an "ideal" scuba tank

[packeteer]

maybe look at side mounting. ie. carry your tank to the water first, then gear up. jump in, clip your tanks on and you're good to go

 

[Aqua-Andy]

As a “person of maturity,” when lugging my tanks or, especially, when scrambling over rocks on a shore entry, I often have wished for lighter tanks. This got me thinking about an “ideal” tank. At first, I thought such an ideal tank would have no weight at all (purely hypothetical, of course). Oh, the joy of diving with such a tank!—or so I thought. But then it dawned on me that were such a tank to exist (with conventional size and working pressure) it would be positively buoyant (because, weighing nothing, it would displace a greater weight of water than its own weight). For example, my (steel) HP80s hold 80 cubic feet of gas at a working pressure of 3442 psi, which works out to an internal volume of 0.34 cubic feet (9.7 liters). In water, an empty weightless tank with that capacity would displace 0.34 cubic feet of water and would thus be 21.9 pounds positively buoyant (in salt water). This led me to revise my definition of “ideal” to be a tank that was neutrally buoyant when empty. Well, my HP80s have an empty weight of 27.7 pounds and are 3 pounds negatively buoyant when empty. Since the negative buoyancy allows me to use three pounds less lead, the effective weight of my tank is 24.7 pounds—only 2.8 pounds more than my so-called “ideal” tank! All this has led me to be very happy with my HP80s (but somehow I still wish they were lighter!).

(Put another way, "good" tank weight reduces positive buoyancy; "bad" tank weight does not. My HP80s have 24.9 pounds of "good" weight and (only) 2.8 pounds of "bad" weight.)

Sounds like you need a re-breather.

 

[The Kraken]

Well, at the tender age of 62 I would consider myself a diver of "maturity".

I regularly walk a hiking trail of 1.5 mile wearing my doube steel HP 80's. With the steel BP I figuring that's about 80 pounds or so.

Yes, people do look at me with an "inquiring" interest, but the heck with them.

So, if I were constrained to one tank, it would be the HP 100.

So there . . . . .

Use it, or lose it . . .

I'm not going out easily.

the K

 

[Rich Keller]

As a “person of maturity,” when lugging my tanks or, especially, when scrambling over rocks on a shore entry, I often have wished for lighter tanks. This got me thinking about an “ideal” tank. At first, I thought such an ideal tank would have no weight at all (purely hypothetical, of course). Oh, the joy of diving with such a tank!—or so I thought. But then it dawned on me that were such a tank to exist (with conventional size and working pressure) it would be positively buoyant (because, weighing nothing, it would displace a greater weight of water than its own weight). For example, my (steel) HP80s hold 80 cubic feet of gas at a working pressure of 3442 psi, which works out to an internal volume of 0.34 cubic feet (9.7 liters). In water, an empty weightless tank with that capacity would displace 0.34 cubic feet of water and would thus be 21.9 pounds positively buoyant (in salt water). This led me to revise my definition of “ideal” to be a tank that was neutrally buoyant when empty. Well, my HP80s have an empty weight of 27.7 pounds and are 3 pounds negatively buoyant when empty. Since the negative buoyancy allows me to use three pounds less lead, the effective weight of my tank is 24.7 pounds—only 2.8 pounds more than my so-called “ideal” tank! All this has led me to be very happy with my HP80s (but somehow I still wish they were lighter!).

(Put another way, "good" tank weight reduces positive buoyancy; "bad" tank weight does not. My HP80s have 24.9 pounds of "good" weight and (only) 2.8 pounds of "bad" weight.)

I prefer steel tanks, own a steel 95 that works at 3000psi and an old (1960) 72. But when I want a light tank for shore diving I use an aluminum 30 on a Miller harness. For ultra light I use a steel 13 when checking out new dive locations from my kayak. I have yet to find the ideal tank for every use so I have different tanks that are suited to different types of dives.

 

[sam1]

Sounds like you need a re-breather.

Well, I have thought about that! In December I did a couple of "try dives" with a Poseidon Discovery Mk VI. (I posted a report at http://www.scubaboard.com/forums/5671020-post2.html .) I have also looked into (a bit) a APD Evolution, but it's not particularly light, at least compared with my current open circuit rig.