seeing as it seems to be hard to find vids of single tank sm.......

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I did 11 single tank sidemount boat dives earlier this month in cayman Brac with an xdeep Stealth TEC.

I found that I was unable to maintain even left - right trim without a compensating weight on my opposite (right side) for most of the dive. This was curious as I have have backmounted with 2 al80s and both an al80 and an al40 on the left and did not have the same trim issue. This was with a dive rite rec bladder.

The Stealth air cell is in one section versus the rec which is doughnut shaped. I am curious as to whether the different shaped bladders might be responsible for the differences my buoyancy experiences.

The only modification that I did regulator wise was removing the long hose on the right regulator set and put it leading down on the left first stage.
 
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Doing single-tank SM on my Bonaire/Aruba trip now. First two dives today, normal weighting and did not have trim problems. I did steal an alternate from my recreational set instead of moving the long hose from the right. Kept the bungie I keep on my alternate and removed the bungie from my left side reg so I could still donate the primary.

While I didn't have trim problems, when I first got in the water on both dives, I did feel left-side heavy but that quickly went away (before any significant air usage.) I think it was just my body getting used to the slight variation. Given how little negative an Al80 is when full, I didn't expect any trim issue. During my SM course this summer, I did go single tank for a portion of a couple of the training dives but I was already in the water with two tanks, swimming around, doing skills and one was just getting rid of the RH tank and laying it on the bottom and swimming around single tank. So I knew I could do it without any trim issues.
 
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@rick00001967 what did you do weight-wise? Add any on the right side?

i had 2 lbs in the pocket at the top of the bc and 9 lbs on a belt. the belt allows me to move the weight up or down on my torso for trim. it also allows me to easily rotate the weight slightly on my waste to adjust for changes in the weight of the tank as you breath it down.
i have read that some can dive with weight in place and never have to adjust. i guess it is a matter of how sensitive you are to the weight changes.
if you start with a 3000 lb allum 80 and breath it down to 500 lbs you have about a 5 lb weight shift. i find it interesting that some people are not affected by this.
 
I did 11 single tank sidemount boat dives earlier this month in cayman Brac with an xdeep Stealth TEC.

I found that I was unable to maintain even left - right trim without a compensating weight on my opposite (right side) for most of the dive. This was curious as I have have backmounted with 2 al80s and both an al80 and an al40 on the left and did not have the same trim issue. This was with a dive rite rec bladder.

The Stealth air cell is in one section versus the rec which is doughnut shaped. I am curious as to whether the different shaped bladders might be responsible for the differences my buoyancy experiences.

remember that with a backmounted donut wing you can trap air in one side or the other to compensate for weight changes on your sides. so you are correct.....you will not be able to do this with your stealth sm system.
 
I use same configuration but on the other side, for whatever reasons, I find it more comfortable to have the single SM tank on my right side...I use a weight belt pocket with 9 pounds weight, I don't tighten it too much so I can adjust and turn the belt to properly trim as the dive progresses...
 
i have read that some can dive with weight in place and never have to adjust. i guess it is a matter of how sensitive you are to the weight changes.
if you start with a 3000 lb allum 80 and breath it down to 500 lbs you have about a 5 lb weight shift. i find it interesting that some people are not affected by this.

I'm thinking that those less affected are probably not drift diving or are constantly skulling anyway.

As i prefer to hang motionless while drifting, I will connect two 3# weights on two 8" leashes to the bottom plate of the harness with bolt snaps. There were 2 holes in the lumbar plate already. Once horizontal they lay on your hip, 1 above the other.

Start the dive with 2 on the opposite side of the cylinder and move easily to tank side as needed. Weight stays attached at all times yet easily dropped.

Not recommended or needed in any tech environments as you will use 2 cylinders and can breathe your ballast.

Trapping air in a donut wing won't work the last half of the dive as the cylinder gets positive and you should have little left in the wing to compensate with unless you are overweighted.
 
I will connect two 3# weights on two 8" leashes to the bottom plate of the harness with bolt snaps. There were 2 holes in the lumbar plate already. Once horizontal they lay on your hip, 1 above the other.

Start the dive with 2 on the opposite side of the cylinder and move easily to tank side as needed. Weight stays attached at all times yet easily dropped.
Have you got a picture? Is the leash nylon or bungee cord with bolt snaps, or just tied? Is the weight held at one point on the leash by tension threading through the weight slots?

Something maybe similar for beginning of dive trim check with 1 lb. exercise weight ingot, but for head to toe rec. backmount trim. Dive 1 lb. bullet weights would work, though they're thicker.
Trim_weight.png


Yours sounds more like a cloths line that you move the weight along. Sounds cool. Maybe a different cloths line version is a bungee cord loop under tension. You could always cut the loop to ditch, though not anywhere near as fast as ditching a pocket. Thanks.
 
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Just a simple loop of heavy paracord line.
Think of it as pushing a loop through 1 slot of a typical weight belt style weight then dropping the bolt snap through the loop. Center on the slot and pull tight.
Just gravity holding it.

The holes on the harness are 3 inches apart centered on the back where the bolt snaps attach individually. Attached on one end only and free to hang. Similar to your picture just a longer leash.

Weights are just moved individually from 1 hip to the other. So 6 lbs on right hip to start, shift 1 as tank gets neutral and shift the other as it gets buoyant.

I can get a picture if needed...
 
I think I have it. Two weights each with doubled over para cord loop to a bolt snap. Hanging on one side of hip at start. Then either use the line length to hang each over other side when needed, or unsnap and move to other side. Nice. Thanks.
 

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