Tank backpack

[Bob DBF]

I find one quite useful when checking out gear in the pool where a BC is completely unnecessary, unless that is what you are testing.


Bob

 

[Basking Ridge Diver]

When I learned - it was a J-valve and a horse collar. Still usable today...

 

[Eric Sedletzky]

I find one quite useful when checking out gear in the pool where a BC is completely unnecessary, unless that is what you are testing.


Bob

me?
No I mean't bottom scrubs, zinc work, and prop unfouling. I'm one of the few dinosaurs that still uses tanks. However, it's a very small part of the business and I only have a few accounts so I can't justify a hookah system right now. The plastic pack and a 72 works perfect for that.

 

[Bob DBF]

Well Eric, if I was in that line of work, I'd do the same thing. I've got a lot more 72's than I have loose change. The reason I got a BP/W and later a Freedom plate was that it was a lot closer to an old plastic backplate and horsecollar than a jacket.


Bob

 

[NAM001]

That's the type of rig I started with in the late 60's . It was a Healthways. Full 1/4" wet suit 50$ 72 tank w/Jvalve 50$ and single hose regulator 50$ USD Rocket fins, knife and backpack 20$ each. All new from monkey wards.

 

[DA Aquamaster]

Scubapro still uses a very similar hard pack in some of their BCs, like the Glide X.

Way back in the 1970s they just used a plate on the back side of the hard pack to sandwich the BC between the hard pack and plate, and it's an approach that still works well today.

Over the years, (once J valves fell out of favor) Scubapro moved from a metal band to nylon webbing and a metal cam buckle to reduce bulk. The advantage of the hard pack is that the stiff plate curved to your back provided much more stability than the soft pack used in other BCs in that era - and the same thing is true today, with very few manufacturers using a soft pack in a BC intended primarily for single tank back mount operation.

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The pair of sex nuts used to connect the hard pack and plate on the Scubapro hard pack also had hollow centers to accommodate tank bolts, so that hard pack worked with doubles as well.

In the picture the OP provided, you'll notice the semicircular section at the bottom of the plate. There is also a matching round depression in the pack that is hidden from view behind the metal cam band. Those two areas are solid molded areas where a hole can be drilled to accommodate tank bolts for double tanks. The hole spacing is narrower than the standard hole spacing used on modern technical diving doubles, but you just need to adjust one of the bands on the tank to get them to work.

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Along side their original jacket style BCD, Scubapro also manufactured their BCP (Buoyancy Control Pack), which used a 45 pound wing sandwiched between the hard pack and back plate. The Scubapro BCP and the Watergill At-Pac were the first commercial back plate and wing systems.

The At-Pac used a much wider larger flat profile plate that incorporated a compartment in the back along the spine that could be filled with lead shot about 1/4" in diameter. Any left over space was filled with marbles to keep the shot from shifting. A trap door was located at the bottom of the compartment to allow the lead shot to be released via a release pin in the event the diver had to dump weight. Bridging was a problem even with the smaller diameter shot, so you needed to load the marbles in first once you determined the volume of shot and marbles needed.

I had both, and the At-Pac had some other issues such as the LP inflator hose running inside the corrugated hose, and an inadequate OPV that could cause the wing to rupture. I used one for awhile before switching to a used Scubapro BCP instead. Most of us BCO users figured out you didn't want to ditch weight in a decompression situation anyway, so for cold water dry suit diving with heavy undergarments, we'd drill a hole in the top of the molded hard pack on our BCPs, fill it with lead shot, then plug the hole. They held about 11 pounds of shot and it served the same function as a V weight does today.

You could still show up on a technical dive boat today with a Scubapro BCP and have a functional technical diving rig. The modern technical diving plates just offer a little more stability with the wider plate, and they keep the tanks about a 1/2" closer to your back.

 

[Jim Lapenta]

You could use that with something like the BC below. It was a gift from a student. The original inflator was too corroded to use but it still holds air. I'm going to be playing with it in the pool over the winter with an al80 and my freedom contour plate. I'd like to find a working original style inflator without the LP hose connection.

 

[drbill]

Used one back in the 60s myself. In fact, I didn't use my first BCD until 1989 when it was required gear as part of a Cousteau dive group. Had to disconnect that one's inflater hose as the inflater kept leaking.

 

[dumpsterDiver]

You could use that with something like the BC below. It was a gift from a student. The original inflator was too corroded to use but it still holds air. I'm going to be playing with it in the pool over the winter with an al80 and my freedom contour plate. I'd like to find a working original style inflator without the LP hose connection.
View attachment 221363

That was my original BC.. The brand/model was Seatech Puffer, as I recall.

 

[spoolin01]

The old ScubaPro model with the additional thin plate, coupled with a small wing, makes for a good tropical travel rig.