12 replies to this topic

[ScubaDadMiami]

Since making the switch over to CCR diving, I have also changed over to carrying my bailout bottle by using a modified sidemount setup rather the side slinging my bottles. Here is a quick comparison and recommendation regarding these configurations.

In a traditional SLINGING system the diver carries bottles clipped to the shoulder d-ring and the waist d-ring. Ideally, this will place the slung bottle to the side of the diver in a parallel position to the body, keeping the configuration streamlined. In reality, however, this configuration usually places the slung bottle's valve somewhat ahead of the diver, and the tail floats upward somewhat (unless the diver uses weights or negative tanks to lessen this effect), preventing the bottle from being as streamlined as the ideal seeks to achieve.

In the traditional SIDEMOUNT system (for deco or bailout, not for full sidemount setups), the front of the deco/bailout bottles are suspended from the backplate via bungee cord, which goes around the tank valve, so that the valve is carried just behind the diver's arm pit. The tail clip goes to a d-ring that the diver wears as part of an extension panel attached to the bottom of the backplate. (There are also entire harness systems that the diver can use instead of attaching this hardware to the backplate.) This system allows the sidemount bottle to ride quite parallel to the diver's body, and allows the bottle to ride in the slip stream of the diver's shoulder. This setup provides very minimal drag in the water. However, it also has some less than ideal issues that go along with the positives.

Due to having the deco bottle hung from bungees, which can hang down a few inches from the backplate in order to place the bottle in the proper position, some divers say that they can feel the bottle waving around as they swim through the water. Also, the position of the tank neck will be so much farther to the rear of the diver than the side slung bottle that it requires additional skill to reach the regulator second stage, the tank valve, and the pressure gauge (there are ways around the pressure gauge issue). Also, should the diver need to remove the bottle during the dive, this will take additional skill, effort and time.

With a MODIFIED SIDEMOUNT system, the diver clips the bottle to the shoulder d-ring rather than making use of the bungee suspension. The tail clip goes on the backplate extension as in the standard sidemount system. With this modified sidemount setup, it will place the deco/bailout bottle just slightly forward of the standard sidemount setup, and your kit will not be quite as streamlined as in full sidemount. However, it is more streamlined than with a side slung system. Also, it makes the regulator and valve on the bailout bottle easy to reach, and it will make seeing your pressure gauge on the bailout bottle easier. It is about as easy to remove and replace as in side slinging.

The modified sidemount setup is a great compromise between the traditional slinging and the traditional sidemount methods. Once you try it, you won't go back to side slinging!

On the left, I include a photo of my open circuit side slung configuration. In the middle, I show two photos of modified sidemounted bottles. On the right I added a diagram of the traditional sidemount system. The modified system would only use the butt extension to the backplate.

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Edited by ScubaDadMiami, 11 April 2006 - 01:35 PM.

[6Gill]

Great post...
Last weekends dive there were two Insperations on the boat.I observed that they were having issuse with their stages(mostly on the surface).This would have made their lives alot easier.The KISS has no counter lungs(unlike yours) so the front area is more open,but I will try this set up soon if for no other reason than to know.

[ScubaDadMiami]

I am now experimenting with a full sidemount setup. However, My first try at a full sidemount setup was a complete disaster.

My plan was to do a couple of easy dives no deeper than 30 feet/9 meters so that I could make some practice runs. While everything seemed to fit on land when setting up my kit at home, I was way, way off with the sidemount setup in the water.

First, it was quite difficult to clip on the tanks aboard the dive boat. So, I elected to just clip my tanks onto my shoulder d-rings (using my tank neck slider bolts), and then I would deal with moving the tanks to their final position after entering the water. However, after hitting the water, I could not get everything worked out on the surface. So, I cut myself a break, figuring I could descend and then play with everything on the bottom until getting used to the setup.

I think it took almost five minutes for me to put everything together on the bottom. Even then, I could not pull the bungees down far enough to work the valves into them properly. (I had them too short). I ended out clipping my tank neck clips onto the bungees rather than having the bungees around the valve knobs. At least this way, I was able to do some dives. Unfortunately, this meant abandoning thoughts of practicing removing and replacing the tanks underwater. I guess that will come later.

