Words to put a smile on the face of any chiropractor 
i like to lock my knees and lift with my back in a jerking twisting motion
How to move double tanks around easily and safely---DIR needs to address this!
- Thread starter danvolker
- Start date
Please register or login
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
- Ability to post and comment on topics and discussions.
- A Free photo gallery to share your dive photos with the world.
- You can make this box go away
Rainer
Contributor
I used to dive in waters in that temp range (36-37F during the winter in MA). We tried several times to make our regs free flow by having two divers suck off one first stage (yes, two second stages). We never managed to get them to free flow... [These were environmentally-sealed diaphragm first stages.] Honestly, I think the better suggestion is to get some decent regs if you're diving in cold (<40F) water. In any case, simply adding doubles (without proper technical training) isn't going to help against managing free flowing regulators.
elan
Contributor
Well, I saw a couple of those cases myself here... Decend regulators do not guarantee they will never freeflow. And do you really need to pay 4K to guess that you need to shutdown your primary post to stop the primary reg flowing... My friend somehow managed to figure it out.
I had to shutdown my left post once because the backup started bubbling... 3 minutes later after re-pressurizing it was working like a breeze for the rest of the dive... In both cases those were either Flatheads or MK17. Both are decent sealed regs.
Many boats will not even let you on without redundant gas.
My friend somehow managed to figure it out.I had to shutdown my left post once because the backup started bubbling... 3 minutes later after re-pressurizing it was working like a breeze for the rest of the dive... In both cases those were either Flatheads or MK17. Both are decent sealed regs.
Many boats will not even let you on without redundant gas.
Rainer
Contributor
4K? And if you mis-diagnose the post failure, what then? I'm not arguing that redundancy isn't warranted for very cold water dives (which of course couldn't be further from the OP's discussion about FL), but if your training and approach to gas failures is as cavalier as "just shut down the offending post", well, you *might* be in that camp of those who grossly over-estimate their abilities to manage failures based on simply having doubles.
Redundancy isn't *just* about gear. It's about knowing how to properly make use of that gear (within the team). Those skills (through GUE) are first taught in C1/T1.
Redundancy isn't *just* about gear. It's about knowing how to properly make use of that gear (within the team). Those skills (through GUE) are first taught in C1/T1.
elan
Contributor
4k i how much one needs to save roughly for the course here.
I probably am the one who overestimates. But lets not forget that the context of the t1/c1 is totaly different, its overhead. We are discussing using doubles in the rec context which for this case means I have an extra tool to save my gas and having ability to get back to the upline minimizing risks associated with going straight up to the surface in some conditions like a current. The worst case is I can still ascend to the surface as a single tank diver. So as long as the double user remembers that doubles do not give them the ticket to tech diving and he is not ignorant enough to shutdown all his valves (if he did it would be a question how he got passed his fundies and he has nothing to do in t1 anyways) i see no problems. Having the doubles doesnot free up the person from other obligations like being a good buddy etc.
I probably am the one who overestimates.
But lets not forget that the context of the t1/c1 is totaly different, its overhead. We are discussing using doubles in the rec context which for this case means I have an extra tool to save my gas and having ability to get back to the upline minimizing risks associated with going straight up to the surface in some conditions like a current. The worst case is I can still ascend to the surface as a single tank diver. So as long as the double user remembers that doubles do not give them the ticket to tech diving and he is not ignorant enough to shutdown all his valves (if he did it would be a question how he got passed his fundies and he has nothing to do in t1 anyways) i see no problems. Having the doubles doesnot free up the person from other obligations like being a good buddy etc.
To just come back to original subject -
Back Pain Part II
Exercises, Stretches, and Nutrition for SCUBA Diving
Dont only do the internet stufff, but actually follow the crap both Mrs Jolie and Mr Cameron are talking about. It helps !
Now, will that be considered ahead of time by the poor rec divers who think diving doubles is cool and break their back because they are not DIR trained ?... it is a different debate.
Back Pain Part II
Exercises, Stretches, and Nutrition for SCUBA Diving
Dont only do the internet stufff, but actually follow the crap both Mrs Jolie and Mr Cameron are talking about. It helps !
Now, will that be considered ahead of time by the poor rec divers who think diving doubles is cool and break their back because they are not DIR trained ?... it is a different debate.
Rainer
Contributor
Yes, you have the tool, but as I keep repeating, you have to know how to use it. It *is* more complicated than "spin some knobs and shut off some regulators" (i.e. mostly what a valve drill teaches). Just adding an extra neck o-ring and regulator that can fail to the equation isn't helping if you can't also make use of them (and that nifty isolator).
For the non-overhead dives you're describing, having redundancy *is* nice, but (again...) it isn't simply a function of having extra gear.
I had similar feelings as you until I completed T1...
And yes, 4K is a *little* bit of an overestimate.
elan
Contributor
May be a *little* but not much, those are fairly recent prices here... Only gas itself for the student and the instructor share approaches 1k + accomodations, food etc. , gasoline or plane tickets - it all adds up.
Having said all that about the doubles, I lately was excercising an idea of diving with a single tank which will keep my rock bottom/emergency and breath of a stage, at least when I dive of a boat in the warm river. I cannot do 2 dives of a set of AL80/LP72 and diving LP108 is not always practical. It's 3 tanks on the boat instead of 2 but seems like a good compromize to me.
Nevertheless, I see I'm adding little value to the conversation so let's go back to the OP subject
I some time ago calculated that the weight of my single tank + extra lead and the weight of the pony was giving me almost the same dry weight as a set of doubles.
Having said all that about the doubles, I lately was excercising an idea of diving with a single tank which will keep my rock bottom/emergency and breath of a stage, at least when I dive of a boat in the warm river. I cannot do 2 dives of a set of AL80/LP72 and diving LP108 is not always practical. It's 3 tanks on the boat instead of 2 but seems like a good compromize to me.
Nevertheless, I see I'm adding little value to the conversation so let's go back to the OP subject
I some time ago calculated that the weight of my single tank + extra lead and the weight of the pony was giving me almost the same dry weight as a set of doubles.
Blackwood
Contributor
What Rainer is getting at, I believe, is that merely strapping a set of iso-manifolded (this is the DIR forum) to one's back does not provide gas redundancy. The manifold, like an h-valve, provides-access-to-gas redundancy.
Without the knowhow to diagnose and properly address a failure, you're essentially wearing a single cylinder with two ports holding twice as much gas and offering more than twice as many failure points. Like singles, a DIN o-ring failure will drain all your gas if you don't react properly, it will just take twice as long to occur. And once you react properly, you should be aware of what you have left and what is no longer functional.
(For DIR, replace "you" with "the team" in the previous 2 sentences)
That isn't to say a formal class is the only way to learn valve failures. Joe T's PDF and a mentor may be as good. But the idea that manifolded doubles in and of themselves provide inherent redundancy is flawed.
Without the knowhow to diagnose and properly address a failure, you're essentially wearing a single cylinder with two ports holding twice as much gas and offering more than twice as many failure points. Like singles, a DIN o-ring failure will drain all your gas if you don't react properly, it will just take twice as long to occur. And once you react properly, you should be aware of what you have left and what is no longer functional.
(For DIR, replace "you" with "the team" in the previous 2 sentences)
That isn't to say a formal class is the only way to learn valve failures. Joe T's PDF and a mentor may be as good. But the idea that manifolded doubles in and of themselves provide inherent redundancy is flawed.
Scott L
Contributor
This thread has taken more sharp turns than a steep mountain road...
Last edited:
Similar threads
