Using back mount doubles as single tanks

[Underwater Tourist]

I custom re-machined my backplate to support single, banded-double, or independent-double setups (singles and IDs with only cambands required - no adapters or STA).

Do you mind attaching a couple of pictures?

 

[-JD-]

Do you mind attaching a couple of pictures?

Started out as a SS dogbone, reverse-profile, Golem Gear Stream plate. Subgravity bought Golem Gear out recently, and it is now available here: Golem Stream Backplate - SubGravity

I don't have pics available currently rigged with the cambands, but if you compare the 1st and last pictures: you can see:

• The upper upper inner-channel camband slots were lengthened down.
• The upper harness mounting wings were notched at the bottom.
• The lower harness mounting wing has a triangular cutout.
• Additional/expanded holes were created for mounting weight and liftbag pouches and for mounting side-mount bungees.

When mounting IDs:

• The upper cambands pass under the notches in the upper harness mount and through the inner-channel slots.
• The lower cambands pass through the triangle cutouts and through the inner-channel slots.

When mounting a single:

• The top and bottom slots on the outside of the channel are used.

When mounting banded doubles:

• Good old fashioned wing nuts or disks will do it using the (now elongated) holes and lower slot.

 

[rob.mwpropane]

Started out as a SS dogbone, reverse-profile, Golem Gear Stream plate. Subgravity bought Golem Gear out recently, and it is now available here: Golem Stream Backplate - SubGravity

I don't have pics available currently rigged with the cambands, but if you compare the 1st and last pictures: you can see:

• The upper upper inner-channel camband slots were lengthened down.
• The upper harness mounting wings were notched at the bottom.
• The lower harness mounting wing has a triangular cutout.
• Additional/expanded holes were created for mounting weight and liftbag pouches and for mounting side-mount bungees.

When mounting IDs:

• The upper cambands pass under the notches in the upper harness mount and through the inner-channel slots.
• The lower cambands pass through the triangle cutouts and through the inner-channel slots.

When mounting a single:

• The top and bottom slots on the outside of the channel are used.

When mounting banded doubles:

• Good old fashioned wing nuts or disks will do it using the (now elongated) holes and lower slot.

Wow, nice work

 

[Underwater Tourist]

@-JD- for Coz trip, I assume you used two al80 as IDs, do you switch the wing for single tank vs ID diving? Or did you find one that’s usable for both?

 

[-JD-]

@-JD- for Coz trip, I assume you used two al80 as IDs, do you switch the wing for single tank vs ID diving? Or did you find one that’s usable for both?

The structure of the camband mounting, requires very open camband slots in the wing for use with IDs. Many of the newer Dive Rite wings have an open cross center structure that works beautifully for it.

I dove that entire trip on ID Al80s and used a DiveRite Rec XT wing which is a hybrid Doubles/Singles wing. Rec Series - Dive Rite

It worked beautifully with the IDs, but I only have one short, shallow dive with it on a single setup. On my upcoming trip to Cozumel in December, I will likely be diving the rig with singles and banded-doubles.

I am trying to find a good deal on a dual bladder Classic of the same style with more lift for use locally with double HP100s.

 

[Nick_Radov]

I personally agree, although I think statistically it's safer to do away with the isolator. More people would be alive today if there was no isolator at all. (as per memory of a discussion hashed out on here by people with much more experience then I). An o ring extrusion is way more rare than a roll off or mishandled valves.

What are the actual statistics? I don't believe that you've actually done the math on this. Let's see some numbers. Every incident report that I have read which involved an inadvertently closed isolator valve could have been prevented by following the correct pre-dive sequence.

The GUE Pre-dive Sequence

As you’d expect, Global Underwater Explorers (GUE) has a standardized approach to prepare your equipment for the dive, and its own pre-dive checklist: the GUE EDGE. Here explorer and filmmaker Dimitris Fifis preps you to take the plunge, GUE-style.

gue.com

 

[Gone for diving]

Every incident report that I have read which involved an inadvertently closed isolator valve could have been prevented by following the correct pre-dive sequence.

