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Back inflation with VDH back plate on Twin Cylinders

Posted: Thu Jul 31, 2014 2:43 pm
by Superlite
In putting together a set of twin 100's I have a dilemma. I intend to use a BIU on this system. Has anyone had any experience using the XS Scuba back inflation unit with a set of twin cylinders? Is there any special way of mounting the BIU to the VDH back plate for twin cylinders? :?:

Re: Back inflation with VDH back plate on Twin Cylinders

Posted: Thu Jul 31, 2014 4:39 pm
by rhwestfall
Not an XS unit, but a DR....

I set the tank bolts so they are "flush" with the face of the VDH plate. I then use some SS "Book Screws" to attach the plate (I'll post a link - just away from it right now). I also have implemented a derlin spacer as the plate is flexing too much to my liking and/or is pinching the wing.

Darn slick if I may say so.

see my post/picture on page 7 of this: viewtopic.php?f=26&t=7167&start=90

update: here is the link to fasteners:
Bolt Depot: http://www.boltdepot.com/Sex_bolts.aspx

Re: Back inflation with VDH back plate on Twin Cylinders

Posted: Thu Jul 31, 2014 5:42 pm
by kiwidiver
I used these.
I have been using a VDH plate on doubles for a while now.
See my post here

viewtopic.php?f=47&t=7027

Re: Back inflation with VDH back plate on Twin Cylinders

Posted: Sat Aug 02, 2014 1:33 am
by kworkman
Find some bands like these. They work great.

Image

Image

Re: Back inflation with VDH back plate on Twin Cylinders

Posted: Sat Aug 02, 2014 11:29 am
by Nemrod
These with red Locktite and all thread:

Image

Or just use a carriage bolt from the plate up rather than from the bands down as with a bent plate.

The wing has to be wide enough to put the bladder outside the tanks footprint. I users DR doubles wing and a old Seatec that I split the inner section so it will spread to accept small double tanks.

Nem

Re: Back inflation with VDH back plate on Twin Cylinders

Posted: Sat Aug 02, 2014 11:35 am
by Superlite
Nemrod seems to have a really great set of fasteners, where did you find them?
My twin 80's have the modern pack half moon mount. My soon to be ready 100's will be getting a harness from Alan. So will be slotting the bands for the harness soon. :) :mrgreen:

Re: Back inflation with VDH back plate on Twin Cylinders

Posted: Sat Aug 02, 2014 11:52 pm
by Nemrod
Superlite wrote:Nemrod seems to have a really great set of fasteners, where did you find them?
My twin 80's have the modern pack half moon mount. My soon to be ready 100's will be getting a harness from Alan. So will be slotting the bands for the harness soon. :) :mrgreen:

Those are just tee nuts, a variation thereof. I got those at the local Ace hardwear man. They are stainless steel.

James

Re: Back inflation with VDH back plate on Twin Cylinders

Posted: Sun Aug 03, 2014 9:05 am
by Superlite
Looks like a trip to my favorite ACE hardware store is in order.
Thanks James :)

Re: Back inflation with VDH back plate on Twin Cylinders

Posted: Sun Aug 03, 2014 10:23 am
by captain
If you can't find stainless ones at Ace try West Marine.

Re: Back inflation with VDH back plate on Twin Cylinders

Posted: Mon Aug 04, 2014 2:23 pm
by Superlite
Didn't think of West Marine. I'll check both Ace and West Marine.

Re: Back inflation with VDH back plate on Twin Cylinders

Posted: Mon Sep 15, 2014 1:15 am
by 9fingers
Nem, I would love to hear in more detail what size double tanks and wings you find works...

Quote: I users DR doubles wing and a old Seatec that I split the inner section so it will spread to accept small double tanks.

I've got a double-tank/double-hose project I'm trying to sort out.

I'll going to PM in case you miss this.

Cheers, Tim

Re: Back inflation with VDH back plate on Twin Cylinders

Posted: Mon Sep 15, 2014 7:28 am
by rhwestfall
AL63's on a DR CCR wing. The short tanks allow you to wear them lower and the offset elbow on the wing is a real plus.

Re: Back inflation with VDH back plate on Twin Cylinders

Posted: Mon Sep 15, 2014 11:29 pm
by Nemrod
9fingers wrote:Nem, I would love to hear in more detail what size double tanks and wings you find works...

Quote: I users DR doubles wing and a old Seatec that I split the inner section so it will spread to accept small double tanks.

I've got a double-tank/double-hose project I'm trying to sort out.

I'll going to PM in case you miss this.

