Doubles VS HP 130

[Leadking]

Tom,

I am not saying I don't believe you have a tail light issue with the Faber lp108 when they get low. I just wonder how or why you do and I do not.

How tall are you and how much weight do you need on your belt to dive with a single 108? doubles? I am 6' tall. Diving wet in up to a 5mm + hooded vest with AL plate, I wouldn't need any weight for any of these faber tanks as singles: lp85, lp108, hp100, & hp133. With a drysuit, I use 6lbs & my SS plate. Doubled, I wouldn't use any weight wet or dry for them.

Looking at the specs the weight swing isn't that different in the two LP108s. It's around 8lbs for both tanks from full to empty. The big difference is where they end up with the Faber being basically 3lb positive empty, so a bit less at 500, but not hugely so.
Faber 108: -5.02 to 2.98
Worthy 108: -10.7 to -2.6


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Back on topic...
Doubles are much safer than a single tank, assuming you are trained in their use and are competent with them.

It's ridiculous to assume "everyone eventually goes tech," as the opposite is true. Very few certified divers have technical diving certification if you look at it as a percentage.

I call b.s. On the weight swings. I was a distributor for both Faber and Worthington. Both companies made tanks by the deep draw method. Worthington has a little more metal in the bottom than Fabers but the weight swings in your post are impossible. The ONLY weight swing in a tank at the same pressure is the weight of the air.

 

[James R]

Well, mr former distributor, I didn't just pull those numbers out of my ass. They're the tank specifications which you could have easily looked up online in less time than it took you to try to call someone out.

ill even help you out:
http://www.xsscuba.com/tank_steel_specs.html

http://bluesteelllc.com/cylinder-specifications.html

 

[grf88]

The weight swings are the weight of the air and from the specifications they are 8 and 8.1 pounds respectively which is probably just a rounding difference so where is the argument.

 

[Doppler]

I call b.s. On the weight swings. I was a distributor for both Faber and Worthington. Both companies made tanks by the deep draw method. Worthington has a little more metal in the bottom than Fabers but the weight swings in your post are impossible. The ONLY weight swing in a tank at the same pressure is the weight of the air.

I'm not sure of the numbers in American Customary Units but gas is not ideal and has mass. I litre has a mass of about 1.2 grams. A Worthington LP 108 is a 16.5 litre tank... or close to it... and the working pressure is 170 bar.

170 x 16.5 = 2805 litres

2805 x 1.2 = 3366 grams = 3.366 kilos = 7.4 pounds. That buoyancy shift (the commonly used term) is of course from full to empty but it's not unusual to see more shift.

 

[Agility]

I own a 15l steel tank (Faber BTW) and a double 8.5l set. the doubles do not provide much more air (17l instead of 15l both are rated at 232 bar)
The doubles fell much better under water, the 15l tank always had me finning to prevent toppling over, no such issue with the double 8.5. The downside is of course weight out of the water.
It you want more bottomtime you might go with double 12l tanks.

 

[Leadking]

I apologize, I deleted the postimmediately after I posted it, as I saw my error in math. Apparently the delete did not hold.

 

[James R]

I had to eat a little crow in this thread too. It's better with hot sauce

 

[halocline]

Guys: I was looking to get into diving doubles to increase bottom time within recreational depths of 130 and above. Then I saw this monster tank HP 130. Its a beast of a tank but for someone looking to increase bottom time at recreational depth do you think doubles are necessary or should an HP 130 do the trick?
CS

There's a really big difference, with the doubles you'll need an extra regulator, a backplate/wing if you don't already have one, manifold/bands, maybe some training or at least a little coaching and practice with the trim/buoyancy and valve control. So going to doubles is a MUCH bigger expense than simply a bigger tank. Filling doubles costs twice as much too, at least around here.

I've having a hard time envisioning much recreational diving that would necessitate doubles. Any diving that requires that much gas is likely to become deco diving at some point and then you're getting into technical training. If I were in the situation you're describing I'd try a few bigger single tanks....try, not buy, before making any decision. Lot's of people like 120s.

OTOH, diving with smallish doubles (LP72s or AL80s) is very comfortable and enjoyable as long as you're not trying to buck a current or move around fast. But there is a bit of a learning curve. And sidemount is very popular these days, you could try that as well, if you're interested in getting into technical diving. If not, stay with a single tank, it's cheaper and easier.

---------- Post added January 2nd, 2014 at 09:41 AM ----------

My advise...avoid the Faber tanks they are not good for back mount single or doubles.

There are all kinds of faber tanks with all kinds of buoyancy characteristics; making this kind of blanket statement is nonsense, especially considering the high popularity of faber tanks. I have a FX100 that's terrific, one of the most sought after doubles sets is faber LP85s, etc.

 

[Instructor_Tom]

---------- Post added January 2nd, 2014 at 09:41 AM ----------

[/COLOR]

There are all kinds of faber tanks with all kinds of buoyancy characteristics; making this kind of blanket statement is nonsense, especially considering the high popularity of faber tanks. I have a FX100 that's terrific, one of the most sought after doubles sets is faber LP85s, etc.

Damn getting called out again, and you say i make blanket statements.

The discussion is focused on HP130s (LP108) which is an 8 1/2 " diameter tank and 26" in height. Why does everyone keep bring in the 7 1/2" diameter tank that is nearly 4" inches shorter. You might as well start comparing an AL80.

And for the record in my neck of the woods "Cave Country" Dbl LP108s are the preferred configuration for back mount not LP85/HP100.

 

[James R]

I read the question as doubles (no size mentioned) vs. a single HP130 in the original post, so a fair comparison would include AL80 doubles as well actually