Feedback on tank positioning.

[Subcooled]

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Beautifully clean hose routing, but can you feather that valve for any significant time? With the opposite hand I guess. Just curious.

Would those Poseidon first stages allow such a neat routing, even if the valve knobs pointed more down? (which would make them more exposed of course)

 

[tbone1004]

location of the valves is not ideal for feathering. If I had to feather for any length of time they would come out of the bungee and hang from the d-ring on the neck leashes.

If the tanks were rotated with the valves farther down, which is something I would prefer to do, this was the first dive on this rig and the attachment points were a bit different than my normal rig, then the first stages would be rotated a bit more to put the SPG's in the same slot under my arm pit. This was done without a long hose because I was diving independent doubles this trip and didn't want to take them out of my box. The left tank wouldn't matter because all three hoses come straight up towards my arm pit so the left is irrelevant. The long hose and drysuit inflator would have less of a bend at the tank crown and would be fine. If I have time tonight I'll put them on a tank and take a picture.

 

[kr2y5]

I just remembered there's also the variant with outlets facing inwards and knob digging into the armpit, as shown at about 4:00 minutes in this video, what do you think about that?

 

[Subcooled]

I have been diving with outlets facing inward (knobs down; love it) or one outlet facing inwards, the other facing outwards (again knobs down), and outlets facing up (knobs on the sides; awkward for me). I have never actually pointed the valve knobs up.

Mr Kakuk has dived a lot more than me and he has chosen to point the knobs UP in that video. Either he manages to reach those knobs easily (e.g. by putting the opposite hand in the armpit) or then the risks caused by awkward feathering are lesser than the risks caused by a knob pointing out or down.

Testing and brains are always preferred over canonical answers.

 

[tbone1004]

Brian also isn't using that reg setup anymore....

This is what the Poseidon would look like if valve was at a 45* angle instead of straight out. This was the only tank in the house at the time, so imagine the knob is the post, and the post is the knob, and since it's normally a stage bottle i didn't do anything to the lower cam band, so ignore that bit too.
You are looking at the tank essentially from my rib cage. This is slightly less ideal for this particular regulator because the HP port is perpendicular to the valve outlet. This would work really well with the Hog D3's though since the HP ports are facing forward a bit. The first stage rotation is solely to get the HP hose in the right spot under my armpit where there is no stress on it from my arm.

 

[Doby45]

I have not "yet" gotten into sidemount, but it is quickly coming down the tracks and my plan to start with was to mimic Kakuk's setup also but with Hog D1s. Plan to use the DiveRite XT secondaries with a left feed secondary from the left tank, hate hoses behind my neck. SMS75 is the planned rig and weighted 80s when I am diving near home and steels when I am down in cave country..

 

[kr2y5]

the regs are right, but the lower attachment should be about an inch behind the valve stem with the first stages down. You have regs right for valve down, and attachment points right for valve up

Ok, another round. Moved the attachment as suggested, shortened bungees by 2 inches. Added an extra bungee for the 50% bottle on the left.

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• kr2y5
• Jun 7, 2016

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• kr2y5
• Jun 7, 2016

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• kr2y5
• Jun 7, 2016

First, something obviously went wrong with the bottle. Bottle rigged like in backmount, trying to put it in the front so it's easier to verify. Lower attachment too short if tucked, too long if untucked. A bit surprised that the bottom is dragging so much, normally bottom is floaty. Perhaps bungee was too tight. In that case, shouldn't the bottom be a bungee as well? Not sure how it's supposed to work when used with standard backmount rigging. I clipped it to the front waist D-rings, by the way.

Even without the bottle, I feel like the tank bottoms are hanging too low, debating whether I should just shorten the bottom attachment a little. That will probably shift tanks to the front, not sure how desirable that is. SPGs don't seem to stick out as much as before anymore, but maybe that's still not acceptable.

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• kr2y5
• Jun 7, 2016

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• Jun 7, 2016

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• kr2y5
• Jun 7, 2016

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• kr2y5
• Jun 7, 2016

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• kr2y5
• Jun 7, 2016

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• kr2y5
• Jun 7, 2016

 

[DevonDiver]

Poseidons are pretty sh1tt% for feather breathing. They free-flow very powerfully. I've seen this happen in real-life, with a deco reg, and the 2nd stage pretty much ejected from the mouth each time the valve was feathered on. In the end, the diver needed two hands to perform the technique..... one to feather the valve, the other to physically old the regulator in his mouth.

Seeing that.... put me off Poseidons for life.... as deco or sidemount regs....

 

[DevonDiver]

First, something obviously went wrong with the bottle. Bottle rigged like in backmount, trying to put it in the front so it's easier to verify. .... A bit surprised that the bottom is dragging so much, normally bottom is floaty.

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• kr2y5
• Jun 7, 2016

Doink!

Look at Rob Neto's article on stage configuration/steamlining..... or see how Steve Martin recommends it.

No 2nd bungee on the stage/deco. If worn underneath (my preference), use a 6" bungee to boltsnap from the bottom. Band configured 1-2" above where your cylinders bands sit. At the top, another bolt-snap on a tight bungee around the valve neck. This results in beautifully trimmed tanks.

 

[tbone1004]

Andy, I agree. Luckily the technique is a bit different. With feathering the valve, it's usually due to a HP seat failure on the first stage causing excessive IP which leads to a freeflow in the second stage. We all know this. With the Poseidons, they have the OPV on the first stage which removes the need to feather and will likely be no less efficient in a real world scenario due to the losses associated with the freeflow. In a training scenario, you shouldn't breathe the reg down anyway since that can promote water ingress. The violent initial purge is not present on the Cyklons fwiw as they are a normal downstream design fwiw. For stage/deco regs, I leave my Jetstreams on and pressurized and just lift the diaphragm off of the needle so they won't freeflow. Haven't had an issue yet. They require legit effort to get to purge with the diaphragm lifted off.

Backgas-you can shorten the clips, just raise the cam bands a bit and it will be fine. I use a 0 length leash on the bottom and my attachment point is measured to be the same distance from the center of the valve knob as the distance from the center of the bungee attachment point to the point on the rail that it clips in. Due to the Contour having the rails it does, I'd measure to the bottom side of the rail as opposed to the middle and you should be OK.

Regarding stage and deco bottles, for cave diving, most of us don't care how the deco bottle looks since it isn't being carried while travelling. Quite often it will just get the top clipped off and the bottom will hang out wherever it decides to chill out during deco. Sometimes it will get clipped off to the crotch strap d-ring. In the ocean, I just don't fill them all the way since I don't like O2 higher than about 2400psi anyway and at that point the bottoms of the tanks will usually float up and into you. They won't be wedged in there since the butt is ever so slightly positive, but it helps. What I think would be a great solution would be to have a longer bungee that went up between the main bottle to the rail and clipped in. Problem here is it can't really be done without rolling upside down. Stage attachment is something we are all still hashing out....