Inverted Tank Configuration

[East West]

I had the idea to use a invert tank configuration many years ago but was swayed by conformity . Back inflation buoyancy compensator did not conform either twenty years ago because the safety for all was the overriding factor. Sure there is a issue with proper regulator protection and customization . Do any members here invert and can share on this topic ? regards Charles

 

[DaleC]

Inverted cylinders don't seem to be that popular in North America but they are somewhat common in Britain. Some forums based there would be a good source of info.

Deputy821 who hangs out in the vintage section here owns several inverted rigs of Australian design (Porpoises) and he could give you lots of info I'm sure.

This is a link to the last thread I can recall on the subject here. I did a mock up of a doubles rig for that discussion to test hose lengths, valve access etc... photos in post #78

http://www.scubaboard.com/forums/technical-diving-specialties/337608-inverted-manifolded-twins.html

I have used a singles rig inverted several times and aside from the issue surrounding first stage protection (need a cage protector) I found no issues that could not be overcome. I put my primary reg on a 5' hose which routes just like a normal "hog looped" reg and my secondary on a standard length hose that routed up between the tanks to sit under my neck the same as a bungiied B/U. My SPG was on a standard length hose, bungiied against the tank half ways up and then clipped off on the left hip. From there it can be read just like a normal SPG.
The one issue I could not overcome is routing to the BCD with a standard length LP hose but then again I dove that set up sans BC so it didn't matter.

Hope that helps.

 

[Rich Keller]

I used an inverted tank as a bail out bottle when diving surface supplied. The only reason we did it that way was to be able to reach the valve to turn it on if it was needed. It was left off so that you did not accidentally use or loss your bail out air before it was needed. Only one hose came off the first stage and went in the side block of the helmet, no BC or SPG were used. Other then that I see no advantage in using this for scuba.

 

[captain]

I see several advantages to the an inverted set up. The valve is easier to reach, there is probably less chance of entanglement, the 2nd stage hose could be routed up the front with a right angle fitting on the second stage and would eliminate side to side pull on the mouthpiece.
The main disadvantage is a easy way to stand the tank up for donning.

 

[Akimbo]

My all-time favorite open circuit rig are the old AGA Divator 324s -- 300 Bar/4351 PSI, 2 cylinder, 4 Liters/bottle, about 80 Ft³. I first used them for bailout in sat because the bottles are only 110mm/4.33" in diameter, a big deal when getting through a 24" hatch and stowing in a crowded bell. The valve and regulator have the best protection I have ever seen. The hemispherical top-end of the cylinders have rubber bumpers that are great for lockouts or shallow wrecks. I am pretty short, and have no trouble reaching the valve.

The downsides are not many people can fill them to capacity and they are about 11 Lbs negative when full so would suck for tropical diving. Also the tapered valve threads are only 12mm/½" so O2 cleaning and inspection is a PIA. Trim in a 7mm wetsuit or drysuit is excellent.

 

[Rich Keller]

My all-time favorite open circuit rig are the old AGA Divator 324s — 300 Bar/4351 PSI, 2 cylinder, 4 Liters/bottle, about 80 Ft³. I first used them for bailout in sat because the bottles are only 110mm/4.33” in diameter, a big deal when getting through a 24” hatch and stowing in a crowded bell. The valve and regulator have the best protection I have ever seen. The hemispherical top-end of the cylinders have rubber bumpers that are great for lockouts or shallow wrecks. I am pretty short, and have no trouble reaching the valve.

The downsides are not many people can fill them to capacity and they are about 11 Lbs negative when full so would suck for tropical diving. Also the tapered valve threads are only 12mm/½” so O2 cleaning and inspection is a PIA. Trim in a 7mm wetsuit or drysuit is excellent.

I always wanted a set of those! I did pick up a manifold on Ebay that would do the same thing with 30s or 40s. Do you have any idea where I could find a Miller harness that was made to use with the Divator tanks?

 

[Teamcasa]

The other issue using an inverted tank is regulator damage when setting the rig down after diving. Most boats are setup for valve-up diving.

 

[muddiver]

The other issue using an inverted tank is regulator damage when setting the rig down after diving. Most boats are setup for valve-up diving.

Just turn your rig over.

 

[Akimbo]

The other issue using an inverted tank is regulator damage when setting the rig down after diving. Most boats are setup for valve-up diving.

They AGAs don't fit inside the single racks on the popular Newton charter dive boats, but neither do standard doubles. Like muddiver mentioned, it is not difficult with regular doubles to flip them 180° since they usually end up flat on the deck before stowing anyway. Regulator protection is so good on the Divator that it is hard to understand why the concept has not been emulated on larger diameter cylinders.

I always wanted a set of those! I did pick up a manifold on Ebay that would do the same thing with 30s or 40s. Do you have any idea where I could find a Miller harness that was made to use with the Divator tanks?

Last I heard, Ben Miller's heirs were still selling the harnesses and hats. You can probably get them from any of the commercial suppliers like Amron.

Miller Diving

I have not seen them, but I understand that XS-Scuba recently purchased Atlantic Diving Equipment who makes what appears to be a pretty good copy of the Miller harnesses plus tech-diver variations.

Atlantic Diving Equipment

I recently figured out that I can use my wing and backplate that is configured for a single on them. Photos attached. It is much easier than having separate wings and Backplates, let alone fooling around with nuts and bolts. For scale, it is a Freedom Plate and Oxycheq Mark V wing. Note that I wear the Divators backward from standard; with the valve handle inside (against my butt). It is even easier to reach, for me anyway, and that much more protected.

 

[dougchartier]

I was actually wondering about this. What capacity tank did you use for bail-out in commercial diving? And was it a steel or aluminum cylinder?

I used an inverted tank as a bail out bottle when diving surface supplied. The only reason we did it that way was to be able to reach the valve to turn it on if it was needed. It was left off so that you did not accidentally use or loss your bail out air before it was needed. Only one hose came off the first stage and went in the side block of the helmet, no BC or SPG were used. Other then that I see no advantage in using this for scuba.