Doubts about tanks for wreck penetration
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DIR-Atlanta
Contributor
DIR typically does not require specific tanks for specific types of diving, except in the case of cave diving, where the LP-104/E8-130 is the preferred tank due to its unique combination of physical size and buoyancy characteristics.duartesss:
For ocean diving, the tanks of choice are either double aluminum 80s for wetsuit diving, or the lightweight steel tanks (E7-120s or similar) for drysuit diving. The specific tank size is usually dictated by the requirements of the dive, which is a combination of depth and duration. FYI, aluminum 80s are roughly equivalent in capacity to your 12L tanks, and E7-120s are roughly equivalent in capacity to your 16L tanks.
So there's typically no distinction drawn between "wreck" diving and regular ocean diving, insofar as the choice of tanks is concerned. It's all just "diving".
jim T.
Guest
I'm looking at buying tanks. Just to be absolutely clear then, I don't need to use double sets at all?
I have lower back issues and was considering a single 130 with slung 40cf pony and/or slung aluminum 80. Can I dive from any boat out your way without doubles? I'm not sure I can even use an LP 85 set yet as opposed to singles. Is there a DIR/GUE depth limit on singles with slung additional gas? Thanks.
I have lower back issues and was considering a single 130 with slung 40cf pony and/or slung aluminum 80. Can I dive from any boat out your way without doubles? I'm not sure I can even use an LP 85 set yet as opposed to singles. Is there a DIR/GUE depth limit on singles with slung additional gas? Thanks.
jim T.
Guest
So, are double sets required at all? Would a single with an H valve and slung pony and/or Al 80 be ok for depths to 150 ft. (more?)
I'm buying tanks but due to back surgery years ago, I don't know if I can even deal with packing LP 85 sets. Singles I can hand up to the boat easier.
Thanks for this additional clarification if you don't mind.
Jim
I'm buying tanks but due to back surgery years ago, I don't know if I can even deal with packing LP 85 sets. Singles I can hand up to the boat easier.
Thanks for this additional clarification if you don't mind.
Jim
jim T.:
I have never heard of a requirement for doubles in open water (you mention boat above), or size for that matter. The only things that matter in open water are using the right gas and the plan needs to account for usage/volume.
There is not a depth limit either.... but in real life a single tank at depth is not going to last very long. Add to that a slung stage as 'double gas' and a stage for travel and some deco gas..... you now have three bottles on your side.... better to have doubles on the back and one/two stages/deco bottles. Doubles are practical.
So no there is no requirement to dive doubles......but it helps..
Now, going into overhead environments, that is a different set of resuirements.
If you have back issues, you WILL mess your back up with doubles, even little LP85's. Take care of that back - once messed up, it's super tough and damn near impossible to get it back to strength. Lots of theoretical divers on this board opine the virtues of doubled HP130's, but in the field, they're backbreakers on a pitching dive boat or after an extended hike into your caving area. One little slip and you're in bad back country for a long stay.
It just cracks me up seeing all the tech guys using handtrucks to ferry their big tanks to their trucks at the dive shop because they can't really carry them very well. They NEVER mind when I offer to load their gear for them. And some of these guys over the years have retired from diving and a couple kinda went and died along the way.
So don't get hung up too much on what you read in here. Try to have some fun and not make it too work-like to go diving.
It just cracks me up seeing all the tech guys using handtrucks to ferry their big tanks to their trucks at the dive shop because they can't really carry them very well. They NEVER mind when I offer to load their gear for them. And some of these guys over the years have retired from diving and a couple kinda went and died along the way.
So don't get hung up too much on what you read in here. Try to have some fun and not make it too work-like to go diving.
Just to clarify on one of Meng_Tze's points... Deco would be an overhead environment.
Personally, I prefer adding an 11L (al80) stage to 12L (lp85 / hp100) tanks vs. having larger doubles. Its 1) more versatile combo to buy and have around and 2) allows me to split up the weight.
Personally, I prefer adding an 11L (al80) stage to 12L (lp85 / hp100) tanks vs. having larger doubles. Its 1) more versatile combo to buy and have around and 2) allows me to split up the weight.
jim T.
Guest
Sorry for the double post...
Yeah, Tom I definitely hear you about taking care of your back. That's exactly my concern. That's why I'm leaning towards a single 130 with a pony or two for bailout and maybe deco down the road with training.
I'd like the redundancy of doubles but I'll have to try 72s and 85s and see if I can even handle those. I can't think of any other solutions for enough gas for 130-200fsw. I don't have the aptitude to go to rebreathers for the foreseeable future-I want to stay with OC Scuba.
RJack. That's more along the lines of what I'm thinking I could handle.
I presume you're talking DOUBLE 80s/100s. I'm thinking that I could dive 100s from a boat but not sure I could get up the ladder. How much of a PITA is it to break modular manifolded doubles down to two singles for shore diving? How much time does it take on average? A modular manifold like Dive Rite's would allow me two H valves for use with the singles. Can manifolds be prematurely worn out with constant reconfiguring or is it just a matter of going through O rings a bit faster?
Thanks Meng Tze, that clarifies things for me.
Yeah, Tom I definitely hear you about taking care of your back. That's exactly my concern. That's why I'm leaning towards a single 130 with a pony or two for bailout and maybe deco down the road with training.
