Thinking Outside the Tank

[UCFKnightDiver]

Modern performance sail boats usually have carbon rigging and hulls. I don't think it's that much of an issue.

A 6000 or higher fill could be really useful for tec and cave, though with boosters, custom compressors, hoses, fittings, valves, 1st stages and whatnot required I see it being quite cost prohibitive in the short term.

Why? Large steel doubles do just fine, and are negative, plus the ideal gas law stops working at some point so you'd have to go bigger anyways to get a huge increase in volume. More wear and tear on regs hoses etc, I can't see being a good thing either.

 

[Rhone Man]

Wrapping metallic cylinders with graphite fiber is one thing, having pure GFRP cylinders is another. Non-destructive testing is outrageously expensive.

I was actually thinking the other way around - coating the graphite fiber cylinders on the outside with some kind of acrylic polymer (not for strength, but to prevent it scratching and banging).

 

[turbine]

Check out Gary Gentile's Technical Diving Handbook. Given the information is dated to say the least. In the chapter/section about tanks he included a write up on carbon coated cylinders. There is also a picture of a cave diver wearing something like four carbon wrapped tanks and a set a steel doubles.The diver is also wearing a weight belt.
I'll stick with my low pressure steel ccr tanks

 

[Blackwood]

I was actually thinking the other way around - coating the graphite fiber cylinders on the outside with some kind of acrylic polymer (not for strength, but to prevent it scratching and banging).

Right... that's what I meant when I said 'pure GFRP cylinders.'

 

[Superlyte27]

The Fire Bottles are very bouyant.

 

[scubafanatic]

I do believe that carbon fiber SCUBA tanks rated to 4500psi already exist and are available out there.

You're right... XS Scuba Luxfer Luxfer Aluminum Scuba Cylinders

 

[Dave1981]

Why? Large steel doubles do just fine, and are negative, plus the ideal gas law stops working at some point so you'd have to go bigger anyways to get a huge increase in volume. More wear and tear on regs hoses etc, I can't see being a good thing either.

This was my initial though also, why fix a problem that isn't there. However if you can double the pressure though you could double your quantity of gas, or penetrate with tanks half the size. More gas and a smaller profile can only be a good thing.

Instead of diving twin 130's @ 3000psi why not dive twin 260's @ 1500psi. Everything would be safer, cheaper and less wear and of course diving large steel doubles is just fine

 

[adm3745]

Why? Large steel doubles do just fine, and are negative, plus the ideal gas law stops working at some point so you'd have to go bigger anyways to get a huge increase in volume. More wear and tear on regs hoses etc, I can't see being a good thing either.

Dave, look up the van der waals equations. You should be able to find compressibility factors for air and the equation will tell you how much air you really have. I did the math once and I remember it being something like ~10 cft less in a 3500 filled LP 108 than you think you have. Oxygen you get more gas than you think you have. 6000 your getting some very diminishing values

ATOMOX Inc. - HeLIUM ANALYZERS

 

[Dave1981]

Good reference. By that, exterpolation gives me the result that (air) filling to 5000psi would return about 13% less than boyle's law would have us believe, and 6000psi 17% less.

I still wouldn't complain at having that extra gas though

 

[adm3745]

Is that an exponential extrapolation?

More gas in a smaller package would be nice. The costs will probably prohibit it from ever happening.