Slow down and dive a little. A blog about cave diving in Mexico.
Coming ashore at Lizard Island Australia

An Approach to mounting stage bottles or bailout bottles with a backplate.

This morning there was a post on Cave Diver’s Forum asking:

When I’m swimming a stage, horizontal of course, the bottom hangs down too low to my liking. I use an aluminum 80 but the bottom doesn’t float up at all. My lower clip is wrapped around the handle strap to take up all the slack, but I still have to hold the bottle up when I’m close to the bottom. Anybody ever use a bungee to hold it in line with the body? ...

To start, I cave dive CCR back mounted, doubles and side mount. The following information focuses on carrying stages or bailout bottles in a back mounted configuration. My current approach has been heavily informed by my experience diving sidemount. I have gone through at least three major evolutions in this process and it is still evolving. This article is based on my personal experience. I have stolen or purchased ideas from a number of people I dive with here in Mexico and in New Jersey. Those people are: Steve Bogaerts, Andrew Driver, Patrick Widmann, Rob Infante, Nando and others. Sorry if I don’t credit you properly. And remember to click on the images!

I remember asking myself the very same question over and over. When I started to sling a bottle, I learned how to do it from my Deco Procedures class and the north east wreck divers. The approach was to buy/make a sling kit for the respective bottle and mount the bottle to your chest d-ring and the waist strap d-ring. Depending on the buoyancy of the bottle, the position of your waist d-ring and the length of your clip lines, this might put it sticking up at a 45 degree angle or leave it dragging in the mud. It was never streamline with my horizontal body. However, in NJ I could get away with this non-sense. I knew it wasn’t right. So I started to look for another solution. When I moved to Mexico and started to dive my CCR in the caves, the inefficiency of this system was magnified. I remember picking up the tank to pass small areas. I remember the tank swinging to and fro as I kicked. It was maddening.

Armadillio Side Mount SystemThe second evolution was to purchase a butt-plate. I selected the ArmadilloCCR Sidemount System. I mounted the butt-plate to the back plate on my rebreather. I decided to use a neck clip instead of the bungee. My neck clip is just a loop of bungee with a clip attached. I put the neck clip on the tank before I install the regulator. I found this easier to deal with then the bungee loops. As soon as I mounted an AL 80 to this setup, I discovered I was woefully leg heavy. The butt-plate transfers the negativity of the tank to your thighs. Neck clip for stage bottle.It was intolerable. It made cave diving frustrating, because I was fighting with my trim the whole time. I like to be able to float in mid water without making adjustments, this was impossible.

As luck would have it, I dropped my CCR head and broke it. While my unit was being repaired, I had to dive backmount which forced me to use a buddy bottle or a stage bottle. I was in sling bottle hell again. However, I started to smarten up. After a couple of dives, I put my butt-plate on my doubles back plate. That failed to live up to the promise. The door handles were in the way. I couldn’t reach my butt ring and my trim was off. However, the tanks were sitting in a much nicer position.

After some discussion with Patrick and going through training with Steve, I finally figured out the problem.Customized Aramdillio Butt-Plate The door handles are the wrong solution. They put the tanks too far back on my body and are inflexible. They can’t help but be in the way.

For evolution three I removed the door handles and installed two d-rings on the butt-plate. The d-rings move the bottle down my body just enough to balance me and put the tank in the correct position. Eureka! The mobility of the d-rings allows me access to my butt ring. Without the door handles gearing up is much easier and the d-rings are much more accessible.

The d-rings are in the correct position when the tanks are negative.Custom adjustable d-ring campared to a standard d-ring. However, when you breathe down the tanks to about 1500, they become buoyant and you need to move their clip position. Or suffer tanks that are bouncing off the ceiling. I use adjustable homemade d-rings on my waist strap for this job. I picked this one up from Steve.

One more thing I learned is, "Balance is key." I make an effort to always carrying two stages, one on each side. If all I need is 80cuft of gas, then I carry two Al40's. If I need more gas, then I add bottles in a sequential way. I up one bottle to an 80 and then the other bottle. I have not found a balanced and streamlined solution to carrying only 1 bottle. If all I need is a Al40, then I suffer with one bottle. An AL40 doesn't throw my balance off wildly.

My rig will continue to evolve as the diving I do demands different configurations and optimizations. I believe there are at least two ways to approach a problem like this: trial-and-error or training. The trial-and-error approach is valid and is time tested, but damn it takes a long time to figure things out and we have a finite number of dives available to experiment. I would prefer to spend my time diving and not hating my gear. If you don’t live in cave country, how will you ever have the time to get it right?

The training method takes years of experimentation and distills it down into the state-of-the-art. It has been demonstrated to me over and over, that this is the most efficient route. I could have gone out and self taught side mount, but after going through training I now know why that is stupid. I estimate that training evolved my skill and gear configuration by at least 50 dives or more.

Find an instructor who is practicing and teaching the state-of-the-art in your desired disciple and schedule a couple of days with him/her. You will be amazed how some of these fundamental issues are resolved immediately and how your diving improves dramatically.

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