Actually, once things were stabilized like this, I was able to have a pretty nice dive. It was great not to have the tanks sticking out ahead of me and getting in the way of my arms. I definitely put forth less effort to move through the water. It even felt easier to backwards kick. The tails were in perfect position. I just need to take care of the top of the tanks, and then I should be in business.

Although I didn't really get a chance to practice removing and replacing my bailout bottles, I did do several drills. So, my time in the water was not wasted.

I am wondering if just lengthening the bungee a bit but continuing to clip the tank neck clip onto the bungee might not be a better way for me to go here.

While my first attempt at this setup did not go well, I do think it will be worth it once I figure it out.

[ScubaDadMiami]

I met some bubblemaker friends of mine today at Jules' Undersea Lodge, in Key Largo (Florida Keys). While one purpose of my visit was to join my friends for some confined water skills practice, my primary objective was to work on making the adjustments to my sidemount configuration.

This place is ideal because it has a platform, in just about two feet of water, a great place to stop for adjustments to equipment after which I can get back in the water to see what the next adjustment should be.

I have made some progress with the sidemount setup, and I still have some difficulties.

On the one hand, making the tail strap so short that the tank would stay at my side (aluminum 40) also made it very difficult to clip the bottle back onto the sidemount panel at the bottom of the backplate. I ended out testing the setup by trying to remove and replace the bottle. Then, I would stop at a steps and platform area, remove my kit, and make adjustments based upon how this drill felt. After this, I would give it a try again, repeating the process several times. I might still have it about an inch too long. So, the tail still tends to float up a bit.

The valve end of the tank was entirely too low, requiring some stops to tighten up the main bungee. I found that I could clip the tank shoulder clip onto the bungee, and that I like doing this better than having to deal with the traditional sidemount setup with the bungee. I am still playing with this aspect of things because I want the bottle to rest up higher but I still want to be able to pull it down to remove and replace using the clip.

Even with things not exactly as I wanted it, I did a test run across the bottom to see how the tank would sit compared to my prior sling setup. I found that my belly would rub against the bottom before the tank would start to touch. Also the tank was behind my shoulder, out of the way. It was very easy to swim through the water this way. So, I think I am getting closer to my goal here.

I am going to try another change or two to see how that goes before settling on the final configuration.

[gcbryan]

Great post...
Last weekends dive there were two Insperations on the boat.I observed that they were having issuse with their stages(mostly on the surface).This would have made their lives alot easier.The KISS has no counter lungs(unlike yours) so the front area is more open,but I will try this set up soon if for no other reason than to know.

I think I'm misunderstanding your post. KISS does have a counter lung but it's back mounted. Is that what you mean?

[6Gill]

Great post...
Last weekends dive there were two Insperations on the boat.I observed that they were having issuse with their stages(mostly on the surface).This would have made their lives alot easier.The KISS has no counter lungs(unlike yours) so the front area is more open,but I will try this set up soon if for no other reason than to know.

I think I'm misunderstanding your post. KISS does have a counter lung but it's back mounted. Is that what you mean?

Thanks Grey both for spotting that and I now know that someone actualy reads my posts

What it should have said was unlike SDM's CCR or the Insperation has an over the shoulder counter lung while the KISS has a back mounted counter lung so the front area is more like the BP/wing in appereance. Because of this I can see why on over the shoulder counter lungs the sidemount set up makes alot of sense.

[ScubaDadMiami]

Okay, it is confirmed: I am definitely insane. I spent this lovely evening in my community pool (high rise living), with my backplate, a 40 tank and my sidemount setup (no other equipment except mask), doing breath hold bottle removal and replacement drills (no sense in wasting pefectly good gas or scrubber for this), making some more adjustments to my setup. I think I am getting close now. (Of course, I have had this foolish notion before, too. )

I was able to remove and replace pretty quickly. Regulator and offboard plug-in hose easily deploy and stow. I went to the bottom of the pool, touching my chest along the bottom without having the tank touch. So, the upper portion of the tank is getting in the right position just under my arm pit, behind my shoulder.