Cheers, Tim
I use either my Seatec horse collar or a DR Rec wing with 45 pounds of lift. The other wing I have used is an old Seatec Seahorse wing that I split to allow a wider center platform to accept double tanks. I bought the DR Rec wing after those experiments.

Contrary to the norm, I do not exclusively dive double hose regulators. My current solo doubles rig is a Hammerhead plate with independent 72s and Conshelf regulators. I also dive a twinset of 50s on a Sherwood center outlet manifold with double hose regulator and a reversed single hose on the left post.

Prior to busting my leg, now a little over four years ago, I had cut my own plate and I was experimenting with various doubles rigs and wings etc. Now, I have lost interest in it as I have no use for double tanks since they are too heavy and just too, too much for me to carry and I see no point in them for my current diving.

The vdh mini-plate can carry small 6.9 twins but it is really too narrow for twins. Of course it is, it was designed to be optimal for singles. I would prefer a center channel for a doubles plate and a little more width. I think Captain made a plate several years back for doubles, a flat plate with a center cutout for the double hose. Mine was similar but without as much of the cutout. That itself is a discussion. I have played around with eliminating the cutout by simply shortening the plate and using a conventional single piece webbing but the issue there is that large people will run out of "arm" room so then a larger shoulder loop has to be left in the harness which then compromises stability of the rig.

I was just fooling around on Table Rock last week and did a 120 foot dive on the Kimberling Bridge, I used a cave filled Faber LP85, Freedom Plate, Mach V 30 wing and I had a aluminum 80 for redundancy slung with a Conshelf. I ran my PRAM on the back tank. I did not use either of my Krakens because they are brand new, only pool tested, sorry, I only do deep solo with a regulator I have used previously on several dives, a rule.

The modern bent doubles plates are as good at carrying doubles as they are horrid with a single tank. The only thing is they force a high tank position especially when used with a double hose regulator. And, when the tank is positioned as low as one might like it, leaving the regulator issue aside, the top band falls of the tank shoulder.

So, the short answer is I have not solved the doubles rig and after busting my leg, I have no need for doubles. :|

Nem

Re: Back inflation with VDH back plate on Twin Cylinders

Posted: Sat Oct 04, 2014 3:49 pm
by 9fingers
Lots of good ideas here. James thanks for the thoughtful reply.

I too had a significant injury many years ago-completely ruptured my left achilles tendon and one year later chainsaw injury to the same leg. I get around fine mostly, but heavy tanks to and from the shore dives here (and heavy backpacking) aren't as easy or fun as they used to be.

I've been thinking of a way to mod a set of mini-doubles and use them for most of my diving here, cold water with drysuit and double hose regs. I have a pair of steel OMS 45's and the pair is manageable at about 35 pounds empty without the manifold. I prefer these 5.5" diameter tanks to anything wider. I would like to get them a little closer together than most of the manifolds I have allow...I have USD's solid bar and J-62, a Nemrod solid bar, Voit & Sherwood Selpac multiple-piece manifold/valves. I'm looking into having some J-60/J-62 valves modified with shorter CGA fittings, or using some modern rebreather tank valves with DIN ports and a Drager DIN crossbar (Tee fitting) manifold that I found last year on a European vintage site.

It would be easier to use a vintage set of European Draeger or Poseidon 7 liter tanks or a modern equivalent, something similar in size and weight to the OMS 45's but those are hard to come by and harder to get hydro'd with their metric neck threads.

After I get the manifold/valves figured out then I'll concentrate on the harness, possible using my VDH plate, and bands. Anyone have a lead on where I can get custom bands made?
I've tried Jurassic Carp on fleabay and haven't got any replies from the peanut king or Vic/detroit mudpuppy who used to make bands for Scrubaboard forum members.

Cheers, Tim

Re: Back inflation with VDH back plate on Twin Cylinders

Posted: Sat Oct 04, 2014 7:48 pm
by antique diver
Nemrod wrote:

....The modern bent doubles plates are as good at carrying doubles as they are horrid with a single tank. The only thing is they force a high tank position especially when used with a double hose regulator. And, when the tank is positioned as low as one might like it, leaving the regulator issue aside, the top band falls of the tank shoulder.
So, the short answer is I have not solved the doubles rig and after busting my leg, I have no need for doubles. :|

Nem
I think that the top band issue of being too high on the tank shoulders might be solved by just lowering the top bands and drilling a new, lower hole on the back plate. Is there any reason that wouldn't work other than the regulator maybe hitting the back plate? Could you just modify the top of the back plate to accommodate the reg? Or is all that pointless if you aren't diving with doubles anyway?