VooDooGasMan
Contributor
Now i do have to agree with dale if this young russian girl can do it, then it must be very easy.
russia tv - YouTube
russia tv - YouTube
Why can't scuba tanks be set up like a firefighter's scba?
- Thread starter TracyN
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Well, there's a laundry list. But for the high points:
Snag resistance
The smooth butt ends of an inverted tank(s) have been far less likely to hook and retain lines and objects. We train by crawling around in zero vis, with cables and lines hung specifically to dangle and snag us. Most of the time they don't (snag, that is), and when they do, it's trivial to clear. Usually, I don't even need to put a hand behind my neck to clear the line. This is in an environment that I would frankly not even consider taking a standard scuba cylinder into because of the snag hazard.
Valve manipulation
Reaching down to the small of the back is far easier than the conventional valve drill over the shoulder. It is so natural of a motion, just like reaching into a hip pocket. Resistance of the exposure suit usually inhibits over-the-shoulder, and at the waist, it has no effect. I can apply more leverage at the waist, too. And finally, a common issue with conventional valve drills is the tendency to lose trim as folks tuck their heads down, this doesn't happen with inverted valves.
Valve protection
Just look at a conventional set of doubles, with the valves stuck out like the horns on a long-horn steer. They're just begging to be bent or rolled off or something. Inverted valves are so protected I don't think I could roll them off if I tried.
Hoses
This has always been a red herring. My long hose is 7' long, what's the big deal if it's an extra 18"? The same for my necklace. Just cook up a similar routing that's simple. (Remember how askance the recreational diver looks at us with a long hose!)
Failures
If I can figure out that I have a "leak" (airgun simulation in training) from the argon bottle while wearing a 12mm Otter Bay hood, I'm sure I can figure out that I have a leak from a 1st stage while wearing inverted cylinders. And the valve manipulation will be quicker, more sure, and thus lose less gas.
What most folks don't realize about firefighting (SCBA) bottles is the valve on the tank is different from a scuba valve. The SCBA valve is designed to take the weight of the bottle without damaging the regulator. Actually, it's designed to be dropped short distances onto the valve. Without ever seeing this valve, of course scuba divers can't even imagine inverted cylinders.
Anyway, that's just a cursory look at why I think "inverted valves" have "upright valves" beat. It's just my opinion though, and I really don't want to get into a point-by-point rebuttal over it.
Most folks that are dead set against inverted cylinders, it's been my experience, have never worn a set. For the love of god, try it before forming an opinion! ...I took some of my technical dive buddies, and had them wear my work SCBA, and asked them to turn on the valve. The look of astonishment was priceless.
Does this mean we'll ever see inverted cylinders? I believe no. The industry has entirely too much inertia with upright cylinders, as well as investment in training, equipment, and legacy equipment. That's okay by me, as long as my dive buddy and I are similarly equipped.
All the best, James
DaleC
Contributor
Fdog answered the question pretty well but...
That's the OP (the bolding is mine). The question wasn't why aren't inverted cylinders commonly used. It was whether they can or can't. There's no "rage against the machine" on my part; just trying to separate fact from bias. Most of the questions asked would evaporate if one took an evening to just play with some hoses and a tank.
When I try different configurations I start from a clean slate - that way I deal with the issues at hand and don't have to drag the hubris of woulda coulda shoulda along for the ride. Is there some thinking involved.. yes - just as there is with any rig. I remember the many evenings spent trying to figure out my first "PADI endorsed" rig.
If one has a configuration already in mind as the "standard" then of course, other configurations will seem to be too much effort in comparison. I don't have that problem as I like a lot of different systems and find using them all to be a lot of fun.
In this case, my personal experience began with just another thread like this one, in which inverted doubles were discussed. There was so much conjecture going on that I decided to take the time to do a mock up in my garage to see what was fact and what was fiction. Most was fiction and the few issues that did arise could be worked through by anyone committed to using doubles that way. After that I liked the idea so much (not really for doubles though) that I put together a singles rig to dive. I continue to dive it sometimes and to further refine the rig.
Tanks come in all sizes. I found an Al 80 to be cumbersome, a St 72 to be good and a HP 80 to be ideal.
I use a 5 foot long hose and it routes the same whether inverted or upright (apparently the distance is the same). My bungiied B/U reg was on a longer standard length octo hose and routed up the right side of the tank to come out by my right neck. My SPG routed up to clip on my chest D ring where I like it but it could also be routed up the tank part way and back down to clip into the left hip D ring if that's what someone wants. The DS whip routes straight from the first stage to the inflator just like a valve up rig. The distance is the same. The hoses are held against the tank with tire tubing. The wing inflator is a problem and a custom hose is needed here. IF ordering a hose online is that big an issue then all I can say is diving inverted isn't for you.
Diving for most is a hobby; one in which we spend thousands of dollars on training, equipment and travel. We spend hours, days, weeks and years studying tables, charts, texts and drills. Yet flipping a tank upside down stumps us or is too much work? How much time does someone spend figuring out their new camera set up.