Just to feel the difference, I switched back to clipping onto my shoulder d-ring and my left waist d-ring; the bottle touched the pool floor about two inches before my chest would touch. So, there is definitely a difference in how the bottles ride in one style verus the other.

I still have to pull the bungee like the dickens when clipping the head of the tank to the bungee (I have placed a d-ring on the bungee, and I clip the tanks to it at the head using a traditional setup), and it does not always go perfectly. However, I think I am now ready to give this a try on some real dives.

The retrieval bungee that goes to the shoulder d-ring might also be a bit long. However, I want to do a test dive or so before playing with that.

The aluminum tanks still float up a bit in the tail (even though full and in fresh water). So, I will have to see how that goes in salt water. I might be able to shorten the tail strap another half inch or so, but I want to do some dives like this before making the last fine adjustments.

I am going to give this (another) try this weekend.

[ScubaDadMiami]

It worked! I did my first dive today after revamping the sidemount set up, and I had success. I removed and replaced my sidemount tanks several times while in full kit, and everything seems to be coming together . . . finally.

I did not wind up using the standard configuration. The main difference between my set up and the standard ones is that I added a stainless round ring onto the end of the bungee loops than hang from the backplate. It is to these rings that I clip standard rigged stages.

Now, any buddy that carries a standard stage can be passed my bottle, easily using it in the standard sling fashion. I can also accept his/her bottle on this set up.

To deploy, just trace the retrieval strap (which goes from the round ring to the shoulder d-ring) to the ring, put a thumb through it, pull, and then clip the tank (shoulder) slider bolt cilip onto the ring. Let go, and the bungee pulls the tank up under my arm pit and behind my shoulder.

I'll need to do a few more dives before settling in on the final adjustments. However, the basics are there, and everything seems to work well.

At this point, the onlly issue that came up was concerning the deployment of the off board plug in hose. I can't see it behind the counterlungs, and it can take a bit of doing to find it by feel. I ended up moving the connector up so that it sticks up above the tank valve and regulator, making it easier to find by feel. Seems to work. I'll need to make a few more test runs to see what I am going to do about this.

Progress!

[6Gill]

I belive the quote your looking for..."I love it when a plan comes togather"

[ScubaDadMiami]

Another two dives today. It was pretty great. I went through some restrictions inside of a wreck just to see how the sidemount configuration would fit compared to slung bottles. The objective was not so much to go to places that would require removal and replacement; I was just trying to get a general feel for any differences in tighter spots.

I also removed and replaced both bottles a number of times. The left side is a fast and easy. The right side, due to my EPIRB on my waist strap, is a little trickier and takes a little longer.

No problems reaching the tank valves or the pull dump for the wing. It really feels quite streamlined in the water, and it seems that it takes less effort in kicking to move about. When I got to the boat, I was able to unclip and pass up the bottles to the boat crew so that I wouldn't have to climb out fully kitted.

I am sold!

[6Gill]

I am sold!

So what kinda price does a scuba bum like yourself fetch these days?I hope you went to a nice home

[ScubaDadMiami]

Yesterday was a good day. I did my first dive that involved removal and replacement of the sidemount tanks to pass wreck restrictions, and that went very well.

We dove on a wreck with a about a 50 foot hallway that is very narrow. So, at the entrance, I took off one of my two sidemount bailout tanks, holding it with my hand as I pulled and glided my way through the stretch. Emerging into a larger cabin at the end of the hall, I easily clipped back on the bottle, and I continued on my way.

On our second dive, I broke out my scooter, and I scootered around for 30 minutes or so with the sidemount tanks for the first time. I honestly can't say that I felt any less drag scootering with the sidemount tanks compared to the side slung tanks. However, things went well, and I had a fun time.

At one point, I scootered between a couple of doorways on the wreck, zig-zagging since one was offset from the other (not a straight shot through them). No problems, and no clanking or touching the wreck with the tanks as I passed through. Very nice.

[ScubaDadMiami]

Another dive with sidemount slung bail out bottles on Sunday. There were a few interesting turns along the way.

