advice on new doubles

[H2Andy]

right now i have two Worthington LP85's. having nothing to compare them to, i like them very much.

the only problem is that i am a bit of an air hog and would like a bit more gas on my back.

the only other problem is that i have a bad back and shoulder (broke L1 vertebrae in 2004), so weight is an issue, not just in the water, but handling the tanks on dry land.

so .. i would like to move up to at least 100 cf but keep the weight around 35 to 40 lbs maximum ... the lighter the better. weight is my determining factor.

any suggestions for what tanks may work for me? i've been looking around, but would appreciate feedback.

thanks in advance

 

[H2Andy]

oh, K... you remind me

any serious objections to HP tanks for Florida cave diving? i am not going to be mixing anything on my tanks. i guess the only worry would be less than optimum fill stations.

but the ones here are fine

 

[Doc Intrepid]

Andy, given your situation I would be looking at a set of E7-100s. they only weigh 32 lbs apiece, they are 7.3" in diameter and 24" long, but at 3442 psi they offer a full 200 cu ft and they can be overfilled if you're in cave country - I use my HP PST 130s in Florida along with many others - many cave divers consider these to be among the best options. I've used Rennakers each time with no complaints.
http://www.caveexcursions.com/c-2-breathing-gas-fills.aspx

In terms of a weight/capacity ratio, they would seem best suited to fit your requirements. Here are some other comparison specs:
http://www.lloydbaileysscuba.com/PST E Series Tanks.htm

Best,

Doc

 

[PerroneFord]

oh, K... you remind me
any serious objections to HP tanks for Florida cave diving?

HP130s are very popular here.

 

[H2Andy]

they are great tanks ... but i think a bit too heavy for me

 

[Kirkandtiger]

If you are already getting good fills, you'll get no benefit switching from Worthington LP 85s to Worthington HP 100s. When pumped up to the same psi, the Low Pressure 85 tanks hold more gas then the High Pressure 100 tanks. For instance at 3600 psi, doubled LP 85s give you about 232 cubic feet of gas, while at the same pressure, doubled HP 100s only give you about 209 cubic feet of gas. - Kirk

 

[mwpowell]

Another option is to stay with your LP85s, and just add stages when you need more gas. This will be easier on your back. What are your buddies diving?

Mike

 

[Arcaporale]

Go with some low pressure 95's, most tech shops will give these a nice overfill to around 3000-3200 range. These tanks are cool because they are nice and short, not to heavy, and have good bouyancy specs, about a pound negative when empty. A low pressure 95 @ 3100 psi will give you a bit more than 110 cubic feet of gas. I also like HP 119's too.

 

[The Kraken]

Hey, guys, I just noticed that this is in the "Cave Diving" forum.
Since I don't do caves and have no intention of doing so, my posts were, in my opinion, unsollicited, therefore I've deleted them.

Sorry, I'll try to pay better attention next time.

the K-aves Ain'g Gonna Happen

 

[H2Andy]

no worries, K ... you didn't have to remove your posts =)

guys, thanks .. that's actually some interesting stuff right there.... my LP85's are effectively 112 cf tanks at 3500 psi (though i didn't think of them that way until just now).

it really makes no sense for me to switch to a HP tank of less capacity than that at 3442 psi since i have no trouble getting 3500 psi fills

mwpowell, your suggestion is nice ... i had thought about it ... but sort of toyed with the idea of having larger tanks AND a stage bottle (plus one deco bottle) to maximize my time underwater