Now, some people won't be interested or find this fun (fair enough). Some can't be bothered, some don't want to stand out as being different and some can't intellectually grasp the process. I don't think that's being unfair. However dismissing the idea out of hand is.
Some of us have a saying (actually a quote by Herbert Spencer):
“There is a principle which is a bar against all information, which is proof against all arguments and which cannot fail to keep a man in everlasting ignorance - that principle is contempt prior to investigation”
Here's a pic of the cover of a text from 1955, one of the first of it's kind in North America
That's the OP (the bolding is mine). The question wasn't why aren't inverted cylinders commonly used. It was whether they can or can't. There's no "rage against the machine" on my part; just trying to separate fact from bias. Most of the questions asked would evaporate if one took an evening to just play with some hoses and a tank.
When I try different configurations I start from a clean slate - that way I deal with the issues at hand and don't have to drag the hubris of woulda coulda shoulda along for the ride. Is there some thinking involved.. yes - just as there is with any rig. I remember the many evenings spent trying to figure out my first "PADI endorsed" rig.
If one has a configuration already in mind as the "standard" then of course, other configurations will seem to be too much effort in comparison. I don't have that problem as I like a lot of different systems and find using them all to be a lot of fun.
In this case, my personal experience began with just another thread like this one, in which inverted doubles were discussed. There was so much conjecture going on that I decided to take the time to do a mock up in my garage to see what was fact and what was fiction. Most was fiction and the few issues that did arise could be worked through by anyone committed to using doubles that way. After that I liked the idea so much (not really for doubles though) that I put together a singles rig to dive. I continue to dive it sometimes and to further refine the rig.
Tanks come in all sizes. I found an Al 80 to be cumbersome, a St 72 to be good and a HP 80 to be ideal.
I use a 5 foot long hose and it routes the same whether inverted or upright (apparently the distance is the same). My bungiied B/U reg was on a longer standard length octo hose and routed up the right side of the tank to come out by my right neck. My SPG routed up to clip on my chest D ring where I like it but it could also be routed up the tank part way and back down to clip into the left hip D ring if that's what someone wants. The DS whip routes straight from the first stage to the inflator just like a valve up rig. The distance is the same. The hoses are held against the tank with tire tubing. The wing inflator is a problem and a custom hose is needed here. IF ordering a hose online is that big an issue then all I can say is diving inverted isn't for you.
Diving for most is a hobby; one in which we spend thousands of dollars on training, equipment and travel. We spend hours, days, weeks and years studying tables, charts, texts and drills. Yet flipping a tank upside down stumps us or is too much work? How much time does someone spend figuring out their new camera set up.
Now, some people won't be interested or find this fun (fair enough). Some can't be bothered, some don't want to stand out as being different and some can't intellectually grasp the process. I don't think that's being unfair. However dismissing the idea out of hand is.
Some of us have a saying (actually a quote by Herbert Spencer):
“There is a principle which is a bar against all information, which is proof against all arguments and which cannot fail to keep a man in everlasting ignorance - that principle is contempt prior to investigation”
Here's a pic of the cover of a text from 1955, one of the first of it's kind in North America
DaleC
Contributor
Here are few pics from my mock up of the doubles. Yes the hoses are messy (I shot on the go as I figured it out) but the idea is there:
dry suit whip
SPG
Valve access
Regs
Air share
Hope that helps.
dry suit whip
SPG
Valve access
Regs
Air share
Hope that helps.
elan
Contributor
Now with the upside down valve positions try to reach the isolator valve in the middle with thick gloves, andlong enough cylinders like al80.
Worked ? You must have long hands.
Now try to reach and work with the valves when you have 2 stages on the side and some stages on the leash
that space becomes very crowded and the leash will wrap the valves in no time . Valves on the shoulders are just there, reach out and shut. They are not obstructed by anything, they are seen and accessible by your partner and you can communicate face to face.
Worked ? You must have long hands.
Now try to reach and work with the valves when you have 2 stages on the side and some stages on the leash
that space becomes very crowded and the leash will wrap the valves in no time . Valves on the shoulders are just there, reach out and shut. They are not obstructed by anything, they are seen and accessible by your partner and you can communicate face to face.
DaleC
Contributor
Really.. basic scuba and your main concern is you have 2 stages on the side and a couple of stages on a leash? What kind of rec dives are you doing? I guess they are hard to fit through the hatch of a mini sub at 1000' too. K.I.S.S.
And by the way, if that is such a problem why do such divers insist on keeping the SPG clipped off on the left hip regardless? Either access is restricted or its not.
The point about the isolator troubled me as well but people do figure it out. Not everyone dives doubles though and with a single tank it is a non issue.
As a bonus feature: diving inverted with a J valve ensures that, should the lever snag on kelp or something, it will be forced into the "reserve ready" setting and you don't need a rod either. Sweet!
And by the way, if that is such a problem why do such divers insist on keeping the SPG clipped off on the left hip regardless? Either access is restricted or its not.
The point about the isolator troubled me as well but people do figure it out. Not everyone dives doubles though and with a single tank it is a non issue.
