Question Who sells backplates optimized for single tanks?

[Nemrod]

The following image and caption are from Huw Porter's Stainless Steel Single-tank SCUBA Backplate where the author is comparing a single tank plate he designed to a standard Halcyon backplate with STA:

Here, the backplates are flat against the floor, using Oxycheq single tank wings with identical centre sections.

Thanks for posting this. I remember seeing some W channel plates and you are eright, they do not perch the tank nearly so high as your photos show.

James

 

[rx7diver]

I found I need to set up my system like that to maintain trim. If I put my tank lower, my feet sink a bit.
Tried different configs and weight placements in the pool, but this way works for me.

Understood. It's a balancing act. When I wear my HP80 (20" long), I need to wear my cylinder really low to get things to balance out for me--which means I cannot easily reach my cylinder valve when I wear my HP80.

And I cannot comfortably wear my HP120 (28" long) as a single cylinder, since I need to wear it very high in order to get things to balance out for me. It would look almost like the pics we're discussing, and I would be hitting the back of my head on my reg's 1st stage.

FWIW, a Luxfer Al 80 is 26" long, an old-school 2,250 psig PST 72 is 25" long, a 3,500 psig PST HP100 is 24" long, and a OMS/Faber LP66 is 22" long. If you get a chance, you might track these down and see if one of these lengths will work better for you.

rx7diver

 

[Tournesol2000]

Understood. It's a balancing act. When I wear my HP80 (20" long), I need to wear my cylinder really low to get things to balance out for me--which means I cannot easily reach my cylinder valve when I wear my HP80.

And I cannot comfortably wear my HP120 (28" long) as a single cylinder, since I need to wear it very high in order to get things to balance out for me. It would look almost like the pics we're discussing, and I would be hitting the back of my head on my reg's 1st stage.

FWIW, a Luxfer Al 80 is 26" long, an old-school 2,250 psig PST 72 is 25" long, a 3,500 psig PST HP100 is 24" long, and a OMS/Faber LP66 is 22" long. If you get a chance, you might track these down and see if one of these lengths will work better for you.

rx7diver

Thanks. Great info. Much appreciated.

 

[Eric Sedletzky]

What we really need is for @Eric Sedletzky to start making Freedom Plates again. Eric, what happened with your experiments using lighter gauge steel for a lightweight plate. Lower material cost (?) and less strenuous to form seems like a winning formula to me. There's certainly demand.

To cut your work time per plate, how about a DIY version that's fully formed but unfinished? If I didn't already have one, I'd be happy to spend some time filing edges if that was the only way to get a plate.

Covid had a lot to do with it. It wasn’t me being a weird nut case about it, it was my laser cutter and all the supply issues, price spikes, etc. I was actually very busy during the whole ordeal doing my hand lettered signs and pinstriping business.
I never stopped working and actually it got busier because I specialize in trucks, and all the trucks people ordered from Peterbilt were coming in and needed signs. So being logistics things don’t stop.
That’s why I decided to concentrate more on that and it just took off. Plates are still in the back of my mind as a winter project when truck lettering slows down, if it slows down?
I actually have made a test plate for very small people and kids. It’s only 13” tall but it has 11” center holes. The idea is to be able to use a wing on either the upper set or lower set of holes for more adjustment. The difference is the plate uses a two piece harness instead of a one piece. The plate is experimental so far. I need to make sure it will work before I sell them. I need a victim though.
This plate is aluminum and has a tank angle wedge.

 

[Nemrod]

I found I need to set up my system like that to maintain trim. If I put my tank lower, my feet sink a bit.
Tried different configs and weight placements in the pool, but this way works for me.

You certainly make a good point. I have heavy feet also but try to use bouyant fins like my Scubapro Go-Sports or Eddy Fins. And, the cylinder being used has a big impact upon trim as aluminum 80s tend to go rear up as they deplete and some of our negative steel tanks remain butt heavy. I just move both cam band pouches to the top/forward cam band for such instance. But, yes, you are right.

James

 

[Nemrod]

I still don't see how this center channel effects the the placement in the X direction, if the diver is in horizontal trim.

It may not depending upon cylinder diameter. With 6.9 or 7.0 diameter tanks the center channel gets really tight near the first stage body when I pull the plate up where I like it to be. But what really limits raising the plate on the tank for standard plates is the STA. If you look at most STAs the upper cam band slots are way up top which limits greatly how high the plate can be positioned on the tank before the cam band falls off the shoulder of the tank. Long ago, I cut a second set of upper slots and jokingly called it the Nemrod (STA) Mod. Today of course you can find a few STAs so configured which eliminates to some degree one of my major complaints.

This photo is 14 or 15 years ago but you can maybe see my first stage is very close to centered between my shoulder blades and still I have plenty of grip area on my tank above the cam band.



James

 

[saxman242]

It may not depending upon cylinder diameter. With 6.9 or 7.0 diameter tanks the center channel gets really tight near the first stage body when I pull the plate up where I like it to be

I'm still not following how this would be any different on a flat plate. The plane tangent to the tank is still the plane tangent to the tank.

Cam band positioning I follow.
The cut-out on the flat plate you posted I follow.

 

[Nemrod]

I'm still not following how this would be any different on a flat plate. The plane tangent to the tank is still the plane tangent to the tank.

Cam band positioning I follow.
The cut-out on the flat plate you posted I follow.

You are right. I will admit when I am wrong or at least when I got my brain cells crossed. You are right. The tangency you describe is as you say. There is one thing, some single plates like the Freedom Plate curve away from that area providing more room. The VDH plate accomplishes the same thing by having the cut out which effectively increases the available space and ability to raise the plate higher on the tank.

It is the STA or cam band positioning and the tank being raised up away off my back I suppose that gives me the heartburn.

 

[saxman242]

Gotcha. I was trying to figure out what I was missing. I've contemplated scratch building a plate in the past and was afraid there was some nuance I was looking past.

 

[lowwall]

Covid had a lot to do with it. It wasn’t me being a weird nut case about it, it was my laser cutter and all the supply issues, price spikes, etc. I was actually very busy during the whole ordeal doing my hand lettered signs and pinstriping business.
I never stopped working and actually it got busier because I specialize in trucks, and all the trucks people ordered from Peterbilt were coming in and needed signs. So being logistics things don’t stop.
That’s why I decided to concentrate more on that and it just took off. Plates are still in the back of my mind as a winter project when truck lettering slows down, if it slows down?
I actually have made a test plate for very small people and kids. It’s only 13” tall but it has 11” center holes. The idea is to be able to use a wing on either the upper set or lower set of holes for more adjustment. The difference is the plate uses a two piece harness instead of a one piece. The plate is experimental so far. I need to make sure it will work before I sell them. I need a victim though.
This plate is aluminum and has a tank angle wedge.View attachment 737676

Damn that's pretty. I think it's funny you did the full polish job on an experimental plate.

Needs a tiny wing to go with it.