I'd like the redundancy of doubles but I'll have to try 72s and 85s and see if I can even handle those. I can't think of any other solutions for enough gas for 130-200fsw. I don't have the aptitude to go to rebreathers for the foreseeable future-I want to stay with OC Scuba.
RJack. That's more along the lines of what I'm thinking I could handle.
I presume you're talking DOUBLE 80s/100s. I'm thinking that I could dive 100s from a boat but not sure I could get up the ladder. How much of a PITA is it to break modular manifolded doubles down to two singles for shore diving? How much time does it take on average? A modular manifold like Dive Rite's would allow me two H valves for use with the singles. Can manifolds be prematurely worn out with constant reconfiguring or is it just a matter of going through O rings a bit faster?
Thanks Meng Tze, that clarifies things for me.
jim T.:
I dive both the tank configurations you mention with no problems.... I use a st.130/H valve and as needed a 19cf. pony for rec. and sport diving,,,super combo. I use a set of double st.85s for longer/deeper diving and my deco mixed gas diving along with deco bottles....piece of cake. You need to be concerned with your 'back surg.' issues....take care not to do anything that would re-injury your back first! I bet you will come up with a good combo....try barrowing from others and sampling a few set-ups first if possible.
DIR-Atlanta
Contributor
DIR doesn't really specify a depth limit for singles, but as I mentioned above, the tanks should be chosen so as to provide sufficient gas for the depth and duration of the dive. And if you are doing any overhead (cave, wreck, or deco), then a redundant reg system should definitely be used.
On the issue of large singles vs doubles, DIR is overwhelmingly in favor of doubles. They are typically more streamlined than a single tank of equivalent capacity, which makes them easier to swim and control in the water. Large single tanks have a tendency to "roll" which makes them more unstable in the water. Also, Y or H valves do not give you the same number of options as a manifold for dealing with a catastrophic gas failure. They are not even discussed in JJ's "Fundamentals" book, if that tells you anything.
I've (thankfully) never had to deal with back problems, so I can't provide much advice there, but I would recommend checking into a small set of doubles before deciding to go with a single.
Regarding so-called "pony" bottles, Cobb's Law applies - "if you think you need a pony bottle, then what you really need is doubles". Pony bottles are often nothing more than a rationale or excuse for some pretty sloppy diving practices (i.e. "it's OK to do this because I've got my pony bottle"). Many people use them as a substitute for a buddy, which is obviously not DIR.
DIR emphasizes buddy diving and proper gas planning and management (i.e. "your buddy is your backup"). The dive should be planned so that sufficient back gas is held in reserve for an emergency. This concept of "Rock Bottom" or "Minimum Gas" is covered pretty well in the Fundamentals course, and should be one of the cornerstones of any dive plan.
So the recommendation from a DIR perspective would be to go with suitably sized doubles for the dives that you are considering. If you cannot tolerate large doubles, then a smaller set combined with a stage bottle might work for you.
And I agree about taking care of your back - the diver himself is always the most important piece of gear, and you want to be sure that you are not doing anything to damage it. Consult with your doctor and tell him or her what you are planning to do with your diving. He or she may be able to make some recommendations, including an exercise program that would strengthen your back or otherwise mitigate some of the problems you are having. Also be aware that Option #1 (i.e. "don't dive") is always available - it's not worth it to risk your long-term health, just for a few minutes of pleaure on a dive.
Hope that helps - if you have any more questions, then please post them.
On the issue of large singles vs doubles, DIR is overwhelmingly in favor of doubles. They are typically more streamlined than a single tank of equivalent capacity, which makes them easier to swim and control in the water. Large single tanks have a tendency to "roll" which makes them more unstable in the water. Also, Y or H valves do not give you the same number of options as a manifold for dealing with a catastrophic gas failure. They are not even discussed in JJ's "Fundamentals" book, if that tells you anything.
I've (thankfully) never had to deal with back problems, so I can't provide much advice there, but I would recommend checking into a small set of doubles before deciding to go with a single.
Regarding so-called "pony" bottles, Cobb's Law applies - "if you think you need a pony bottle, then what you really need is doubles". Pony bottles are often nothing more than a rationale or excuse for some pretty sloppy diving practices (i.e. "it's OK to do this because I've got my pony bottle"). Many people use them as a substitute for a buddy, which is obviously not DIR.
DIR emphasizes buddy diving and proper gas planning and management (i.e. "your buddy is your backup"). The dive should be planned so that sufficient back gas is held in reserve for an emergency. This concept of "Rock Bottom" or "Minimum Gas" is covered pretty well in the Fundamentals course, and should be one of the cornerstones of any dive plan.
So the recommendation from a DIR perspective would be to go with suitably sized doubles for the dives that you are considering. If you cannot tolerate large doubles, then a smaller set combined with a stage bottle might work for you.
And I agree about taking care of your back - the diver himself is always the most important piece of gear, and you want to be sure that you are not doing anything to damage it. Consult with your doctor and tell him or her what you are planning to do with your diving. He or she may be able to make some recommendations, including an exercise program that would strengthen your back or otherwise mitigate some of the problems you are having. Also be aware that Option #1 (i.e. "don't dive") is always available - it's not worth it to risk your long-term health, just for a few minutes of pleaure on a dive.
Hope that helps - if you have any more questions, then please post them.
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