Thoughts on setting up backmounted independent doubles

[Boston Breakwater]

So, I am curious how people who dive backmounted independent doubles set up their gear.

Rather than dive sidemount in areas where twin sets are not available, I would like to set up a set up independent doubles. The concept is to be able to switch out tanks on a backplate easily. This eliminates the use of traditional stainless steel bands and bolts.

I am aware of the ap diving adapter, but am interested in other alternatives.

My thought is that some plates like the Xsscuba highland and the Ist plates have four upper and four lower tank band slots. The two slots on either side of the plate are cut so that the bend is between them. Would it not be possible to mount a band on either side, top and bottom, for a total of four bands for the two tanks?

Since the band utilizes the bend in the plate, it would seem to lend stability to the mounting not unlike the way a single tank adapter achieves its greater stability.

The regsets could then be mounted on the valves with the appropriate second stages, pressure gauges, and inflators. This could be like a set of doubles regulators with the addition of a pressure gauge for the right side tank. Obviously, since they are not manifolded, you would have to practice sidemount breathing techniques.

Xsscuba is unaware of anyone who has done this before. I would have tried it earlier this year, but their plates are back ordered.

No need to turn this into a manifold versus independent twins discussion.

View attachment 618370

Hello. Interesting post......Thanks.
Cheers.

 

[tursiops]

This case illustrates the big advantage of a manifold over indies.

And also illustrates that sidemount is conducive to feathering....

 

[lowwall]

So my preference for Independent doubles is for a different reason but just as important for me.

I can fill my own tanks - but I am a fireman and I am required to fill in a fill station which means fill each tank independently.

Mount the left tank upside down? Solves the reach issue and as a fireman you are presumably already familiar with bottom-mounted valves.

Probably unworkable on the boat though.

 

[Basking Ridge Diver]

Mount the left tank upside down? Solves the reach issue and as a fireman you are presumably already familiar with bottom-mounted valves.
Probably unworkable on the boat though.

So years ago Akimbo on this board - had one of his friends making a "guard" so you could mount the tanks upside down and protect them from being damaged - I never got one of the guards but the idea was intriguing.

Anyway I digress - the point was not that I could not reach the valves - the point was I could not fill doubles in the fill station - so I took my manifold off and started diving independent doubles. I would not change my style now - and the flexibility of being able to swap tanks in and out during a surface interval gave me an appreciation of independent doubles.

YMMV

 

[lowwall]

So years ago Akimbo on this board - had one of his friends making a "guard" so you could mount the tanks upside down and protect them from being damaged - I never got one of the guards but the idea was intriguing.

Anyway I digress - the point was not that I could not reach the valves - the point was I could not fill doubles in the fill station - so I took my manifold off and started diving independent doubles. I would not change my style now - and the flexibility of being able to swap tanks in and out during a surface interval gave me an appreciation of independent doubles.

YMMV

I guess "mount" was the wrong word. I was thinking of them as independent. One up, one down in cam bands.

 

[garyh]

I think you would still want the AP blocks. They sit between the cylinders and help a lot. You can do this with three slots, one in the centre line. I think that is how my Spiro BCD is set up.

Back in my Guts days I sold a few set ups for this.
Btm line was 2 Sta's bolted back to back with ss eyebolts between them to bolt to the backplate.
Doesn't help with the left/right valve thing though.

 

[lowwall]

How about extra long cam bands and a couple of these spacers? Aquatec SP-100 Scuba Tank back pace spacer | Scuba-Do.com Note the metal bars in the end of the spacers to route the bands through.

I also see there were at least two companies making independent double cam band sets like the following photo that are no longer available. I guess there's not much of a market for this.

Found one in the UK that's reasonable priced (before shipping anyway) and says they are in stock. Webbing Twinning Bands | Northern Diver

Edit: there's an old thread here showing your original idea with a DSS plate Independent backmount doubles with DSS backplate

 

[tbone1004]

@lowwall you use normal cam bands with those spacer blocks as an FYI. If you used extra long ones you'd be locking both of them down together and would get a little screwy

 

[divezonescuba]

I hadn’t thought about this earlier until I saw some of the pictures.

The use of the nylon tank Cam bands would also easily allow for AL80s and LP50s To be independently twinned.

 

[lowwall]

@lowwall you use normal cam bands with those spacer blocks as an FYI. If you used extra long ones you'd be locking both of them down together and would get a little screwy

It looks like you can do it either way. The point of the bars in the end of these particular spacer blocks is to keep everything aligned when using one long cam band to hold both tanks. As the accompanying text says (in not-great English):

Used with two cam bands or ... for extra-long band and block as a set... The key to the system is an interlocking. A quick-release tank band passes through each component.

I suspect two sets of bands would be much more stable if your backplate has the necessary 4 slots.