Side mount curiosity

[Michelle]

When you're diving sidemount, are you always breathing from independent regs? I've read about Armadillo, etc., but is that always the case? I understand the rationale behind being able to switch back and forth between regs, especially if something goes wrong, but is there any setup whereby you can essentially isolate a valve (other than switching off your first stage)? Such questions plague me late at night.

[andrebasso]

When you're diving sidemount, are you always breathing from independent regs? I've read about Armadillo, etc., but is that always the case? I understand the rationale behind being able to switch back and forth between regs, especially if something goes wrong, but is there any setup whereby you can essentially isolate a valve (other than switching off your first stage)? Such questions plague me late at night.

I have seen a high pressure flexible steel cable that is used to create a connection between two dive cylinders. The cable I have seen comes packaged with tanks bands and was designed primarily as a way to connect two independant cylinders in a standard back mounted fashion. I guess you could conceivably use the cable across the chest in a side mount style effectively breathing off both cylinders at the same time. The one problem with this setup though is that the steel cable does not have an an isolator valve. The other problem is that in a side mount configuration the cylinders are always shifting and moving and this may put critical stress on the connecion ends of the flexible cable. With no isolator valve on the steel cable, if one end were to come loose or break off due to movement and stress, well you would loose your ENTIRE GAS SUPPLY. Not good. So, the answer is that you technically can breath off both cylinders but it might ( I don't know the cable specs) be more dangerous in the end. Probably the reason why I've never seen anyone do this. Let's give this rig a new name. The suicide setup.

[Michelle]

Um, sorry I'm not half as a jive and two spools too cool but I think under the man's tank one two and I have one reel shy thirty one oh eye one more I'd walk the plank if my bro yo understated he dont have watcha chacallit undemoted then whatchallit again one time demoted if you weren't lookin at me one time, me just having fun mofo...let your ass out have a good time...oh was this a test? I guess I got carried away. I hate it when that happens.

[andrebasso]

Um, sorry I'm not half as a jive and two spools too cool but I think under the man's tank one two and I have one reel shy thirty one oh eye one more I'd walk the plank if my bro yo understated he dont have watcha chacallit undemoted then whatchallit again one time demoted if you weren't lookin at me one time, me just having fun mofo...let your ass out have a good time...oh was this a test? I guess I got carried away. I hate it when that happens.

The side mount freestyler, cool... One reg, two regs, the girl doesn't know, redundancy issues, is her air gonna free flow? haha.

[Duncan Price]

I have seen a high pressure flexible steel cable that is used to create a connection between two dive cylinders. <snip> Probably the reason why I've never seen anyone do this. Let's give this rig a new name. The suicide setup.

Rob Parker did this for his 1985 Wookey dive. A pair of Accurex high pressure composite tanks were worn one on each side. Both tanks had Y valves with a HP hose connecting the two worn around the front of the body. I guess that there must have been a way of purging the cross-connect for disassembly. This was a carefully thought out rig.

[andrebasso]

I have seen a high pressure flexible steel cable that is used to create a connection between two dive cylinders. <snip> Probably the reason why I've never seen anyone do this. Let's give this rig a new name. The suicide setup.

Rob Parker did this for his 1985 Wookey dive. A pair of Accurex high pressure composite tanks were worn one on each side. Both tanks had Y valves with a HP hose connecting the two worn around the front of the body. I guess that there must have been a way of purging the cross-connect for disassembly. This was a carefully thought out rig.

Wow, someone actually has done this...Interesting. More interesting to me though, why don't more divers use the HP composite tanks like they used to. I remember seeing so many photos in the eighties of these 4500-5000psi tanks. I know you can't use them for helium as it leaks out at those pressures (small molecule or something), but if used for just air or enriched air, would'nt those tanks be useful in today's diving?

[curtschu]

Two main reasons you don't see HP composite tanks used for scuba

1. The buoyancy characteristics of those tanks is not go. They get very buoyant empty.

2. The material will absorb moister over a period of time and affect the strength of the composite.

They work great for fire dept scba since they are lighter and they don't soak in water all the time.

They get very buoyant empty.

That's putting it mildly, 007.

I had someone leave some 4500s for fills (I believe it was a textile mill that does periodic fire drills). A customer picked one up and asked why we didn't use these instead. I tossed one into the pool and it floated like a cork.

Russell

[andrebasso]

Hey guys, I did a little research on the net. What about the 4350psi "s106w" by Luxfer, they market it as a scuba cylinder and apparently it's only 3 lbs positive when totally empty in saltwater. Any thoughts why more divers don't use this one? Look like it could be perfect as a stage cylinder, small and compact but gives you 106cft of air with somewhat favorable bouyancy characteristics for cave diving. (with 2/3's of the air depleted it would be almost neutral in fresh water.)

[Arnold Mesiser]

I think pretty well any expedition Bill Stone had a hand in back then used the Acurex tanks.Wakulla,Huatla and Pena Colorada,I think some of the stuff in Australia utilized these as well.Luxfer makes hoop wrap composite tanks now.Some of the sump divers up here were looking at them but they don't trust the durability and inabilty to see damage under the carbon fibre wrap.Nice and light for the sherpa with lead being easy to cache for any bouyancy problems.Maybe one day they will be deemed durable enough?