I am pro isolators,

But if the guy that started the hog method doesn't use one, I will take notice and definitely think about,

involved an inadvertently closed isolator valve could have been prevented by following the correct pre-dive sequence.

How about adding in, the actual dive,

the sequence is to check all valves, when running out of air or breathing hard????

During the dive, that's what matters,

 

[rob.mwpropane]

What are the actual statistics? I don't believe that you've actually done the math on this. Let's see some numbers. Every incident report that I have read which involved an inadvertently closed isolator valve could have been prevented by following the correct pre-dive sequence.

The GUE Pre-dive Sequence

As you’d expect, Global Underwater Explorers (GUE) has a standardized approach to prepare your equipment for the dive, and its own pre-dive checklist: the GUE EDGE. Here explorer and filmmaker Dimitris Fifis preps you to take the plunge, GUE-style.

gue.com

Nick... you are fun to duel with Challenge accepted!

Everyone can say after the fact they "should" have done X, Y, Z, but the reality is there are numerous cases of deaths with a closed isolator. I don't think any of those people did so intentionally, and most would be alive with a solid manifold. The chances of anyone becoming complacent or not knowing the "righty tighty, lefty loosey" by heart in a panic situation is much greater then a blown tank o ring or burst disc, PLUS, the isolator itself introduces failure points that otherwise wouldn't be there.

I personally (as stated before) am comfortable with an isolator, but that previous discussion on here was eye opening, and believe it or not, guys with 1000's and 1000's of dives all sort of agree that a solid manifold would be safer overall.

Here's the thread, very interesting perspective that goes against your thinking.

Crossbar and isolator valve: do they help?

Manifolded twins have long been the gold standard for safety for technical dives. I wonder how much safety benefit the isolator valve actually provides. Have there been any accidents or incidents where the ability (or lack of it) to close the isolator valve made a difference in the outcome of...

scubaboard.com

 

[Twiny]

Nick... you are fun to duel with Challenge accepted!

Everyone can say after the fact they "should" have done X, Y, Z, but the reality is there are numerous cases of deaths with a closed isolator. I don't think any of those people did so intentionally, and most would be alive with a solid manifold. The chances of anyone becoming complacent or not knowing the "righty tighty, lefty loosey" by heart in a panic situation is much greater then a blown tank o ring or burst disc, PLUS, the isolator itself introduces failure points that otherwise wouldn't be there.

I personally (as stated before) am comfortable with an isolator, but that previous discussion on here was eye opening, and believe it or not, guys with 1000's and 1000's of dives all sort of agree that a solid manifold would be safer overall.

Here's the thread, very interesting perspective that goes against your thinking.

Crossbar and isolator valve: do they help?

Manifolded twins have long been the gold standard for safety for technical dives. I wonder how much safety benefit the isolator valve actually provides. Have there been any accidents or incidents where the ability (or lack of it) to close the isolator valve made a difference in the outcome of...

scubaboard.com

Hi, one thing to remind is that when diving twinset the spg has 2 missions : not only displaying the pressure but checking if the manifold isolator is open or closed : In a DIR configuration, the spg is on the left and the LH is on the right (anyway never on the same side). If during the dive the spg still displays the start pressure of 200 bars (or whatever) then the diver immediately knows that the isolator is closed. A simple check of the spg easily allow to double check that the isolator is open.
Having an accident because of a closed isolator is only possible if it comes together with negligence or poor training.
Starting a dive with a closed isolator can happen but tec diving and not checking your spg during a dive will never be safe whatever the configuration

 

[rob.mwpropane]

Having an accident because of a closed isolator is only possible if it comes together with negligence or poor training.

Hey man, I'm not disputing anyone's "theories", I'm simply saying there was another perspective presented here on Scubaboard that was eye opening (at least for me). Read the thread and then see if you still feel 100% the same way.

I believe you are free to dive however you want, but foolishly thinking that "one way" is THE way without ever having discussions about it is a little close minded. That type of dogma isn't necessarily healthy (imo).