the above is mine and a lot of other divers in my area and we do a lot of Boat Diving where your lucky to get 3000psi! Its all about KISS!

 

[ucfdiver]

The steel 95 is rated at 95cubic ft of air at 2450psi so a 3000psi fill will give you over 110cubic ft! In a package about the same size as an 80cft tank and anyone, even a portable compressor can fill it! I understand the HP argument, but I like my stuff full! It is personal preference and the above is mine and a lot of other divers in my area and we do a lot of Boat Diving where your lucky to get 3000psi! Its all about KISS!

Oh good lord......

A steel LP tank holds darn near the exact same amount of gas as an equally sized (volume) high pressure tank.

LP104 = HP130 at equal pressures.

You can always get a LP104 filled to it's rated pressure, but you can't always get a HP130 to it's rated pressure. HOWEVER, a HP130 filled to the LP104's rated pressure holds the same amount of gas. A LP104 filled to 3440 holds the same amount of gas as a HP130 filled to 3440.

The only difference is some places won't over fill LP tanks. You're never going to get MORE gas in a LP cylinder than the same volume HP cylinder.

I'll quote the post of mine that I use each time this comes up

This debate goes on way too much. It's really simple to make the decision once you understand some of the basic math, but far too often I read "hp are lighter", or "lp hold more air", and while both of those statements are true, there's a little more to it than that.

If you're filling in cave country, LP tanks are the best value. Here's basically the the LP/HP equivalency if you're in an area that overfills, and then I'll try to explain it so you don't have to just take my word on it.

LP85's = 100's
LP95's = 120's
LP104/108/112's=130's
LP120's=HP149's

Once you take a basic cave/cavern class, you'll learn about "tank factors" which basically says for every 100psi, the tank has ___ cuft of air. Here's how that's calculated- (tank volume(in cuft)/rated pressure*100)

For example, a LP104 has a tank factor of 104/2640*100 = 3.9. This means for every 100psi, you get 3.9 cuft of gas.

A 133 has a tank factor of 133/3442*100=3.9. This means for every 100psi, you get 3.9 cuft of gas.....see a pattern?

So at 3400psi (34*3.9) you get basically 132 cu/ft in either tank.

Now, one argument for LP tanks is that on dive boats, often times you can't get a "full fill" on a HP tank. Let's say that you can only get a 2640psi fill. Well then, the 133's and 104's both hold 104 cuft at that pressure. Basically figure out the size tanks you want in regards to volume, and if you can't get overfills where you're diving, get HP tanks, if you can, you might can save money by getting LP tanks.

You'll hear HP tanks are lighter than LP tanks. While this is true, remember what we just learned. Saying that a LP120 is heavier than a HP120 is true, but the LP120 can hold 149cuft when filled to 3500ish, while the HP120 can only hold 120cuft. Compare the LP95's, and you'll see that the weight is nearly identical, because they're the same size tanks.

Many shops consider overfilling LP tanks dangerous despite the fact that it's been going on for nearly 2 decades without a single known incident. I've had my personal tanks filled to 3600 every single time without complaint.

At this point, if buying new, I'd buy HP tanks, the price difference just isn't enough to make it worth ALWAYS getting tanks filled in cave country....sometimes it would be nice if I could get my tanks filled in Orlando before heading to Ginnie for a midnight dive.

 

[Papa_Bear]

As I said personal preference! Oh my dear lord! Take a chill pill and I am thrilled for you, do you understand how a compressor works? How much harder it is to get that last few PSI? Volume is a function of size and pressure! I don't think you read or understood what I was saying! I certainly am having a hard time getting your point or why the "Oh good lord......" 36 years and 4200 plus dives and I get that? I have put on my back just about every combination you can think of and I still own and dive LP95 here locally, lp108s in the Caves of Florida, and whatever is available on dive boats and resorts! I own everything from a 13cft to 120cft and all are low pressure do to practicality! In compressors there is a law of diminishing returns, not to mention wear and tare! But you can dive anything you want, just like I said, a matter of preference! I stated mine and yours I am not too sure?

 

[NudeDiver]

Now, now boys. Play nice. It's not like you're at the WSOP Main Event Final Table.

Unfortunately, I'm not either.

I'm not going to be buying tanks any time soon, but I did get an important point from this thread. That is - find out the maximum bar of pressure I can get locally before buying tanks. Don't want to piss away money on functionality I can't even access. So, thanks

On that note - as I write this, a thought occurs to me. If I ever get one of those portable compressors that I could ever afford to buy, odds are good that it will not have a very high pressure rating. That much more reason to get LP tanks.

So, thanks
nd

 

[spoolin01]

There are differences in manufacture from what I understand - Worthington hot dip galvanizes its tanks, which means heating them slightly, Faber spray galvanizes then paints their tanks. I believe there may be more profound differences in the way the tanks are made due to Worthington using a new manufacturer, but more knowledgeable folks will have to clarify all this.

I've got one Faber HP120 and two Faber LP120s. All are nearing their 2nd rehydro and are holding up fine - no external rust, even only the slightest flash where the new hydro dates were stamped. If you need 120cu ft - and I do since I usually stay above 50 ft and want the longest dives possible - go with the LPs. They are bigger, heavier, and positive when empty, but with the LPs I rarely get less than 110 cu ft and often a little more than 120, with the HP I rarely get more than 110 cu ft unless I fill it myself, often much less. It's just the way LDS fills seem to work around here. It also seems to be the case that with drysuit diving and 30-35 lbs of lead, the slight differences in tank bouyancy characteristics just don't get noticed. If I thought I only wanted 100 cu ft, I'd dive the HP120 exclusively.

 

[DaleC]

Well, I'm not getting in the middle of that :shocked2:

Claymore, I think Pasley had some good ideas. I know that my air comsumption has gone down a lot with more dives and getting the bouyancy under control.
I see in your profile that you are in the "gear aquisition" phase (know what that's like) so here are some thoughts that I had regarding tanks.

First, check out the cost of renting vs filling and decide how often you will be diving. At my LDS I can rent 2 full AL80's for 1 dollar more than it cost to fill 2 of my own. Buying tanks was last on my gear list and I finally bought some used ones just so I wasn't tied to the LDS pickup/return times.

Some of my buddies keep pushing me to buy ST130's (they like to go deep) but I sometimes solo and mainly enjoy flora and fauna so I usually choose to dive in the 60ft or less range. A cheap AL 80 does me just fine for those depths (I usually have to take a piss by the time my air runs out) and on those occasions that I go deeper I just rent the 130. It depends where you are going with your diving down the road though.

If you go with big tanks you will have to start being very careful regarding your NDL's in a rec setting. AL 80's are somewhat self limiting that way which might be better in the beginning. The first time I rented 2 ST130's for a days diving I blew my 2nd dive's NDL by a mile and was lucky I didn't get bent. May be it's just me but having all that extra gas isn't always a good thing. Now if I do rent a 130 for a deeper dive I just get one and use an Al80 for the second dive.
I know someone will say that following a proper dive plan will solve those issues and I agree 100% in advance

Just some random thoughts that may or may not apply to your situation. I'm not trying to talk you out of a big tank but you may not really need one and there are plenty of cheap used AL80's out there that will serve well in rec diving till you figure out what you really want/need.


Good luck.