The current was very strong as we made our way down the line to the wreck of the Guy Harvey, located in 145 feet of water off of Pomano Beach (north of Fort Lauderdale), Florida. My buddy was in the process of conducting a test on his new Evolution rebreather to see how long the CO2 scrubber system would last when compared to his Inspiration model rebreather. He had previously put about 4.5 hours on the scrubber material.

This was my first live drop from a dive boat since making the switch to CCR and sidemounting. No issues to report there (though I did turn to descend a little prematurely, leaving a little too much gas in my drysuit for my liking).

I hit the float ball line at only about ten feet of depth, grabbed on, and began to pull my way down to the wreck. At about 100 feet or so, I stopped for about 30 seconds to regain my strength while making sure that my respiration rate did not climb any higher than it already was. It was hard work!

Finally, I pulled myself down to about 120 feet, and I let go of the line, falling behind a lee side of the upper wreck structure. My buddy and I gave the okay to each other, and we proceeded down to the main deck of the wreck.

While passing over some structure, my bail out bottle regulator slider bolt clip hooked onto some fishing line. This was no drill; I would have to remove the bottle to either unwind or cut the line while still trying to catch my breath and deal with the current, which was largely reduced by the wreck structure ahead of me, at the same time. It took a little longer to accomplish than I would have liked. However, I removed the bottle, traced the fishing line, and I was unable to unwind it without having to cut anything. I replaced my bailout, re-stowed the regulator (which had gotten pulled out a bit from the fishing line), and advanced to enter the wreck's engine room.

Rather than remove the bottles for entry, as I did on my prior wreck dive above, I decided to roll to my side, threading through a narrow opening into the ship's interior. It was pretty narrow from side to side, but it was as tall as a standard doorway vertically. I slipped through the crack, and I was inside. The sidemount bottles went through without even touching.

Once in the engine room, I rolled back to the prone trim position. I needed to do a bit of buoyancy adjustment, and I drifted slowly down to the floor. I added some gas to my wing, and I moved back to where I wanted to be in the water column. Hey, I said that I still have to work on buoyancy issues with the CCR, didn't I? At least I made sure to touch the bottom so lightly that I didn't blow silt all over the place.

I went around the engine, and I turned to look back at my buddy. No buddy there. So, I reversed course, and I exited the wreck. My buddy came over some structure, and he was breathing off of an open circuit regulator. What the . . . ?

He signalled that he was low on something. I thought that he meant the oxygen tank. So, I offered to pass him my extra tank with oxygen in it. Rather than accept it, he gave me the thumb. So, I turned and we proceeded to head to the ascent line.

The current was still running briskly as we made our way up the line, pausing for our decompression stops starting at 70 feet. I could feel the last of the divers on the wreck below us unwrapping the grapnel and chain from the wreck. Finally, as the anchor came loose from the wreck, we were drifting at near the speed of the current, and all of the hard work came to an end.

During the remainder of the ascent, I continued to monitor my buddy to see what was going on. He pointed to his back and gave a signal to indicate that he was low. Then, he pointed to his mask, and I saw a tiny stream of bubbles exiting the bottom and some water inside. Putting two and two together, I thought that he was telling me that he had been exhaling to clear his leaky mask, causing the loss of his oxygen. I again offered my oxygen, which he declined.

Next, I looked at his monitor. Did I mention that my buddy was from Germany? Other than "Warnung," I couldn't figure out what the rest of the words on the screen meant. So, I just made sure to monitor my buddy, and we ascended together even remaining about five extra minutes on the last stop before surfacing.

We gave the okay sign to the boat, and it ran over to us from its observation point in the distance. I unclipped my sidemount tanks, handing them up to the DM before injecting a last shot of oxygen into the loop, removing my fins, and climbing aboard.

Back on the boat, my buddy informed me that just as he was entering the slit to the engine room, he got a warning from his scrubber monitor, indicating that the scrubber material was at the end of its life. Rather than risk pushing it any farther, he (IMHO wisely) decided to abort the dive on open circuit. He did have a small mask leak along the way, but he still had plenty of oxygen. The low signal he kept giving me was low scrubber life.

So, other than some twists and turns along the way, I worked very hard but had a fun dive. The sidemounting continues to go well. I am not an expert by any means yet, but I continue to practice and learn just how useful such a set up can be.