The Octopus Conundrum

[Nemrod]

Hi James, just out of interest, what is you SRMV? I consider mine reasonably low, at 0.35 cu ft/min, but would not generally dive with a mini-tank, as I appreciate my bottom time so much. I solo with a 19 cu ft pony, enough for me for all recreational depths. I often do not take my pony for dives above 60 ft.

I was sitting in the first day of class, Adolescent Psychology, the professor walked in and first up asked to know everybody's IQ. So right up this eager dufus on the first row (where else) raises his hand and spouts of some number. Remarkable, imagine, he had the lowest IQ in that whole class. And I think that was the point of the lecture he had planned, something about Bell Curves or some such nonsense. So, to be clear, , you will not get me to play this game. Gotta know when to hold them, know when to fold them and know when to lay them cards down. This is a time for me to hold.

Okay, it is lower than that but your .35 is, surprise, a good planning number for conservative open water diving for me. As to the mini-tank comment, again, if the tank is large enough to complete the planned dive with the planned reserves then it is large enough and if it is not then I go bigger.

Guys, y'all really hung up on my using a 63cf are not you? Look at it this way, for decades the steel 72 was the go to tank. That size was said to be "just right" because the average diver could not get into deco with it, yeah right. Something about a Bell Curve, huh? A steel 72 is at working pressure 65.8cf. You really think that little 3cf is going to keep me from bouncing against deco limits and up shallow, well, it is apparent that you guys are not 61yo because there are things that limit bottom time that are not related to air consumption.

You did know that SCUBA diving is a competitive sport, right? At least it is with the vintage diver group. Last one in and first one out is a dead rotten fish. If you think for one second that Nemrod is going to give away my SRMV numbers so Luis and Herman can sandbag me you are wrong, and you momma is wrong too.

I am not very smart, I am just very smart at not being very smart. I was gifted in that regard.

N

 

[scubadada]

I was sitting in the first day of class, Adolescent Psychology, the professor walked in and first up asked to know everybody's IQ. So right up this eager dufus on the first row (where else) raises his hand and spouts of some number. Remarkable, imagine, he had the lowest IQ in that whole class. And I think that was the point of the lecture he had planned, something about Bell Curves or some such nonsense. So, to be clear, , you will not get me to play this game. Gotta know when to hold them, know when to fold them and know when to lay them cards down. This is a time for me to hold.

Okay, it is lower than that but your .35 is, surprise, a good planning number for conservative open water diving for me. As to the mini-tank comment, again, if the tank is large enough to complete the planned dive with the planned reserves then it is large enough and if it is not then I go bigger.

Guys, y'all really hung up on my using a 63cf are not you? Look at it this way, for decades the steel 72 was the go to tank. That size was said to be "just right" because the average diver could not get into deco with it, yeah right. Something about a Bell Curve, huh? A steel 72 is at working pressure 65.8cf. You really think that little 3cf is going to keep me from bouncing against deco limits and up shallow, well, it is apparent that you guys are not 61yo because there are things that limit bottom time that are not related to air consumption.

You did know that SCUBA diving is a competitive sport, right? At least it is with the vintage diver group. Last one in and first one out is a dead rotten fish. If you think for one second that Nemrod is going to give away my SRMV numbers so Luis and Herman can sandbag me you are wrong, and you momma is wrong too.

I am not very smart, I am just very smart at not being very smart. I was gifted in that regard.

N

My brief inquiry was not meant to put you on the defensive, just trying to better understand your choice of cylinder. My most frequent dives are drift, with an average depth of about 55 feet, for about an hour an a quarter. For me, a small cylinder would almost always be inadequate though it appears to meet your requirements on some of your dives.

Actually, I am 61 years old, but, diving is not a competitive sport for me.

Good diving, Craig

 

[Searcaigh]

What??? I always travel with my pony. Most often a 13cf but if I want to I can bring my 27cf and never had a problem. I just pack them in my checked bag with the valve removed along with a copy of the TSA regs on compressed air bottles. I screw in the valve when I get there and get a fill and I'm good for the duration of the trip.

I have so much gear with me that adding a pony for my traveling would start to cause issues, in particular when flying around or to and from Middle East destinations.

 

[MXGratefulDiver]

If you are diving a single rig, Hog set up, with a slung pony, and there is a failure of your main supply, to which regulator does your the muscle memory take you?

Depends on the nature of the failure. I'd most likely go for the necklace ... but if it's a first stage failure that won't do me much good now, will it? That's fine ... there's plenty of time for plan B at that point. Or would that be plan C?

Just wondering because if on a double set you would go to your bungeed second and shut down a post. If on a single rig, will muscle memory take you to the bungeed necklace or to the pony? Are you wrapping the pony reg or keeping it bungeed to and integral to the pony? Just curious. I do not believe you are depending on rote memory and muscles do not really have memory. But I understand what you are saying.

I haven't dived back-mounted doubles in at least five years ... if I'm in doubles it's side-mount. But I dive often enough to be able to switch mental gears without too much difficulty. It's like my cars ... I own two almost identical Honda Elements. One's an automatic transmission and the other's a standard shift. And I use them both fairly frequently. So yes, I do occasionally find my left foot unconsciously going for a clutch pedal that isn't there ... or my hand instinctively reaching for the shifter when it doesn't need to ... but it's an easily recoverable error. Same thing happens when diving ... I sometimes will find myself instinctively reaching for gear that belongs to the "other" configuration ... but it only takes a second to realize the error and make a correction. Certainly nothing that would get me in trouble in an emergency. Like driving, I dive often enough to be able to make those corrections almost without conscious thought.