As a bonus feature: diving inverted with a J valve ensures that, should the lever snag on kelp or something, it will be forced into the "reserve ready" setting and you don't need a rod either. Sweet!
DevonDiver
N/A
James & Dale - thanks for the detail and taking time to explain
elan
Contributor
Dale you made good points I agree its BS (basic scuba ) but its good to have same kind of config whether you dive tech today and reef rec tomorrow
as for spg you do not have to have a lightning fast access as you have to have with valves thus you can take your time digging it out
As for j valve would we have some kind of Double Hose long hose setup in this case
) but its good to have same kind of config whether you dive tech today and reef rec tomorrow as for spg you do not have to have a lightning fast access as you have to have with valves thus you can take your time digging it out
As for j valve would we have some kind of Double Hose long hose setup in this case
fdog did a really good job of summing up a fire SCBA. The only thing that I'll add is that in general, our cylinders are much smaller than those for SCUBA. A carbon fiber 4500 psi, 45 cubic foot cylinder is only 21 1/2 inches long and even though inverted, does not stand on it's regulator. The valve body is designed to be stood inverted and the regulators on most of the new scba are mask mount. I'm not aware of any new fire units that still have belt mount regs.
I'm not suggesting that inverted tanks can't work better in some situations, but I do think that they would subject the 1st stage to unecessary damage during boat dives or rough shore entries.
I'm not suggesting that inverted tanks can't work better in some situations, but I do think that they would subject the 1st stage to unecessary damage during boat dives or rough shore entries.
I have been experimenting with an integrated valve protector for inverted doubles. The current prototypes are shown in the attached photos. The guard is fabricated aluminum that incorporates a handle (for carrying topside) and heavy-duty bumpers so it protects paintwork on the boat. The next generation will be very similar with a few dimension changes and cleaner fabrication. Protection is excellent.
The isolation valve points to the butt and can easily be reached by bending forward in the water. I had them adjusted too low on one dive and simply bent forward and leaned left to swing the isolation valve into my right hand. Post valves can be reached without bending just like on many rebreathers. I used the Vindicator Valve Handles which indicate red for closed and green for open. They were a little long for the isolation valve so I cut about ½" off. They worked fine for the post valves.
The round-stock handle sticks out a little past the first stages so they might rub against the suit but cant see much force. The handle rests against the butt. DIN regulators are required for this design and the current layout is a little too tight. The trim is fine, though some weight could be removed with more fabrication effort and using tubing instead of solid round stock. It is very strong to the point and could be made from lighter plate as well.
The cylinders in the images are Faber LP-45s and HP-72s. My prime objective was to support progressive equalization. I also needed a rig that met SDI Solo requirements for redundant air that would satisfy charter boat skippers. They both have 190mm isolation manifolds instead of the standard 215mm. The HP-72s required custom bands since there was only ½" between cylinders. I used Captains technique to fabricate them.
I am still fooling around with hose routing. Carrying the assembled rig when you arent wearing it is a little awkward at the moment because hoses drag depending on if they are valve-up or down. The blue webbing at the top is a rescue/deadman ring. I have not given up adapting my Freedom plate to these doubles rigs but wanted to sort everything else out before tackling that project.
My favorite discovery of this whole project is the heavy-duty bumpers, which are modified hockey pucks. They drill like wood. A counterbore allows the head of a 3/8-UNC stainless carriage bolt to be well recessed and still have plenty of material so they will take serious abuse.
The isolation valve points to the butt and can easily be reached by bending forward in the water. I had them adjusted too low on one dive and simply bent forward and leaned left to swing the isolation valve into my right hand. Post valves can be reached without bending just like on many rebreathers. I used the Vindicator Valve Handles which indicate red for closed and green for open. They were a little long for the isolation valve so I cut about ½" off. They worked fine for the post valves.
The round-stock handle sticks out a little past the first stages so they might rub against the suit but cant see much force. The handle rests against the butt. DIN regulators are required for this design and the current layout is a little too tight. The trim is fine, though some weight could be removed with more fabrication effort and using tubing instead of solid round stock. It is very strong to the point and could be made from lighter plate as well.
The cylinders in the images are Faber LP-45s and HP-72s. My prime objective was to support progressive equalization. I also needed a rig that met SDI Solo requirements for redundant air that would satisfy charter boat skippers. They both have 190mm isolation manifolds instead of the standard 215mm. The HP-72s required custom bands since there was only ½" between cylinders. I used Captains technique to fabricate them.
I am still fooling around with hose routing. Carrying the assembled rig when you arent wearing it is a little awkward at the moment because hoses drag depending on if they are valve-up or down. The blue webbing at the top is a rescue/deadman ring. I have not given up adapting my Freedom plate to these doubles rigs but wanted to sort everything else out before tackling that project.
My favorite discovery of this whole project is the heavy-duty bumpers, which are modified hockey pucks. They drill like wood. A counterbore allows the head of a 3/8-UNC stainless carriage bolt to be well recessed and still have plenty of material so they will take serious abuse.
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