Speaking of a rare failure of a main regulator or main supply. I am going to breath that supply until it gives me nothing before transitioning to my pony regulator or with an independent doubles rig, before going over to it. But, I will burp the pony reg to make sure it is ready to rock and roll when I do switch, if I need to, because gents, Nemrod is on his way to the surface. My muscle memory says, no air, go up now!

N

I tend to favor bigger tanks, so I don't have to worry about that problem. That, and I've so ingrained gas management into my dive plans and profiles that I rarely ever give air supply a thought during the dive. My last solo dive was on a 119, with an AL40 pony. I went to 92 feet, averaged about 58 feet, and my total dive time was 76 minutes. I came up with about 1200 psi left in the tank. If I'm going deeper or staying longer, I'll use my sidemount rig and bring along two 100's ... that's more than enough gas to do the dive without worrying about "no air" ... it's just how I roll.

... Bob (Grateful Diver)

 

[Laurie S.]

Don't you find that Air2's drag on the bottom if you need to be close to the bottom?

No, never, it stays very close to my body. And, I'm on the bottom a lot because I'm a photographer. I have a much bigger problem with the retractor on my compass getting stuck between two rocks.

 

[Dr. Lecter]

If I'm diving single tank lately, I'm in the 'single 2nd stage on a 22" hose and necklaced' camp, simply because I'm zipping around relatively shallow sites solo on a DPV. No need to worry about sharing air and an additional 2nd stage would either free flow easily as I zoom about or require the kind of in-line shutoffs I put on ponies/BO/deco bottles.

What I really need to do is get rid of my wing and LPI hose, taking the 1st stage down to one LP hose and one HP hose for the SPG, just to see the DM reactions.

 

[diver 85]

Already hooked up so why take the time to unhook it??

 

[Nemrod]

Already hooked up so why take the time to unhook it??

Since you ask, because it serves no purpose for a solo diver, it is not redundancy and only serves to be a failure point and extra stuff to drag along. An octopus second serves as redundancy for your buddy, the solo diver has no buddy so therefore needs instead a fully redundant system such as a pony, isolation doubles or independent doubles or a plan for the surface. And I know you know all this.

Thus my original poorly presented question, would an Air II/integrated octo-inflator increase substantially the failure risk over a standard power inflator mechanism, considering that I would eliminate the octopus from my first stage. Would be net, net or a reduction in failure points?

N

---------- Post added March 10th, 2015 at 08:46 PM ----------

No, never, it stays very close to my body. And, I'm on the bottom a lot because I'm a photographer. I have a much bigger problem with the retractor on my compass getting stuck between two rocks.

Similar here, even though it is not a big problem, I tire of the slung bottle holding me off and banging my camera and just plain dragging it around, as small as it is. But Dumpster Diver has provided me several suggestions for a mini-pony back mounted.

---------- Post added March 10th, 2015 at 08:51 PM ----------

My brief inquiry was not meant to put you on the defensive, just trying to better understand your choice of cylinder. My most frequent dives are drift, with an average depth of about 55 feet, for about an hour an a quarter. For me, a small cylinder would almost always be inadequate though it appears to meet your requirements on some of your dives.

Actually, I am 61 years old, but, diving is not a competitive sport for me.

Good diving, Craig

I am, for real, sorry you misunderstood my slightly warped sense of humor, I was not offended and I am still not telling.

But, again, you guys seem hung up on my preferred 63cf tank. Okay, make it a 163cf and I just tote around 100cf I never need. Never mind it being the size of a dirigible. Seriously, the dive you described, I would do with adequate reserves on a 63. It is what it is. If it is big enough to complete the planned dive with adequate reserves then it is enough and if it is not then I go bigger.

Did you freak out at 61? I mean, 60 was no big deal but I am kind of getting upset over 61, now a few days away. Oh well, game over I guess, nothing left to do but hang around scubaboard and aggravate people. Woe upon me.

N

 

[NWA395]

What is your redundant system when solo diving? Admittedly, I do not use one above 60 feet (more or less). But assuming you do?

Like I said in my original post, I am considering an Air II or integrated inflator/octopus second for both buddy and solo. This for travel diving so I do not have to reconfigure or tote extra gear for rigging my favored set ups for solo or buddy.

N

Nemrod,

With a non diving wife and dive buddies on different schedules I often dive solo, probably 50% of the time.

Dive depths limited to 45' and dive times limited to 60 min or turn the dive at 1/3.

As you know it does require a bit of self discipline to ensure a good self check of gear and sticking to your dive plan.

No redundant air supply but 19cf pony is on the radar...but even then, solo will be a max of 70 based on local conditions

 

[scubadada]

Did you freak out at 61? I mean, 60 was no big deal but I am kind of getting upset over 61, now a few days away. Oh well, game over I guess, nothing left to do but hang around scubaboard and aggravate people. Woe upon me.

N

No, went diving, was lucky enough to be in Florida for this birthday